Pitfalls in the design of distributed routing algorithms

Perlman, Radia; Varghese, George

doi:10.1145/52324.52330

“…In addition to the books cited above, see, for example, discussions of the various ARPANET routing algorithms [20], [24], [25]; the Exterior Gateway Protocol used in the NSFNET [40] and the Border Gateway Protocol (BGP) that replaced it [37], [38], [47], [48]; the related work by Estrin et al on routing between administrative domains [6], [13]; Perlman and Varghese's discussion of difficulties in designing routing algorithms [32]; Deering and Cheriton's seminal work on multicast routing [10]; Perlman's comparison of the popular OSPF and IS-IS protocols [33]; and Baransel et al survey of routing techniques for very high speed networks [2].…”

Section: Related Researchmentioning

confidence: 99%

End-to-end routing behavior in the Internet

Paxson

¹

1997

IEEE/ACM Trans. Networking

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The large-scale behavior of routing in the Internet has gone virtually without any formal study, the exception being Chinoy's analysis of the dynamics of Internet routing information [Ch93]. We report on an analysis of 40,000 end-to-end route measurements conducted using repeated "traceroutes" between 37 Internet sites. We analyze the routing behavior for pathological conditions, routing stability, and routing symmetry. For pathologies, we characterize the prevalence of routing loops, erroneous routing, infrastructure failures, and temporary outages. We find that the likelihood of encountering a major routing pathology more than doubled between the end of 1994 and the end of 1995, rising from 1.5% to 3.4%. For routing stability, we define two separate types of stability, "prevalence," meaning the overall likelihood that a particular route is encountered, and "persistence," the likelihood that a route remains unchanged over a long period of time. We find that Internet paths are heavily dominated by a single prevalent route, but that the time periods over which routes persist show wide variation, ranging from seconds up to days. About 2/3's of the Internet paths had routes persisting for either days or weeks. For routing symmetry, we look at the likelihood that a path through the Internet visits at least one different city in the two directions. At the end of 1995, this was the case half the time, and at least one different autonomous system was visited 30% of the time.

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“…The problem of routing in data networks has been a subject of continual research interest for the past two decades [1], [4], [12], [13], [21], [23], [26], [28] and many routing protocols have been studied and used in practical networks [6], [18], [22], [25], [30]. The stability issues in Internet routing have attracted much attention [15], [20].…”

Section: Related Workmentioning

confidence: 99%

New dynamic algorithms for shortest path tree computation

Narváez¹,

Siu

²

,

Tzeng

³

2000

IEEE/ACM Trans. Networking

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The Open Shortest Path First (OSPF) and IS-IS routing protocols widely used in today's Internet compute a shortest path tree (SPT) from each router to other routers in a routing area. Many existing commercial routers recompute an SPT from scratch following changes in the link states of the network. Such recomputation of an entire SPT is inefficient and may consume a considerable amount of CPU time. Moreover, as there may coexist multiple SPTs in a network with a set of given link states, recomputation from scratch causes frequent unnecessary changes in the topology of an existing SPT and may lead to routing instability. In this paper, we present new dynamic SPT algorithms that make use of the structure of the previously computed SPT. Besides efficiency, our algorithm design objective is to achieve routing stability by making minimum changes to the topology of an existing SPT (while maintaining shortest path property) when some link states in the network have changed.We establish an algorithmic framework that allows us to characterize a variety of dynamic SPT algorithms including dynamic versions of the well-known Dijkstra, Bellman-Ford, D'Esopo-Pape algorithms, and to establish proofs of correctness for these algorithms in a unified way. The theoretical asymptotic complexity of our new dynamic algorithms matches the best known results in the literature.

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“…In addition to the books cited above, see, for example, discussions of the various ARPANET routing algorithms [MFR78,MRR80,KZ89]; the Exterior Gateway Protocol used in the NSFNET [Ro82] and the Border Gateway Protocol (BGP) that replaced it [RL95, RG95,Tr95a,Tr95b]; the related work by Estrin et al on routing between administrative domains [BE90,ERH92]; Perlman and Varghese' s discussion of difficulties in designing routing algorithms [PV88]; Deering and Cheriton' s seminal work on multicast routing [DC90]; Perlman' s comparison of the popular OSPF and IS-IS protocols [Pe91]; and Baransel et al' s survey of routing techniques for very high speed networks [BDG95].…”

Section: Related Researchmentioning

confidence: 99%

End-to-end routing behavior in the Internet

Paxson

¹

1996

Conference Proceedings on Applications, Technologies, Architectures, and Protocols for Computer Communications

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The large-scale behavior of routing in the Internet has gone virtually without any formal study, the exception being Chinoy's analysis of the dynamics of Internet routing information [Ch93]. We report on an analysis of 40,000 end-to-end route measurements conducted using repeated "traceroutes" between 37 Internet sites. We analyze the routing behavior for pathological conditions, routing stability, and routing symmetry. For pathologies, we characterize the prevalence of routing loops, erroneous routing, infrastructure failures, and temporary outages. We find that the likelihood of encountering a major routing pathology more than doubled between the end of 1994 and the end of 1995, rising from 1.5% to 3.4%. For routing stability, we define two separate types of stability, "prevalence," meaning the overall likelihood that a particular route is encountered, and "persistence," the likelihood that a route remains unchanged over a long period of time. We find that Internet paths are heavily dominated by a single prevalent route, but that the time periods over which routes persist show wide variation, ranging from seconds up to days. About 2/3's of the Internet paths had routes persisting for either days or weeks. For routing symmetry, we look at the likelihood that a path through the Internet visits at least one different city in the two directions. At the end of 1995, this was the case half the time, and at least one different autonomous system was visited 30% of the time.

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Pitfalls in the design of distributed routing algorithms

Cited by 17 publications

References 7 publications

End-to-end routing behavior in the Internet

End-to-end routing behavior in the Internet

New dynamic algorithms for shortest path tree computation

End-to-end routing behavior in the Internet

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