Configuring Stub Areas - HP 7102dl - ProCurve Secure Router Configuration Manual

IP Routing—Configuring RIP, OSPF, BGP, and PBR
Configuring OSPF
N o t e
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If your entire WAN is only one area, you should define all networks as part of
area 0.
Move to the OSPF configuration mode context and enter:
Syntax: network <A.B.C.D> <wildcard bits> area <area ID | A.B.C.D>
You use wildcard bits to define networks rather than a subnet mask. In this
way, you can specify an entire range of addresses or subnets. For example,
you might enter:
ProCurve(config-ospf)# network 10.1.0.0 0.0.255.255 area 1
You can identify an area by an IP address rather than by an area ID.
You can enter any number of commands to place interfaces in an OSPF area,
and you can configure any number of OSPF areas. The network ranges you
use can overlap. If an interface falls into the range for more than one area, it
will be part of the area defined by the first command entered.
If at all possible, however, you should avoid configuring overlapping ranges:
it can lead to confusion and misconfigurations.

Configuring Stub Areas

You must define a stub area on the ABR that connects to it as well as on all
routers internal to the area.
A stub area is an area that only receives traffic destined to hosts on its own
subnets. That is, it does not forward traffic from one area to another. Unless
the topology of a site is very large and complicated, you should configure it
as a single area. The rule of thumb is that an OSPF area should have fewer
than 50 routers. Particularly if the site has only one connection to the WAN, it
should be a stub area. Configuring the area as a stub will decrease the amount
of bandwidth and processing power OSPF requires from devices in the area.
To define an area as a stub, enter the following OSPF configuration command:
Syntax: area <area ID> stub
You should not configure area 0 as a stub area because, as the network
backbone, area 0 must transit traffic.
For example, if you want to configure area 1 as a stub area, enter:
ProCurve(config-ospf)# area 1 stub