A Recoverable Protocol for Loop-Free Distributed Routing

A Recoverable Protocol for Loop-Free Distributed Routing
Author: Adrian Segall
Publisher:
Total Pages: 50
Release: 1978
Genre: Algorithms
ISBN:

An algorithm for adaptive routing in data-communication networks is presented. The algorithm uses distributed computation, provides loop-free routing for each destination in the network, adapts to changes in network flows and is completely failsafe. The latter means that after arbitrary failures and additions of nodes and links, the network recovers in finite time in the sense of providing routing paths between all physically connected nodes. Proofs of all these properties are provided in a separate paper. (Author).

Design and Analysis of Distributed Routing Algorithms

Design and Analysis of Distributed Routing Algorithms
Author: Shree N. Murthy
Publisher:
Total Pages: 150
Release: 1994
Genre: Algorithms
ISBN:

Route assignment is one of the operational problems of communication network, and adaptive routing schemes are required to achieve real time performance. This thesis introduces, verifies and analyses two new distributed, shortest-path routing algorithms, which are called, Path-Finding Algorithm (PFA) and Loop-Free Path-Finding Algorithm (LPA). Both algorithms require each routing node to know only the distance and the second-to-last-hop (or predecessor) node to each destination. In addition to the above information, LPA uses an efficient inter-neighbor coordination mechanism spanning over a single hop. PFA reduces the formation of temporary loops significantly, while LPA achieves loop-freedom at every instant by eliminating temporary loops. The average performance of these two algorithms is compared with the Diffusing Update Algorithm (DUAL) and an ideal link state (ILS) using Dijkstra's shortest-path algorithm by simulation; this performance comparison is made in terms of time taken for convergence, number of packets exchanged and the total number of operations required for convergence by each of the algorithms. The simulations were performed using a C-based simulation tool called Drama, along with a network simulation library. The results indicated that the performance of PFA is comparable to that of DUAL and ILS and that a significant improvement in performance can be achieved with LPA over DUAL and ILS.

The Adaptive Routing Problem for Large Store-and-Forward Computer-Communication Networks

The Adaptive Routing Problem for Large Store-and-Forward Computer-Communication Networks
Author: C. E. Houstis
Publisher:
Total Pages: 174
Release: 1977
Genre:
ISBN:

This research investigates and evaluates routing procedures for large store-and-forward message switched computer communication networks. Existing network topologies are examined. An adaptive routing algorithm is developed dealing with message routing when the full length message is transmitted in its entirety. A thresholding technique is used to work with variations in message length. The algorithm's performance is evaluated by comparison with the performance of the exact mathematical deterministic routing problem. In order to apply the routing strategy to large networks, a partitioning approach is used. A partitioning algorithm is developed for communications network topologies. This algorithm uses a generalized labeling technique to find the appropriate partitions of the original network. The adaptive routing algorithm is modified in order to take into account large network considerations. Then it is applied to the partitioned network in a two-level hierarchical structure. The exact two-level modified adaptive routing algorithm is described. Some new network topologies found in the literature are examined from the routing problem point of view. All the algorithms are tested by computer simulation. The adaptive routing algorithms have been implemented using two different simulation languages. (Author).

Distributed Routing for Very Large Networks Based on Link Vectors

Distributed Routing for Very Large Networks Based on Link Vectors
Author: Jochen Behrens
Publisher:
Total Pages: 238
Release: 1997
Genre: Algorithms
ISBN:

Routing is the network-layer function that selects the paths that data packets travel from a source to a destination in a computer communication network. This thesis is on distributed adaptive routing algorithms for large packet-switched networks. A new type of routing algorithms for computer networks, the link-vector algorithm (LVA) is introduced. LVAs use selective dissemination of topology information. Each router running an maintains a subset of the topology that corresponds to adjacent links and those links used by its neighbor routers in their preferred paths to known destinations. Based on that subset of topology information, the router derives its own preferred paths and communicates the corresponding link-state information to its neighbors. An update message contains a vector of updates; each such update specifies a link and its parameters. LVAs can be used for different types of routing policies. LVAs are shown to have better performance than the ideal link-state algorithm based on flooding and the distributed Bellman-Ford algorithm.