Geographic routing

About: Geographic routing is a research topic. Over the lifetime, 11687 publications have been published within this topic receiving 302224 citations.

Adaptive Deadlock-Free Routing in Multicomputers Using Only One Extra Virtual Channel

Abstract: We present three protocols defin ing the relationship between messages and the chan nel resources requested: request-then-hold, requestthen wait, and request-then-relinquish. Based on the three protocols, we develop an adaptive deadlockfree routing algorithm called the SP routing. The SP routing uses shortest paths and is fully-adaptive, so messages can be routed via any of the shortest paths from the source to the destination. Since it is a minimal or shortest routing, the SP routing guar antees the freedom of livelocks. The SP routing is not limited to a specific network topology. The main requirement for an applicable network topology is that there exists a deterministic, minimal, deadlock-free routing algorithm. Most ex isting network topologies are equipped with such an algorithm. In this paper, we present an adaptive deadlock-free routing agorithm for n-dimensional meshes by using the SP routing. The hardware re quired by the SP routing uses only one extra virtual channel as compared to the deterministic routing.

Capacity efficient distributed routing of mesh-restored lightpaths in optical networks

Abstract: A mesh-restored lightpath in an optical network has a primary route and a diversely routed backup route. The wavelength channels on the primary route of a mesh-restored lightpath are dedicated for that lightpath whereas the wavelength channels on the backup route are shared among different mesh-restored lightpaths. Wavelength channels are shared in a way that ensures restoration of all lightpaths affected by any single link failure. In the centralized scenario, complete knowledge of the network state allows determination of the sharability of a backup channel during path computation. This information is not available in the distributed scenario. Use of 1+1 routing algorithms for mesh-restored lightpaths leads to inefficient capacity sharing. We propose distributed routing techniques to decrease the capacity efficiency gap between centralized routing and 1+1 routing of mesh-restored lightpaths. The algorithm uses information about the number of available and (shared) backup channels in a link, which can be disseminated through traffic engineering extensions to OSPF. A sharing database at each OXC maintains information about the lightpaths whose primary or backup paths traverse that OXC. The approach involves distributed determination of the sharability of a link on the backup path during path signaling using the sharing database at each OXC on the backup path. This, combined with a retry scheme facilitated by crankback routing extensions to CR-LDP/RSVP-TE to reduce lightpath blocking, leads to capacity efficient distributed routing of mesh-restored lightpaths.

Classification and Comparison of Routing Techniques in Wireless Ad Hoc Networks

Abstract: Wireless ad hoc network is a collection of mobile nodes forming a temporary network without the aid of any centralized administration or standard support services regularly available on conventional networks. It differs from the infrastructure-based network by not having base stations to rely on but the network achieves connectivity by using an ad hoc routing protocol. Absence of any fixed infrastructure pose number of different problems to this area. Some of the challenges that require standard solutions include routing, bandwidth constraints, hidden terminal problem and limited battery power. Routing is the process of information exchange between two hosts in networks. Routing is the first area that attainedfocus since the invention of commercialized mobile ad hoc networks In this paper, we present a comprehensive review for routing features and techniques in wireless ad hoc networks. For more than a dozen typical existing routing protocols, we compare their properties according to different criteria, and categorize them according to their routing strategies and relationships.

Bypass routing: An on-demand local recovery protocol for ad hoc networks

Abstract: On-demand routing protocols for ad hoc networks reduce the cost of routing in high mobility environments. However, route discovery in on-demand routing is typically performed via network-wide flooding, which consumes a substantial amount of bandwidth. In this paper, we present bypass routing, a local recovery protocol that aims to reduce the frequency of route request floods triggered by broken routes. Specifically, when a broken link is detected, a node patches the affected route using local information, which is acquired on-demand, and thereby bypasses the broken link. We implemented SLR (Source Routing with Local Recovery) as a prototype of our approach. Simulation studies show that SLR achieves efficient and effective local recovery while maintaining acceptable overhead.