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142
PlanetSeer: Internet Path Failure Monitoring and Characterization in Wide-Area Services
- In OSDI
, 2004
"... Detecting network path anomalies generally requires examining large volumes of traffic data to find misbehavior. We observe that wide-area services, such as peerto-peer systems and content distribution networks, exhibit large traffic volumes, spread over large numbers of geographically-dispersed end ..."
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Cited by 105 (10 self)
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Detecting network path anomalies generally requires examining large volumes of traffic data to find misbehavior. We observe that wide-area services, such as peerto-peer systems and content distribution networks, exhibit large traffic volumes, spread over large numbers of geographically-dispersed endpoints. This makes them ideal candidates for observing wide-area network behavior. Specifically, we can combine passive monitoring of wide-area traffic to detect anomalous network behavior, with active probes from multiple nodes to quantify and characterize the scope of these anomalies. This approach provides several advantages over other techniques: (1) we obtain more complete and finergrained views of failures since the wide-area nodes already provide geographically diverse vantage points; (2) we incur limited additional measurement cost since most active probing is initiated when passive monitoring detects oddities; and (3) we detect failures at a much higher rate than other researchers have reported since the services provide large volumes of traffic to sample. This paper shows how to exploit this combination of wide-area traffic, passive monitoring, and active probing, to both understand path anomalies and to provide optimization opportunities for the host service. 1
ROFL: Routing on Flat Labels.
, 2006
"... ABSTRACT It is accepted wisdom that the current Internet architecture conflates network locations and host identities, but there is no agreement on how a future architecture should distinguish the two. One could sidestep this quandary by routing directly on host identities themselves, and eliminati ..."
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Cited by 105 (5 self)
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ABSTRACT It is accepted wisdom that the current Internet architecture conflates network locations and host identities, but there is no agreement on how a future architecture should distinguish the two. One could sidestep this quandary by routing directly on host identities themselves, and eliminating the need for network-layer protocols to include any mention of network location. The key to achieving this is the ability to route on flat labels. In this paper we take an initial stab at this challenge, proposing and analyzing our ROFL routing algorithm. While its scaling and efficiency properties are far from ideal, our results suggest that the idea of routing on flat labels cannot be immediately dismissed.
Moving beyond end-to-end path information to optimize cdn performance
- In IMC
, 2009
"... Replicating content across a geographically distributed set of servers and redirecting clients to the closest server in terms of latency has emerged as a common paradigm for improving client performance. In this paper, we analyze latencies measured from servers in Google’s content distribution netwo ..."
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Cited by 86 (9 self)
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Replicating content across a geographically distributed set of servers and redirecting clients to the closest server in terms of latency has emerged as a common paradigm for improving client performance. In this paper, we analyze latencies measured from servers in Google’s content distribution network (CDN) to clients all across the Internet to study the effectiveness of latency-based server selection. Our main result is that redirecting every client to the server with least latency does not suffice to optimize client latencies. First, even though most clients are served by a geographically nearby CDN node, a sizeable fraction of clients experience latencies several tens of milliseconds higher than other clients in the same region. Second, we find that queueing delays often override the benefits of a client interacting with a nearby server. To help the administrators of Google’s CDN cope with these
Finding a Needle in a Haystack: Pinpointing Significant BGP Routing Changes in an IP Network
- In NSDI
, 2005
"... The performance of a backbone network is vulnerable to interdomain routing changes that affect how traffic travels to destinations in other Autonomous Systems (ASes). Despite having poor visibility into these routing changes, operators often need to react quickly by tuning the network configuration ..."
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Cited by 81 (10 self)
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The performance of a backbone network is vulnerable to interdomain routing changes that affect how traffic travels to destinations in other Autonomous Systems (ASes). Despite having poor visibility into these routing changes, operators often need to react quickly by tuning the network configuration to alleviate congestion or by notifying other ASes about serious reachability problems. Fortunately, operators can improve their visibility by monitoring the Border Gateway Protocol (BGP) decisions of the routers at the periphery of their AS. However, the volume of measurement data is very large and extracting the important information is challenging. In this paper, we present the design and evaluation of an online system that converts millions of BGP update messages a day into a few dozen actionable reports about significant routing disruptions. We apply our tool to two months of BGP and traffic data collected from a Tier-1 ISP backbone and discover several network problems previously unknown to the operators. Validation using other data sources confirms the accuracy of our algorithms and the tool’s additional value in detecting routing disruptions. 1
Building an AS-topology model that captures route diversity
- IN PROC. OF ACM SIGCOMM
, 2006
"... An understanding of the topological structure of the Internet is needed for quite a number of networking tasks, e.g., making decisions about peering relationships, choice of upstream providers, inter-domain traffic engineering. One essential component of these tasks is the ability to predict routes ..."
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Cited by 71 (12 self)
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An understanding of the topological structure of the Internet is needed for quite a number of networking tasks, e.g., making decisions about peering relationships, choice of upstream providers, inter-domain traffic engineering. One essential component of these tasks is the ability to predict routes in the Internet. However, the Internet is composed of a large number of independent autonomous systems (ASes) resulting in complex interactions, and until now no model of the Internet has succeeded in producing predictions of acceptable accuracy. We demonstrate that there are two limitations of prior models: (i) they have all assumed that an Autonomous System (AS) is an atomic structure — it is not, and (ii) models have tended to oversimplify the relationships between ASes. Our approach uses multiple quasi-routers to capture route diversity within the ASes, and is deliberately agnostic regarding the types of relationships between ASes. The resulting model ensures that its routing is consistent with the observed routes. Exploiting a large number of observation points, we show that our model provides accurate predictions for unobserved routes, a first step towards developing structural models of the Internet that enable real applications.
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.
