Mitigation of Transient Loops in IGP Networks_Camera Ready

Routing loops have recently re-emerged as an important issue in new carrier class Ethernet technologies such as IEEE 802.1aq. While they can waste resources through full link utilization, routing loops were originally mitigated in IP networks by TTL expiration, resulting in wasted resources before packets were dropped after a few seconds. In this paper a new mitigation approach based upon Early Packet Dropping (EPD) is developed, in which a router can drop looping packets earlier than expected if full link utilization will occur before TTL expiration. While the EPD algorithm deals only with loops between two nodes, a proposed solution known as TTL Relaxation is also combined with this loop mitigation mechanism in order to minimize the use of EPD and minimize the performance degradation introduced by loops between more than two nodes.