R. Yanagida, S. N. Bhatti.Mobility-Mulithoming Duality. Future Internet, vol. 16, no. 10, pages 1-42. Oct 2024.
| URL | .bib | 10.3390/fi16100358 |
abstract
In modern Internet-based communication, especially mobile systems, a mobile node (MN) will commonly have more than one possibility for Internet Protocol (IP) connectivity. For example, an MN such as a smartphone may be associated with an IEEE 802.11 network at a site while also connected to a cellular base station for 5G. In such a scenario, the smartphone might only be able to utilise the IEEE 802.11 network, not making use of the cellular connectivity simultaneously. Currently, IP does not allow applications and devices to easily utilise multiple IP connectivity opportunities—multihoming for the MN—without implementing special mechanisms to manage them. We demonstrate how the use of the Identifier Locator Network Protocol (ILNP), realised as an extension to IPv6, can enable mobility with multihoming using a duality mechanism that treats mobility and multihoming as the same logical concept. We present a network layer solution that does not require any modification to transport protocols, can be implemented using existing application programming interfaces (APIs), and can work for any application. We have evaluated our approach using an implementation in Linux and a testbed. The testbed consisted of commercial equipment to demonstrate that our approach can be used over existing network infrastructure requiring only normal unicast routing for IPv6.
G. T. Haywood, S. N. Bhatti.Defence against side-channel attacks for encrypted network communication using multiple paths. Cryptography, vol. 8, no. 2, pages 1-26. May 2024.
| URL | .bib | 10.3390/cryptography8020022 |
abstract
As more network communication is encrypted to provide data privacy for users, attackers are focusing their attention on traffic analysis methods for side-channel attacks on user privacy. These attacks exploit patterns in particular features of communication flows such as interpacket timings and packet sizes. Unsupervised machine learning approaches, such as Hidden Markov Models (HMMs), can be trained on unlabelled data to estimate these flow attributes from an exposed packet flow, even one that is encrypted, so it is highly feasible for an eavesdropper to perform this attack. Traditional defences try to protect specific side channels by modifying the packet transmission for the flow, e.g., by adding redundant information (padding of packets or use of junk packets) and perturbing packet timings (e.g., artificially delaying packet transmission at the sender). Such defences incur significant overhead and impact application-level performance metrics, such as latency, throughput, end-to-end delay, and jitter. Furthermore, these mechanisms can be complex, often ineffective, and are not general solutions—a new profile must be created for every application, which is an infeasible expectation to place on software developers. We show that an approach exploiting multipath communication can be effective against HMM-based traffic analysis. After presenting the core analytical background, we demonstrate the efficacy of this approach with a number of diverse, simulated traffic flows. Based on the results, we define some simple design rules for software developers to adopt in order to exploit the mechanism we describe, including a critical examination of existing communication protocol behavior.
S. N. Bhatti, G. Haywood, R. Yanagida.End-to-End Privacy for Identity & Location with IP. NIPAA-21 - 2nd Workshop on New Internetworking Protocols, Architecture and Algorithms (ICNP 2021). Virtual event (COVID-19). Nov 2021.
| PDF | .bib | 10.1109/ICNP52444.2021.9651909 |
abstract
We describe protocol features to provide both Identity Privacy and Location Privacy at the network layer that are truly end-to-end, strengthening the trust model by constraining the boundary of trust to only the communicating parties. We show that Identity Privacy and Location Privacy can be provided by changing only the addressing model, whilst still remaining compatible with IPv6. Using the Identifier-Locator Network Protocol (ILNP), it is possible to use ephemeral end-system ILNP Node Identity (NID) values to improve identity privacy. Using the ILNP Locator values with dynamic bindings, it is possible to use multiple IPv6 routing prefixes as network Locator (L64) values to provide (topological) location privacy. This is achieved: (a) whilst maintaining end-to-end state for transport protocols, without proxies, tunnels, or gateways at the transport layer or application layer; and (b) without the use of cryptographic techniques, so performance is not impacted.
R. Yanagida, S. N. Bhatti.Seamless Internet connectivity for ubiquitous communication. PURBA2019, Pervasive Urban Applications Workshop (UBICOMP 2019). London, UK. Sep 2019.
| PDF | .bib | 10.1145/3341162.3349315 |
abstract
The direct and flexible use of any network connectivity that is available within an urban scenario is essential for the successful operation of ubiquitous systems. We demonstrate seamless communication across different networks without the use of middleware, proxies, tunnels, or address translation, with minimal (near-zero) packet loss to communication flows as handoff occurs between networks. Our solution does not require any new functions in existing networks, will work on existing infrastructure, and does not require applications to be re-designed or re-engineered. Our solution requires only modifications to the end-systems involved in communication, so can be deployed incrementally only for those end-systems that require the functionality. We describe our approach and its design, based on the use of the Identifier-Locator Network Protocol (ILNP), which can be realised directly on IPv6. We demonstrate the efficacy of our solution with testbed experiments based on modifications to the Linux kernel v4.9 LTS, operating directly over IPv6, and using unmodified binary applications utilising directly the standard socket(2) POSIX.1-2008 API, and standard C library calls. As our approach is `end-to-end', we also describe how to maintain packet-\-level secrecy and identity privacy for the communication flow as part of our approach.
D. Phoomikiattisak, S. N. Bhatti.End-To-End Mobility for the Internet Using ILNP. Wireless Communications and Mobile Computing, vol. 2019, no. Article ID 7464179, pages 29. Apr 2019.
| URL | .bib | 10.1155/2019/7464179 |
abstract
As the use of mobile devices and methods of wireless connectivity continue to increase, seamless mobility becomes more desirable and important. The current IETF Mobile IP standard relies on additional network entities for mobility management, can have poor performance, and has seen little deployment in real networks. We present a host-based mobility solution with a true end- to-end architecture using the Identifier-Locator Network Protocol (ILNP). We show how the TCP code in the Linux kernel can be extended allowing legacy TCP applications that use the standard C sockets API to operate over ILNP without requiring changes or recompilation. Our direct testbed performance comparison shows that ILNP provides better host mobility support than Mobile IPv6 in terms of session continuity, packet loss, and handoff delay for TCP.
R. Yanagida, S. N. Bhatti.End-to-end networking with ILNP in Linux. Netdev 0x13, Technical Conference on Linux Networking. Prague, CZ. Mar 2019.
| URL | .bib |
abstract
The Identifier-Locator Network Protocol (ILNP) is de- fined as an Experimental Internet Protocol by the Inter- net Research Task Force (IRTF) in RFCs 6740-6748. At the heart of the ILNP architecture is a radical approach to addressing for the Internet: the deprecation of IP addresses, to be replaced by the use of node Identifiers and network Locators. The key benefits of ILNP are to allow much functionality, such as IP-level mobility, to be realised purely end-to-end, without new network entities (e.g. proxies, middleboxes, and tunnels), and without additional routing state in the network. This means that control of the operation of functionality, such as IP-level mobility, remains at the network edge, at the site network, and ultimately, within end-systems. However, for backwards compatibility with existing infrastructure and for allowing incremental deployment, ILNP is implemented in Linux by (a) allowing existing applications to operate without modification over the current socket(2) API; and (b) by having a “wire image” for packets that is the same as IPv6. Most of the work done on ILNP since the publication of RFCs 6740-6748 has been on Linux. We describe the ILNP architecture, as well as the functionality of an implementation of ILNP in the Linux kernel, including results of testbed experiments for IP-level mobility.
M. Abu-Tair, S. N. Bhatti.IEEE 802.11ac MU-MIMO Wireless LAN cells with Legacy Clients. AINA 2017 - 31st IEEE Intl. Conf. Advanced Information Networking and Applications. Taipei, Taiwan. Mar 2017.
| PDF | .bib | 10.1109/AINA.2017.46 |
abstract
We provide an empirical evaluation of an IEEE 802.11ac Wireless Local Area Network (WLAN) cell with Multiple User Multiple Input Multiple Output (MU-MIMO) technology. We conducted our experiments on a testbed comprising consumer equipment under different office scenarios using 40MHz and 80MHz channels. This is the first performance study of MU-MIMO with 802.11ac in an operational scenario using a commercial access point. We find that, for clients that do not support MU-MIMO, operating in a cell that has MU-MIMO enabled may result in reduced performance.
M. Abu-Tair, S. N. Bhatti.Impact of cell load on 5GHz IEEE 802.11 WLAN. PAEWN 2017 - 12th Intl. Wkshp. Performance Analysis and Enhancement of Wireless Networks. Taipei, Taiwan. Mar 2017.
| PDF | .bib | 10.1109/WAINA.2017.27 |
abstract
We have conducted an empirical study of the latest 5GHz IEEE 802.11 wireless LAN (WLAN) variants of 802.11n (5GHz) and 802.11ac (Wave 1), under different cell load conditions. We have considered typical configurations of both protocols on a Linux testbed. Under light load, there is no clear difference between 802.11n and 802.11ac in terms of performance and energy consumption. However, in some cases of high cell load, we have found that there may be a small advantage with 802.11ac. Overall, we conclude that there may be little benefit in upgrading from 802.11n (5GHz) to 802.11ac in its current offering, as the benefits may be too small.
S. N. Bhatti, D. Phoomikiattisak, B. Simpson.IP without IP addresses. AINTEC 2016 - 12th Asian Internet Engineering Conf.. Bangkok, Thailand. Nov/Dec 2016.
| PDF | .bib | 10.1145/3012695.3012701 |
abstract
We discuss a key engineering challenge in implement- ing the Identifier- Locator Network Protocol (ILNP), as described in IRTF Experimental RFCs 6740-6748: en- abling legacy applications that use the C sockets API. We have built the first two OS kernel implementations of ILNPv6 (ILNP as a superset of IPv6), in both the Linux OS kernel and the FreeBSD OS kernel. Our eval- uation is in comparison with IPv6, in the context of a topical and challenging scenario: host mobility imple- mented as a purely end-to-end function. Our exper- iments show that ILNPv6 has excellent potential for deployment using existing IPv6 infrastructure, whilst offering the new properties and functionality of ILNP.
D. Phoomikiattisak, S. N. Bhatti.Control Plane Handoff Analysis for IP Mobility. WMNC 2016 - 9th IFIP Wireless and Mobile Networking Conf.. Colmar, France. Jul 2016.
| PDF | .bib | 10.1109/WMNC.2016.7543931 |
abstract
Seamless host mobility is vital to future network mobility, and has been an active research area for a long time. Much research focuses on the performance of the data plane. In this paper, we present comprehensive analyses on the control (signalling) plane in the IETF Mobile IPv6, and compare it with the IRTF Identifier-Locator Network Protocol (ILNP). The control plane behaviour is important in order to assess the robustness and scalability of the mobility protocol. ILNP has a different mobility model from Mobile IPv6: it is a host-based, end- to-end architecture and does not require additional network-layer entities. Hence, the control signals are exchanged only between the end systems. We provide model-based analyses for handoff signalling, and show that ILNP is more efficient than MIPv6 in terms of robustness and scalability. The analytical models we present could also be adapted for other mobility solutions, for comparative assessment.
O. Ejembi, S. N. Bhatti.Go Green with EnVI: The Energy-Video Index. ISM 2015 - IEEE Intl. Symp. Multimedia. Miama, FL, USA. Dec 2015.
| PDF | .bib | 10.1109/ISM.2015.50 |
abstract
Video is the most prevalent traffic type on the Internet today. Significant research has been done on measuring user’s Quality of Experience (QoE) through different metrics. We take the position that energy use must be incorporated into quality metrics for digital video. We present our novel, energy- aware QoE metric for video, the Energy-Video Index (EnVI). We present our EnVI measurements from the playback of a diverse set of online videos. We observe that 4K-UHD (2160p) video can use ∼30% more energy on a client device compared to HD (720p), and up to ∼600% more network bandwidth than FHD (1080p), without significant improvement in objective QoE measurements.
O. Ejembi, S. N. Bhatti.Client-side Energy Costs of Video Streaming. GreenCom 2015 - 11th IEEE Intl. Conf. Green Computing and Communications. Sydney, NSW, Australia. Dec 2015.
| PDF | .bib | 10.1109/DSDIS.2015.49 |
abstract
Through measurements on our testbed, we show how users of Netflix could make energy savings of up to 34% by adjusting video quality settings. We estimate the impacts of these quality settings on the energy consumption of client systems and the network. If users exercise choice in their video streaming habits, over 100 GWh of energy a year could be saved on a global scale. We discuss how providing energy usage information to users of digital video could enable them to make choices of video settings to reduce energy usage, and we estimate savings on associated electricity costs and carbon emissions.
D. Phoomikiatissak, S. N. Bhatti.Mobility as a First Class Function. WiMob 2015 - 11th IEEE Intl. Conf. Wireless and Mobile Computing, Networking and Communications. Abu Dhabi, UAE. Oct 2015.
| PDF | .bib | 10.1109/WiMOB.2015.7348051 |
abstract
Seamless host mobility has been a desirable feature for a long time, but was not part of the original design of the Internet architecture or protocols. Current approaches to network-layer mobility typically require additional network-layer entities for mobility management, which add complexity to the current engineering landscape of the Internet. We present a host-based, end-to-end architecture for host mobility using the Identifier-Locator Network Protocol (ILNP). ILNP provides mobility support as a first class function, since mobility management is controlled and managed by the end-systems, and does not require additional network-layer entities. We demonstrate an instance of ILNP that is a superset of IPv6 – called ILNPv6 – that is implemented by extending the current IPv6 code in the Linux kernel. We make a direct comparison of performance of ILNPv6 and Mobile IPv6, showing the improved performance of ILNPv6.
C. Khorakhun, S. N. Bhatti.mHealth through quantified-self: a user study. HealthCom 2015 - 17th IEEE Intl. Conf. e-Health Networking, Applications and Services. Boston, MA, USA. Oct 2015.
| PDF | .bib | 10.1109/HealthCom.2015.7454520 |
abstract
We describe a user study of a mHealth prototype system based on a wellbeing scenario, exploiting the quantified-self approach to measurement and monitoring. We have used off-the-shelf equipment, with opensource, web-based, software, and exploiting the increasing popularity of smartphones and self- measurement devices in a user study. We emulate a mHealth scenario as a pre-clinical experiment, as a realistic alternative to a clinical scenario, with reduced risk to sensitive patient medical data. We discuss the efficacy of this approach for future mHealth systems for remote monitoring. Our system used the popular Fitbit device for monitoring personal wellbeing data, the Diaspora online social media platform (OSMP), and a simple Android/iOS remote notification application. We implemented remote monitoring, asynchronous user interaction, multiple actors, and user-controlled security and privacy mechanisms. We propose that the use of a quantified-self approach to mHealth is particularly valuable to undertake research and systems development.
O. Ejembi, S. N. Bhatti.The Energy Cost of your Netflix Habit. e-Energy 2015 - 6th ACM Intl. Conf. Future Energy Systems. Bangalore, India. July 2015.
| PDF | .bib | 10.1145/2768510.2770951 |
abstract
Through measurements on our testbed, we show how users of Netflix could make energy savings of up to 34% by adjusting video quality settings. By using Netflix as a case study, we aim to assess the impact of energy usage in Video-on-demand (VoD) services. We estimate the potential impact of video quality settings on energy usage on a global scale.
M. Abu-Tair, S. N. Bhatti.Introducing IEEE 802.11ac into existing WLAN deployment scenarios. WiOpt 2015 - 13th Intl. Symp. Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiNMeE 2015 - IEEE Intl. Workshop on Wireless Networks: Measurements and Experimentation). Mumbai, India. May 2015.
| PDF | .bib | 10.1109/WIOPT.2015.7151029 |
abstract
In mature wireless LAN (WLAN) deployments, we show that introducing 802.11ac could have little benefit compared to existing 802.11n deployments. Using a testbed with common characteristics for an existing WLAN deployment (such as an office environment), we compare throughput for 802.11ac and 802.11n (in both 5GHz and 2.4GHz bands). We find that 802.11ac has lower throughput than for 802.11n for our testbed configuration. We also provide an evaluation of energy usage for 802.11ac and 802.11n.
O. Ejembi, S. N. Bhatti.Towards Energy Benchmarking for Green Video. SustainIT 2015 - 4th IFIP Conference on Sustainable Internet and ICT for Sustainability. Madrid, Spain. April 2015.
| PDF | .bib | 10.1109/SustainIT.2015.7101375 |
abstract
Digital video is responsible for the largest proportion of traffic on the Internet today – upto ∼70\%. However, very little published research has examined the energy impact of this growing traffic type on a global scale (on client systems, servers and in the network). We summarise results and lessons learned from our measurement-based experiments on the energy use of digital video. By providing users with appropriate information and feedback, we could enable changes in user behaviour to save energy during use of digital video. We discuss the ongoing development of our benchmark tool which generates information on energy usage for users or other interested stakeholders.
