Advertising Networks And Establishing Ospf Areas; Defining An Ospf Network Within An Area - HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual

IP Routing—Configuring RIP, OSPF, BGP, and PBR
Configuring OSPF
13-42
to identify the routers at remote sites. In addition, loopback interfaces are
always up as long as the router has at least one functioning link. Conse-
quently, the router's ID will not change if an interface goes down and up
again. When you set each router's ID in a loopback interface, you create a
coherent identification system.
Create the loopback interface from the global configuration mode context:
Syntax: interface loopback <interface number>
Assign the loopback interface an IP address. The IP address is purely for
identifying the router:
ProCurve(config-loop 1)# ip address 192.168.255.1 /24
You can also assign the loopback a valid IP address in your network. You
should follow your organization's policy for identifying routers.

Advertising Networks and Establishing OSPF Areas

You configure areas from the OSPF configuration mode context. For each
router, you must establish the areas on which it has at least one interface.
You must:
specify OSPF networks and place them in an area
define whether an area is a stub area
For an ABR, you must also configure route summarization. The ABR should
know the total range of IP addresses in each of its areas. It can then advertise
its link to the area as a whole in a summary LSA, which it sends to routers
in other areas.

Defining an OSPF Network Within an Area

When you define an OSPF network, you fulfill three tasks:
You enable the router to advertise its connection to this network.
You enable interfaces on the network to run OSPF.
You place the network in an area.
If an interface has more than one address, you must enable OSPF on the
network on which the interface has its primary address.
Placing a network in an area allows the router to learn about other networks
in the area. The router generates a topology of the area, which it uses to
calculate routes to any other network in the area.