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121
Characterizing the Internet hierarchy from multiple vantage points
- IN PROC. IEEE INFOCOM
, 2002
"... The delivery of IP traffic through the Internet depends on the complex interactions between thousands of autonomous systems (ASes) that exchange routing information using the Border Gateway Protocol (BGP). This paper investigates the topological structure of the Internet in terms of customer-provide ..."
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Cited by 384 (19 self)
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The delivery of IP traffic through the Internet depends on the complex interactions between thousands of autonomous systems (ASes) that exchange routing information using the Border Gateway Protocol (BGP). This paper investigates the topological structure of the Internet in terms of customer-provider and peer-peer relationships between ASes, as manifested in BGP routing policies. We describe a technique for inferring AS relationships by exploiting partial views of the AS graph available from different vantage points. Next we apply the technique to a collection of ten BGP routing tables to infer the relationships between neighboring ASes. Based on these results, we analyze the hierarchical structure of the Internet and propose a five-level classification of ASes. Our characterization differs from previous studies by focusing on the commercial relationships between ASes rather than simply the connectivity between the nodes.
Stable Internet Routing Without Global Coordination
- IEEE/ACM Transactions on Networking
, 2000
"... The Border Gateway Protocol (BGP) allows an autonomous system (AS) to apply diverse local policies for selecting routes and propagating reachability information to other domains. However, BGP permits ASes to have conflicting policies that can lead to routing instability. This paper proposes a set of ..."
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Cited by 343 (44 self)
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The Border Gateway Protocol (BGP) allows an autonomous system (AS) to apply diverse local policies for selecting routes and propagating reachability information to other domains. However, BGP permits ASes to have conflicting policies that can lead to routing instability. This paper proposes a set of guidelines for an AS to follow in setting its routing policies, without requiring coordination with other ASes. Our ap-proach exploits the Internet's hierarchical structure and the commercial relationships between ASes to impose a partial order on the set of routes to each destination. The guide-lines conform to conventional traffic-engineering practices of ISPs, and provide each AS with significant flexibility in se-lecting its local policies. Furthermore, the guidelines ensure route convergence even under changes in the topology and routing policies. Drawing on a formal model of BGP, we prove that following our proposed policy guidelines guaran-tees route convergence. We also describe how our method-ology can be applied to new types of relationships between ASes, how to verify the hierarchical AS relationships, and how to realize our policy guidelines. Our approach has sig-nificant practical value since it preserves the ability of each AS to apply complex local policies without divulging its BGP configurations to others. 1.
Detecting BGP Configuration Faults with Static Analysis
- in Proc. Networked Systems Design and Implementation
, 2005
"... The Internet is composed of many independent autonomous systems (ASes) that exchange reachability information to destinations using the Border Gateway Protocol (BGP). Network operators in each AS configure BGP routers to control the routes that are learned, selected, and announced to other routers. ..."
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Cited by 188 (15 self)
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The Internet is composed of many independent autonomous systems (ASes) that exchange reachability information to destinations using the Border Gateway Protocol (BGP). Network operators in each AS configure BGP routers to control the routes that are learned, selected, and announced to other routers. Faults in BGP configuration can cause forwarding loops, packet loss, and unintended paths between hosts, each of which constitutes a failure of the Internet routing infrastructure. This paper describes the design and implementation of rcc, the router configuration checker, a tool that finds faults in BGP configurations using static analysis. rcc detects faults by checking constraints that are based on a high-level correctness specification. rcc detects two broad classes of faults: route validity faults, where routers may learn routes that do not correspond to usable paths, and path visibility faults, where routers may fail to learn routes for paths that exist in the network. rcc enables network operators to test and debug configurations before deploying them in an operational network, improving on the status quo where most faults are detected only during operation. rcc has been downloaded by more than sixty-five network operators to date, some of whom have shared their configurations with us. We analyze network-wide configurations from 17 different ASes to detect a wide variety of faults and use these findings to motivate improvements to the Internet routing infrastructure. 1
R.: A measurement study on the impact of routing events on end-to-end Internet path performance
- ACM SIGCOMM CCR
, 2006
"... Extensive measurement studies have shown that end-to-end Inter-net path performance degradation is correlated with routing dynam-ics. However, the root cause of the correlation between routing dynamics and such performance degradation is poorly understood. In particular, how do routing changes resul ..."