M. Abu-Tair, S. N. Bhatti.Upgrading 802.11 deployments: a critical examination of performance. AINA 2015 - IEEE 29th Intl. Conf. Advanced Information Networking and Applications. Seoul, Korea. Mar 2015.
| PDF | .bib | 10.1109/AINA.2015.278 |
abstract
The increased demand for communications and Internet access makes Wireless Local Area Networks (WLANs) one of the most popular solutions for network connectivity. In this paper, we examine the performance and the energy efficiency of WLANs in 2.4 GHz and 5 GHz and discuss paths for upgrading. Our results show that it is worth upgrading to the 5 GHz bands from the 2.4 GHz band for 802.11n, especially for applications that are sensitive to packet loss. We also show that it is little benefit in upgrading from 802.11n 5 GHz to its successor 802.11ac in terms of performance and energy efficiency. We consider overall performance as well as the energy efficiency of 802.11n 2.4 GHz, 802.11n 5 GHz and 802.11ac protocols, all with 40MHz channels, to give a typical 802.11 office scenario. It is clear that 802.11ac can achieve slightly higher throughput compared to 802.11 for flows of large packets. However, the comparatively small benefits of 802.11ac may not justify the cost of buying and deploying new equipment for the upgrade.
C. Khorakhun, S. N. Bhatti.Remote Health Monitoring Using Online Social Media. EAI Endorsed Transactions on Ubiquitous Environments, vol. 14, no. 3. Nov 2014.
| PDF | .bib | 10.4108/ue.1.3.e2 |
abstract
Remote monitoring is an essential part of future mHealth systems for the delivery of personal and pervasive healthcare, especially to allow the collection of personal bio-data outside clinical environments. Yet, by its very nature, it presents considerable challenges: it will be a highly distributed task, requiring collection of bio-data for a myriad of cources, to be marshalled at the clinical site via secure communication channels. To address these challenges, we propose the use of an online social media platform (OSMP) as a key component of a near-future remote health monitoring system. By exploiting existing infrastructure, initial costs can be reduced, at the same time as allowing fast and flexible application development. An OSMP would have user benefits also: patients and healthcare professionals can be presented with familiar interfaces, while application developers can work with a set of technologies that are widely used and well-known. Internet-based access also helps to provide wide-ranging connectivity for mobile applications. Additionally, the use of a social media context allows existing social interactions within the healthcare regime to be modelled within a *carer network*, working in harmony with, and providing support for, existing relationships and interactions between patients and healthcare professionals. We focus on the use of an OSMP to enable two primitive functions which we consider essential for mHealth, and on which larger personal healthcare services could be built: *remote health monitoring* of personal bio-data, and an *alert system* for asynchronous notifications. We analyse the general requirements in a carer network for these two primitive functions, in terms of four different viewpoints within the carer network: the *patient*, the *doctor* in charge, a professional *carer*, and a *family* member (or friend) of the patient. We discuss the suitability of OSMPs in terms of functionality, performance, security \& privacy, as well as the potential for cost reduction.
C. Khorakhun, S. N. Bhatti.Wellbeing as a proxy for a mHealth study. QSPH 2014 - IEEE Wkshp. The Role of Quantified Self for Personal Healthcare. Belfast, UK. Nov 2014.
| PDF | .bib | 10.1109/BIBM.2014.6999286 |
abstract
The quantified-self is a key enabler for mHealth. We propose that a wellbeing remote monitoring scenario can act as a suitable proxy for mHealth monitoring by the use of an online social network (OSN). We justify our position by discussing the parallelism in the scenario between purpose-driven wellbeing and mHealth scenarios. The similarity between these two scenarios in terms of privacy and data sharing is discussed. By using such a proxy, some of the legal and ethical complexity can be removed from experimentation on new technologies and systems for mHealth. This enables technology researchers to carry out investigation and focus on testing new technologies, system interactions as well as security and privacy in healthcare in pre- clinical experiments, without loss of context. The analogy between two purpose-driven scenarios, i.e. fitness monitoring in wellbeing scenario and remote monitoring in mHealth, is discussed in terms of a practical example: we present a prototype using a wellbeing device -- Fitbit -- and an open source online social media platform (OSMP) -- Diaspora.
O. Ejembi, S. N. Bhatti.Help Save The Planet: Please Do Adjust Your Picture. MM 2014 - 22nd ACM Intl. Conf. Multimedia. Orlando, FL, USA. Nov 2014.
| .bib | 10.1145/2647868.2654897 |
abstract
Allowing digital video users to make choices of picture size and codec would significantly reduce energy usage, electricity costs and the carbon footprint of Internet users. Our empirical investigation shows a difference of up to a factor of 3 in energy usage for video decoding using different codecs at the same picture size and bitrate, on a desktop client system. With video traffic already responsible for the largest and fastest growing proportion of traffic on the Internet, a significant amount of energy, money and carbon output is due to video. We present a simple methodology and metrics that can be used to give an intuitive, quantitative and comparable assessment of the energy usage of video decoding. Providing energy usage information to users would empower them to make sensible choices. We demonstrate how small energy savings for individual client systems could give significant energy savings when considered at a global scale.
C. Khorakhun, S. N. Bhatti.Using Online Social Media Platforms for Ubiquitous, Personal Health Monitoring. HealthCom 2014 - 16th IEEE Intl. Conf. e-Health Networking, Applications and Services. Natal, BR. Oct 2014.
| PDF | .bib | 10.1109/HealthCom.2014.7001856 |
abstract
We propose the use of an open and publicly accessible online social media platform (OSMP) as a key component for ubiquitous and personal remote health monitoring. Remote monitoring is an essential part of future mHealth systems for the delivery of personal healthcare allowing the collection of personal bio-data outside clinical environments. Previous mHealth projects focused on building private and custom platforms using closed architectures, which have a high cost for implementation, take a long time to develop, and may provide limited access and usability. By exploiting existing and publicly accessible infrastructure using an OSMP, initial costs can be reduced, at the same time as allowing fast and flexible application development at scale, whilst presenting users with interfaces and interactions that they are familiar with. We survey and discuss suitability of OSMPs in terms of functionality, performance and the key challenge in ensuring appropriate levels of security and privacy.
S. N. Bhatti, D. Phoomikiatissak, R. J. Atkinson.Fast, Secure Failover for IP. MILCOM 2014 - 33rd IEEE Military Communications Conf.. Baltimore, MD, USA. Oct 2014.
| PDF | .bib | 10.1109/MILCOM.2014.50 |
abstract
We describe a mechanism for fast, secure failover for IP. The mechanism is invisible to end-systems: sessions are maintained during failover. Our novel approach is to model the failover as a mobility problem, and use a mobility solution in order to implement change in connectivity. Our system is based on the Identity Locator Network Protocol (ILNP), an Experimental IRTF protocol. Our empirical results from a testbed emulation show that there is almost zero gratuitous loss during failover.
D. Phoomikiatissak, S. N. Bhatti.IP-Layer Soft Handoff Implementation in ILNP. MobiArch 2014 - ACM Wkshp. Mobility in the Evolving Internet Architecture. Hawaii, USA. Sep 2014.
| PDF | .bib | 10.1145/2645892.2645895 |
abstract
We present the first results of an implementation of IP-layer soft handoff, based on the Identifier Locator Network Protocol (ILNP). In our testbed experiments, we show minimal gratuitous packet loss in vertical handoff scenarios (WiFi-3G). Unlike the IETF Mobile IP proposals, the ILNP uses a purely end-to-end architecture, and does not require proxies, middleboxes or tunnelling to support mobility. Our testbed is based on an in-kernel implementation using a modified Linux IP stack.
Y. Yu, S. N. Bhatti.The cost of virtue: Reward as well as feedback are required to reduce user ICT power consumption. e-Energy 2014 - 5th ACM Intl. Conf. Future Energy Systems. Cambridge, UK. Jun 2014.
| .bib | 10.1145/2602044.2602063 |
abstract
We show that students in a school lab environment will change their behaviour to be more energy efficient, when appropriate incentives are in place, and when measurement-based, real-time feedback about their energy usage is provided. Rewards incentivise `non-green' users to be `green' as well as encouraging those users who already claim to be `green'. Measurement-based feedback improves user energy awareness and helps users to explore and adjust their use of computers to become `greener', but is not sufficient by itself. In our measurements, weekly mean group energy use as a whole reduced by up to 16\%; and weekly individual user energy consumption reduced by up to 56\% during active use. The findings are drawn from our longitudinal study that involved 83 Computer Science students; lasted 48 weeks across 2 academic years; monitored a total of 26778 hours of active computer use; collected approximately 3.2TB of raw data.
M. Abu-Tair, S. N. Bhatti.Energy Usage of UDP and DCCP over 802.11n. AINA 2014 - IEEE 28th Intl. Conf. Advanced Information Networking and Applications. Victoria, Canada. May 2014.
| PDF | .bib | 10.1109/AINA.2014.40 |
abstract
We show that the Datagram Congestion Control Protocol (DCCP) provides ~10% -- ~40% greater energy efficiency than the User Datagram Protocol (UDP) in a wireless LAN (WLAN) client. Our empirical evaluation uses a testbed comprised of consumer components and opensource software to measure typical performance that can be expected by a user, rather than highly-tuned performance which most users will not be able to configure. We focus our measurements on a scenario using IEEE 802.11n at 5GHz as energy efficiency will be particularly important to mobile and wireless users. We consider overall performance as well as the energy efficiency of the protocol usage to give a rounded comparison of UDP and DCCP. Overall, we see there would be great benefit in many applications using DCCP instead of UDP.
B. Simpson, S. N. Bhatti.An identifier-locator approach to host multihoming. AINA 2014 - IEEE 28th Intl. Conf. Advanced Information Networking and Applications. Victoria, Canada. May 2014.
| PDF | .bib | 10.1109/AINA.2014.22 |
abstract
Host multihoming allows individual hosts to be multiply connected to the network, e.g. by concurrent use of two network prefixes, each network prefix tied to a separate network interface. Such multihoming capability improves the host's ability to implement such features as load-balancing, fail-over and multi-path transport protocols. However, IP does not directly support host multihoming today. The * Identifier / Locator split* solution space is seen as one way for reducing such negative impact. We present an evaluation of host- multihoming as a prototype implementation of the *Identifier Locator Network Protocol (ILNP)* on FreeBSD, as a superset of IPv6 -- called ILNPv6. We demonstrate load-balancing using ILNPv6 multihoming and compare performance with IPv6 forwarding at the end host.
D. Phoomikiattisak, S. N. Bhatti.Network Layer Soft Handoff for IP Mobility. PM2HW2N 2013 - 8th ACM Intl. Wkshp. Performance Monitoring, Measurement and Evaluation of Heterogeneous Wireless and Wired Networks. Barcelona, Spain. Nov 2013.
| PDF | .bib | 10.1145/2512840.2512843 |
abstract
We present an empirical evaluation of network-layer soft handoff for IP mobility. Such functionality is not currently available for Mobile IP. Our new approach, based on the Identifier Locator Network Protocol (ILNP), requires no additional network entities such as proxies and it does not require modification of any routing protocols. Only the communicating hosts need to to have their end-system protocol stacks updated and so it is incrementally deployable. In our performance evaluation, we find that soft handoff minimises packet loss, with the observed packet loss during handoff being no worse than the natural loss of the end-to-end path.
C. Khorakhun, S. N. Bhatti.Alerts for Remote Health Monitoring Using Online Social Media Platforms. HealthCom 2013 - 15th IEEE Intl. Conf. e-Health Networking, Applications and Services. Lisbon, PT. Oct 2013.
| PDF | .bib | 10.1109/HealthCom.2013.6720662 |
abstract
Alerts are an essential part of future remote health monitoring. We assess the feasibility of leveraging online social media for such capability to enable the delivery of healthcare outside clinical sites. We have implemented alerts triggered by bio-data and to act as notifications of management-related actions in relation to the operation of an example heart-monitoring application. We have examined the suitability of online social media platforms using Facebook and Twitter as example platforms. A Facebook application was developed to deliver configurable alerts to four different actor viewpoints in a *carer network*; the patient; the doctor in charge; the professional carer; and a family member of the patient. The suitability of the application was analysed as well as an initial examination of the reliability of alert delivery. We conclude that online social media systems could offer suitable platforms for alerts in remote health monitoring.
C. Khorakhun, S. N. Bhatti.Remote Health Monitoring Using Online Social Media Systems. WMNC 2013 - IFIP/IEEE Joint Wireless and Mobile Networking Conference. Dubai, UAE. Apr 2013.
| PDF | .bib | 10.1109/WMNC.2013.6548953 |
abstract
Remote monitoring is considered an essential part of future eHealth systems to enable the delivery of healthcare outside clinical sites at reduced cost, while improving quality of patient care. We examine the use of online social networks for remote health monitoring. By exploiting the existing infrastructure, initial costs can be reduced and fast application development is possible. Facebook is used as an example platform: as a platform allowing user-defined applications, development is flexible and can be arranged quickly to suit different requirements of patients and health professionals. We analyse the general requirements of a remote monitoring scenario and the process of building and using a Facebook application to meet these requirements. Four different access viewpoints are implemented to suit the requirements of each user in our example scenario to form a carer network: the patient, the doctor in charge, professional carers, and family members of the patient. The suitability of the application is analysed including security and privacy issues. We conclude that online social media systems could offer a suitable platform for developing certain types of remote monitoring capability.
Zhang R., Wang L., Parr G., Aliu O.G., Awoseyila B., Azarmi N., Bhatti S. N., Bodanese E., Chen H., Dianati M., Dutta A., Fitch M., Giridhar K., Hailes S., Hari K.V.S., Imran M.A., Jagannatham A.K., Karandikar A., Kawade S., Zafar Ali Khan M., Kompalli S.C., Langdon P., Narayanan B., Mauthe A., McGeehan J., Mehta N., Millet K., Moessner K., Rajashekar R., Ramkumar B., Ribeiro V., Vasudevan K., Hanzo L., Bigham J..Advances in base- and mobile-station aided cooperative wireless communications: An overview. IEEE VTM - Vehicular Technology Magazine, vol. 8, no. 1, pages 57-69. Mar 2013.
| .bib | 10.1109/MVT.2012.2234254 |
abstract
In recent years, there has been an upsurge of research interest in cooperative wireless communications in both academia and industry. This article presents a simple overview of the pivotal topics in both mobile station (MS)- and base station (BS)- assisted cooperation in the context of cellular radio systems. Owing to the ever-increasing amount of literature in this particular field, this article is by no means exhaustive, but is intended to serve as a roadmap by assembling a representative sample of recent results and to stimulate further research. The emphasis is initially on relay-base cooperation, relying on network coding, followed by the design of cross-layer cooperative protocols conceived for MS cooperation and the concept of coalition network element (CNE)-assisted BS cooperation. Then, a range of complexity and backhaul traffic reduction techniques that have been proposed for BS cooperation are reviewed. A more detailed discussion is provided in the context of MS cooperation concerning the pros and cons of dispensing with high-complexity, power-hungry channel estimation. Finally, generalized design guidelines, conceived for cooperative wireless communications, are presented.
M. Tauber, S. N. Bhatti, N. Melnikov, J. Schoenwaelder.The Case for Heterogeneous WLAN Environments for Converged Networks. ICNC 2013 - IEEE Intl. Conf. Computing, Networking and Communications. San Diego, CA, USA. Jan 2013.
| PDF | .bib | 10.1109/ICCNC.2013.6504056 |
abstract
We demonstrate that in a future converged network scenario, it may be beneficial to allow selection of 802.11 variant based on application requirements. We analyse traces from the campus network from the University of Twente, comprising ∼5000 users. We have evaluated a performance envelope derived from testbed experiments for individual IEEE 802.11 variants and compare these with the traffic patterns from the campus network. From our comparison, we find that specific IEEE 802.11 variants (e.g. 802.11g or 802.11n) may be better suited to specific applications, such as video streaming, rather than using a single WLAN standard for all traffic.
