Browse Prior Art Database

Hybrid Routing Technique for Packet Switched Networks

IP.com Disclosure Number: IPCOM000082215D
Original Publication Date: 1974-Oct-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Rudin, H: AUTHOR

Abstract

Existing routing techniques for packet-switched networks are either centralized (decisions made in a central unit) or decentralized (decisions made in nodes). In the first case, central decisions are based on knowledge of the overall situation, but there is a time delay between changes of local situations and corresponding routing decision modifications. Decentralized routing rapidly responds to local changes but lacks overall optimization.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 1

Hybrid Routing Technique for Packet Switched Networks

Existing routing techniques for packet-switched networks are either centralized (decisions made in a central unit) or decentralized (decisions made in nodes). In the first case, central decisions are based on knowledge of the overall situation, but there is a time delay between changes of local situations and corresponding routing decision modifications. Decentralized routing rapidly responds to local changes but lacks overall optimization.

Improvements can be achieved by hybrid routing, i.e., by adding a distributed function to a mainly centralized routing strategy: Nodes are permitted to make limited decisions based on the local situation, within an overall routing procedure which is determined by a Network Routing Center (NRC).

The NRC sends information to each node, specifying what the NRC believes to be the best of the n best outgoing trunks for every possible destination node. This information is updated at regular or asynchronous intervals. It is based on status data which the NRC receives from the nodes on a synchronous or an asynchronous basis. Each node, in case a pair of possible trunks was suggested for a destination, routes a packet out on that trunk with the shorter waiting time.

A specific procedure for the NRC to make its selection is called delta-routing. The NRC always determines two or more alternate trunks for each node and each possible destination. If the difference between the transmission delay for the optimum path and that of the next most optimum path is...