Topology Aware Overlay Networks
- in IEEE INFOCOM
"... Abstract — Recently, overlay networks have emerged as a means to enhance end-to-end application performance and availability. Overlay networks attempt to leverage the inherent redundancy of the Internet’s underlying routing infrastructure to detour packets along an alternate path when the given prim ..."
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Cited by 61 (1 self)
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Abstract — Recently, overlay networks have emerged as a means to enhance end-to-end application performance and availability. Overlay networks attempt to leverage the inherent redundancy of the Internet’s underlying routing infrastructure to detour packets along an alternate path when the given primary path becomes unavailable or suffers from congestion. However, the effectiveness of these overlay networks depends on the natural diversity of overlay paths between two endhosts in terms of physical links, routing infrastructure, administrative control, and geographical distribution. Several recent studies realized that a measurable number of path outages were unavoidable even with use of such overlay networks. This stems from the fact that overlay paths might overlap with each other when overlay nodes are selected without considering the underlying topology. An overlay network’s ability to quickly recover from path outages and congestion is limited unless we ensure path independence at the IP layer. This paper proposes a novel framework for topologyaware overlay networks. In this framework, we expressly design overlay networks, aiming to maximize path independence without degrading performance. We develop measurement-based heuristics for 1) placement of overlay nodes inside an ISP and 2) selection of a set of ISPs. We base our analysis on extensive data collection from 232 points in 10 ISPs, and 100 PlanetLab nodes. On top of node placement, we present measurement-based verification to conclude that single-hop overlay routing performs as well as multi-hop routing with respect to both availability and performance. Our analysis results show that a single-hop overlay path provides the same degree of path diversity as the multihop overlay path for more than 90 % of source and destination pairs. Finally, we validate the proposed framework using real Internet outages to show that our architecture is able to provide a significant amount of resilience to real-world failures. I.
Where the Sidewalk Ends: Extending the Internet AS Graph Using Traceroutes From P2P Users
"... An accurate Internet topology graph is important in many areas of networking, from deciding ISP business relationships to diagnosing network anomalies. Most Internet mapping efforts have derived the network structure, at the level of interconnected autonomous systems (ASes), from a limited number of ..."
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Cited by 55 (12 self)
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An accurate Internet topology graph is important in many areas of networking, from deciding ISP business relationships to diagnosing network anomalies. Most Internet mapping efforts have derived the network structure, at the level of interconnected autonomous systems (ASes), from a limited number of either BGP- or traceroutebased data sources. While techniques for charting the topology continue to improve, the growth of the number of vantage points is significantly outpaced by the rapid growth of the Internet. In this paper, we argue that a promising approach to revealing the hidden areas of the Internet topology is through active measurement from an observation platform that scales with the growing Internet. By leveraging measurements performed by an extension to a popular P2P system, we show that this approach indeed exposes significant new topological information. Based on traceroute measurements from more than 992, 000 IPs in over 3,700 ASes distributed across the Internet hierarchy, our proposed heuristics identify 23, 914 new AS links not visible in the publicly-available BGP data – 12.86 % more customer-provider links and 40.99 % more peering links, than previously reported. We validate our heuristics using data from a tier-1 ISP and show that they correctly filter out all false links introduced by public IP-to-AS mapping. We have made the identified set of links and their inferred relationships publically available.
NetDiagnoser: Troubleshooting network unreachabilities using end-to-end probes and routing data
- IN CONEXT
, 2007
"... The distributed nature of the Internet makes it difficult for a single service provider to troubleshoot the disruptions experienced by its customers. We propose NetDiagnoser, a troubleshooting algorithm to identify the location of failures in an internetwork environment. First, we adapt the wellknow ..."
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Cited by 48 (4 self)
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The distributed nature of the Internet makes it difficult for a single service provider to troubleshoot the disruptions experienced by its customers. We propose NetDiagnoser, a troubleshooting algorithm to identify the location of failures in an internetwork environment. First, we adapt the wellknown Boolean tomography technique to work in this environment. Then, we significantly extend this technique to improve the diagnosis accuracy in the presence of multiple link failures, logical failures (for instance, misconfigurations of route export filters), and incomplete topology inference. In particular, NetDiagnoser takes advantage of rerouted paths, routing messages collected at one provider’s network and Looking Glass servers. We evaluate each feature of Net-Diagnoser separately using C-BGP simulations on realistic topologies. Our results show that NetDiagnoser can successfully identify a small set of links, which almost always includes the actually failed/misconfigured links.
Achieving Sub-50 Milliseconds Recovery upon BGP Peering Link Failures
- in Co-Next 2005
, 2005
"... We first show by measurements that BGP peering links fail as frequently as intradomain links and usually for short periods of time. We propose a new fast-reroute technique where routers are prepared to react quickly to interdomain link failures. For each of its interdomain links, each router precom ..."
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Cited by 47 (2 self)
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We first show by measurements that BGP peering links fail as frequently as intradomain links and usually for short periods of time. We propose a new fast-reroute technique where routers are prepared to react quickly to interdomain link failures. For each of its interdomain links, each router precomputes a protection tunnel, i.e. an IP tunnel to an alternate nexthop which can reach the same destinations as via the protected link. We propose a BGPbased auto-discovery technique that allows each router to learn the candidate protection tunnels for its links. Each router selects the best protection tunnels for its links and when it detects an interdomain link failure, it immediately encapsulates the packets to send them through the protection tunnel. Our solution is applicable for the links between large transit ISPs and also for the links between multi-homed stub networks and their providers. Furthermore, we show that transient forwarding loops (and thus the corresponding packet losses) can be avoided during the routing convergence that follows the deactivation of a protection tunnel in BGP/MPLSVPNs and in IP networks using encapsulation.