M. Tauber, S. N. Bhatti.Low RSSI in WLANs: Impact on Application-Level Performance. ICNC 2013 - IEEE Intl. Conf. Computing, Networking and Communications. San Diego, CA, USA. Jan 2013.
| PDF | .bib | 10.1109/ICCNC.2013.6504066 |
abstract
Widespread use of wireless LAN (WLAN) may soon cause an over-crowding problem in use of the ISM spectrum. One way in which this manifests itself is the low Received Signal Strength Indication (RSSI) at the WLAN stations, impacting performance. Meanwhile, the IEEE 802.11 standard is being evolved and extended, for example with new coding schemes and the 802.11n standard, which makes use of 5GHz and 2.4GHz. We report on measurements of the upper and lower bounds of performance with good and poor RSSI in 802.11g and 802.11n. We find that in operation under poor (low) RSSI, performance is indeed impacted. In some cases the impact is such that there may be little benefit in using the newer 802.11n over the mature 802.11g.
M. Tauber, S. N. Bhatti.The Effect of the 802.11 Power Save Mechanism (PSM) on Energy Efficiency and Performance During System Activity. GreenCom 2012 - IEEE Intl. Conf. Green Computing and Communications. Besancon, France. Nov 2012.
| PDF | .bib | 10.1109/GreenCom.2012.81 |
abstract
802.11 WLAN is a popular choice for wireless access on a range of ICT devices. A growing concern is the increased energy usage of ICT, for reasons of cost and environmental protection. The Power Save Mode (PSM) in 802.11 deactivates the wireless network interface during periods of inactivity. However, applications increasingly use push models, and so devices may be active much of the time. We have investigated the effectiveness of PSM, and considered its impact on performance when a device is active. Rather than concentrate on the NIC, we have taken a system-wide approach, to gauge the impact of the PSM from an application perspective. We experimentally evaluated performance at the packet level and system-wide power usage under various offered loads, controlled by packet size and data rate, on our 802.11n testbed. We have measured the system- wide power consumption corresponding to the individual traffic profiles and have derived application-specific effective energy-usage. We have found that in our scenarios, no significant benefit can be gained from using PSM.
R. J. Atkinson, S. N. Bhatti.Identifier-Locator Network Protocol (ILNP) Architectural Description. RFC 6740 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6740 |
abstract
This document provides an architectural description and the concept of operations for the Identifier-Locator Network Protocol (ILNP), which is an experimental, evolutionary enhancement to IP.This is a product of the IRTF Routing Research Group.
R. J. Atkinson, S. N. Bhatti.Identifier-Locator Network Protocol (ILNP) Engineering Considerations. RFC 6741 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6741 |
abstract
This document describes common (i.e., version independent) engineering details for the Identifier-Locator Network Protocol (ILNP), which is an experimental, evolutionary enhancement to IP. This document is a product of the IRTF Routing Research Group.
R. J. Atkinson, S. N. Bhatti, S. Rose.DNS Resource Records for the Identifier-Locator Network Protocol (ILNP). RFC 6742 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6742 |
abstract
This note describes additional optional resource records for use with the Domain Name System (DNS).These optional resource records are for use with the Identifier-Locator Network Protocol (ILNP).This document is a product of the IRTF Routing Research Group.
R. J. Atkinson, S. N. Bhatti.ICMP Locator Update Message for the Identifier-Locator Network Protocol for IPv6 (ILNPv6). RFC 6743 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6743 |
abstract
This note specifies an experimental ICMPv6 message type used with the Identifier-Locator Network Protocol (ILNP). The Identifier-Locator Network Protocol (ILNP) is an experimental, evolutionary enhancement to IP.This message is used to dynamically update Identifier/Locator bindings for an existing ILNP session.This is a product of the IRTF Routing Research Group.
R. J. Atkinson, S. N. Bhatti.IPv6 Nonce Destination Option for the Identifier-Locator Network Protocol for IPv6 (ILNPv6). RFC 6744 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6744 |
abstract
The Identifier-Locator Network Protocol (ILNP) is an experimental, evolutionary enhancement to IP.ILNP has multiple instantiations. This document describes an experimental Nonce Destination Option used only with ILNP for IPv6 (ILNPv6).This document is a product of the IRTF Routing Research Group.
R. J. Atkinson, S. N. Bhatti.ICMP Locator Update Message for the Identifier-Locator Network Protocol for IPv4 (ILNPv4). RFC 6745 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6745 |
abstract
This note defines an experimental ICMP message type for IPv4 used with the Identifier-Locator Network Protocol (ILNP).ILNP is an experimental, evolutionary enhancement to IP.The ICMP message defined herein is used to dynamically update Identifier/Locator bindings for an existing ILNP session.This is a product of the IRTF Routing Research Group.
R. J. Atkinson, S. N. Bhatti.IPv4 Options for the Identifier-Locator Network Protocol (ILNP). RFC 6746 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6746 |
abstract
This document defines two new IPv4 Options that are used only with the Identifier-Locator Network Protocol for IPv4 (ILNPv4).ILNP is an experimental, evolutionary enhancement to IP.This document is a product of the IRTF Routing Research Group.
R. J. Atkinson, S. N. Bhatti.Address Resolution Protocol (ARP) for the Identifier-Locator Network Protocol for IPv4 (ILNPv4). RFC 6747 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6747 |
abstract
This document defines an Address Resolution Protocol (ARP) extension to support the Identifier-Locator Network Protocol for IPv4 (ILNPv4). ILNP is an experimental, evolutionary enhancement to IP.This document is a product of the IRTF Routing Research Group.
R. J. Atkinson, S. N. Bhatti.Optional Advanced Deployment Scenarios for the Identifier-Locator Network Protocol (ILNP). RFC 6748 (Experimental). Internet Engineering Task Force. Nov 2012.
| URL | .bib | 10.17487/RFC6748 |
abstract
This document provides an Architectural description and the Concept of Operations of some optional advanced deployment scenarios for the Identifier-Locator Network Protocol (ILNP), which is an evolutionary enhancement to IP.None of the functions described here is required for the use or deployment of ILNP.Instead, it offers descriptions of engineering and deployment options that might provide either enhanced capability or convenience in administration or management of ILNP-based systems.
S. N. Bhatti, R. Atkinson.Secure & Agile Wide-area Virtual Machine Mobility. MILCOM 2012 - 31st IEEE Military Communications Conf.. Orlando, FL, USA. Oct 2012.
| PDF | .bib | 10.1109/MILCOM.2012.6415716 |
abstract
Global Information Grid (GIG) operations would benefit greatly from improved support for virtual machines (VMs) that can migrate not only between physical devices within a datacentre, but also between physical devices located on different continents, while maintaining their existing IP communications sessions. Such VM migration can enable improvements with: CPU load-balancing, network traffic-engineering, distributed denial of service (DDoS) mitigation, fault-tolerance, and resilience. Existing migration approaches often require complex network configuration and management, may often require use of expensive proprietary technologies, and also often require active cooperation from upstream service providers. We describe a VM mobility approach that enables datacentre operators to directly and unilaterally provide and control intra-site and wide-area VM mobility. We present several use cases with different degrees of location transparency. Our mechanism is based on a new naming approach which has been recommended for progression within the IETF.
M. Tauber, S. N. Bhatti, Y. Yu.Towards Energy-Awareness In Managing Wireless LAN Applications. NOMS 2012 - IEEE Network Operations and Management Symp.. Maui, Hawaii, USA. Apr 2012.
| PDF | .bib | 10.1109/NOMS.2012.6211930 |
abstract
We have investigated the scope for enabling WLAN applications to manage the trade-off between performance and energy usage. We have conducted measurements of energy usage and performance in our 802.11n WLAN testbed, which operates in the 5 GHz ISM band. We have defined an effective energy usage envelope with respect to application-level packet transmission, and we demonstrate how performance as well as the effective energy usage envelope is effected by various configurations of IEEE 802.11n, including transmission power levels and channel width. Our findings show that the packet size and packet rate of the application flow have the greatest impact on application- level energy usage, compared to transmission power and channel width. As well as testing across a range of packet sizes and packet rates, we emulate a Skype flow, a YouTube flow and file transfers (HTTP over Internet and local server) to place our results in context. Based on our measurements we discuss approaches and potential improvements of management in effective energy usage for the tested applications.
S. N. Bhatti, R. Atkinson, J. Klemets.Integrating Challenged Networks. MILCOM 2011 - 30th IEEE Military Communications Conf.. Baltimore, MD, USA. Nov 2011.
| PDF | .bib | 10.1109/MILCOM.2011.6127596 |
abstract
For a comprehensive information coverage across theatre, it is necessary to integrate many different sources of data which are likely to use protocols specific to a specialised purpose. For example, resource-constrained or challenged networks such as sensor systems and MANET systems, using their own protocols, may be used in conjunction with other Internet Protocol (IP) based communication and need to be integrated into the GIG. While such integration may be possible today, the engineering is complex and the resultant system may be difficult to configure and maintain, as well as being brittle when systems changes or reconfiguration is required. Furthermore, when security and identity issues are considered, the additional overhead for enabling integration within the context of sensor systems and MANETs raises challenging technology issues. Based on our ongoing work, we present a potential solution which organises such systems based on identity and location, but allows integration with Internet- wide communication.
M. Tauber, S. N. Bhatti, Y. Yu.Application Level Energy and Performance Measurements in a Wireless LAN. GreenCom 2011 - IEEE/ACM Intl. Conf. Green Computing and Communications. Chengdu, Sichuan. Aug 2011.
| PDF | .bib | 10.1109/GreenCom.2011.26 |
abstract
We present an experimental evaluation of energy usage and performance in a wireless LAN cell based on a test bed using the 5 GHz ISM band for 802.11a and 802.11n. We have taken an application-level approach, by varying the packet size and transmission rate at the protocol level and evaluating energy usage across a range of application transmission rates using both large and small packet sizes. We have observed that both the application's transmission rate and the packet size have an impact on energy efficiency for transmission in our test bed. We also included in our experiments evaluation of the energy efficiency of emulations of YouTube and Skype flows, and a comparison with Ethernet transmissions.
D. Rehunathan, S. N. Bhatti, O. Chandran, P. Hui.vNurse: Using virtualisation on mobile phones for remote health monitoring. HealthCom 2011 - IEEE Intl. Conf. e-Health Networking Applications and Services. Columbia, MO, USA. Jun 2011.
| PDF | .bib | 10.1109/HEALTH.2011.6026792 |
abstract
We present vNurse, a system based on a smartphone platform that permits comprehensive, secure and modular patient remote monitoring outside a clinical environment, e.g. in the home. Using both virtualisation of the phone OS and virtual mobile networks of sensors with full Internet Protocol (IP) connectivity, we enable real- time remote sensor readings of patient Wireless Body Area Networks (WBANs) to be stored, processed and forwarded securely to healthcare practitioners based at clinical sites, while patients are remote or mobile.
M. Bateman, S. N. Bhatti.Simple, Weakly-coupled, Invisible Middleware (SWIM). AINA 2011 - IEEE Intl. Conf. Advanced Information Networking and Applications. Singapore. Apr 2011.
| PDF | .bib | 10.1109/AINA.2011.108 |
abstract
One of the operational goals of a middleware platform is to provide a mechanism of distributing computation requests in a way that hides from the programmer the complexity of the underlying systems platform. This means that distribution mechanisms used to harness a set of computer and network resources should not expose to the programmer the detailed systems aspects which are unrelated to their application. Ideally, the programmer should be left to concentrate on the functionality of his/her application without having to be concerned with how the distribution is achieved or how the resources are used. However, this is not true today: programmers need to be aware of details of the middleware in use and are constrained by it in the design of their application, e.g. API constraints. We present a proof-of-concept demonstration of a middleware platform that imposes absolutely no constraints on the programmer apart form those used in the programming language itself. We demonstrate the efficacy of our approach with a prototype implementation in Java, running on a cluster of 20 nodes with a performance comparison with XML-RPC and Java-RMI.
S. N. Bhatti, R. Atkinson.Reducing DNS Caching. GI 2011 - IEEE Global Internet Symp.. Shanghai, China. Apr 2011.
| PDF | .bib | 10.1109/INFCOMW.2011.5928919 |
abstract
Motivated by our ongoing work exploring an alternative Internet architecture, we wish to make use of naming services in order to support functionality such as: host and network mobility; application and/or virtual machine migration; and various forms of traffic control (e.g. multi-homing). Currently, the Domain Name System (DNS) is used to resolve names to DNS records, with relatively large time-to-live (TTL) values (several thousands of seconds) for caching the results. To support new agile services and systems, cached results may need to have much lower TTL values, so that cached DNS values do not become stale as system changes occur, e.g. changes to end-system location information to support new methods of mobility. However, current conventions for DNS configuration normally use conservatively high TTL values. We have conducted an empirical study of a live DNS deployment where we have reduced to zero the TTL values of records for the entire School of Computer Science at the University of St Andrews. Our results show that the increase in DNS load is much lower than might be expected, following a highly non-linear decrease with respect to the TTL value of the DNS records.
D. Rehunathan, S. Bhatti, V. Perrier, P. Hui.The Study of Mobile Network Protocols with Virtual Machines. SIMUTOOLS 2011 - Intl. ICST Conf. Simulation Tools and Techniques. Barcelona, Spain. Mar 2011.
| PDF | .bib | 10.4108/icst.simutools.2011.245607 |
abstract
With the rapid proliferation of wireless mobile devices in today’s society, it is becoming increasingly useful to aggregate mobile devices moving together as a single mobile network. It is also necessary to test new mobile network applications and protocols (e.g. NEMO) in realistic scenarios, where an incremental development approach can be adopted in order to experiment and explore. We present a simulation framework, Cloonix-Net, a virtual network tool using User Mode Linux (UML) machines, for the purposes of building and testing such scenarios. We show that studying mobile network protocols with such a framework is a beneficial step towards better understanding network mobility protocols.
D. Rehunathan, S. Bhatti.Application of Virtual Mobile Networking to Real-Time Patient Monitoring. ATNAC 2010 - Australasian Telecommunication Networks and Applications Conf.. Auckland, New Zealand. Nov 2010.
| PDF | .bib | 10.1109/ATNAC.2010.5679557 |
abstract
We aim to merge the benefits of network mobility and virtualisation to provide a simple, mobile and secure method for providing mobile network (as opposed to mobile host) platforms. We demonstrate our approach by showing the use of a mobile network of sensors and wide area connectivity for maintaining and managing a Wireless Body Area Networks (WBAN) for healthcare. WBANs are a mature field of research, where the challenges and applications have been explored for quite some time. One of the most promising applications for WBANs is healthcare. Wireless sensors are used to monitor patient health statistics and activity. With the ubiquity of wireless mobile personal devices (such as smart phones), their increased CPU and power capability, the feasibility of using them to build mobile network platforms is increasingly possible. In this paper we describe our novel approach, which is to utilise, through virtualisation, an individual's smartphone not only as a mobile router that manages his personal mobile network, but also as a platform to host his WBAN.
R. Atkinson, S. N. Bhatti, S. Hailes.Evolving the Internet Architecture Through Naming. IEEE JSAC - Journal of Selected Areas in Communication, vol. 28, no. 8, pages 1319-1325. Oct 2010.
| PDF | .bib | 10.1109/JSAC.2010.101009 |
abstract
Challenges face the Internet Architecture in order to scale to a greater number of users while providing a suite of increasingly essential functionality, such as multi-homing, traffic engineering, mobility, localised addressing and end-to-end packet-level security. Such functions have been designed and implemented mainly in isolation and retrofitted to the original Internet architecture. The resulting engineering complexity has caused some to think of 'clean slate' designs for the long-term future. Meanwhile, we take the position that an evolutionary approach is possible for a practical and scaleable interim solution, giving much of the functionality required, being backwards compatible with the currently deployed architecture, with incremental deployment capability, and which can reduce the current routing state overhead for the core network. By enhancing the way we use naming in the Internet Architecture, it is possible to provide a harmonised approach to multi-homing, traffic engineering, mobility, localised addressing and end-to-end packet-level security, including specific improvement to the scalability of inter-domain routing, and have these functions co-exist harmoniously with reduced engineering complexity. A set of proposed enhancements to the current Internet Architecture, based on naming, are described and analysed, both in terms of architectural changes and engineering practicalities.
