Cisco 3560G 48TS Software Configuration Guide - Page 620

Configuring IP Addressing Chapter 30 Configuring IP Unicast Routing ICMP Router Discovery Protocol (IRDP) Router discovery allows the switch to dynamically learn about routes to other networks using IRDP. IRDP allows hosts to locate routers. When operating as a client, the switch generates router discovery packets. When operating as a host, the switch receives router discovery packets. The switch can also listen to Routing Information Protocol (RIP) and Interior Gateway Routing Protocol (IGRP) routing updates and use this information to infer locations of routers. The switch does not actually store the routing tables sent by routing devices; it merely keeps track of which systems are sending the data. The advantage of using IRDP is that it allows each router to specify both a priority and the time after which a device is assumed to be down if no further packets are received. Each device discovered becomes a candidate for the default router, and a new highest-priority router is selected when a higher priority router is discovered, when the current default router is declared down, or when a TCP connection is about to time out because of excessive retransmissions. The only required task for IRDP routing on an interface is to enable IRDP processing on that interface. When enabled, the default parameters apply. You can optionally change any of these parameters. Beginning in privileged EXEC mode, follow these steps to enable and configure IRDP on an interface: Step 1 Step 2 Command configure terminal interface interface-id Step 3 ip irdp Step 4 ip irdp multicast Step 5 ip irdp holdtime seconds Step 6 ip irdp maxadvertinterval seconds Step 7 ip irdp minadvertinterval seconds Step 8 ip irdp preference number Step 9 Step 10 Step 11 Step 12 ip irdp address address [number] end show ip irdp copy running-config startup-config Purpose Enter global configuration mode. Enter interface configuration mode, and specify the Layer 3 interface to configure. Enable IRDP processing on the interface. (Optional) Send IRDP advertisements to the multicast address (224.0.0.1) instead of IP broadcasts. Note This command allows for compatibility with Sun Microsystems Solaris, which requires IRDP packets to be sent out as multicasts. Many implementations cannot receive these multicasts; ensure end-host ability before using this command. (Optional) Set the IRDP period for which advertisements are valid. The default is three times the maxadvertinterval value. It must be greater than maxadvertinterval and cannot be greater than 9000 seconds. If you change the maxadvertinterval value, this value also changes. (Optional) Set the IRDP maximum interval between advertisements. The default is 600 seconds. (Optional) Set the IRDP minimum interval between advertisements. The default is 0.75 times the maxadvertinterval. If you change the maxadvertinterval, this value changes to the new default (0.75 of maxadvertinterval). (Optional) Set a device IRDP preference level. The allowed range is -231 to 231. The default is 0. A higher value increases the router preference level. (Optional) Specify an IRDP address and preference to proxy-advertise. Return to privileged EXEC mode. Verify settings by displaying IRDP values. (Optional) Save your entries in the configuration file. 30-12 Catalyst 3560 Switch Software Configuration Guide 78-16156-01