The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Zhili Zhang - One of the best experts on this subject based on the ideXlab platform.
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failure insensitive routing for ensuring service availability
International Workshop on Quality of Service, 2003Co-Authors: Srihari Nelakuditi, Sanghwan Lee, Zhili ZhangAbstract:Intra-domain routing protocols employed in the Internet route around failed links by having routers detect adjacent link failures, exchange link state changes, and recompute their routing tables. Due to several delays in detection, propagation and recomputation, it may take tens of seconds to minutes after a link failure to resume forwarding of packets to the affected destinations. This discontinuity in destination reachability adversely affects the quality of continuous media applications such as Voice over IP. Moreover, the resulting service unavailability for even a short duration could be catastrophic in the world of e-commerce. Though careful tuning of the various parameters of the routing protocols can accelerate convergence, it may cause instability when the majority of the failures are transient. To improve the failure resiliency without jeopardizing the routing stability, we propose a local rerouting based approach called failure insensitive routing. Under this approach, upon a link failure, adjacent router suppresses global updating and instead initiates local rerouting. All other routers infer potential link failures from the packet's Incoming Interface, precompute Interface specific forwarding We demonstrate that the proposed approach provides higher service availability than the existing routing schemes.
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IWQoS - Failure insensitive routing for ensuring service availability
Lecture Notes in Computer Science, 2003Co-Authors: Srihari Nelakuditi, Sanghwan Lee, Zhili ZhangAbstract:Intra-domain routing protocols employed in the Internet route around failed links by having routers detect adjacent link failures, exchange link state changes, and recompute their routing tables. Due to several delays in detection, propagation and recomputation, it may take tens of seconds to minutes after a link failure to resume forwarding of packets to the affected destinations. This discontinuity in destination reachability adversely affects the quality of continuous media applications such as Voice over IP. Moreover, the resulting service unavailability for even a short duration could be catastrophic in the world of e-commerce. Though careful tuning of the various parameters of the routing protocols can accelerate convergence, it may cause instability when the majority of the failures are transient. To improve the failure resiliency without jeopardizing the routing stability, we propose a local rerouting based approach called failure insensitive routing. Under this approach, upon a link failure, adjacent router suppresses global updating and instead initiates local rerouting. All other routers infer potential link failures from the packet's Incoming Interface, precompute Interface specific forwarding We demonstrate that the proposed approach provides higher service availability than the existing routing schemes.
Srihari Nelakuditi - One of the best experts on this subject based on the ideXlab platform.
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Mitigating transient loops through Interface-specific forwarding
Computer Networks, 2008Co-Authors: Srihari Nelakuditi, Zifei Zhong, Ram Keralapura, Junling Wang, Chen-nee ChuahAbstract:Under link-state routing protocols such as OSPF and IS-IS, when there is a change in the topology, propagation of link-state advertisements, path recomputation, and updating of forwarding tables (FIBs) will all incur some delay before traffic forwarding can resume on alternate paths. During this convergence period, routers may have inconsistent views of the network, resulting in transient forwarding loops. Previous remedies proposed to address this issue enforce a certain order among the nodes in which they update their FIBs. While such approaches succeed in avoiding transient loops, they incur additional message overhead and/or increased convergence delay. We explore an alternative approach, loopless Interface-specific forwarding (LISF), that mitigates transient loops by forwarding a packet based on both its Incoming Interface and destination address. LISF needs to compute and update Interface-specific instead of Interface-independent forwarding tables. But it requires neither the synchronization of FIB updates at different nodes nor the modification of the existing link-state routing mechanisms. LISF is easily deployable with current routers if they already maintain a FIB at each Interface for lookup efficiency. This paper presents the LISF approach, illustrates its strengths and limitations, discusses four alternative implementations of it and evaluates their performance.
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GLOBECOM - CAM05-4: Handling Multiple Network Failures through Interface Specific Forwarding
IEEE Globecom 2006, 2006Co-Authors: Junling Wang, Zifei Zhong, Srihari NelakuditiAbstract:It has been observed that transient failures are fairly common in IP backbone networks and there have been several proposals based on local rerouting to provide high network availability despite transient failures. Previously, we proposed failure inferencing based fast rerouting for IP backbone networks that ensures delivery of a packet to its destination if there exists a path when a single link fails but can cause forwarding loops in case of multiple simultaneous failures. On the other hand, blacklist-aided forwarding, we proposed earlier for wireless mesh networks, provides loop-free forwarding even in the presence of multiple failed links in the network but requires that each packet carry a blacklist of failed links encountered along its path. Our aim is to achieve the best of both these approaches, i.e., successfully deliver packets while ensuring loop-freedom even in case of multiple failures without changing packet format. We propose blacklist-based Interface-specific forwarding (BISF) that infers a blacklist, a list of links that might have failed, based on a packet's Incoming Interface and its destination, and determines the next-hop by excluding the blacklisted links. We show that BISF is loop-free regardless of the number of failures in the network while forwarding packets successfully in most cases.