D. Rehunathan, S. N. Bhatti.A Comparative Assessment of Routing for Mobile Networks. WiMob 2010 - 6th IEEE Intl. Conf. Wireless and Mobile Computing, Networking and Communications. Niagara Falls, Canada. Oct 2010.
| PDF | .bib | 10.1109/WIMOB.2010.5645029 |
abstract
Wireless mobile devices are becoming increasingly prevalent in society. As a result, aggregation of network connectivity through the use of mobile networks is becoming increasingly relevant to service providers as well as for mobile users. The current approach being pursued within the IETF Mobile Extensions for IPv6 (MEXT) WG, is based on the Network Mobility (NEMO) architecture. NEMO uses IP-in-IP tunnelling for providing mobile network capability on an existing IPv6 network. This approach can result in non-optimal routing between source and destination nodes. Other proposals such as OptiNets extend NEMO and try to address issues such as sub-optimal routing. There are alternative approaches also being proposed, such as the Identifier Locator Network Protocol (ILNPv6), which is based on the use of naming, to enable a flexible and integrated mobile network capability based on IPv6.We have conducted a comparative analysis of the cost of providing optimal routing, in terms of packet and bandwidth overhead, based on an emulation, using data from the London Circle Line metropolitan railway as a scenario. Our analysis shows that these different approaches to mobility offer significantly different performance trade-offs in routing for mobile networks, depending on the constraints of the network scenario.
Y. Yu, S. N. Bhatti.Energy Measurement for the Cloud. ISPA 2010 - IEEE Intl. Symp. Parallel and Distributed Processing with Applications. Taipei, Taiwan. Sep 2010.
| PDF | .bib | 10.1109/ISPA.2010.29 |
abstract
One of the aims of cloud-based services is to offer cost savings through elastic service provision. This elasticity refers to use of resources by the customer and the provision of resources by the provider. An increasingly important resource to consider is energy (or power). As cloud services are intended to be ‘always on’ the energy costs of cloud service provision is already significant, and will continue to rise as global energy prices continue to rise and more users make use of cloud services. While providers can invest in energy-efficient hardware, how can we make users (customers) energy- aware, and incentivise users towards energy- efficient use of cloud systems? Clearly, being able to measure actual energy usage will allow the provision of suitable feedback to users, as well as enable new energy-aware systems metrics that allow systems management policies to become responsive to energy usage. We list the requirements and described a prototype for such an energy measurement system.
M. Rogers, S. N. Bhatti.Private Peer-to-Peer Networks. Handbook of Peer-to-Peer Networking (Springer US), pages 813-828. Mar 2010.
| PDF | .bib | 10.1007/978-0-387-09751-0_28 |
abstract
This chapter offers a survey of the emerging field of private peer-to-peer networks, which can be defined as Internet overlays in which the resources and infrastructure are provided by the users, and which new users may only join by personal invitation. The last few years have seen rapid developments in this field. We describe deployed systems, classify them architecturally, and identify some technical and social tradeoffs in the design of private peer-to-peer networks.
M. Bateman, S. N. Bhatti.TCP Testing: How Well Does ns2 Match Reality?. AINA 2010 - 24th IEEE Intl. Conf. Advanced Information Networking and Applications. Curtin University of Technology, Perth, Australia. April 2010.
| PDF | .bib | 10.1109/AINA.2010.133 |
abstract
New transport protocols continue to appear as alternatives to the Transmission Control Protocol (TCP). Many of these are are designed to address TCP’s inefficiency in operating over paths with a high bandwidth-delay product (BDP). To test these new protocols, especially comparatively, and to understand their interactions, extensions to the ns2 simulator allow real code from the linux kernel to be used within the ns2 simulations. However, how does the performance of such configurations compare to test-bed experiments of the same configuration? Although, anecdotally, there are often comments within the research community about such issues, there are no studies that quantify the differences for a specific protocol suite. Using a simple testbed, we assess four different transport protocols in a comparative study to examine how well ns2 matches reality. Our tests are all conducted at 100Mb/s over a wide range of delay and router buffer conditions: end-to-end delays from 25ms to 400ms, with end-to-end path buffering of 20% to 100% of the BDP. We find that in our simple configuration, there are significant differences in performance between ns2 and the testbed.
R. Atkinson, S. N. Bhatti, S. Hailes.ILNP: mobility, multi-homing, localised addressing and security through naming. Telecommunication Systems, vol. 42, no. 3-4, pages 273-291. Dec 2009.
| URL | .bib | 10.1007/s11235-009-9186-5 |
abstract
Internet users seek solutions for mobility, multi- homing, support for localised address management (i.e. via NATs), and end-to-end security. Existing mobility approaches are not well integrated into the rest of the Internet architecture, instead primarily being separate extensions that at present are not widely deployed. Because the current approaches to these issues were developed separately, such approaches often are not harmonious when used together. Meanwhile, the Internet has a number of namespaces, for example the IP address or the Domain Name. In recent years, some have postulated that the Internet’s namespaces are not sufficiently rich and that the current concept of an address is too limiting. One proposal, the concept of separating an address into an Identifier and a separate Locator, has been controversial in the Internet community for years. It has been considered within the IETF and IRTF several times, but always was rejected as unworkable. This paper takes the position that evolving the naming in the Internet by splitting the address into separate Identifier and Locator names can provide an elegant integrated solution to the key issues listed above, without changing the core routing architecture, while offering incremental deployability through backwards compatibility with IPv6.
S. N. Bhatti, M. Bateman.Effects of On-path Buffering on TCP Fairness. AINA 2009 - IEEE 23rd Intl. Conf. Advanced Information Networking and Applications. Bradford, UK. May 2009.
| PDF | .bib | 10.1109/AINA.2009.142 |
abstract
Keeping router buffering low helps minimise delay (as well as keeping router costs low), whilst increasing buffering minimises loss. This is a trade-off for which there is no single 'correct' solution. In order to maintain effective throughput for TCP, whilst minimising router buffer requirements, current results suggest that different amounts of buffering are needed depending on the position in the network (e.g., edge or core), and on the relative capacity of ingress and egress links to a router. However, today we have several different variants of TCP in use, and each is designed to have different behaviour especially on paths with high bandwidth-delay product (BDP) values. We use a testbed to investigate the effects of different amounts of 'on-path' buffering (OPB) on the performance of four TCP variants - TCP NewReno, BIC, CUBIC, and Compound TCP - over various end-to-end round-trip-times (RTTs). Specifically, we consider how the variants respond when competing for bandwidth on a bottleneck link. We find that overall performance depends on both the RTT and the OPB provision, and that the observed behaviour is not consistent across the range of RTT and OPB values.
G. Bigwood, T. Henderson, S. Bhatti.Social Delay-Tolerant Network Routing. WWCSS 2009 - 2nd Winter Workshop on Complexity in Social Systems. Institute for Complexity Sciences, Lisbon, Portugal. Jan 2009.
| PDF | .bib |
abstract
Routing in mobile delay-tolerant networks faces new challenges such as mobility and the dynamic nature of the network. Social network information may be useful for routing since mobile nodes in the same social network may be encountered more often and thus be more successful at message-passing. Collecting this social network information, however, can be challenging. We compare a social network traced from user encounters with a user-declared social network, and show some of the differences between these two networks.
S. N. Bhatti, E. Brady, K. Hammond, J. McKinna.Domain Specific Languages (DSLs) for Network Protocols. NGNA 2009 - 1st Intl. Workshop Next Generation Network Architecture. Montreal, Quebec, Canada. Jun 2009.
| PDF | .bib | 10.1109/ICDCSW.2009.64 |
abstract
Next generation network architectures will benefit from the many years of practical experience that have been gained in designing, using and operating network protocols. Over time, the networking community has gradually improved its understanding of networked systems in terms of architecture, design, engineering and testing. However, as protocols and networked systems become more complex, it is our contention that it will be necessary for programming techniques to evolve similarly so that they better support the design, implementation and testing of both the functional and the non-functional requirements for the network protocols that will be used.We therefore envisage new levels of programming language support that permit: (a) the design and implementation of new protocols with provably correct construction; (b) inline testing; and (c) the expression of protocol behaviour within the design. Based on our ongoing work with both network protocols and programming language design, we believe that exploiting the capabilities of work in domain specific languages (DSLs) will allow us to meet such requirements, allowing straightforward and "correct-by-construction" design and implementation of next generation network protocols.
S. N. Bhatti, M. Bateman.Transport Protocol Throughput Fairness. JNW - Journal of Networks, vol. 4, no. 9, pages 881-894. Nov 2009.
| PDF | .bib | 10.4304/jnw.4.9.881-894 |
abstract
Interest continues to grow in alternative transport protocols to the Transmission Control Protocol (TCP). These alternatives include protocols designed to give greater efficiency in high-speed, high-delay environments (so-called high-speed TCP variants), and protocols that provide congestion control without reliability. For the former category, along with the deployed base of ‘vanilla’ TCP – TCP NewReno – the TCP variants BIC and CUBIC are widely used within Linux: for the latter category, the Datagram Congestion Control Protocol (DCCP) is currently on the IETF Standards Track. It is clear that future traffic patterns will consist of a mix of flows from these protocols (and others). So, it is important for users and network operators to be aware of the impact that these protocols may have on users. We show the measurement of fairness in throughput performance of DCCP Congestion Control ID 2 (CCID2) relative to TCP NewReno, and variants Binary Increase Congestion control (BIC), CUBIC and Compound, all in "out- of-the-box" configurations. We use a testbed and end-to-end measurements to assess overall throughput, and also to assess fairness – how well these protocols might respond to each other when operating over the same end-to-end network path. We find that, in our testbed, DCCP CCID2 shows good fairness with NewReno, while BIC, CUBIC and Compound show unfairness above round-trip times of 25ms.
Y. Huang, S. Handurukande, S. N. Bhatti.Autonomic MANET Routing Protocols. JNW - Journal of Networks, vol. 4, no. 8, pages 743-753. Oct 2009.
| PDF | .bib | 10.4304/jnw.4.8.743-753 |
abstract
In Mobile Ad hoc Networks (MANETs), timers have been used widely to maintain routing (state) information. The use of fixed- interval timers is simple to implement but, in practise, may be difficult to configure in dynamic operational environments, and so may give reduced performance in the presence of frequent topology changes. This paper proposes a self-tuning timer approach within a simple control system for MANET routing protocols with the aim of allowing dynamic, autonomic, re-calibration of routing update frequencies. A novel dynamic timer algorithm is presented to automatically tune routing performance by adapting timer intervals to network conditions. Our simulation results have shown that, compared to the default fixed timer approach, the proposed algorithm could effectively improve routing throughput without manual configuration.
R. Atkinson, S. N. Bhatti, S. Hailes.Site-controlled Secure Multi-homing and Traffic Engineering for IP. MILCOM 2009 - 28th IEEE Military Communications Conf.. Boston, Massachusetts, USA. Oct 2009.
| PDF | .bib | 10.1109/MILCOM.2009.5380044 |
abstract
Site multi-homing is an important capability in modern military networks. Resilience of a site is greatly enhanced when it has multiple upstream connections to the global information grid, including the global Internet. Similarly, the ability to provide traffic engineering for a site can be important in reducing delays and packet loss over low-bandwidth and/or high-delay uplinks. Current approaches to site multi-homing and site traffic engineering (a) require assistance from a trusted network service provider; (b) inject significant additional routing information into the global Internet routing system. This approach reduces flexibility, does not scale and is a widespread concern today. The proposed identifier-locator network protocol (ILNP) offers backward compatible extensions for IPv6 to enable a site to (a) use multiple routing prefixes concurrently, without needing to advertise these more-specific site prefixes upstream to the site's service providers; (b) enables edge-site controlled traffic engineering and localised addressing, without breaking end-to-end connectivity. This feature combination provides both multi-homing and traffic engineering capabilities without any adverse impact on the routing system and does not require anything more than unicast routing capability in the provider network. ILNP enables concurrent multi-path transmission for a flow, without requiring multicast routing, to increase flow resilience to path interruptions. This technique has a secondary security benefit of reducing the risk of an adversary successfully blocking an ILNP flow via a denial-of-service attack on any single path or single link.
D. Rehunathan, R. Atkinson, S. N. Bhatti.Enabling mobile networks through secure naming. MILCOM 2009 - 28th IEEE Military Communications Conf.. Boston, MA, USA. Oct 2009.
| PDF | .bib | 10.1109/MILCOM.2009.5379843 |
abstract
Mobile networks are increasingly important in land-, sea-and air-based military scenarios. The interest in supporting network mobility for Internet protocol (IP) networks has led to the network mobility (NEMO) protocol extensions being proposed for IP within the IETF. These extensions are based on the work already completed on host mobility for mobile IP (MIP). The current work is based on the use of software agents: a home agent (HA) intercepts packets destined for the addresses in the mobile network and uses an IP-in-IP tunnel to send the packets to the mobile router (MR) located at a care of address (CoA), which terminates the tunnel. As the mobile network moves to new IP networks, the MR updates the HA with its new CoA. While this tunnelling approach represents a sound engineering solution for backwards compatibility, and is the only one that has been pursued within the IETF, it has seen little deployment, either in support of mobile hosts or mobile networks. We make the case for an alternative approach based on secure naming. We make a comparison in operation with the current tunnelling-based approach, both in architecture and by analysis of protocol operation. Our initial analyses indicate that a naming-based approach shows promise as a viable alternative to a tunnelling-based approach, and could offer other architectural benefits.
K. Carlberg, S. Bhatti, J. Crowcroft.IP version 10.0: a strawman design beyond IPv6. ReArch 2009 - ACM Workshop on Re-Architecting the Internet. Rome, Italy. Dec 2009.
| PDF | .bib | 10.1145/1658978.1658984 |
abstract
After nearly 14 years since the first version of IPv6 was defined by the Internet Engineering Task Force (IETF), there is still just a minimal amount of native IPv6 deployment in today's Internet. Clearly, the evolution of IPv6 since its initial roots as the Simple Internet Protocol has turned the next generation IP effort into one lacking any significant "must have" features. This paper revisits the subject of a next generation IP and presents a new design that builds upon previous and on-going research in proposing a strawman design that we term IPv10.0. Our objective is to present a starting point for discussion of a new IP version that is extensible, introduces new architectural features, and prompts new innovative capabilities.
G. Kannan, Y. Huang, S. N. Bhatti, S. Merchant, U. Desai.A Cross Layer Routing Protocol for Multihop Cellular Networks. WPC - Wireless Personal Communications, vol. 51, no. 3, pages 427-447. Nov 2009.
| PDF | .bib | 10.1007/s11277-009-9751-y |
abstract
We propose a cross-layer routing protocol for a Code Division Multiple Access (CDMA) Multihop Cellular Network (MCN). In designing the routing protocol for MCN, multiple constraints are imposed on intermediate relay node selection and end-to-end path selection. The constraints on relay nodes include willingness for cooperation, sufficient neighbourhood connectivity and the level of interference offered on the path. Path constraints include end-to- end throughput and end-to-end delay. A facile incentive mechanism is presented to motivate the cooperation between nodes in call forwarding. In addition, we present a route resilience scheme in the event of dynamic call dropping. In particular, a fast neighbour detection scheme for route resilience is proposed. Instead of using periodic HELLO messages as in traditional ad-hoc routing, the proposed neighbour detection scheme adopts an explicit handshake mechanism to reduce neighbour detection latency. We conclude the paper by demonstrating the superior performance of the proposed routing protocol compared with the other well known routing algorithms.
Y. Huang, S. N. Bhatti, S.-A. Sorensen.The impact of topology update strategies on the performance of a proactive MANET routing protocol. IJPED - Intl. Journal of Parallel, Emergent and Distributed Systems, vol. 23, no. 6, pages 447-460. Oct 2008.
| PDF | .bib | 10.1080/17445760801945524 |
abstract
Although there have been a number of performance studies of proactive mobile ad hoc network (MANET) routing protocols, little attention has been paid to the impacts of topology update strategies on routing performance. This paper presents an analysis of several topology update strategies for a proactive MANET routing protocol. The goal of this paper is to better understand how topology update strategies can contribute to topology maintenance in proactive MANETs and thus impact the overall performance, based on simulations involving optimised link state routing (OLSR), a popular MANET protocol. Our contribution includes (1) a quantitative analysis of the impacts of proactive update intervals on the routing performance of OLSR; (2) evaluating the performance of reactive topology updates and proactive updates for OLSR.
R. Atkinson, S. N. Bhatti, S. Hailes.Harmonised Resilience, Security and Mobility Capability for IP. MILCOM 2008 - 27th IEEE Military Communications Conf.. San Diego, CA, USA. Nov 2008.
| PDF | .bib | 10.1109/MILCOM.2008.4753321 |
abstract
Military communications currently require secure end-to-end, resilient connectivity via multi-homed connections, and need to support both mobile hosts and mobile networks. Today, such functions are possible to some degree, but the functions are not harmonised. Standards that support these functions were designed independently and implemented in isolation. So, achieving converged capabilities for optimal communications in forward operating areas is a technical challenge, and results in a complex network landscape which is likely to be difficult to operate and manage, and brittle under failure conditions. From our ongoing work, we present a new naming approach and use this to formulate a proposal to provide the following capability harmoniously: (a) multi-homed connectivity for traffic engineering and resilience; (b) true end-to-end network-layer security with high compatibility with the HAIPE architecture; (c) support for mobile hosts and mobile networks. Our approach is backwards compatible with IPv6 network equipment (existing IPv6 backbones can be used), and is also incrementally deployable.
