Abstract

One key component of traffic engineering is a concept known as constraint based routing. In constraint based routing a topology database is maintained on all participating nodes. This database contains a complete list of all the links in the network that participate in traffic engineering and for each of these links a set of constraints, which those links can meet. Bandwidth, for example, is one essential constraint. Since the bandwidth available changes as new LSPs are established and terminated the topology database will develop inconsistencies with respect to the real network. It is not possible to increase the flooding rates arbitrarily to keep the database discrepancies from growing. A new mechanism is proposed whereby a source node can learn about the successes or failures of its path selections by receiving feedback from the paths it is attempting. This information is most valuable in failure scenarious but is benificial during other path setup functions as well. This fed-back information can be incorporated into subsequent route computations, which greatly improves the accuracy of the overall routing solution by significantly reducing the database discrepancies.

Authors

Peter Ashwood-Smith (petera@nortel.ca)
Bilel Jamoussi (jamoussi@nortel.ca)
Don Fedyk (dwfedyk@nortel.com)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)