| 7.3 |  | IGRP |
| 7.3.3 |  | IGRP routes |

| IGRP advertises three types of routes: Interior System Exterior Interior Interior routes are routes between subnets of a network attached to a router interface. If the network attached to a router is not subnetted, IGRP does not advertise interior routes. System System routes are routes to networks within an autonomous system. The Cisco IOS software derives system routes from directly connected network interfaces and system route information provided by other IGRP-speaking routers or access servers. System routes do not include subnet information. Exterior Exterior routes are routes to networks outside the autonomous system that are considered when identifying a gateway of last resort. The Cisco IOS software chooses a gateway of last resort from the list of exterior routes that IGRP provides. The software uses the gateway (router) of last resort if a better route is not found and the destination is not a connected network. If the autonomous system has more than one connection to an external network, different routers can choose different exterior routers as the gateway of last resort.
| Interactive Media Activity Checkbox: IGRP Routes After completing this activity, the student will be able to understand IGRP routes.
| Web Links Interior Gateway Protocol - IGRP http://www.firewall.cx/ index.php?c=igrp