G. Bigwood, D. Rehunathan, M. Bateman, T. Henderson, S. N. Bhatti.Exploiting self-reported social networks for routing in ubiquitous computing environments. SAUCE 2008 - 1st Intl. Workshop on Social Aspects of Ubiquitous Computing Environments. Avignon, France. Oct 2008.
| PDF | .bib | 10.1109/WiMob.2008.86 |
abstract
Mobile, delay-tolerant, ad hoc and pocket-switched networks may form an important part of future ubiquitous computing environments. Understanding how to efficiently and effectively route information through such networks is an important research challenge, and much recent work has looked at detecting communities and cliques to determine forwarding paths. Such detected communities, however, may miss important aspects. For instance, a user may have strong social ties to another user that they seldom encounter; a detected social network may omit this tie and so produce sub-optimal forwarding paths. Moreover, the delay in detecting communities may slow the bootstrapping of a new delay-tolerant network. This paper explores the use of self-reported social networks for routing in mobile networks in comparison with detected social networks discovered through encounters. Using encounter records from a group of participants carrying sensor motes, we generate detected social networks from these records. We use these networks for routing, and compare these to the social networks which the users have self-reported on a popular social networking website. Using techniques from social network analysis, we find that the two social networks are different. These differences, however, do not lead to a significant impact on delivery ratio, while the self-reported social network leads to a significantly lower cost.
S. N. Bhatti, M. Bateman, D. Rehunathan, T. Henderson, G. Bigwood, D. Miras.Revisiting Inter-flow Fairness. BROADNETS 2008 - 5th Intl. Conf. Broadband Communications, Networks and Systems. London, UK. Sep 2008.
| PDF | .bib | 10.1109/BROADNETS.2008.4769146 |
abstract
Many new transport protocols are being defined, including, for example, variants of the Transmission Control Protocol (TCP), to better match the requirements of new applications. A key issue in the evaluation of protocol flows, in terms of their performance, is how fair they are to other flows. Specifically, it is important to understand how a mix of existing and/or new protocols will interact with each other when using the same network resources. Such observations help to inform protocol design, and allow an assessment of potential impacts on users. We present a simple, yet effective, methodology for examining a specific case of inter-flow fairness based solely on measurements of flow performance. As well as using an existing fairness metric, we propose a new metric which provides a richer information summary for the evaluation of fairness.
H. Haddadi, R. Landa, A. W. Moore, S. N. Bhatti, M. Rio, X. Che.Revisiting the Issues on NetFlow Sample and Export Performance. ChinaCom 2008 - 3rd Intl. Conf. Communications and Networking in China. Hangzhou, China. Aug 2008.
| PDF | .bib | 10.1109/CHINACOM.2008.4685060 |
abstract
The high volume of packets and packet rates of traffic on some router links makes it exceedingly difficult for routers to examine every packet in order to keep detailed statistics about the traffic which is traversing the router. Sampling is commonly applied on routers in order to limit the load incurred by the collection of information that the router has to undertake when evaluating flow information for monitoring purposes. The sampling process in nearly all cases is a deterministic process of choosing 1 in every N packets on a per-interface basis, and then forming the flow statistics based on the collected sampled statistics. Even though this sampling may not be significant for some statistics, such as packet rate, others can be severely distorted. However, it is important to consider the sampling techniques and their relative accuracy when applied to different traffic patterns. In this paper, we assess the performance of the sampling process as used in NetFlow in detail, and we discuss some techniques for the compensation of loss of monitoring detail.
R. Atkinson, S. N. Bhatti, S. Hailes.Mobility through naming: impact on DNS. MobiArch 2008 - 3rd ACM Intl. Workshop on Mobility in the Evolving Internet Architecture. Seattle, WA, USA. Aug 2008.
| PDF | .bib | 10.1145/1403007.1403010 |
abstract
An Identifier/Locator addressing scheme can enable a new approach to mobile hosts and mobile networks. Identifier and Locator information is stored in Domain Name System (DNS) Resource Records. In our on-going work using the Identifier-Locator Network Protocol (ILNP), the DNS would be updated with new Locator values as hosts and/or networks move; new sessions would obtain the correct Locator(s) for a mobile host and/or mobile network from the DNS, in much the same way as currently happens for IP address resolution. However, this use of the DNS is not currently required for IP mobility. We examine the potential impact on DNS from using a naming approach to mobility.
M. Rogers, S. N. Bhatti.Cooperation under Scarcity: The Sharer's Dilemma. AIMS 2008 - 2nd Intl. Conf. Autonomous Infrastructure, Management and Security. Bremen, Germany. Jul 2008.
| PDF | .bib | 10.1007/978-3-540-70587-1_3 |
abstract
Many researchers have used game theory to study the problem of encouraging cooperation in peer-to-peer and mobile ad hoc networks, where resources are provided collectively by the users. Previous work has modelled the problem as either a multi-player social dilemma or a network of two-player prisoner’s dilemmas, but neither of these approaches captures a crucial aspect of the problem, namely scarcity: when resources are limited, players must not only consider how to establish and sustain cooperation with each opponent, but how to allocate resources among their opponents in order to maximise the total cooperation received. This paper presents a new game theoretic model of cooperation under scarcity, the sharer’s dilemma, and a simple expected utility strategy that is shown to perform well against a wide range of opponents. The expected utility strategy can easily be applied to file sharing networks to create an incentive for users to contribute resources.
Y. Huang, S. N. Bhatti.Fast-Converging Distance Vector Routing for Wireless Mesh Networks. WWASN 2008 - 5th Workshop on Wireless Ad hoc and Sensor Networks. Beijing, China. Jun 2008.
| PDF | .bib | 10.1109/ICDCS.Workshops.2008.83 |
abstract
A major concern about distance-vector routing protocols for wireless mesh networks is its slow convergence in the presence of link changes, which can potentially degrade network stability. This paper studies the impact of update intervals on network convergence and proposes a fast-converging distance-vector routing algorithm. Our simulation results have shown that the proposed algorithm could effectively reduce convergence latency and improve throughput without leading to a significant increase in control overhead.
S. N. Bhatti, M. Bateman, D. Miras.A Comparative Performance Evaluation of DCCP. SPECTS 2008 - Intl. Symp. Performance Evaluation of Computer and Telecommunication Systems. University of Edinburgh, UK. Jun 2008.
| PDF | .bib |
abstract
Interest continues to grow in alternative transport protocols to the Transmission Control Protocol (TCP). These alternatives include protocols designed to give greater efficiency in high-speed, high-delay environments (so-called high-speed TCP variants), and protocols that provide congestion control without reliability. For the former category, along with the deployed base of 'vanilla' TCP - TCP NewReno - the TCP variants BIC and Cubic are widely used within Linux: for the latter category, the Datagram Congestion Control Protocol (DCCP) is currently on the IETF Standards Track. It is clear that future traffic patterns will consist of a mix of flows from these protocols (and others). So, it is important for users and network operators to be aware of the impact that these protocols may have on users. We assess the performance of DCCP CCID2 relative to TCP NewReno, and variants BIC and CUBIC, all in "out-of- the box" configurations. We use a testbed and end-to-end measurements to assess overall throughput, and also to assess fairness - how well these protocols might respond to each other when operating over the same end-to-end network path. We find that DCCP CCID2 shows good fairness with NewReno under our test conditions, while BIC and CUBIC show unfairness above round-trip times of 25 ms.
Y. Huang, G. Kannan, S. N. Bhatti, S. N. Merchant U. B. Desai.Route Dynamics for Shortest Path First Routing in Mobile Ad Hoc Networks. WTS 2008 - 7th IEEE Wireless Telecommunications Symp.. Pomona CA, USA. Apr 2008.
| PDF | .bib | 10.1109/WTS.2008.4547570 |
abstract
This paper investigates the route dynamics of shortest-path first (SPF) routing in mobile ad hoc networks (MANETs). In particular, we find, from a statistical analysis of route duration and route change interval, that route dynamics may require complex modelling. Our analysis considers various mobility models, node velocities and node densities of the MANET network. Our findings show that, in a MANET with moderate or high rate of mobility, the route duration could be approximated by an exponential distribution with approximate parameters, while the route duration of specific lengths could not. Our findings suggest that minimum hop-count routing in MANETs may be inappropriate and that further investigation is required in order to develop models that let us understand MANET route dynamics.
M. Bateman, S. N. Bhatti, G. Bigwood, D. Rehunathan, C. Allison, T. Henderson, D. Miras.A Comparison of TCP Behaviour at High Speeds Using ns-2 and Linux. CNS 2008 - 11th Communications and Networking Simulation Symp.. Ottawa, Canada. Apr 2008.
| PDF | .bib | 10.1145/1400713.1400718 |
abstract
There is a growing interest in the use of variants of the Transmission Control Protocol (TCP) in high-speed networks. ns-2 has implementations of many of these high-speed TCP variants, as does Linux. ns-2, through an extension, permits the incorporation of Linux TCP code within ns-2 simulations. As these TCP variants become more widely used, users are concerned about how these different variants of TCP might interact in a real network environment -- how fair are these protocol variants to each other (in their use of the available capacity) when sharing the same network. Typically, the answer to this question might be sought through simulation and/or by use of an experimental testbed. So, we compare with TCP NewReno the fairness of the congestion control algorithms for 5 high-speed TCP variants -- BIC, Cubic, Scalable, High-Speed and Hamilton -- on both ns-2 and on an experimental testbed running Linux. In both cases, we use the same TCP code from Linux. We observe some differences between the behaviour of these TCP variants when comparing the testbed results to the results from ns-2, but also note that there is generally good agreement.
Y. Huang, S. N. Bhatti, S. Handurukande.Autonomic Tuning of Routing for MANETs. ACNM 2008 - 2nd Workshop on Autonomic Communications and Network Management. Salvador da Bahia, Brazil. Apr 2008.
| PDF | .bib | 10.1109/NOMSW.2007.49 |
abstract
In mobile ad hoc networks (MANETs), timers have been widely used to maintain routing (state) information. The use of fixed- interval timers is simple to implement but, in practise, may be difficult to configure in dynamic operational environments, and so may give reduced performance in the presence of frequent topology changes. This paper proposes a self-tuning timer approach within a simple control system for MANET routing protocols with the aim of allowing dynamic, autonomic, re-calibration of routing update frequencies. A novel dynamic timer algorithm is presented to automatically tune routing performance by adapting timer intervals to network conditions. Our simulation results have shown that, compared to the default fixed timer approach, the proposed algorithm could effectively improve routing throughput without manual configuration.
Y. Huang, S. N. Bhatti, S.-A. Sorensen.Self-Tuning Network Support for MANETs. NOMS 2008 - IEEE Network Operations and Management Symposium. Salvador da Bahia, Brazil. Apr 2008.
| PDF | .bib | 10.1109/NOMS.2008.4575275 |
abstract
Rapid and unpredictable topology changes and resource constraints make delivering packets in a MANET (mobile ad hoc network) a challenging task. Routing information has to be updated to reflect the topology changes and maintain the correctness of route selection. On the other hand, the dissemination of control messages has to be optimised for efficient resource usage and to alleviate channel contention problems. To solve this problem, this dissertation focuses on how to automatically tune routing performance for MANETs in terms of packet delivery ratio and control overhead. The impacts of soft state signalling, especially the refresh intervals, are studied under various scenarios. A variety of topology advertisement strategies are presented. Two self-tuning neighbour detection schemes are proposed, the dynamic timer algorithm and the fast neighbour handshake algorithm, in order to enhance routing performance.
D. Miras, M. Bateman, S. Bhatti.Fairness of High-Speed TCP Stacks. AINA 2008 - 22nd IEEE Intl. Conf. Advanced Information Networking and Applications. Okinawa, Ginowan, Japan. Mar 2008.
| PDF | .bib | 10.1109/AINA.2008.143 |
abstract
We present experimental results evaluating fairness of several proposals to change the TCP congestion control algorithm, in support of operation on high bandwidth-delay- product (BDP) network paths. We examine and compare the fairness of New Reno TCP BIC, Cubic, Hamilton-TCP, highspeed-TCP and Scalable-TCP. We focus on four different views of fairness: TCP-friendliness RTT-fairness, intra- and inter-protocol fairness.
R. Atkinson, S. N. Bhatti, S. Hailes.A Proposal for Unifying Mobility with Multi-Homing, NAT, & Security. MobiWAC 2007 - 5th ACM Intl. Workshop on Mobility Management and Wireless Access. Chania, Crete Island, Greece. Oct 2007.
| PDF | .bib | 10.1145/1298091.1298105 |
abstract
Internet users seek solutions for mobility, multi-homing, support for localised address management (i.e. via NATs), and end-to- end security. Existing mobility approaches are not well integrated into the rest of the Internet architecture, instead primarily being separate extensions that at present are not widely deployed. Because the current approaches to these issues were developed separately, such approaches often are not harmonious when used together. Meanwhile, the Internet has a number of namespaces, for example the IP address or the Domain Name. In recent years, some have postulated that the Internet's namespaces are not sufficiently rich and that the current concept of an address is too limiting. One proposal, the concept of separating an address into an Identifier and a separate Locator, has been controversial in the Internet community for years. It has been considered within the IETF and IRTF several times, but always was rejected as unworkable. This paper takes the position that evolving the naming in the Internet by splitting the address into separate Identifier and Locator names can provide an elegant integrated solution to the key issues listed above, without changing the core routing architecture, while offering incremental deployability through backwards compatibility with IPv6.
M. Rogers, S. N. Bhatti.An Adaptive Routing Protocol for Censorship-Resistant Communication. i-Society 2007 - 3rd Intl. Conf. Information Society. Indiana, USA. Oct 2007.
| PDF | .bib |
abstract
In open-membership networks such as peer-to-peer overlays and mobile ad hoc networks, messages must be routed across an unknown and changing topology where it may not be possible to establish the identities or trustworthiness of all the nodes involved in routing. This paper describes a decentralised, adaptive routing protocol in which nodes use feedback in the form of unforgeable acknowledgements (U-ACKs) to discover dependable routes without knowing the identities of the endpoints or the structure of the network beyond their immediate neighbours. Our protocol is designed to survive faulty or misbehaving nodes and reveal minimal information about the communicating parties, making it suitable for use in censorship- resistant communication.
Y. Huang, S. N. Bhatti, S.-A. Sorensen.Reducing Neighbour Detection Latency in OLSR. PIMRC 2007 - 18th IEEE Intl. Symp. Personal, Indoor and Mobile Radio Communications. Athens, Greece. Sep 2007.
| PDF | .bib | 10.1109/PIMRC.2007.4394779 |
abstract
This paper presents a fast neighbour detection scheme for a proactive MANET routing protocol. Instead of using periodic HELLO messages, the proposed scheme adopts explicit handshake mechanism to reduce the latency in neighbour detection. In particular, two route handshake options are presented, namely the Broadcast based handshake (BHS) algorithm and Unicast based handshake (UHS) algorithm. Our simulation results show that the proposed scheme improves routing performance, especially in networks with moderate or high mobility. In low-density networks, the unicast option improves the routing throughput significantly without introducing extra control overhead.
R. Atkinson, S. N. Bhatti, S. Hailes.Mobility as an Integrated Service Through the Use of Naming. MobiArch 2007 - 2nd ACM/IEEE Intl. Workshop on Mobility in the Evolving Internet Architecture. Kyoto, Japan. Aug 2007.
| PDF | .bib | 10.1145/1366919.1366921 |
abstract
As Mobile IP is deployed, so the requirements for its deployment evolve, reflecting the actual use of IP networks today. This includes the ability to use Mobile IP with IPsec, NATs and multi- homed networks. Furthermore, new requirements arise as people start to use IP in scenarios where the whole network is mobile (e.g. military networks), and where edge-networks may not be IP-enabled (e.g. sensor networks), but there is a requirement to interoperate across an IP network. In all these cases, rather than engineering retro-fits, creating an increasingly complex network landscape with possible unforeseen feature interactions and dependencies, we would prefer an integrated architectural solution. We present, from our ongoing work, a solution that would seem to meet all these needs, through a modified use of naming and addressing. Our proposal is incrementally deployable and existing core network routers & routing protocols need not change.
