An analysis of loop formation in OLSRv2 in ad-hoc networks and limiting its negative impact

Speakman, Lee; Owada, Yasunori; Mase, Kenichi

Abstract

Transient routing loops have been observed to form in Ad-hoc Networks running the OLSRv2 routing protocol. The looping traffic significantly increases the impact on the surrounding network and its traffic thus degrading end-to-end transmission by a significant factor even though only a small proportion of the traffic may enter these loops and only for a brief time. This becomes significantly more evident when Link Layer Notification is used to catch broken links, inadvertently leading to the increase in loops. The ways in which these loops form and why Link Layer Notification significantly increases the number of loops is analyzed. Two methods of Loop Detection is introduced in this paper and used in combination with Packet Discard to selectively and preemptively discard those packets that are unlikely to reach their destination and are contributing to the load on the network. The effect of this Loop Suppression is to negate the detrimental effects on surrounding traffic and is found to improve network performance significantly.

• Presentation Conference Type: Conference Paper (published)
• Conference Name: IEEE International CQR (Communications Quality and Reliability) Workshop
• Start Date: Apr 28, 2008
• End Date: May 1, 2008
• Acceptance Date: Dec 15, 2007
• Online Publication Date: May 1, 2008
• Publication Date: Apr 28, 2008
• Deposit Date: Jan 19, 2025