Chapter 11: OSPF Configuration Guide

Add a stub host to an OSPF area.

ospf

add

stub-host to-area <area-

 

addr>backbone cost <num>

 

 

 

 

Add a network to an OSPF area for

ospf

add

networksummary-range

summarization.

<IPaddr/mask> to-area<area-addr>

 

backbone [restrict] [host-net]

 

 

 

 

Configuring OSPF Area Parameters

The SSR allows configuration of various OSPF area parameters, including stub areas, stub cost and authentication method. Information about routes which are external to the OSPF routing domain is not sent into a stub area. Instead, there is a default external route generated by the ABR into the stub area for destinations outside the OSPF routing domain. To further reduce the number of link state advertisements sent into a stub area, you can specify the no-summarykeyword with the stub option on the ABR to prevent it from sending summary link advertisement (link state advertisements type 3) into the stub area.

Stub cost specifies the cost to be used to inject a default route into a stub area. An authentication method for OSPF packets can be specified on a per-area basis.

To configure OSPF area parameters, enter the following commands in the Configure mode.

Specify an OSPF area to be a stub area.

ospf set area <area-num>stub [no-summary]

 

 

Specify the cost to be used to inject a

ospf set area <area-num>stub-cost <num>

default route into a stub area.

 

Note: If this command is not specified,

 

no default route is injected into

 

the OSPF stub area.

 

 

 

Specify the authentication method to be

ospf set area <area-num>[stub]

used by neighboring OSPF routers.

[authentication-method nonesimplemd5]

 

 

Creating Virtual Links

In OSPF, virtual links can be established:

To connect an area via a transit area to the backbone

To create a redundant backbone connection via another area

Each Area Border Router must be configured with the same virtual link. Note that virtual links cannot be configured through a stub area.

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Cabletron Systems 9032578-05 Configuring Ospf Area Parameters, Creating Virtual Links, Add a stub host to an Ospf area