M. Rogers, S. N. Bhatti.How to Disappear Completely: A Survey of Private Peer-to-Peer Networks. SPACE 2007 - 1st Intl. Workshop Sustaining Privacy in Autonomous Collaborative Environments. Bronswick, New Monkton, Canada. Jul 2007.
| PDF | .bib |
abstract
This paper offers a survey of the emerging field of private peer-to-peer networks, which can be defined as internet overlays in which the resources and infrastructure are provided by the users, and new users may only join by personal invitation. The last few years have seen rapid developments in this field, many of which have not previously been described in the research literature. We describe deployed systems, classify them architecturally, and identify some technical and social tradeoffs in the design of private peer-to-peer networks.
M. Rogers, S. N. Bhatti.A Lightweight Mechanism for Dependable Communication in Untrusted Networks. DSN 2007 - 37th IFIP/IEEE Annual Conf. Dependable Systems and Networks. Edinburgh, UK. Jun 2007.
| PDF | .bib | 10.1109/DSN.2007.9 |
abstract
We describe a method for enabling dependable forwarding of messages in untrusted networks. Nodes perform only relatively lightweight operations per message, and only the originator and destination need to trust each other. Whereas existing protocols for dependable communication rely on establishing a verifiable identity for every node, our protocol can operate in networks with unknown or varying membership and with no limits on the creation of new identities. Our protocol supports the maintenance of unlinkability: relays cannot tell whether a given originator and destination are communicating. The destination of each message generates an unforgeable acknowledgement (U-ACK) that allows relays and the originator to verify that the message was delivered unmodified to the destination, but relays do not need to share keys with the originator or destination, or to know their identities. Similarly, the endpoints do not need to know the identities of the relays. U-ACKs can be seen as a building block for dependable communication systems; they enable nodes to measure the level of service provided by their neighbours and optionally to adjust the level of service they provide in return, creating an incentive for nodes to forward messages. Our work is ongoing.
Y. Huang, S. N. Bhatti, S.-A. Sorensen.Analysing the Impact of Topology Update Strategies on the Performance of a Proactive MANET Routing Protocol. WWASN 2007 - 4th Workshop on Wireless Ad hoc and Sensor Networks, Toronto. Ontario, Canada. Jun 2007.
| PDF | .bib | 10.1109/ICDCSW.2007.22 |
abstract
This paper presents an analysis of several topology update strategies for proactive MANET routing protocols. Although there have been a number of performance studies of proactive MANET routing protocols, little attention has been paid to the impacts of topology update strategies on routing performance. The goal of this paper is to better understand how topology update strategies can contribute to topology maintenance in proactive mobile ad hoc networks and thus impact the overall performance. Our contribution includes (1) a quantitative analysis on the impacts of proactive update intervals on the routing performance; (2) evaluating the performance of reactive topology updates and proactive updates for proactive routing protocols.
Y. Huang, S. N. Bhatti, S.-A. Sorensen.Adaptive MANET Routing for Low Overhead. ADAMUS 2007 - 1st IEEE WoWMoM Workshop on Adaptive and DependAble Mission- and bUsiness-critical mobile Systems. Helsinki, Finland. Jun 2007.
| PDF | .bib | 10.1109/WOWMOM.2007.4351682 |
abstract
In wireless mission-critical systems, systems may be resource-constrained including limited bandwidth, so minimising protocol overhead, whilst maintaining performance, is important. Proactive MANET routing protocols tend to provide smaller route discovery latency than on-demand protocols because they maintain route information to all the nodes in the network at all time. However, such protocols may impose excessive soft-state routing control overhead which is generated by disseminating periodic update messages. In order to mitigate the side effects of the soft-state control over-heads, we propose two adaptive proactive routing algorithms, namely DT_MIAD and DT_ODPU. By tuning the value of refresh intervals dynamically and automatically, refresh updates are triggered based on traffic conditions and node mobility. We show through simulations that the proposed adaptive routing algorithms can outperform a traditional proactive routing protocol (OLSR).
R. Atkinson, M. Lad, S. N. Bhatti, S. Hailes.A Proposal for Coalition Networking in Dynamic Operational Environments. MILCOM 2006 - 25th IEEE Military Communications Conf.. Washington DC, USA. Oct 2006.
| PDF | .bib | 10.1109/MILCOM.2006.302077 |
abstract
At present, military communications within battlefields are very restricted, both by policy and due to technology limitations. In Southwest Asia today, there are needlessly long and complex communications paths, often involving multiple relays and use of constrained-bandwidth MILSATCOM back-haul outside the theatre, when nearby forces could communicate directly via existing interoperable radios. This is a current problem for NATO and Coalition forces. The current Internet protocol suite lacks core support for mobility, scalable support for multi-homed nodes, and does not provide the capabilities needed for optimal communications in forward operating areas. We propose a coalition-based, multi-homed approach leveraging both local-area and wide-area connectivity, improving both the flexibility and robustness of communication, without conflicting with the security policy of sensitive communication. The Coalition Peering Domain (CPD) is a distributed, self-configuring architecture that supports the secure, collaborative networking relationships needed to provide this flexibility and robustness. The CPD facilitates the inter-connection of cooperating, but administratively separate, network segments. The CPD exploits multi-homed and multi-path communication to better-utilise all available connectivity. The identifier-locator network protocol (ILNP) provides native support for improved scalability in multi-homing and mobility, while easing use of network layer security and allowing inter-operation across different administrative domains. Our approach is compatible with current work in mobile ad-hoc networking (MANET). ILNP has excellent compatibility with IPv6: existing IPv6 backbone networks do not require any modification to carry ILNP traffic natively. There are practical, realistic and deployable engineering solutions to realise the CPD and ILNP within the framework of IPv6.
R. Atkinson, S. N. Bhatti.An Introduction to the Identifier Locator Network Protocol (ILNP). LCS 2006 - London Communications Symp.. London, UK. Sep 2006.
| PDF | .bib |
abstract
Mobility, multi-homing, local addressing and end-to-end security at the network layer remain challenging even with the advent of IPv6. We propose a new network protocol, which can be built upon IPv6 incrementally, that breaks the address into two separate entities, a Locator and an Identifier, with crisp semantics for each, that seeks to solve these issues through an improved naming and addressing architecture.
Y. Huang, S. N. Bhatti, S.-A. Sorenson.A Comparison of Temporal and Topological Soft State Updates for a Proactive MANET Routing Protocol. LCS 2006 - London Communications Symp.. London, UK. Sep 2006.
| PDF | .bib |
abstract
In an mobile ad hoc networks (MANET), each node maintains routing information about other nodes in the network at all times. The nodes propagate state refresh messages to maintain correct routing information. In this paper we present a quantitative analysis on the impact of temporal updates and topological updates for a proactive MANET routing protocol and assess its impact on performance. Simulation results show that the temporal state updates have a significant impact on the throughput, while the topological state updates do not. Furthermore, frequent topological state updates in relatively high-density networks lead to performance degradation because of the large overhead introduced.
Y. Huang, S. N. Bhatti, D. Parker.Tuning OLSR. PIMRC 2006 - 17th IEEE Intl. Symp. Personal, Indoor and Mobile Radio Communications. Helsinki, Finland. Sep 2006.
| PDF | .bib | 10.1109/PIMRC.2006.254160 |
abstract
Optimised link state routing (OLSR) is a popular protocol for use in MANET networks. In this paper, we investigate the different impacts of tuning refresh interval timers on OLSR performance under various scenarios (varying node density and node speed). Based on the simulation results with NS2, we find that although reducing refresh intervals could improve OLSR's performance, the intervals for some message types (HELLO messages) have a bigger impact on OLSR performance than for other message types. We find that the impact of the interval timer grows with increased network mobility and node density.
M. Lad, S. N. Bhatti, S. Hailes, P. Kirstein.Coalition-Based Peering for Flexible Connectivity. PIMRC 2006 - 17th IEEE Intl. Symp. Personal, Indoor and Mobile Radio Communications. Helsinki, Finland. Sep 2006.
| PDF | .bib | 10.1109/PIMRC.2006.254070 |
abstract
Mobile devices available today provide users the ability to communicate using a number of different wireless network interfaces. However, these devices do not yet fully exploit the potential for multi-homed and multi-path communication allowing them to better utilise all the connectivity that is available to them. We present here the coalition peering domain (CPD), an architecture that supports collaborative networking relationships between mobile devices. This improves the speed and robustness of communication through more flexible use of all available connectivity.
D. Quercia, M. Lad, S. Hailes, L. Capra, S. N. Bhatti.Survivable wireless networking — Autonomic bandwidth sharing in mesh networks. BT Technology Journal, vol. 24, no. 3, pages 99-107. Jul 2006.
| PDF | .bib | 10.1007/s10550-006-0081-2 |
abstract
Mesh networking has recently received considerable attention, largely as a mechanism for providing enhanced connectivity without the need to install additional expensive infrastructure. It relies on the fact that underutilised local area connectivity can be used to connect constrained devices to those that possess wide-area uplink capabilities. However, at present, proposals for uplink bandwidth sharing are limited by the use of a traditional view of routing in which multiple end-user devices are associated with each individual uplink in such a way that all their off-network traffic is routed through that particular gateway. While this has the merit of simplicity, it is possible for a subset of gateways to be overloaded while others remain underutilised. We propose a new type of local mesh network, called the Coalition Peering Domain, the goal of which is to maximise Internet connectivity dynamically, smoothing out the usage of uplink capacity, albeit at the cost of slightly more complex control and management. Within this paper, we describe three main routing and addressing issues and then propose novel mechanisms that partially address those issues.
D. Quercia, M. Lad, S. Hailes, L. Capra, S. N. Bhatti.STRUDEL: Supporting trust in the dynamic establishment of peering coalitions. SAC 2006 - ACM Symp. on Applied Computing. Bourgogne University, Dijon, France. Apr 2006.
| PDF | .bib | 10.1145/1141277.1141719 |
abstract
The Coalition Peering Domain (CPD) is a recent innovation within the field of mesh networking. It facilitates the management of community-area networks in a distributed and scalable form, allowing devices to pool their network resources (particularly egress links) to the common good. However, as in P2P systems, this form of cooperative sharing architecture raises significant concerns about the effect of free-riders: nodes that utilise the bandwidth of others without providing an adequate return to the community. To address this problem, we propose STRUDEL, a distributed framework that tackles the problem of free-riders and consists of: (i) a mechanism for the detection of malicious peers; (ii) a formal Bayesian trust model, to assess peers' trustworthiness; (iii) a forwarding mechanism based on the maximisation of trust-informed utility.
L. Sacks, H. Sellappan, S. Zachariadis, S. N. Bhatti, P. Kirstein, W. Fritsche, G. Gessler, K. Mayer.On the manipulation of JPEG2000, in-flight, using active components on next generation satellites. IWAN 2005 - 7th IFIP Annual Intl. Working Conf. Active and Programmable Networks. CICA, Sophia Antipolis, La Cote d'Azur, France. Nov 2005.
| PDF | .bib | 10.1007/978-3-642-00972-3_24 |
abstract
This paper describes two approaches to manipulating JPEG2000 frames with programmable and active networks. The first approach is the use of transcoding and the second is intelligent dropping. These two approaches where considered, in particular, for possible deployment with space based platforms; specifically, communication satellites which are not only IP enabled but may host active components. Each approach offers different possibilities and may be suitable for solving overlapping but different problems.
S. G. Methley, M. Crisp, J. Newman, M. Rio, S. Bhatti P. A. Ramsdale, A. Atefi.Efficient mobile mesh networking: attractions, myths and techno-economic roadmap to successful commercial innovation. DySpan 2005 - 1st IEEE Intl. Symp. New Frontiers in Dynamic Spectrum Access Networks. Baltimore, MD, USA. Nov 2005.
| PDF | .bib | 10.1109/DYSPAN.2005.1542653 |
abstract
This paper examines four scalability hypotheses of interest for mobile meshes via the following questions: 'Do meshes self- generate capacity as new nodes join?' 'Are meshes more spectrally efficient?' 'Do directional antennas confer significant benefits for hand-held below 3.5 GHz?' 'No' is the answer because these hypotheses, whilst having a theoretical basis, can be shown to rely on inappropriate real world assumptions. However the following hypothesis is found to be true: 'Meshes may improve spectrum utilization'. Importantly however, there remain properties of meshes which make them uniquely attractive, such as coverage extension. However this raises a further question over the ability of mobile mesh architecture to provide a guaranteed quality of service. Finally, the wider aspects of commercial innovation are considered
S. G. Methley, M. Crisp, J. Newman, M. Rio, P. A. Ramsdale, S. Bhatti, A. Atefi.Efficient Mobile Mesh Networking:Testing Scalability Hypotheses. 6th IEE Intl. Conf. 3G and Beyond. London, UK. Nov 2005.
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abstract
This paper examines four scalability hypotheses of interest for mobile meshes via the following questions: 'Do meshes self- generate capacity as new nodes join?' 'Are meshes more spectrally efficient?' 'Do directional antennas confer significant benefits for hand-helds below 3.5GHz?' 'No' is the answer because these hypotheses, whilst having a theoretical basis, can be shown to rely on inappropriate real world assumptions. However the following hypothesis is found to be true: 'May meshes improve spectrum utilisation?'
W. Fritsche, K. Mayer, P. Kirstein, S. Bhatti, L. Sacks, S. Zachariadis.Programmable Active Networking supporting Next Generation Multimedia Services in Satellite Network. ICSSC 2005 - 23rd AIAA Intl. Communications Satellite Systems Conf.. Rome, Italy. Sep 2005.
| PDF | .bib |
abstract
The vision of Programmable Active Networking is to increase the systems flexibility and to allow components and services to evolve and develop, without vendors or operators needing to completely re- build their systems. From this aspect especially the space segment of satellite networks could take benefit. The first commercial regenerative satellite systems are now available, providing mainly switching services on the link layer; in future also IP routing functionality will become available. However, from the design of these satellite systems throughout their long time of operation the continuous development of multimedia services progresses significantly, coupled with rapidly and dynamically changing requirements to the underlying networks. As all these requirements cannot be foreseen during the design phase of satellite systems, Programmable Active Networking provides a mean for a dynamic adaptation of satellite networks to these newly arising requirements. During the installation of satellite networks Programmable Active Networking functionality is added to the various involved components, to satellite hubs, to satellite receiver equipment, or also to the space segment itself. This functionality will allow throughout the lifetime of operation of satellite components the remote uploading of new code and its execution in a specific environment. This new code could serve different purposes; for example it could add a new functionality, such as a newly available transcoder to be used for adapting multimedia streams to the characteristics of different satellite beams, or it could also transmit just a new policy for configuring an existing transcoding service. To optimally exploit its benefits, a careful design of Programmable Active Networking functionality for satellite networks is required and needs to especially consider aspects of security, performance and network operation. For example the distribution of active components could be abused for performing network attacks; consequently appropriate security functionality has to be included, like the authentication and integrity protection of the distributed code. To avoid the execution of malfunctioning code on sensitive components like the space segment, one should perform plausibility checks and run the code in protected environments like a Java sandbox. As processing power and memory are expensive especially in the space segment, resource intensive functionality needs to be executed in the ground segment whenever possible. To make the introduction of Programmable Active Networking as economically as possible, its design should be applicable to a broad variety of multimedia services.
M. Lad, S. N. Bhatti, S. Hailes, P. Kirstein.Enabling Coalition-Based Community Networking. LCS 2005 - London Communications Symp.. London, UK. Sep 2005.
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abstract
Recent advances in local-area networking capabilities have enabled the emergence of a new class of community-based edge networks. These involve the direct interconnection of machines or local networks between community members. However, such interconnection, or peering, is usually carried out by individuals on an ad hoc basis and requires a level of expertise to configure and maintain. We present a new architectural element for such community-area networks — the Coalition Peering Domain — and show why it is needed to better utilise available resources.
S. Zachariadis, L. Sacks, S. N. Bhatti, P. Kirstein, W. Fritz, K. Mayer, G. Gessler.A Component-Based Active Network System for Satellite Platforms. LCS 2005 - London Communications Symp.. London, UK. Sep 2005.
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abstract
Active networks are networks that can be reprogrammed by injecting customized programs into some of the nodes of the network, which change the computation that is performed on packets flowing through them. Active networks have been successfully used to offer adaptable routing mechanisms in disaster scenarios, to dynamically compress data before transmitting, etc. In this paper, we discuss the advantages that an active approach would offer for satellite network systems. We describe issues with the deployment of an active networking platform on a satellite. We detail the design and implementation of a component based active networking platform, which is able to dynamically deploy, instantiate and reprogram software components on a satellite system. We also show how the platform is used to build dynamic media transcoding services and test the implementation of our system.
