Cyclades-PR1000
Chapter 9 - Routing Protocols 76
STEP SIX
It is not always possible to connect all areas directly to the backbone. When an area is connected to the backbone only
through another area, two virtual links must be created. One from the backbone to the unattached area and one from
the unattached area to the backbone. If this occurs in the network containing the router, enter the Virtual Links Menu
to configure this link. In the table listing the parameters, the link between Area 3 (router 8) and the backbone is used
as an example.
Virtual Links Menu CONFIG =>IP =>OSPF =>VIRTUAL LINKS
Parameter Description
Transit Area ID ID of the OSPF Area sandwiched between this router and the back bone. In the figure,
area 2 is the area used to link Router 8 with the Backbone. Thi s ID has the form of an
IP address.
Neighbor's ID Router ID of router at end of virtual link. In the example, this will be Router 6.
Virtual Link Status Activates the virtual link.
Parameters available only when
Virtual Link Status
is
Active
.
Transit Delay in
Seconds Estimated transit time in secon ds to route a packet from Router 8 to Router 6. Use the
preset value (1) or increase the number for slow links.
Retransmit Interval in
Seconds* Time in seconds between link-state advertisement retransmissions for adj acencies
belonging to this interface.
Hello Interval in
Seconds* Time in seconds between the hell o packets on this interface.
Dead interval in
Seconds* Inactivity time (seconds) befo re a neighbor router is consi dered down.
Password* String of up to 8 characters used t o authenticate OSPF packages. Th e use of this
password is enabled in CONF IG
=>IP=>OSPF=>AREA=>AUTHENTICATION TYPE.
* Inside a given area, these 4 parameters should be the same for all routers. In the example virtual link, they
should be the same as those used for the backbone.