Michael Mackay

A scenario-based review of IPv6 transition tools

Momentum for IPv6 transition is on the rise, and many transition tools and techniques are available to ISPs, enterprise networks, and unmanaged networks. From a transitioning perspective, the ISP environment is interesting because the operators migration approaches will define, quite strictly, the extent of IPv6 services that their customers receive. As such, the ISPs (scalable) migration decisions have direct knock-on effects for customers. In the future, customers might require ISPs to offer value-added lPv6 services that not only have performance-based restrictions, but security and mobility considerations, as well.

A Managed IPv6 Transitioning Architecture for Large Network Deployments

With IPv6 transitioning still in a relative state of flux, the need has emerged for methods to control this crucial aspect of IPv6 deployments. This article makes the case for transitioning architectures as a realistic solution to this issue, specifically within large-scale networks. The site transitioning architecture (STA) supports the deployment, operation, and management of IPv6 transitioning mechanisms. The authors provide an overview of the STAs design and operation, noting that its flexible, simple, and secure architecture is suitable for the duration of the IPv6 deployment process, regardless of the underlying network environment.

An Integrated Management Supervisor for End-to-End Management of Heterogeneous Contents, Networks, and Terminals enabling Quality of Service

End-to-end support for Quality of Service (QoS) has been broadly discussed in the literature. Many technologies have been proposed, each focusing on specific aspects for providing QoS guarantees to the end user. However, the integrated management of the end-to-end chain preserving QoS in heterogeneous environments is still a significant issue and insufficiently addressed to date. In this paper we propose an integrated management supervisor that takes into account the requirements from all stakeholders along the multimedia content delivery chain and provides an end-to-end management solution enabling QoS to the end user. This architecture and the subsystems that can be distributed along the end-to-end chain are detailed in this paper.

Providing Grid Schedulers with Passive Network Measurements

Grids offer the potential to carry out difficult computing tasks and achieve superior aggregate performance through the utilization of remote resources and transparent collaboration between independent bodies (whether individuals or organizations). Grids are highly complex systems consisting of heterogeneous resources on disparate hosts interconnected across different Autonomous Systems and virtual organizations via a mixture of communication standards. Operating in such environments often proves erratic. Monitoring grid resources allows grid schedulers to adapt to changes in the status of remote resources and the network paths between them. Thus, monitoring the status of the different grid components is critical in order to ensure optimum performance. In this paper we introduce a distributed solution, GridMAP, to collect network and end-host resource measurements, analyze their performance and feed these statistics and predictions back to schedulers. At this stage, we present our implementation of a passive TCP-SYN technique to provide GridMAP with round trip time and throughput measurements and we evaluate our approach against ping and iperf.

IPv6 migration implications for network management - introducing the site transitioning framework (STF)

The paper outlines the need to supplement the current work on network management for IPv6 with a system specifically to support IP transitioning. As something that is likely to play a major role in any IPv6 network for the considerable future, support for managing the transitioning aspects of managed networks is vital in terms of their infrastructure and service provision. While there is work being carried out within the IETF and other bodies on the management of IPv6 networks, the management aspects relating to transitioning require special attention as they are likely to be among the more dynamic over the period of IPv4/IPv6 interoperation and, importantly, have yet to be fully addressed. The paper introduces the site transitioning framework, which unifies a sites transitioning infrastructure under a single architecture in order to simplify its management and operation. We outline its design and operation, highlighting the advantages that this method would introduce. Finally, the STF concept is demonstrated using a case study of an IPv6 site based interoperation scenario.

A comparative performance study of IPv6 transitioning mechanisms – NAT-PT vs. TRT vs. DSTM

One of the major challenges faced by the IPv6 community in recent years has been to define the scenarios in which transitioning mechanisms should be used and which ones should be selected given a specific scenario. This paper aims to supplement this by presenting the results of a comparative evaluation carried out on three major IPv6 interoperation mechanisms; NAT-PT, TRT and DSTM. This work attempts not only to determine the outright performance of each mechanism against the other but also against a theoretical evaluation of the specification. Our results show that while DSTM performs well both NAT-PT and TRT place significant overheads on the network.

IPv6 deployment support using an IPv6 transitioning architecture - The site transitioning architecture (STA)

With IPv6 being increasingly regarded as ‘ready’ for deployment, developers are now addressing the operational issues related to IPv6. One key aspect of this is IPv6 transitioning and more specifically it’s management and use within networks. This paper puts forward an IPv6 transitioning architecture that offers a managed approach to the deployment and usage of transitioning mechanisms within medium-to-large scale networks. The aim of this is to provide a simple, robust and secure architecture for IPv6 deployment regardless of the type of network used.

Characterising a grid site's traffic

Grid computing has been widely adopted for intensive high performance computing. Since grid resources are distributed over complex large-scale infrastructures, understanding grid site data traffic behaviour is important for efficient resource utilisation, performance optimisation, and the design of future grid sites as well as traffic-aware grid applications. In this paper, we study and analyse the traffic generated at a grid site in the Large Hadron Collider (LHC) Computing Grid (LCG). We find that most of the generated traffic is TCP-based and that a small set of grid applications generate significant amounts of the data. Upon analysing the different traffic metrics, we also find that the traffic exhibits long-range dependence and self-similarity. We also investigate packet-level metrics such as throughput, packet rate, round trip time (RTT) and packet loss. Our study establishes that these metrics can be well represented by Gaussian mixture models. The findings we present in this paper will enable accurate grid site traffic monitoring and potentially on-the-fly traffic modelling and prediction. It will also lead to a better understanding of grid sites traffic behaviour and contribute to more efficient grid site planning, traffic management, data transmission protocol optimisation, and data-aware grid application design.

Combined Adaptation and Caching of MPEG-4 SVC in Streaming Scenarios

A key objective of the ENTHRONE II Project is the ability to optimise the delivery of multimedia content to a wide group of heterogeneous users. One example of this is in the cooperative deployment of adaptation and caching functionality in the edge network. This hybrid approach makes it possible not only to store content locally, thus minimising the cost incurred through subsequent requests, but also to better serve heterogeneous groups of users by dynamically adapting the content to suit a wide range of terminal devices. In this paper, we describe and evaluate how the cooperative deployment of MPEG-21-based adaptation and caching of MPEG-4 SVC can result in improvements both in the quality of the content received at the user terminal and the resources consumed during the delivery.