Router_A#debug ip igrp events
IGRP event debugging is on
Router_A#
IGRP: sending update to 255.255.255.255 via Ethernet0 (172.16.0.1)
IGRP: Update contains 0 interior, 2 system, and 0 exterior routes.
IGRP: Total routes in update: 2
IGRP: sending update to 255.255.255.255 via Serial0 (172.17.0.1)
IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
IGRP: Total routes in update: 1
IGRP: received update from 172.17.0.2 on Serial0
IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
IGRP: Total routes in update: 1
IGRP: sending update to 255.255.255.255 via Ethernet0 (172.16.0.1)
IGRP: Update contains 0 interior, 2 system, and 0 exterior routes.
IGRP: Total routes in update: 2
IGRP: sending update to 255.255.255.255 via Serial0 (172.17.0.1)
IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
IGRP: Total routes in update: 1