When does a Cisco router initiate a routing request out its interfaces?

A Cisco router that runs a distance vector routing protocol initiates a routing request out its interfaces if any of these conditions are met:

The interface goes down.

There is any change to the routerglobal configuration command.

There is any change to the metricconfiguration command.

The clear ip routeEXEC command is used.

The shutdowninterface configuration command is used.

The router is booted.

There is any change to the ip addresscommand.

The request is sent out to all interfaces configured for that particular protocol no matter which interface triggers the request. The request is sent out to one interface only if that is the only interface configured for the protocol.

When the debug ip igrp eventsor the debug ip igrp transactionscommand is enabled, you see this in any of these situations:

IGRP: broadcasting request on Ethernet0  IGRP: broadcasting request on Ethernet1  IGRP: broadcasting request on Ethernet2  IGRP: broadcasting request on Ethernet3