Abstract-What does a child's search of a large, complex cartoon for the eponymous character (Waldo) have to do with Internet routing? Network operators also search complex datasets, but Waldo is the least of their worries. Routing oscillation is a much greater concern. Networks can be designed to avoid routing oscillation, but the approaches so far proposed unnecessarily reduce the configuration flexibility. More importantly, apparently minor changes to a configuration can lead to instability. Verification of network stability is therefore an important task, but unlike the child's search, this problem is NP hard. Until now, no practical method was available for large networks. In this paper, we present an efficient algorithm for proving stability of iBGP, or finding the potential oscillatory modes, and demonstrate its efficacy by applying it to the iBGP configuration of a large Tier-2 AS.
Routing oscillation is highly detrimental. It can decrease performance and lead to a high level of update churn placing unnecessary workload on router the problem is distributed between many providers. However, iBGP -the routing protocol used to distribute routes inside a single Autonomous System -has also been shown to oscillate. Despite the fact that iBGP is configured by a single provider according to apparently straight forward rules, more than eight years of research has not solved the problem of iBGP oscillation. Various solutions have been proposed but they all lack critical features: either they are complicated to implement, restrict routing flexibility, or lack guarantees of stability. In this paper we propose a very simple adaptation to the BGP decision process. Despite its simplicity and negligible cost we prove algebraically that it prevents iBGP oscillation. We extend the idea to provide routing flexibility, such as respecting the MED attribute, without sacrificing network stability.
Abstract-BGP data contains artifacts introduced by the measurement infrastructure which can substantially affect analysis. This is especially important in operational systems where "crying wolf" will result in an operator ignoring alarms. In this paper, we investigate the causes of measurement artifacts in BGP data -cross-checking and using properties of the data to infer the presence of an artifact and minimize its impact.We have developed a prototype tool, CleanBGP, which detects and corrects the effects of artifacts in BGP data, which we believe should be used prior to the analysis of such data. CleanBGP provides the user with an understanding of the artifacts present, a mechanism to remove their effects, and consequently the limitations of results can be fully quantified.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.