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IWQoS - Avoiding transient loops through Interface-specific forwarding
Quality of Service – IWQoS 2005, 2005Co-Authors: Zifei Zhong, Srihari Nelakuditi, Chen-nee Chuah, Ram Keralapura, Junling Wang, Sanghwan LeeAbstract:Under link-state routing protocols such as OSPF and IS-IS, when there is a change in the topology, propagation of link-state announcements, path recomputation, and updating of forwarding tables (FIBs) will all incur some delay before traffic forwarding can resume on alternate paths. During this convergence period, routers may have inconsistent views of the network, resulting in transient forwarding loops. Previous remedies proposed to address this issue enforce a certain order among the nodes in which they update their FIBs. While such approaches succeed in avoiding transient loops, they incur additional message overhead and increased convergence delay. We propose an alternate approach, loopless Interface-specific forwarding (LISF), that averts transient loops by forwarding a packet based on both its Incoming Interface and destination. LISF requires no modifications to the existing link-state routing mechanisms. It is easily deployable with current routers since they already maintain a FIB at each Interface for lookup efficiency. This paper presents the LISF approach, proves its correctness, discusses three alternative implementations of it and evaluates their performance.
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failure insensitive routing for ensuring service availability
International Workshop on Quality of Service, 2003Co-Authors: Srihari Nelakuditi, Sanghwan Lee, Zhili ZhangAbstract:Intra-domain routing protocols employed in the Internet route around failed links by having routers detect adjacent link failures, exchange link state changes, and recompute their routing tables. Due to several delays in detection, propagation and recomputation, it may take tens of seconds to minutes after a link failure to resume forwarding of packets to the affected destinations. This discontinuity in destination reachability adversely affects the quality of continuous media applications such as Voice over IP. Moreover, the resulting service unavailability for even a short duration could be catastrophic in the world of e-commerce. Though careful tuning of the various parameters of the routing protocols can accelerate convergence, it may cause instability when the majority of the failures are transient. To improve the failure resiliency without jeopardizing the routing stability, we propose a local rerouting based approach called failure insensitive routing. Under this approach, upon a link failure, adjacent router suppresses global updating and instead initiates local rerouting. All other routers infer potential link failures from the packet's Incoming Interface, precompute Interface specific forwarding We demonstrate that the proposed approach provides higher service availability than the existing routing schemes.
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IWQoS - Failure insensitive routing for ensuring service availability
Lecture Notes in Computer Science, 2003Co-Authors: Srihari Nelakuditi, Sanghwan Lee, Zhili ZhangAbstract:Intra-domain routing protocols employed in the Internet route around failed links by having routers detect adjacent link failures, exchange link state changes, and recompute their routing tables. Due to several delays in detection, propagation and recomputation, it may take tens of seconds to minutes after a link failure to resume forwarding of packets to the affected destinations. This discontinuity in destination reachability adversely affects the quality of continuous media applications such as Voice over IP. Moreover, the resulting service unavailability for even a short duration could be catastrophic in the world of e-commerce. Though careful tuning of the various parameters of the routing protocols can accelerate convergence, it may cause instability when the majority of the failures are transient. To improve the failure resiliency without jeopardizing the routing stability, we propose a local rerouting based approach called failure insensitive routing. Under this approach, upon a link failure, adjacent router suppresses global updating and instead initiates local rerouting. All other routers infer potential link failures from the packet's Incoming Interface, precompute Interface specific forwarding We demonstrate that the proposed approach provides higher service availability than the existing routing schemes.
Jun-ichiro Itojun Hagino - One of the best experts on this subject based on the ideXlab platform.
