Configuring IP unnumbered for RIP and IGRP is done in the same way as explained previously. The excerpts from the configurations of RouterA and RouterC that follow show how to configure IP unnumbered on a serial interface.
!hostname RouterA!interface serial1ip unnumbered Ethernet0!!hostname RouterC!interface serial1ip unnumbered TokenRing0!
The following show interface commands from RouterA and RouterC show that IP unnumbered is now in use on both serial interfaces.
RouterA#show interface serial 1Serial1 is up, line protocol is up Hardware is HD64570 Interface is unnumbered. Using address of Ethernet0 (220.127.116.11) MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec, rely 255/255, load 1/255RouterC#show interface serial 1 ...