Installing and Administering Internet Services

260 Chapter 8
Configuring gated
Configuring the OSPF Protocol
Enabling OSPF
The default router identifier used by OSPF is the address of the first
interface on the router encountered by gated. To set the router identifier
to a specific address, specify the routerid interface statement in the
Definition class of the /etc/gated.conf file.
NOTE The OSPF protocol should be enabled only for routers. Once the OSPF
protocol is enabled for a system, the system is treated as a router by
other routers, and not a host.
The OSPF protocol is enabled for a node with the ospf statement in the
Protocol class of the /etc/gated.conf file. The clause yes (or on) tells
gated to enable the OSPF protocol at this node and process all OSPF
packets coming in from other nodes. If you do not specify an OSPF line in
your configuration file, ospf no is assumed. The clause no (or off) tells
gated to disable the OSPF protocol at this node.
The following is an example of the statement to enable OSPF:
ospf yes { ... }
Other statements that are defined for the OSPF protocol configuration
are explained in the following sections.
Defining Areas
Every OSPF router is associated with one or more areas. The area
statement identifies an OSPF area. The value is in the form of a dotted
quad, or a number between 1 and 4294967295. To define an area, you
also need to specify the following:
• The address(es) of the network(s) that make up the area.
• The router interface(s) used to communicate with the area.
Note that the configuration of an area border router contains multiple
area definitions; a different router interface is defined for each area.
Figure 8-4 shows an example of an area border router that is connected
to area 0.0.0.1 through interface 193.2.1.33 and to area 0.0.0.2 through
interface 193.2.1.17.