Default Route Installation

RS1# ip show routes

Destination Gateway Owner Netif

----------- ------- ----- -----

default 12.1.1.2 ISIS_L1 fe1/1

10.1.1.0/30 12.1.1.2 ISIS_L1 fe1/1

12.1.1.0/24 directly connected - fe1/1

13.1.1.1 13.1.1.1 - lo0

127.0.0.1 127.0.0.1 ARP lo0

192.168.1.0/24 directly connected - fe2/1

192.168.2.0/24 12.1.1.2 ISIS_L1 fe1/1

L1 routers install default to nearest L2 router automagically.