Failure Insensitive Routing for Ensuring Service Availability

IEEE Transactions on Computers, 2003

Link-state routing protocols, such as OSPF and IS-IS, are widely used in the Internet today. In link-state routing protocols, global network topology information is first collected at each node. A shortest path tree (SPT) is then constructed by applying Dijkstra's shortest path algorithm at each node. Link-state protocols usually require the flooding of new information to the entire (sub)network after changes in any link state (including link faults). Narvaez et al. proposed a fault-tolerant link-state routing protocol without flooding. The idea is to construct a shortest restoration path for each unidirectional link fault. Faulty link information is distributed only to the nodes in the restoration path and only one restoration path is constructed. It is shown that this approach is loop-free. However, the Narvaez et al. approach is inefficient when a link failure is bidirectional because a restoration path is unidirectional and routing tables of nodes in the path are partially updated. In addition, two restoration paths may be generated for each bidirectional link fault. In this paper, we extend the Narvaez et al. protocol to efficiently handle a bidirectional link fault by making the restoration path bidirectional. Several desirable properties of the proposed extended routing protocol are also explored. A simulation study is conducted to compare the traditional link-state protocol, the source-tree protocol, the Narvaez et al. unidirectional restoration path protocol, and the proposed bidirectional restoration path protocol.

International journal of engineering research and technology, 2014

We observe that there is failure in an IP network and these failures are common which may creat an obstacle. A localized on demand link state routing is used in such a case to make the failure chances negligible. We here use Greedy Forwarding and Blacklist based forwarding algorithm for handling such a failure within our IP network. Greedy based uses a weight based distribution which find out efficient path and then work along with the blacklist to get most efficient path during packet forwarding. LOLS i.e. localized on demand link state routing make it to work on multiple failures thus we can handle multiple failures within a network. This paper elaborates how it implements to assure forwarding to all reachable destinations in case of any two link failure. LOLS, each packet has a blacklist, which has a set of failed links along its path, and the next hop is determined by eliminating the blacklisted links. We also used Multiple Routing Configuration Protocol in a purpose for faster ...

Proceedings of the 2007 ACM CoNEXT conference on - CoNEXT '07, 2007

Internet interdomain routing is policy-driven, and thus physical connectivity does not imply reachability. On average, routing on today's Internet works quite well, ensuring reachability for most networks and achieving reasonable performance across most paths. However, there is a serious lack of understanding of Internet routing resilience to significant but realistic failures such as those caused by the 911 event, the 2003 Northeast blackout, and the recent Taiwan earthquake in December 2006. In this paper, we systematically analyze how the current Internet routing system reacts to various types of failures by developing a realistic failure model, and then pinpoint reliability bottlenecks of the Internet. For validity of our simulation results, we generate topology graphs by addressing concerns over the incompleteness of topology and the inaccuracy of inferred AS relationships. By focusing on the impact of structural and policy properties, our analysis provides guidelines for future Internet design. The simulation tool we provide for analyzing routing resilience is also efficient to scale to Internet-size topologies.

Eighth Sense Research Group

ABSTRACT IP network is mostly associated with a number of failures and these failures can make our system degraded i.e. makes our system weaker and the packet forwarding becomes a crucial issue at such times. Now here we use an implementation of different algorithm in such a way that we can minimize the chances of failure within such a network and thus making it convenient and reliable. The system is made enough powerful to handle these failures within a network at their own level. We have suggested a powerful schema which enables our system to overcome its initial drawback and making it flexible. We hereby offer a corresponding system working on Greedy Forwarding and Blacklist Based Algorithm. We have integrated our system along with the LOLs i.e. localized on demand link state routing for greater efficiency. The main aim of our system is to handle failures by using both the algorithms simultaneously i.e. on one hand check for the blacklist based algorithm and on the other hand check for the greedy forwarding algorithm. The Greedy forwarding includes weight based distribution of the packets. On the other hand blacklist checks the blacklist table which maintains record of degraded links within network. Now here we have a powerful mechanism to re-route [6] the packet although the network goes into the state of failure. Keywords: - Packet Forwarding, Greedy Forwarding, Blacklist Based Forwarding, Rerouting.

Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.

With the emergence of Voice over IP and other real-time business applications, there is a growing demand for an IP network with high service availability. Unfortunately, in today's Internet, transient failures occur frequently due to faulty interfaces, router crashes, etc., and current IP networks lack the resiliency needed to provide high availability. To enhance availability, we proposed failure inferencing based fast rerouting (FIFR) approach that exploits the existence of a forwarding table per linecard, for lookup efficiency in current routers, to provide fast rerouting similar to MPLS, while adhering to the destination-based forwarding paradigm. In our previous work, we have shown that the FIFR approach can deal with single link failures. In this paper, we extend the FIFR approach to ensure loop-free packet delivery in case of single router failures also, thus mitigating the impact of many scenarios of failures. We demonstrate that the proposed approach not only provides high service availability but also incurs minimal routing overhead.