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D – RFC2292 “Advanced Sockets API for IPv6”
IPv6 Network Programming, 2005Co-Authors: Jun-ichiro Itojun HaginoAbstract:Publisher Summary Specifications are in progress for changes to the sockets API to support IP version 6 [RFC-2133]. These changes are for TCP and UDP-based applications and will support most end-user applications in use today: Telnet and FTP clients and servers, HTTP clients and servers, and the like. But another class of applications exists that will also be run under IPv6. These are called “advanced” applications, and today this includes programs such as Ping, Traceroute, routing daemons, multicast routing daemons, and router discovery daemons. The API feature typically used by these programs that make them “advanced” is a raw socket to access ICMPv4, IGMPv4, or IPv4, along with some knowledge of the packet header formats used by these protocols. To provide portability for applications that use raw sockets under IPv6, some standardization is needed for the advanced API features. There are other features of IPv6 that some applications will need to access: Interface identification (specifying the outgoing Interface and determining the Incoming Interface) and IPv6 extension headers that are not addressed in [RFC-2133]: Hop-by-Hop options, Destination options, and the Routing header (source routing). This chapter provides API access to these features too.
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E – RFC3542 “Advanced Sockets Application Program Interface (API) for IPv6”
IPv6 Network Programming, 2005Co-Authors: Jun-ichiro Itojun HaginoAbstract:Publisher Summary Today, the portability of applications using IPv4 raw sockets is quite high, but this is mainly because most IPv4 implementations started from a common base (the Berkeley source code) or at least started with the Berkeley header files. This allows programs such as Ping and Traceroute, for example, to compile with minimal effort on many hosts that support the sockets API. With IPv6, however, there is no common source code base that implementers are starting from, and the possibility for divergence at this level between different implementations is high. To avoid a complete lack of portability amongst applications that use raw IPv6 sockets, some standardization is necessary. This chapter provides sockets Application Program Interface (API) to support “advanced” IPv6 applications, as a supplement to a separate specification, RFC 3493. The expected applications include Ping, Traceroute, routing daemons, and the like, which typically use raw sockets to access IPv6 or ICMPv6 header fields. This chapter proposes some portable Interfaces for applications that use raw sockets under IPv6. There are other features of IPv6 that some applications will need to access: Interface identification (specifying the outgoing Interface and determining the Incoming Interface), IPv6 extension headers, and path Maximum Transmission Unit (MTU) information. This chapter provides API access to these features too. Additionally, some extended Interfaces to libraries for the “r” commands are defined. The extension will provide better backward compatibility to existing implementations that are not IPv6-capable.
Sanghwan Lee - One of the best experts on this subject based on the ideXlab platform.
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IWQoS - Avoiding transient loops through Interface-specific forwarding
Quality of Service – IWQoS 2005, 2005Co-Authors: Zifei Zhong, Srihari Nelakuditi, Chen-nee Chuah, Ram Keralapura, Junling Wang, Sanghwan LeeAbstract:Under link-state routing protocols such as OSPF and IS-IS, when there is a change in the topology, propagation of link-state announcements, path recomputation, and updating of forwarding tables (FIBs) will all incur some delay before traffic forwarding can resume on alternate paths. During this convergence period, routers may have inconsistent views of the network, resulting in transient forwarding loops. Previous remedies proposed to address this issue enforce a certain order among the nodes in which they update their FIBs. While such approaches succeed in avoiding transient loops, they incur additional message overhead and increased convergence delay. We propose an alternate approach, loopless Interface-specific forwarding (LISF), that averts transient loops by forwarding a packet based on both its Incoming Interface and destination. LISF requires no modifications to the existing link-state routing mechanisms. It is easily deployable with current routers since they already maintain a FIB at each Interface for lookup efficiency. This paper presents the LISF approach, proves its correctness, discusses three alternative implementations of it and evaluates their performance.
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failure insensitive routing for ensuring service availability
International Workshop on Quality of Service, 2003Co-Authors: Srihari Nelakuditi, Sanghwan Lee, Zhili ZhangAbstract:Intra-domain routing protocols employed in the Internet route around failed links by having routers detect adjacent link failures, exchange link state changes, and recompute their routing tables. Due to several delays in detection, propagation and recomputation, it may take tens of seconds to minutes after a link failure to resume forwarding of packets to the affected destinations. This discontinuity in destination reachability adversely affects the quality of continuous media applications such as Voice over IP. Moreover, the resulting service unavailability for even a short duration could be catastrophic in the world of e-commerce. Though careful tuning of the various parameters of the routing protocols can accelerate convergence, it may cause instability when the majority of the failures are transient. To improve the failure resiliency without jeopardizing the routing stability, we propose a local rerouting based approach called failure insensitive routing. Under this approach, upon a link failure, adjacent router suppresses global updating and instead initiates local rerouting. All other routers infer potential link failures from the packet's Incoming Interface, precompute Interface specific forwarding We demonstrate that the proposed approach provides higher service availability than the existing routing schemes.
