AIS AI2524 Protocol Configuration Steps Create Virtual Links, Generate a Default Route

Chapter 8: AI2524 Protocol Configuration Steps

Create Virtual Links

In OSPF, all areas must be connected to a backbone area. If there is break in backbone continuity, or if the backbone is purposefully parti- tioned, you can establish a virtual link.

To establish a virtual link, type this command in router configuration mode:

area area-idvirtual-link router-id[hello- interval seconds] [retransmit-interval seconds] [transmit-delay seconds] [deadinterval seconds] [[authentication-key key] [message-digest-key keyid md5 key]]

To display information about virtual links, use th show ip ospf virtual-linksEXEC command. To display the router ID of an OSPF router, use the show ip ospf EXEC command.

Generate a Default Route

You can force an autonomous system boundary router to generate a default route into an OSPF routing domain. Whenever you specifically configure redistribution of routes into an OSPF routing domain, th router automatically becomes an autonomous system boundary router. However, an autonomous system boundary router does not, by default, generate a default route into the OSPF routing domain.

To force the autonomous system boundary router to generate a default route, type this command in router configuration mode:

default-information originate [always] [metric metricvalue] [metric-type type-

value] [route-map map-name]

Configure Lookup of DNS Names

You can configure OSPF to look up Domain Naming System (DNS) names for use in all OSPF show command displays. This featur makes it easier to identify a router, because it is displayed by nam rather than by its router ID or neighbor ID.

To configure DNS name lookup, type this command in global config- uration mode

ip ospf name-lookup

August 1997	Page 8-7
2524UM