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ACM SIGCOMM 2011

June 14th, 2011 Shi Zhou Comments off

Our work on Internet IPv4/IPv6 routing is published in the Proceedings of the ACM SIGCOMM 2011 conference.

ACM

Title: Detecting and Assessing the Hybrid IPv4/IPv6 AS Relationships

Authors: Vasileios Giotsas and Shi Zhou

Abstract: The business relationships between the Autonomous Systems (ASes) play a central role in the Internet BGP routing. Existing algorithms on inferring AS relationships relied on AS connectivity data and were profoundly based on the valley-free rule. They have produced inaccurate and conflicting results, and they did not distinguish between IPv4 and IPv6. Recently we proposed a new approach to infer AS relationships using the BGP Community and Local Preference attribute data, which provide an unexploited wealth of reliable information on the AS relationships. We obtain the actual AS relationships for 72% of the IPv6 AS links that are visible in the RouteViews and RIPE RIS repositories in August 2010. Our results show that as many as 13% of AS links that serve both IPv4 and IPv6 traffic have different relationships depending on the IP version. We call them the hybrid IPv4/IPv6 relationships. We observe that the hybrid links are present in a large number of IPv6 AS paths and a significant portion of such paths do not follow the valley-free rule, indicating that the global reachability in the IPv6 Internet requires the relaxation of the valley-free rule. Our work highlights the importance of correctly inferring the AS relationships and the need to appreciate the distinct characteristics of IPv6 routing policies.

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Inferring AS relationships from BGP Attributes

June 14th, 2011 Shi Zhou Comments off

Our latest paper on the Internet AS relationships is now available at

arXiv:1106.2417 [cs.NI]

Title: Inferring AS relationships from BGP Attributes

Authors: Vasileios Giotsas and Shi Zhou

Abstract: Business relationships between autonomous systems (AS) are crucial for Internet routing. Existing algorithms used heuristics to infer AS relationships from AS topology data. In this paper we propose a different approach to infer AS relationships from more informative data sources, namely the BGP Community and Local Preference attributes. These data contain rich information on AS routing policies and therefore closely reflect AS relationships. We accumulate the BGP data from RouteViews, RIPE RIS and route servers in August 2010 and February 2011. We infer the AS relationships for 39% of links that are visible in our BGP data. They cover the majority of links among the Tier-1 and Tier-2 ASes. The BGP data also allow us to discover special relationship types, namely hybrid relationship, partial-transit relationship, indirect peering relationship and backup links. Finally we evaluate and analyse the problems of the existing inference algorithms.

Vasileios started his PhD in September 2009. He is funded by an EPSRC DTA studentship.

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Anil’s Best Student Paper Award at PURBA 2011

June 14th, 2011 Shi Zhou Comments off

Congratulations to my PhD student Anil Bawa-Cavia. His paper “Sensing the Urban: Using location-based social network data in urban analysis” has won the “Best Student Paper” Award at the 1st Workshop on Pervasive Urban Applications (PURBA) hosted by the 9th International Conference on Pervasive Computing in San Francisco, CA in June 2011.

Anil started his PhD in September 2009. He is funded by the EPSRC project SCALE, which is led by his second supervisor, Prof. Michael Batty, Chairman of Centre for Advanced Spatial Analysis (CASA), UCL.

His personal website, quotesque.net, provides a collection of interesting staff. Highly recommended!

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