Equal-cost multi-path routing

About: Equal-cost multi-path routing is a research topic. Over the lifetime, 10472 publications have been published within this topic receiving 249362 citations.

Distributed energy-efficient cooperative routing in wireless networks

Abstract: Recently, the merits of cooperative communication in the physical layer have been explored. However, the impact of cooperative communication on the design of the higher layers has not been well-understood yet. Cooperative routing in wireless networks has gained much interest due to its ability to exploit the broadcast nature of the wireless medium in designing power efficient routing algorithms. Most of the existing cooperation based routing algorithms are implemented by finding a shortest path route first and then improving the route using cooperative communication. As such, these routing algorithms do not fully exploit the merits of cooperative communications, since the optimal cooperative route might not be similar to the shortest path route. In this paper, we propose a cooperation-based routing algorithm, namely, the minimum power cooperative routing (MPCR) algorithm, which makes full use of the cooperative communications while constructing the minimum-power route. The MPCR algorithm constructs the minimum-power route, which guarantees certain throughput, as a cascade of the minimum-power single-relay building blocks from the source to the destination. Thus, any distributed shortest path algorithm can be utilized to find the optimal cooperative route with polynomial complexity. Using analysis, we show that the MPCR algorithm can achieve power saving of 65.61% in regular linear networks and 29.8% in regular grid networks compared to the existing cooperation-based routing algorithms, where the cooperative routes are constructed based on the shortest-path routes. From simulation results, MPCR algorithm can have 37.64% power saving in random networks compared to those cooperation-based routing algorithms.

Fast local rerouting for handling transient link failures

Abstract: Link failures are part of the day-to-day operation of a network due to many causes such as maintenance, faulty interfaces, and accidental fiber cuts. Commonly deployed link state routing protocols such as OSPF react to link failures through global link state advertisements and routing table recomputations causing significant forwarding discontinuity after a failure. Careful tuning of various parameters to accelerate routing convergence may cause instability when the majority of failures are transient. To enhance failure resiliency without jeopardizing routing stability, we propose a local rerouting based approach called failure insensitive routing. The proposed approach prepares for failures using interface-specific forwarding, and upon a failure, suppresses the link state advertisement and instead triggers local rerouting using a backwarding table. With this approach, when no more than one link failure notification is suppressed, a packet is guaranteed to be forwarded along a loop-free path to its destination if such a path exists. This paper demonstrates the feasibility, reliability, and stability of our approach.

Network routing with path vector protocols: theory and applications

Abstract: Path vector protocols are currently in the limelight, mainly because the inter-domain routing protocol of the Internet, BGP (Border Gateway Protocol), belongs to this class. In this paper, we cast the operation of path vector protocols into a broad algebraic framework and relate the convergence of the protocol, and the characteristics of the paths to which it converges, with the monotonicity and isotonicity properties of its path compositional operation. Here, monotonicity means that the weight of a path cannot decrease when it is extended, and isotonicity means that the relationship between the weights of any two paths with the same origin is preserved when both are extended to the same node. We show that path vector protocols can be made to converge for every network if and only if the algebra is monotone, and that the resulting paths selected by the nodes are optimal if and only if the algebra is isotone as well.Many practical conclusions can be drawn from instances of the generic algebra. For performance-oriented routing, typical in intra-domain routing, we conclude that path vector protocols can be made to converge to widest or widest-shortest paths, but that the composite metric of IGRP (Interior Gateway Protocol), for example, does not guarantee convergence to optimal paths. For policy-based routing, typical in inter-domain routing, we formulate existing guidelines as instances of the generic algebra and we propose new ones. We also show how a particular instance of the algebra yields a sufficient condition for signaling correctness of internal BGP.

Diverse routing in optical mesh networks

Abstract: We study the diverse routing problem in optical mesh networks. We use a general framework based on shared risk link groups to model the problem. We prove that the diverse routing problem is indeed NP-complete, a result that has been conjectured by several researchers previously. In fact, we show that even the fiber-span-disjoint paths problem, a special case of the diverse routing problem, is also NP-complete. We then develop an integer linear programming formulation and show through numerical results that it is a very viable method to solve the diverse routing problem for most optical networks found in many applications which typically have no more than a few hundred nodes and fiber spans.

Synchronization mechanism for link state packet routing

Abstract: A method of providing loop free and shortest path routing of data packets in a network having a plurality of switches, routing messages for communicating network topology information between the switches, a plurality of links connecting the switches and a plurality of channels connecting the switches to the links. The loop free routing of data packets is achieved through modifications to known link state packet (LSP) routing protocols and permits each switch to inform adjacent switches in the network of the information in the switch's database used to compute forwarding tables. A switch uses a received LSP to compute a forwarding table and informs neighboring switches on attached links of the routing change. The switch discards any subsequent data packets whose path would be affected by the changed routing information. The discarding of data packets continues until the switch receives notification from each adjacent switch affected by the changed routing information that all affected routing paths have been recalculated and the forwarding table of each affected switch has been updated. Thus, while adjacent switches temporarily contain inconsistent LSP databases and possibly inconsistent forwarding tables, the looping of data packets is prevented. Shortest path routing for data packets from a source endnode to a destination endnode is achieved by assuring that the first switch to forward the packet is on the shortest path to the packet's destination endnode. A source endnode transmits a data packet with an appropriate destination header and the determination of the actual routing path is performed transparently to endnodes. A data packet reaches its destination endnode by following the shortest path possible based on the network topology as represented in the database of the first switch that forwards it.