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IWQoS - Failure insensitive routing for ensuring service availability
Lecture Notes in Computer Science, 2003Co-Authors: Srihari Nelakuditi, Sanghwan Lee, Zhili ZhangAbstract:Intra-domain routing protocols employed in the Internet route around failed links by having routers detect adjacent link failures, exchange link state changes, and recompute their routing tables. Due to several delays in detection, propagation and recomputation, it may take tens of seconds to minutes after a link failure to resume forwarding of packets to the affected destinations. This discontinuity in destination reachability adversely affects the quality of continuous media applications such as Voice over IP. Moreover, the resulting service unavailability for even a short duration could be catastrophic in the world of e-commerce. Though careful tuning of the various parameters of the routing protocols can accelerate convergence, it may cause instability when the majority of the failures are transient. To improve the failure resiliency without jeopardizing the routing stability, we propose a local rerouting based approach called failure insensitive routing. Under this approach, upon a link failure, adjacent router suppresses global updating and instead initiates local rerouting. All other routers infer potential link failures from the packet's Incoming Interface, precompute Interface specific forwarding We demonstrate that the proposed approach provides higher service availability than the existing routing schemes.
Stéphane Cateloin - One of the best experts on this subject based on the ideXlab platform.
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improving load balancing with multipath routing
International Conference on Computer Communications and Networks, 2008Co-Authors: Pascal Mérindol, Jean-jacques Pansiot, Stéphane CateloinAbstract:Internet service providers have to provision network resources to optimize bandwidth utilization. Dynamic routing protocols take traffic variations into account to control the load distribution. Multipath routing protocols attempt to take advantage of the path diversity to bring network robustness and reliability. Indeed, with a specific traffic engineering policy, they enable load balancing across several paths. Our aim is to compute a set of loopfree paths in order to allow routers to share the load on several next hops depending on current load measurement. In this paper, we first describe our original Incoming Interface Multipath Routing technique, DT(p), then we present a scheme for load balancing, DT(p)-TE, based on link monitoring. We evaluate and compare our technique with several existing approaches by a set of simulations, using different scenarios and topologies. The simulations results suggest that the path diversity achieved with our proposition can significantly improve the network response time.
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Providing protection and restoration with distributed multipath routing
2008Co-Authors: Pascal Mérindol, Jean-jacques Pansiot, Stéphane CateloinAbstract:Multipath routing is an interesting tool to provide a fast reaction time to protect networks from failure or congestion. Indeed, a local alternate path computation allows to faster reroute the traffic without flooding the entire network with Link State Advertisements. The restoration depends therefore on the protection guaranteed by each router. Distributed techniques allow to entrust the potential restoration to each router where it is possible. We distinguish multipath routing and fast rerouting techniques to underline the possibility to use alternate routes for load balancing or just as backup solution. In this paper we first summarize our Incoming Interface multipath routing technique and then analyze its capabilities in terms of protection. We evaluate several routing techniques to achieve a good coverage. Results indicate that our hop by hop routing multipath protocol performs almost as well as the best unipath rerouting technique whereas it can also be used for proportional routing.
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ICCCN - Improving Load Balancing with Multipath Routing
2008 Proceedings of 17th International Conference on Computer Communications and Networks, 2008Co-Authors: Pascal Mérindol, Jean-jacques Pansiot, Stéphane CateloinAbstract:Internet service providers have to provision network resources to optimize bandwidth utilization. Dynamic routing protocols take traffic variations into account to control the load distribution. Multipath routing protocols attempt to take advantage of the path diversity to bring network robustness and reliability. Indeed, with a specific traffic engineering policy, they enable load balancing across several paths. Our aim is to compute a set of loopfree paths in order to allow routers to share the load on several next hops depending on current load measurement. In this paper, we first describe our original Incoming Interface Multipath Routing technique, DT(p), then we present a scheme for load balancing, DT(p)-TE, based on link monitoring. We evaluate and compare our technique with several existing approaches by a set of simulations, using different scenarios and topologies. The simulations results suggest that the path diversity achieved with our proposition can significantly improve the network response time.