M. Rogers, S. N. Bhatti.Cooperation in Decentralised Networks. LCS 2005 - London Communications Symp.. London, UK. Sep 2005.
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abstract
This paper describes a new model of cooperation between autonomous participants in decentralised networks. Our approach is based on reciprocation between immediate neighbours, which does not require any centralised infrastructure for accounting or identity management. We describe the conditions that are necessary for reciprocation to occur, and show how reciprocation between immediate neighbours can support multi-hop interactions such as packet forwarding.
F. Huici, S. N. Bhatti, J. Souter.ExSERT: Enabling Distributed Monitoring at Internet Exchange Points. LCS 2005 - London Communications Symp.. London, UK. Sep 2005.
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abstract
Internet Exchange Points (IXPs) carry a significant portion of Internet traffic. One of their principal activities is to monitor their networks to ensure their effective and reliable operation. In particular, Euro-IX, an association of most European IXPs, has a requirement to perform distributed monitoring and to be able to share monitoring tools and data among its members. However, currently available tools are either commercial point monitoring tools or do not provide a mechanism for easy creation and sharing of new monitoring tools and data. In this paper we present ExSERT, the Extensible Secure Event and Report Toolkit, which will provide solutions to these problems.
Y. Huang, D. Miras, S. N. Bhatti.Model Based Analysis of Soft State Signaling Protocols. LCS 2005 - London Communications Symp.. London, UK. Sep 2005.
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abstract
The concept of soft state was introduced in the late 1980s and has been widely used in various Internet protocols. However, there is still no comprehensive understanding or well-accepted models on performance (resilience, robustness etc.) of soft state protocols. This paper presents a model based analysis on resilience of soft state signalling protocols based on probability theory. The model could be used to evaluate failure recovery time in the presence of state inconsistency for protocols such as RSVP. This work in progress aims towards an accurate and comprehensive model for signalling protocols.
Y. Huang, S. N. Bhatti.Resilient State Management in Large Scale Networks. IWQoS 2005 - 13th Intl. Workshop on Quality of Service. Passau, Germany. June 2005.
| PDF | .bib | 10.1007/11499169_31 |
abstract
This paper describes, briefly, ongoing research on resource reservation state management, including research motivations and initial design.
Y. Huang, S. N. Bhatti.Scaleable Signaling Underlay for Overlay Networks. ICON 2004 - 12th IEEE Intl. Conf. on Networking. Singapore. Nov 2004.
| PDF | .bib | 10.1109/ICON.2004.1409187 |
abstract
This paper presents the design of a scalable decentralized signaling underlay infrastructure, which features a DHT based management information storage and query-based state lookup mechanism. The signaling underlay is aimed to apply a decentralized "peer-to- peer" style searching and discovering engine into the management and control plane of the overlay network, including grid networks and p2p applications, to facilitate deployment of QoS service.
Y. Huang, S. N. Bhatti.Decentralized Resilient Grid Resource Management Overlay Networks. SCC 2004 - IEEE Intl. Conf. Services Computing. Shanghai, China. Sep 2004.
| PDF | .bib | 10.1109/SCC.2004.1358027 |
abstract
Recently, grid and peer-to-peer overlays have attracted attention from research communities as well as industry. However, the overwhelming majority of industrial, commercial and academic activities are geared around applications, servers, and middleware. There have been some efforts in the management of the underlying networks (the connectivity for the overlays), but far from enough. This paper proposes a resilient, fault-adaptive, overlay resource management framework, with lightweight state management infrastructure, taken from some ongoing work by the authors in this area. This research aims to solve the problems of: (a) managing distributed network resources in a decentralized way; (b) providing resilient QoS for highly dynamic networks.
R. Atkinson, S. N. Bhatti.Naming Enhancements for the Internet. LCS 2004 - London Communications Symp.. London, UK. Sep 2004.
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abstract
The Internet has a number of different namespaces used by its myriad protocols and applications. Unfortunately overloaded naming semantics are creating widespread issues. This position paper reviews the existing namespaces, current naming issues, and then proposes a strawman approach to resolving the current naming issues.
F. Saka N. Pezzi A. di Donato J. Orellana P. Clarke Y-T Li S. Dallison R. Hughes-Jones S. Bhatti R. Smith R. Tasker.Enabling advanced high performance networks and end-systems for Grid applications. AHM 2004 - e-Science All Hands Meeting. Nottingham, UK. Aug 2004.
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abstract
The MB-NG project brings together users, industry, equipment providers and e-science applications. The project aims are: to construct a high-performance leading edge quality of service (QoS) network; to demonstrate end-to-end managed bandwidth services in a multi-domain environment and to investigate high performance data transport mechanisms for Grid data transfer across heterogeneous networks. We report on the major successes in the area of QoS and managed bandwidth, the achievements in the area of end-hosts and the benefits to applications.
M. Rio, A. di Donato, F. Saka, N. Pezzi, R. Smith, S. N. Bhatti, P. Clarke.Quality of Service Networking for High Performance Grid Applications. Journal of Grid Computing, vol. 1, no. 4, pages 329-343. Dec 2003.
| PDF | .bib | 10.1023/B:GRID.0000037551.92756.4e |
abstract
This paper reports on different efforts to provide quality of service (QoS) Networking to Grid applications done in the context of the MB-NG, GRS and DataTAG EU projects. These are leading edge network research projects involving more that 50 researchers in the UK, Europe and North America, concerned with the development and testing of protocols and standards for the next generation of high speed networks. We have implemented and tested the Differentiated Services Architecture (DiffServ) in a multi-domain, 2.5 Gbits/s network (the first such deployment) defining appropriate Service Level Agreements (SLAs) to be used between administrative domains to guarantee end-to-end Quality of Service. We characterised several hardware implementations of DiffServ and concluded on their appropriateness for several network scenarios. Since current and future Grid applications will have to use modified mechanisms of congestion control we have evaluated old and new TCP implementations over a Differentiated Services Networks. These quality of service tests have also included innovative MPLS (Multi- Protocol Label Switching) experiments to establish guaranteed bandwidth connections to Grid applications in a fast and efficient way. We have also developed a software based bandwidth broker architecture for Grids based on IETF standards which allows applications to transparently request dynamic and advanced reservations and implemented it in a real experimental network. We finally report on experiences delivering Quality of Service networking to high performance applications like Particle Physics data transfer and High Performance Computation. This includes quantitative results on the performance improvements that QoS brought to real data transfers in the context of High Performance Computing.
T. Henderson, S. N. Bhatti.Networked games - a QoS-sensitive application for QoS insensitive users?. RIPQOS 2003 - ACM SIGCOMM Workshop on Revisiting IP QoS: What have we learned, why do we care?. Karlsruhe, Germany. Aug 2003.
| PDF | .bib | 10.1145/944592.944601 |
abstract
Research into providing different levels of network Quality of Service (QoS) often assumes that there is a large market for QoS- sensitive applications that will be fulfilled once QoS-enabled networks have been deployed. Multiplayer networked games are an example of such an application that requires QoS, and hence will only become popular if QoS is made widely available. The prima facie evidence, however, is that games are already popular, in spite of the existing QoS-free best-effort Internet.Networked games may have become popular despite the lack of QoS because players "make do" with what is available to them. Such popularity is a double-edged sword. It may mean that there is a demand, as yet unfulfilled, from game players for QoS-enabled networks. On the other hand, it may mean that players have become accustomed to playing games without QoS, and therefore might be less willing to pay for higher QoS when it does eventually become available.In this paper we present the results of a short experiment to examine the QoS tolerances of game players. We use a set of popular First Person Shooter (FPS) game servers that are publicly available to Internet users at large. By systematically altering the network latency to the servers, we attempt to study whether degraded QoS (in the form of higher network delay) affects a user's decision to participate in the game.We find that increased network delay has an effect on a user's decision to join a game server. It appears, however, that there is no significant difference in the number of players who leave the game as a result of increased delay. We speculate that this may be due to a user's enjoyment exceeding their QoS-sensitivity, and discuss the implications of our findings with respect to providing and charging for QoS.
S. N. Bhatti, S.-A. Sorensen, P. Clarke, J. Crowcroft.Network QoS for Grid Systems. IJHPCA - Intl. Journal of High Performance Computing Applications, vol. 17, no. 3, pages 219-236. Aug 2003.
| PDF | .bib | 10.1177/1094342003173009 |
abstract
Grid users may wish to have fine-grained control of quality of service (QoS) guarantees in a network in order to allow timely data transfer in a distributed application environment. We present a discussion of the issues and problems involved, with some critical analysis. We propose possible solutions by making reference to and analysing existing work. Also, we describe the mechanisms being proposed as part of a work-in-progress (being conducted by the authors) that uses a peer-to-peer approach to micro-manage network capacity allocations at the edge of the network, at end-sites, in a multi-domain scenario. Scheduling controllers at the end-sites are employed, which are subject to local administrative controls and have flexibility in resource allocation based on user requests for network capacity. We highlight the issues in scaling such systems to large numbers of users and the issues concerning the interfaces available to applications and end-users for accessing such services.
S. N. Bhatti, P. Kirstein, P. Clarke, T. Chown, D. Hutchison.IPv6 - Good for Grid: a position statement from a technical viewpoint. 1st 6NET Workshop. Zagreb, Croatia. May 2003.
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abstract
IPv6 offers great benefits to the Grid infrastructure and Grid applications, and so the Grid community should support research in this area. This is discussed briefly in the context of several key features of IP networking, namely: addressing and routing, mobility, end-system configuration, high-performance communication, quality of service (QoS) support, provision of security services, group communications and transition.
M. Pias, J. Crowcroft, S. Wilbur, T. Harris, S. N. Bhatti.Lighthouses for Scalable Distributed Location. IPTPS 2003 - 2nd Intl. Workshop on Peer-to-Peer Systems. Berkeley, CA, USA. Feb 2003.
| PDF | .bib | 10.1007/978-3-540-45172-3_26 |
abstract
This paper introduces Lighthouse, a scalable location mechanism for wide-area networks. Unlike existing vector-based systems such as GNP, we show how network-location can be established without using a fixed set of reference points. This lets us avoid the communication bottlenecks and single-points-of-failure that otherwise limit the practicality of such systems.
M. Pias, S. Wilbur, S. N. Bhatti, Jon Crowcroft.Securing the Internet metering and billing. GLOBECOM 2002 - IEEE Global Telecommunications Conf.. Taipei, Japan. Nov 2002.
| PDF | .bib | 10.1109/GLOCOM.2002.1188468 |
abstract
In the near future, billing for network services will not only be concerned with time or volume based accounting but also in ways of measuring the quality of the service provided. Dynamic price schemes, such as congestion-based charging, have been proposed. In some of these models, the charging infrastructure relies on the distribution of electronic tariffs to end-users machines. The tariff structure includes the price information and an algorithm to calculate the charge. Thus, the monitoring of network usage according to this tariff is essential within these frameworks. However, little attention has been given to the security issues associated with Internet metering in these schemes. This has had a great impact on the new models proposed today, since security has become a major concern in open networks. Systems that naturally have incentive to fraud, such as metering systems used for billing purposes, must deal with security threats in large scale environments. The article compiles the security issues of a dynamic networked system where electronic tariffs and service level agreement (SLA) structures are distributed among service providers and customers. To address these issues, a set of security protocols is outlined.
S. N. Bhatti, P. Clarke.Larging it for the Grid: Big Networking for Big Science. AHM 2002 - e-Science All Hands Meeting. Sheffield, UK. Sep 2002.
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abstract
Key words to describe the work: quality of service (QoS), network control, resource management, high-speed networking. Key Results: in progress – national and international high-speed, manageable, flexible, QoS-controlled network connectivity. How does the work advance the state-of-the-art?: to provide control of the network for users from their desktops whilst still allowing network administrators to operate the network to meet users’ needs in a scaleable with respect to user demand. Motivation (problems addressed): the need to enable connectivity for distributed applications, with requirements to access large amounts of data remotely (e.g. bio-informatics, high-energy physics, radio astronomy, socio-economic data-mining) or with requirements for real-time interaction (e.g. distributed simulation, distributed control, real- time remote visualisation, high-quality video and audio for remote language teaching or conferencing.
T. Henderson, J. Crowcroft, S. N. Bhatti.Congestion pricing: Paying your way in communication networks. IEEE Internet Computing, vol. 5, no. 5, pages 85-89. Sep/Oct 2001.
| PDF | .bib | 10.1109/4236.957899 |
abstract
Network congestion is a fundamental problem facing Internet users today. A network where users are selfish, and thus reluctant to defer to other users, may result in the famous "tragedy of the commons", where, in the absence of controls, a shared resource is overconsumed by individuals who consider only their personal costs and not the cost to society as a whole. In terms of the Internet, the "tragedy" could be viewed as congestive collapse, resulting from overconsumption of the shared network resource. It is important to distinguish congestion pricing from other forms of network pricing. Charging network users for the congestion they cause can lead to more efficient network utilization by forcing them to take social costs into account. In a congestion-pricing framework, the congestion charge would replace usage and QoS charges. Users would pay their ISPs a subscription charge to cover fixed costs and a congestion charge only when appropriate. This pricing scheme is feasible because, in the absence of congestion, the marginal cost of a network link is practically zero. Congestion pricing can also benefit network operators. By indicating the level of congestion and the user tolerance of it in their networks, congestion pricing can inform operators about when to re-provision and increase network capacity
T. Henderson, S. N. Bhatti.Modelling user behaviour in networked games. SIGMM 2001 - ACM 9th Intl. Conf. Multimedia. Ottawa, Ontario, Canada. Oct 2001.
| PDF | .bib | 10.1145/500141.500175 |
abstract
In this paper we attempt to gain an understanding of the behaviour of users in a multipoint, interactive communication scenario. In particular, we wish to understand the dynamics of user participation at a session level. We present wide-area session level traces of the popular multiplayer networked games Quake and Half-Life. These traces were gathered by regularly polling 2256 game servers located all over the Internet, and querying the number of players present at each server and how long they had been playing. We analyse three specific features of the data: the number of players in a game, the interarrival times between players and the length of a player's session. We find significant time-of-day and network externality effects in the number of players. Player duration times fit an exponential distribution, while interarrival times fit a heavy-tailed distribution. The implications of our findings are discussed in the context of provisioning and charging for network quality of service for multipoint and multicast transmission. This work is ongoing.
P. Gevros, P. Kirstein, J. Crowcorft, S. N. Bhatti.Congestion Control Mechanisms and the Best Effort Service Model. IEEE Network, vol. 15, no. 3, pages 16-26. May/Jun 2001.
| PDF | .bib | 10.1109/65.923937 |
abstract
In the last few years there has been considerable research toward extending the Internet architecture to provide quality of service guarantees for the emerging real-time multimedia applications. QoS provision is a rather controversial endeavour. At one end of the spectrum there were proposals for reservations and per-flow state in the routers. These models did not flourish due to the network's heterogeneity the complexity of the mechanisms involved, and scalability problems. At the other end, proposals advocating that an over-provisioned best effort network will solve all the problems are not quite convincing either. The authors believe that more control is clearly needed for protecting best effort service. An important requirement is to prevent congestion collapse, keep congestion levels low, and guarantee fairness. Appropriate control structures in a best effort service network could even be used for introducing differentiation. This could be achieved without sacrificing the best effort nature of the Internet or stressing its architecture beyond its limits and original design principles. We revisit the best effort service model and the problem of congestion while focusing on the importance of cooperative resource sharing to the Internet's success, and review the congestion control principles and mechanisms which facilitate Internet resource sharing
S. N. Bhatti, J. Crowcroft.QoS Sensitive Flows: Issues in IP Packet Handling. IEEE Internet Computing, vol. 4, no. 4, pages 48-57. Jul/Aug 2000.
| PDF | .bib | 10.1109/4236.865087 |
abstract
IP-based networks were never designed for real time traffic, yet QoS support in such networks is needed to accommodate both global use and the more demanding applications now emerging. Changes in packet handling, in particular, will help provide QoS support in IP networks. The article focuses on the issues and principles concerning router modification for IP packet handling.
T. Henderson, S. N. Bhatti.Protocol independent multicast pricing. NOSSDAV 2000 - 10th Intl. Workshop on Network and Operating Systems Support for Digital Audio and Video. The University of North Carolina at Chapel Hill, NC, USA. Jun 2000.