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Cited by 68 (6 self)
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Extensive measurement studies have shown that end-to-end Inter-net path performance degradation is correlated with routing dynam-ics. However, the root cause of the correlation between routing dynamics and such performance degradation is poorly understood. In particular, how do routing changes result in degraded end-to-end path performance in the first place? How do factors such as topological properties, routing policies, and iBGP configurations affect the extent to which such routing events can cause perfor-mance degradation? Answers to these questions are critical for im-proving network performance. In this paper, we conduct extensive measurement that involves both controlled routing updates through two tier-1 ISPs and active probes of a diverse set of end-to-end paths on the Internet. We find that routing changes contribute to end-to-end packet loss sig-nificantly. Specifically, we study failover events in which a link failure leads to a routing change and recovery events in which a link repair causes a routing change. In both cases, it is possible to experience data plane performance degradation in terms of in-creased long loss burst as well as forwarding loops. Furthermore, we find that common routing policies and iBGP configurations of ISPs can directly affect the end-to-end path performance during routing changes. Our work provides new insights into potential measures that network operators can undertake to enhance network performance.
Design Principles of Policy Languages for Path Vector Protocols
- In Proc. ACM SIGCOMM’03
, 2003
"... (URI) program administered by the Office of Naval Research (ONR). A shortened form of this work has ..."
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Cited by 52 (11 self)
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(URI) program administered by the Office of Naval Research (ONR). A shortened form of this work has
Computing the Types of the Relationships between Autonomous Systems
, 2003
"... We investigate the problem of computing the types of the relationships between Internet Autonomous Systems. We refer to the model introduced by Gao (IEEE/ACM Transactions on Networking, 9(6):733–645, 2001) and Subramanian et al. (IEEE Infocom, 2002) that bases the discovery of such relationships o ..."
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Cited by 51 (6 self)
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We investigate the problem of computing the types of the relationships between Internet Autonomous Systems. We refer to the model introduced by Gao (IEEE/ACM Transactions on Networking, 9(6):733–645, 2001) and Subramanian et al. (IEEE Infocom, 2002) that bases the discovery of such relationships on the analysis of the AS paths extracted from the BGP routing tables. We characterize the time complexity of the above problem, showing both NP-completeness results and efficient algorithms for solving specific cases. Motivated by the hardness of the general problem, we propose approximation algorithms and heuristics based on a novel paradigm and show their effectiveness against publicly available data sets. The experiments provide evidence that our algorithms perform significantly better than state-of-the-art heuristics.
Implications of Autonomy for the Expressiveness of Policy Routing
- IEEE/ACM Trans. Network
, 2007
"... Thousands of competing autonomous systems must cooperate with each other to provide global Internet connectivity. Each autonomous system (AS) encodes various economic, business, and performance decisions in its routing policy. The current interdomain routing system enables each AS to express policy ..."
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Cited by 47 (0 self)
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Thousands of competing autonomous systems must cooperate with each other to provide global Internet connectivity. Each autonomous system (AS) encodes various economic, business, and performance decisions in its routing policy. The current interdomain routing system enables each AS to express policy using rankings that determine how each router in the AS chooses among different routes to a destination, and filters that determine which routes are hidden from each neighboring AS. Because the Internet is composed of many independent, competing networks, the interdomain routing system should provide autonomy, allowing network operators to set their rankings independently, and to have no constraints on allowed filters. This paper studies routing protocol stability under these conditions. We first demonstrate that certain rankings that are commonly used in practice may not ensure routing stability. We then prove that, when providers can set rankings and filters autonomously, guaranteeing that the routing system will converge to a stable path assignment essentially requires ASes to rank routes based on AS-path lengths. We discuss the implications of these results for the future of interdomain routing.
