To configure the virtual link, define it on the routers that are at each end of the link. No configuration for the virtual
link is required on the other routers on the path through the transit area (such as routing switch "B" in this
example.)
Figure 37: Defining OSPF virtual links within a network
To configure the virtual link on routing switch "A," enter the following command specifying the area 1 interface on
routing switch "C":
switch(ospf)# area 1 virtual-link 209.157.22.1
To configure the virtual link on routing switch "C," enter the following command specifying the area 1 interface on
routing switch "A":
switch(ospf)# area 1 virtual-link 10.0.0.1
For descriptions of virtual link interface parameters you can either use in their default settings or reconfigure as
needed, see
Changing the dead interval on a virtual link
on page 217.
Changing the dead interval on a virtual link
For more information, see
Adjusting virtual link performance by changing the interface settings
261.
Syntax:
area
area-id
virtual link
ip-address
dead-interval 1-65535
Used in the router OSPF context on both ABRs in a virtual link to change the number of seconds that a neighbor
router waits for a hello packet from the specified interface before declaring the interface "down." This should be
some multiple of the hello interval. The
dead-interval
setting must be the same on both ABRs on a given
virtual link.
area-id
Specifies the OSPF area in which both ABRs in a given virtual link operate. In this use, the area ID is
sometimes termed "transit area ID."
This value must be the same for both ABRs in the virtual link.
Chapter 11 Open Shortest Path First Protocol (OSPF)
217
