SMC Networks SMC6724L3 manual 204, Configuring Virtual Links

normal area

CONFIGURING THE SWITCH

Configuring Virtual Links

All OSPF areas must
connect to the backbone. If
an area does not have a				isolated
direct physical connection to				area
the backbone, you can
configure a virtual link that				ABR
provides a logical path to the			virtual
backbone. To connect an
			link
isolated area to the	backbone	ABR

backbone, the logical path can cross a single non-backbone area (i.e.,

transit area) to reach the backbone. To define this path, you must configure an ABR that serves as an endpoint connecting the isolated area to the common transit area, and specify a neighboring ABR as the other endpoint connecting the common transit area to the backbone itself. (Note that you cannot configure a virtual link that runs through a stub or NSSA area.)

Virtual links can also be used to create a redundant link between any area and the backbone to help prevent partitioning, or to connect two existing backbone areas into a common backbone.

Command Attributes

•Area ID – Identifies the transit area for the virtual link. (The area ID must be in the form of an IP address.)

•Neighbor Router ID – Neighbor router at other end of the virtual link. This must be an Area Border Router (ABR) that is adjacent to both the backbone and the transit area for the virtual link.

•Events – The number of state changes or error events on this virtual link.

The other items are described under “Configuring OSPF Interfaces,” page 3-198.

Note: This router supports up 64 virtual links.

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