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abstract
Current multicast pricing proposals are dependent on specific routing protocols or require changes to the existing IP multicast model. Given that multicast has only seen limited deployment thus far, such schemes may become redundant if the multicast service model changes. We believe that instead of altering multicast delivery methods to suit particular pricing schemes, a multicast pricing scheme should be designed around the generic concept of multipoint communication, without depending on the underlying transmission methods. We highlight limitations of existing work in this area and present a work-in-progress; a framework that enables this separation between transmission and pricing.
J. Crowcroft, S. N. Bhatti, C. Perkins.What is the place for user-network signalling in the 21st Century?. UKTS 2000 - 16th UK Teletraffic Symp.. Nortel Networks, Harlow, UK. May 2000.
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abstract
In the provision of multiservice network services, much attention has been focused on the use of user- network (UN) signalling. UN signalling plays an important role in connection- oriented networks. In such networks, it can be used for admission control, providing resource allocation (resource reservation), enabling new services, accounting information (for generating bills) as well as allow collection of statistics that can aid in dimensioning and capacity planning. We argue that UN signalling is not required for IP-based networks and that; a) for an IP-based network other mechanisms may be more suitable for providing the features listed above; b) to insist that there is UN signalling in IP-based networks that reproduces the signalling mechanisms already used in the telco- network can hinder the deployment of new applications in IP-based networks.
S. N. Bhatti.IP and Integrated Services. Handbook of Communications Technologies: The Next Decade (Springer-Verlag Gmbh), pages 217-238. Nov 1999.
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S. N. Bhatti, G. Knight.Enabling QoS adaptation decisions for Internet applications. Computer Networks, vol. 31, no. 7, pages 669-692. Apr 1999.
| PDF | .bib | 10.1016/S0169-7552(98)00294-3 |
abstract
We present a network model that allows processing of QoS (quality of service) information about media flows to enable applications to make adaptation decisions. Our model is based around a multi-dimensional spatial representation that allows QoS information describing the flow constructions and QoS parameters – flow-states – to interact with a representation of the network QoS. The model produces reports about the compatibility between the flow-states and the network QoS, indicating which flow-states the network can currently support. The simple nature of the reports allows the application to make decisions, dynamically, on which flow-state it should use. The model is relatively lightweight and scaleable. We demonstrate the use of the model by simulation of a dynamically adaptive audio tool. Our work is ongoing.
S. N. Bhatti, G. Knight.On management of CATV full service networks: a European perspective. IEEE Network, vol. 12, no. 5, pages 28-39. Sep/Oct 1998.
| PDF | .bib | 10.1109/65.730749 |
abstract
The CATV network operators hope to offer digital services and evolve their networks to full service networks. There are many hurdles for them at the moment in the transition to a digital network and digital service offering from the current analog-based technology. Key to the success of the transition will be a well-integrated and capable management system to allow CATV operators and service providers to control the network as well as the services they will offer. The CATV operators need to agree on a common data communication infrastructure and plan how their new digital services will be offered to subscribers without disrupting the current customer base of analog service users. The choice of network technology and data communication protocols will have a strong influence on the network management technology chosen. A vital element for the provision of a common open communication architecture as well as for the purposes of network management is that the IP is used. The adoption of existing standards is vital in order to establish a fast route to open network management for CATV networks. It is possible that CATV operators and service providers will have to integrate existing SNMP management systems and TMN/OSI management, with newer integrated service management systems based on TINA and implemented on a CORBA platform. There is a strong need to address security issues before any of these technologies can be deployed for service. There is currently investment (deployed systems and research) which uses each of the technologies mentioned, so these technologies will need to coexist. This article highlights the differences between the North American and European network architectures, and outlines the European network and network management scenario. This is based on the authors involvement in a Pan-European CATV project, Integrated Broadband Communication over Broadcast Networks-IBCoBN.
S. N. Bhatti, G. Knight.QoS Assurance vs. Dynamic Adaptability for Applications. NOSSDAV 1998 - 8th Intl. Workshop on Network and Operating System Support for Digital Audio and Video. Computer Laboratory, University of Cambridge, UK. Jul 1998.
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abstract
Enabling adaptability to network QoS (quality of service) is seen as a key feature for future applications. One way to approach adaptability is to build it into the net- work and allow applications to signal their requirements to the network. This means that resource reservation mechanisms must be available end-to-end, which is not always the case, especially on the Internet. Also, user preferences affect how the application is used. So the application must be dynamically adaptive, taking into account the application’s capabilities, the available network QoS and the user preferences. We suggest that it is possible to build practicable QoS summaries that capture all these inputs and allow dynamic adaptability.
S. N. Bhatti, G. Knight.Notes on a QoS information model for making adaptation decisions. HIPPARCH 1998 - 4th Intl. Workshop on High Performance Protocol Architectures. Dept. of Computer Science, UCL, London, UK. Jun 1998.
| PDF | .bib |
abstract
We present a network model that allows processing of QoS (quality of service) information about media flows to enable applications to make adaptation decisions. Our model is based around a multi-dimensional spatial representation that allows QoS information describing the flow constructions and QoS parameters – flow-states – to interact with a representation of the network QoS. The model produces reports about the compatibility between the flow-states and the network QoS, indicating which flow-states the network can currently support. The simple nature of the reports allows the application to make decisions, dynamically, on which flow-state it should use. The model is relatively lightweight and scaleable. We demonstrate the use of the model by simulation of a dynamically adaptive audio tool. Our work is ongoing.
S. N. Bhatti, G. Knight.Issues in Residential Broadband Internet Service Provision. JENC8 - 8th Joint European Networking Conf.. Edinburgh, UK. May 1997.
| PDF | .bib |
abstract
The CATV industry sees itself as extending to become a FSN (full service network) provider, and so would like to offer data services, notably IP (Internet Protocol) connectivity. Cable companies have the raw network capacity to the home that gives them the potential to offer broadband services that can not be matched by traditional PSTN/modem connectivity. In the home, SoHo (small-office /home-office) and SME (small-to-medium enterprise) environments, use of applications such as electronic mail and the World Wide Web (WWW, the Web) are proving to be very popular and effective. Also applications allowing such functions as conferencing are becoming avail- able. Broadband residential services will enable cheap accessibility of such functions from the CPN (customer premises network).
S. N. Bhatti, K. M. T. McCarthy, G. Knight, G. Pavlou.Secure management information exchange. Journal of Network and Systems Management, vol. 4, no. 3, pages 251-277. Sep 1996.
| PDF | .bib | 10.1007/BF02139146 |
abstract
This paper describes the design and implementation of a secure management protocol for the management of distributed applications. The protocol is a modified use of the ISO CMIP protocol, with additional mechanisms and behaviour to provide the following security services:Mutual authentication of communicating parties. Both parties can prove to each other that they are who they claim to be by the exchange of signed credentials.Stream integrity for management information packets (protocol data units—PDUs). The management information exchanged between the parties is protected from replay, misordering, modification, insertion, and deletion of the PDUs.Confidentiality of the management PDUs. Only the communicating parties can read the information passed between them. The mechanism used also provides a level of back traffic protection and perfect forward secrecy. In previous work we have implemented a public-key based system. Here, we present an experiment based on the use of a secret-key mechanism, for a faster, lightweight approach. The authentication mechanism makes use of the MD5 algorithm and the DES encryption standard. The PDU integrity mechanisms make use of a pseudo random number sequence for PDU numbering and the MD5 algorithm for generating unforgeable signatures for the PDUs.
G. Knight, S. N. Bhatti, S. Clayman.A Data and Telecommunications Gateway between the Internet and ISDN. INET1995 - 5th Annual Conference of the Internet Society. Honolulu, Hawaii, USA. Jun 1995.
| PDF | .bib |
abstract
This paper describes work carried out at University College London to integrate public narrow-band ISDN services into the Internet world. The aim of the work is to provide a gateway that allows access to global Internet resources for users with Basic Rate ISDN access. The gateway not only supports traditional data applications but also newer multi-media, multicast applications such as VAT and WB. A subsidiary aim is to make it possible for a PSTN user to dial-in and join an Internet VAT conference
G. Knight, S. N. Bhatti.Some experiences with secure management. JENC6 - 6th Joint European Networking Conf.. Tel Aviv, Israel. May 1995.
| PDF | .bib |
abstract
This paper describes work carried out in the ESPRIT MIDAS project to provide secure management facilities. The work is based on extensions to the OSI CMIP management protocol which provide for mutual authentication at association set-up and integrity checks in all PDUs. The first version of this mechanism has been implemented and tested; in practice it has been found to be rather slow in operation. This paper proposes a series of measures designed to streamline operation and so improve performance. A major goal of the work has been to provide secure access to management information. This implies the existence of a flexible, yet implementable, access control model. The limitations of the existing standards in this area are discussed.
S. N. Bhatti, G. Knight, D. Gurle, P. Rodier.Secure Remote Management. ISINM4 - 4th International Symposium on Integrated Network Management. Santa Barbara, CA, USA. May 1995.
| PDF | .bib | 10.1007/978-0-387-34890-2_14 |
abstract
Much of the network management technology today still centres around a remote monitoring approach. One would like to have a more intrusive management capability but in a large distributed system one must have confidence that management activities can not be subverted. whether by accident or by malicious intent. To achieve this goal, one requires the management applications to have security mechanisms that will prevent unprivileged users from altering the system accidentally but also, more importantly, to prevent possible attacks from a thrid party who may disrupt or misuse services. This paper describes some services and mechanisms with which the authors have experimented to allow secure remote management of a distributed system in a real service environment. Although there are many standards documents describing various security mechanisms, some aspects of these documents are not stable and in other cases we can not apply the mechanisms they describe due to restrictions in our development environment. In such cases we have had to make some adaptations.
G. Pavlou, K. McCarthy, S. N. Bhatti, J. N. DeSouza.Exploiting the Power of OSI Management for the Control of SNMP-capable Resources Using Generic Application Level Gateways. ISINM4 - 4th International Symposium on Integrated Network Management. Santa Barbara, CA, USA. May 1995.
| PDF | .bib | 10.1007/978-0-387-34890-2_38 |
abstract
A major aspect of Open Systems' network management is the inter-working between distinct Management architectures. This paper details the development of a generic object oriented application level gateway that achieves seamless coexistence between OSI and SNMPv1 management systems. The work builds upon the Network Management Forum's "ISO/CCITT and Internet Management Coexistence" activities. The power of the OSI Systems Management Functions is made available for the management of SNMPv1 based resources, bringing fully event driven management to the SNMP domain.
G. Pavlou, K. McCarthy, G. Knight, S. N. Bhatti.The OSIMIS Platform: Making OSI Management Simple. ISINM4 - 4th International Symposium on Integrated Network Management. Santa Barbara, CA, USA. May 1995.
| PDF | .bib | 10.1007/978-0-387-34890-2_41 |
abstract
The OSIMIS (OSI Management Information Service) platform provides the foundation for the quick, efficient and easy construction of complex management systems. It is an object-oriented development environment in C++ based on the OSI Management Model that hides the underlying protocol complexity (CMIS/P) and harnesses the power and expressiveness of the associated information model through simple to use Application Program Interfaces (APIs). OSIMIS combines the thoroughness of the OSI models and protocols with advanced distributed systems concepts pioneered by ODP to provide a highly dynamic distributed information store. It also combines seamlessly the OSI management power with the large installed base of Internet SNMP [SNMP] capable network elements. OSIMIS supports particularly well a hierarchical management organisation through hybrid manager-agent applications and may embrace a number of diverse technologies through proxy systems. This paper explains the OSIMIS components, architecture, philosophy and direction.
G. Knight, S. N. Bhatti, L. Deri.Secure Remote Management in the ESPRIT MIDAS Project. ULPAA - IFIP TC6/WG6.5 International Working Conference on Upper Layer Protocols, Architectures and Applications. Barcelona, Spain. Jun 1994.
| PDF | .bib |
abstract
This paper describes work carried out in the ESPRIT "MIDAS" project to provide for secure management in the context of the ISO standards for network and system management. The intention of the MIDAS work is to make use of security mechanisms which have already been standardised (for example X.509 authentication) and to make these available through a conventional implementation of the CMIP protocol. The principle application for MIDAS is the management of large X.400 systems. The paper presents an analysis of the security requirements for this application and describes the details of the mechanisms which are being implemented.
G. Pavlou, S. N. Bhatti, G. Knight.Automating the OSI to Internet Management Conversion Through the Use of an Object-Oriented Platform. IFIP TC6/WG6.4 Intl. Conf. on Advanced Information Processing Techniques for LAN and MAN Management. Versailles, France. Apr 1993.
| PDF | .bib |
abstract
OSI provides a powerful object-oriented management model that is infinitely scalable and extensible but is only now beginning to see widespread support. The Internet model has followed a less powerful but simpler approach which has led to an already large installed base of manageable equipment. In the future, even if OSI becomes ubiquitous, the two solutions will have to coexist as the level of investment on Internet management technology is already high. A natural path for this coexistence is to provide a conversion from the Internet to the OSI model and use proxy systems that will provide an OSI view of all existing Internet- manageable resources. This paper discusses how the generation of such proxy systems can be automated through a set of well defined conversion rules and suitable object-oriented infrastructure in the form of a generic management platform. The approach followed for the proxy system is mostly stateless, with optimised cacheing for scoping of transient objects and filtering. Complex issues are highlighted.
Datasets
R. Yanagida, S. N. Bhatti.Mobility Multihoming Duality (dataset). Oct 2024.
| URL | .bib | 10.17630/663a1ff8-5e96-47c1-8793-dc4610bf2579 |
abstract
Dataset to accompnay paper "Mobility–Multihoming Duality". Future Internet, 16(10), Article 358. https://doi.org/10.3390/fi16100358
G. T. Haywood, S. N. Bhatti.Defence against side-channel attacks for encrypted network communication using multiple paths (dataset). May 2024.
| URL | .bib | 10.17630/bf2ffcc2-8663-42a8-b019-ca18005236ba |
abstract
Dataset and related code (Bash, Python, Rust) to accompany the paper "Defence against side-channel attacks for encrypted network communication using multiple paths", Cryptography, 8(2), 22, 2024. https://doi.org/10.3390/cryptography8020022
G. T. Haywood, S. N. Bhatti, R. Yanagida.ILNP - Identifier-Locator Network Protocol : FreeBSD 14.0 @ IETF118/Prague (dataset). Jan 2024.
| URL | .bib | 10.17630/8a1f128b-8362-446e-8e7e-fea5a2dab97f |
abstract
This data-set is evidence of a successful experiment to test basic, international connectivity for the FreeBSD implementation of the Identifier Locator Network Protocol (ILNP), on 04-05 November 2023. The experiment was run between a client system connected to the IETF network at the IETF118 Hackathon (at IETF118/Prague, Czech Republic), and a server at the University of St Andrews (Scotland, UK). The experiment used native IPv6 applications to show that they can benefit directly from use of ILNP without needing to be modified (i.e. using the standard C sockets API), and working directly over an existing IPv6 network, with no proxies, no tunnelling, no address translation, and using standard unicast routing.
S. N. Bhatti.dns-2009-q4-count : data files for paper, "Reducing DNS Caching", from GI2011. Dec 2022.
| URL | .bib | 10.17630/0763a84a-565f-439d-a018-07d063032afa |
abstract
This set of **data files** (constituting the **Database**) are for the GI2011 paper: "Reducing DNS caching", by S. N. Bhatti and R. Atkinson. GI2011 - IEEE Global Internet Symposium 2011. IEEE Conference on Computer Communications Workshops (INFOCOM WORKSHOPS), 2011, pp. 792-797. DOI: 10.1109/INFCOMW.2011.5928919. Each file is a human-readable text file. Each file is, effectively, a time series : DNS request numbers sampled at 1-second intervals. A full description is available in a README file in the tar ball.
G. Bigwood, D. Rehunathan, M. Bateman, T. Henderson, S. N. Bhatti.Dataset for paper: "Exploiting self-reported social networks for routing in ubiquitous computing environments (2008). Jun 2011.
| URL | .bib | 10.15783/C7S59X |
abstract
This is the dataset for paper: G. Bigwood, D. Rehunathan, M. Bateman, T. Henderson, S. N. Bhatti. Exploiting self-reported social networks for routing in ubiquitous computing environments. SAUCE 2008 - 1st Intl. Workshop on Social Aspects of Ubiquitous Computing Environments. Avignon, France. Oct 2008. https://doi.org/10.1109/WiMob.2008.86
https://orcid.org/0000-0002-5566-9997