Rationality and Traffic Attraction: Incentives for Honest Path Announcements in BGP
, 2008
"... We study situations in which autonomous systems (ASes) may have incentives to send BGP announcements differing from the AS-level paths that packets traverse in the data plane. Prior work on this issue assumed that ASes seek only to obtain the best possible outgoing path for their traffic. In reality ..."
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Cited by 43 (7 self)
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We study situations in which autonomous systems (ASes) may have incentives to send BGP announcements differing from the AS-level paths that packets traverse in the data plane. Prior work on this issue assumed that ASes seek only to obtain the best possible outgoing path for their traffic. In reality, other factors can influence a rational AS’s behavior. Here we consider a more natural model, in which an AS is also interested in attracting incoming traffic (e.g., because other ASes pay it to carry their traffic). We ask what combinations of BGP enhancements and restrictions on routing policies can ensure that ASes have no incentive to lie about their data-plane paths. We find that protocols like S-BGP alone are insufficient, but that S-BGP does suffice if coupled with additional (quite unrealistic) restrictions on routing policies. Our game-theoretic analysis illustrates the high cost of ensuring that the ASes honestly announce data-plane paths in their BGP path announcements.
Route oscillations in i-bgp with route reflection
- In Proc. SIGCOMM
, 2002
"... We study the route oscillation problem [16, 19] in the Internal Border Gateway Protocol (I-BGP) [18] when route reflection is used. We pro-pose a formal model of I-BGP and use it to show that even deciding whether an I-BGP configuration with route reflection can converge is an NP-Complete problem. W ..."
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Cited by 43 (0 self)
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We study the route oscillation problem [16, 19] in the Internal Border Gateway Protocol (I-BGP) [18] when route reflection is used. We pro-pose a formal model of I-BGP and use it to show that even deciding whether an I-BGP configuration with route reflection can converge is an NP-Complete problem. We then propose a modification to I-BGP and show that route reflection cannot cause the modified protocol to diverge. Moreover, we show that the modified protocol converges to the same stable routing configuration regardless of the order in which messages are sent or received.
Incentive-compatible interdomain routing (Extended Abstract)
- PROC. OF THE 7TH CONFERENCE ON ELECTRONIC COMMERCE (EC’06)
, 2006
"... The routing of traffic between Internet domains, or Autonomous Systems (ASes), a task known as interdomain routing, is currently handled by the Border Gateway Protocol (BGP) [17]. Using BGP, autonomous systems can apply semantically rich routing policies to choose interdomain routes in a distributed ..."
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Cited by 40 (13 self)
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The routing of traffic between Internet domains, or Autonomous Systems (ASes), a task known as interdomain routing, is currently handled by the Border Gateway Protocol (BGP) [17]. Using BGP, autonomous systems can apply semantically rich routing policies to choose interdomain routes in a distributed fashion. This expressiveness in routing-policy choice supports domains ’ autonomy in network operations and in business decisions, but it comes at a price: The interaction of locally defined routing policies can lead to unexpected global anomalies, including route oscillations or overall protocol divergence (see, e.g., [20]). Networking researchers have addressed this problem by devising constraints on policies that guarantee BGP convergence without unduly limiting expressiveness and autonomy (see, e.g., [7, 8]). In addition to taking this engineering or “protocol-design ” approach, researchers have approached interdomain routing from an economic or “mechanism-design” point of view. It is known that lowest-cost-path (LCP) routing can be implemented in a truthful, BGP-compatible manner [3] but that several other natural classes of routing policies cannot [2, 5]. In this paper, we present a natural class of interdomain-routing policies that is more realistic than LCP routing and admits incentive-compatible, BGP-compatible implementation. We also present several positive steps toward a general theory of incentive-compatible interdomain routing.