Computers & Electrical Engineering, 2013

In the internet environment, the Diversity-path-aware Border Gateway Protocol (D-BGP) increases path diversity by advertising multiple paths. In case of a route failure, D-BGP, selects the most disjoint alternative path, but does not consider its quality moreover because update messages are propagated both for the best path and for alternate paths, D-BGP has messaging. To overcome these limitations, we propose a robust BGP protocol that increases fault tolerance and reduces update message overhead. After establishing shortest paths using D-BGP, our protocol selects an alternate path based on link availability of the link and bandwidth. It utilizes Path Exploration Damping (PED) to delay update messages of alternate paths with worst-case scenario. Simulation results justify that our proposed BGP is failure free and performs better than D-BGP.

2010 IEEE Network Operations and Management Symposium - NOMS 2010, 2010

Intradomain routing in IP networks follows shortest paths according to administrative link costs. When several equalcost shortest paths exist, routers that use equal-cost multipath (ECMP) distribute the traffic over all of them. To produce singleshortest path (SSP) routing, a selection mechanism (tie-breaker) chooses just one of the equal-cost paths. Tie-breakers are poorly standardized and use information that may change over time, which makes SSP routing unpredictable. Therefore, link costs producing unique shortest paths (USP) are preferred.

2008

Routing technologies are discussed in this dissertation with the goal of improving the network availability. The "highly available Internet" is defined as the Internet with functions to forecast and control the network availability. An implementation strategy to approach to the highly available Internet and to the Dependable Internet is described. This dissertation provides a routing simulator called SimRouting to calculate the network availability, an example of oscillation-tolerant OSPF routing protocol, a family of new multipath route calculation algorithms called MARA, and a new multipath routing architecture called Drouting. The reliability of communication network depends on various components, for example, the reliability of hardware communication devices, the stability of communication protocols and software systems, the availability of sufficient capacity of network resources, and the reliability of network operators. Current research focuses on a specific one of these reliability components. For example, research on fault-tolerant systems targets the reliability of individual communication devices, circuits, and systems. Research on communication protocols targets their stability. Traffic engineering research focuses on the utilization of the network bandwidth capacity. The current Internet is built upon the combinations of these individual reliability research technologies. Combining the existing research on reliability of specific components does not improve the practical reliability of the entire communication network for two reasons: 1) Current research does not cover all reliability components. For example, studies on technologies to prevent software bugs, hardware bugs, and mis-configurations by network operators, are not adequate. 2) For many reliability components, no fallback plan is provided when the responsible technologies fail. If a fault-tolerant system or a stabilizing technology for a communication protocol fails, the communication network may cease to function until it is manually repaired. Consequently, the reliability of overall communication network is not sufficient, and the reliability of the Internet is not high enough for mission-critical communication. Focusing on the routing technologies, this research improves the availability of the entire communication system, as the first step of the reliability research for the Internet. Since the routing technology decides the network path that determines the reliability and the ii ABSTRACT iii performance of the communication, it is the most important entity for a communication network. Through the aggressive and proactive utilization of multipaths, this dissertation provides a method to bypass trouble spots, even unpredictable ones. This research focuses on the intra-domain routing system. This research contributes to improving the availability of the IP network through the proposals of 1) a method to estimate the availability of the communication network system considering its routing system, 2) a method to stabilize a routing system, 3) a new routing algorithm to calculate maximum alternative routes in a hop-by-hop network, 4) a new routing architecture to improve the availability of the network via the use of alternative routes, and 5) a method to implement traffic engineering on the new routing architecture. This research as a whole constructs a routing architecture and its peripheral functions that are required for the highly available Internet.

Proceedings of the ACM SIGCOMM 2023 Conference

We present PRR (Protective ReRoute), a transport technique for shortening user-visible outages that complements routing repair. It can be added to any transport to provide benefits in multipath networks. PRR responds to flow connectivity failure signals, e.g., retransmission timeouts, by changing the FlowLabel on packets of the flow, which causes switches and hosts to choose a different network path that may avoid the outage. To enable it, we shifted our IPv6 network architecture to use the FlowLabel, so that hosts can change the paths of their flows without application involvement. PRR is deployed fleetwide at Google for TCP and Pony Express, where it has been protecting all production traffic for several years. It is also available to our Cloud customers. We find it highly effective for real outages. In a measurement study on our network backbones, adding PRR reduced the cumulative region-pair outage time for RPC traffic by 63-84%. This is the equivalent of adding 0.4-0.8 "nines" of availability.

After a link or router failure within a network, a process of network convergence starts. During this process, the network is experiencing serious connectivity issues, in which different destinations may become unreachable and which may cause difficulties for critical and sensitive services. In order to address these issues, IP Fast ReRoute (IPFRR) mechanisms have been developed. The main goal of all IPFRR mechanisms is to minimize the network recovery time after a link or router failure. Using the IPFRR mechanisms, the network recovery time during a link or router failure takes only a few milliseconds. In this paper, we focus on the analysis of existing IPFRR mechanisms. We describe the main problematic areas of existing IPFRR mechanisms. Several IPFRR mechanisms have already been proposed. The key feature of these mechanisms is the calculation of an alternative route before the failure occurs. The computation of alternative route requires network topology information and therefore most of the existing IPFRR mechanisms strongly depend on the usage of distance-vector or link-state routing protocols. Our research shows, that pre-computing and dependence on routing protocols are primary problematic areas, which limit usage of existing IPFRR mechanisms in IP networks.