Loop elimination mechanism

Loop control protocols such as the spanning tree protocols cannot be configured on IRF physical interfaces. However, IRF has its own mechanism to eliminate loops. Before an IRF member device forwards a packet, it identifies whether loops exist on the forwarding path based on the source and destination physical interfaces and the IRF topology. If a loop exists, the device discards the packet on the source interface of the looped path. This loop elimination mechanism will drop a large number of broadcast packets on the IRF physical interfaces. To reduce SNMP notifications of packet drops when you use SNMP tools, do not monitor packet forwarding on the IRF physical interfaces.