Points to Remember

• IGRP uses a composite metric that is calculated by a combination of delay, bandwidth, reliability, load, and MTU.

• The show ip route command displays entries in the IP routing table for the router in which this command is issued.

• The show ip protocols command displays filters, parameters, and network information details corresponding to the active routing protocol configured in the router.

• The show ip route igrp Number command displays only the IGRP routes in the routing table.

• The show interface command displays information about network interfaces within the IGRP network.

• The show running-config command displays the current updated operating configuration for IGRP in the router where this command is executed.

• The debug ip igrp transaction command lists detailed contents of both sent and received IGRP updates.

• The debug ip igrp events command lists summary contents of both sent and received IGRP updates.

• The ping ip-addr/hostname command tests the network connectivity with a specified network address.

• The undebug all command sets the IGRP debugging system off for the current router.

• Misconfiguration problems in IGRP can occur when IGRP routes are missing from the routing table, IGRP is not installing all possible equal cost paths, or if ASN is misconfigured.

• The clear ip route * command refreshes the current routing table.

• The passive interface command prevents the interface from sending routing updates.

• Equal cost path refers to multiple routes to a common destination with same metric values.