Lorenzo Colitti
Lorenzo obtained a master's degree in electronic engineering at Roma Tre University and later a Ph.D in networking at the same institution with a thesis on Internet topology discovery using active probing. He has performed research on IPv6, Internet topology discovery, interdomain routing, and BGP anycast. He is currently working on Internet performance metrics and routing optimization.
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As IPv4 address space approaches exhaustion, large networks are deploying IPv6 or preparing for deployment. However, there is little data available about the quantity and quality of IPv6 connectivity. We describe a methodology to measure IPv6 adoption from the perspective of a Web site operator and to evaluate the impact that adding IPv6 to a Web site will have on its users. We apply our methodology to the Google Web site and present results collected over the last year. Our data show that IPv6 adoption, while growing significantly, is still low, varies considerably by country, and is heavily influenced by a small number of
large deployments. We find that native IPv6 latency is comparable to IPv4 and provide statistics on IPv6 transition mechanisms used.
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Investigating prefix propagation through active BGP probing
Giuseppe Di Battista
Maurizio Patrignani
Maurizio Pizzonia
Massimo Rimondini
Microprocessors and Microsystems, 31, no. 7 (2007), pp. 460-474
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To devise effective network engineering strategies and to assess the quality of upstream providers, network operators would greatly benefit from the knowledge of which Internet paths might be traversed by the traffic flows entering their networks in the case of network faults or when traffic engineering measures are used. However, current methodologies do not provide this information. This paper presents methodologies to discover alternate paths that might be selected in the presence of network faults or different routing policies and to deduce the routing policies of other operators. The techniques are validated through extensive experimentation on the Internet.
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An Active Approach to Measuring Routing Dynamics Induced by Autonomous Systems
Samantha Lo
Rocky K. C. Chang
Workshop of Experimental Computer Science (ExpCS), ACM (2007)
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We present an active measurement study of the routing dynamics induced by AS-path prepending, a common method for controlling the inbound traffic of a multi-homed ISP. Unlike other inter-domain inbound traffic engineering methods, AS-path prepending not only provides network resilience but does not increase routing table size. Unfortunately, ISPs often perform prepending on a trail-and-error basis, which can lead to suboptimal results and to a large amount of network churn. We study these effects by actively injecting prepended routes into the Internet routing system using the RIPE NCC RIS route collectors and observing the resulting changes from almost 200 publicly-accessible sources of BGP
information. Our results show that our prepending methods are simple and effective and that a small number of ASes is often responsible for large amounts of the route changes caused by prepending. Furthermore, we show that our methods are able to reveal hidden prepending policies to prepending and tie-breaking decisions made by ASes; this is useful for further predicting the behavior of prepending.
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