Cisco 3560G 48TS Software Configuration Guide - Page 631

Chapter 30 Configuring IP Unicast Routing Configuring IGRP To disable IP summarization, use the no ip summary-address rip router configuration command. In this example, the major net is 10.0.0.0. The summary address 10.2.0.0 overrides the autosummary address of 10.0.0.0 so that 10.2.0.0 is advertised out interface Gigabit Ethernet port 2, and 10.0.0.0 is not advertised. In the example, if the interface is still in Layer 2 mode (the default), you must enter a no switchport interface configuration command before entering the ip address interface configuration command. Note If split horizon is enabled, neither autosummary nor interface summary addresses (those configured with the ip summary-address rip router configuration command) are advertised. Switch(config)# router rip Switch(config-router)# interface gi0/2 Switch(config-if)# ip address 10.1.5.1 255.255.255.0 Switch(config-if)# ip summary-address rip 10.2.0.0 255.255.0.0 Switch(config-if)# no ip split-horizon Switch(config-if)# exit Switch(config)# router rip Switch(config-router)# network 10.0.0.0 Switch(config-router)# neighbor 2.2.2.2 peer-group mygroup Switch(config-router)# end Configuring IGRP Interior Gateway Routing Protocol (IGRP) is a dynamic, distance-vector routing, proprietary Cisco protocol for routing in an autonomous system (AS) that contains large, arbitrarily complex networks with diverse bandwidth and delay characteristics. IGRP uses a combination of user-configurable metrics, including internetwork delay, bandwidth, reliability, and load. IGRP also advertises types of routes: interior, system, and exterior, as shown in Figure 30-4. • Interior routes are routes between subnets in the network attached to a router interface. If the network attached to a router is not subnetted, IGRP does not advertise interior routes. • System routes are routes to networks within an autonomous system. The router 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 routes are routes to networks outside the AS that are considered when identifying a gateway of last resort. The router chooses a gateway of last resort from the list of exterior routes that IGRP provides if it does not have a better route for a packet and the destination is not a connected network. If the AS has more than one connection to an external network, different routers can choose different exterior routers as the gateway of last resort. 78-16156-01 Catalyst 3560 Switch Software Configuration Guide 30-23