IP Routing Features

Configuring OSPF

Example. Figure 16-1shows an OSPF area border router, Routing Switch-A, that is cut off from the backbone area (Area 0). To provide backbone access to Routing Switch-A, you can add a virtual link between Routing Switch-A and Routing Switch-C using Area 1 as a transit area. To configure the virtual link, you define the link on the router that is at each end of the link. No configuration for the virtual link is required on the routers in the transit area.

To define the virtual link on Routing Switch-A, enter the following commands:

HPswitch(ospf)# area 1 virtual-link 209.157.22.1

HPswitch(ospf)# write memory

Enter the following commands to configure the virtual link on Routing

Switch-C:

HPswitch(ospf)# area 1 virtual-link 10.0.0.1

HPswitch(ospf)# write memory

Syntax: area <ip-addr> <num> virtual-link <router-id> [authentication-key dead-interval hello-interval retransmit-interval transmit- delay <value>]

The area <ip-addr> <num> parameter specifies the transit area.

The <router-id>parameter specifies the router ID of the OSPF router at the remote end of the virtual link. To display the router ID on an HP Series 5300XL Switch, enter the show ip command.

See “Modify Virtual Link Parameters” below for descriptions of the optional parameters.

Modify Virtual Link Parameters

OSPF has some parameters that you can modify for virtual links. Notice that these are a subset of the parameters that you can modify for physical inter- faces. cost is not configured for virtual links, it is calculated by route calcula­ tion.

You can modify default values for virtual links using the following CLI command at the OSPF router level of the CLI, as shown in the following syntax:

Syntax: area <num> <ip-addr> virtual-link <ip-addr> [authentication-key <string>] [dead-interval <num>] [hello-interval <num>] [retransmit-interval <num>] [transmit-delay <num>]

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