OSPF Areo 0 and Virtual links

Unanswered Question
Sep 26th, 2008
User Badges:

guys basic question abt ospf virtual links.....for exaple three routers are connected A,B,C And B router serials are connected and are in areo the fethernet of the routers are in area 10 so do we need virtual connection to area 0 or not if yes why if not why??? whats the rule of thumb for virtual links......

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Jon Marshall Fri, 09/26/2008 - 05:41
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

In OSPF all areas in the same AS must be physically connected to area 0 so a router (ABR - Area Border Router) that connects area 0 to area 10 for example would have at least one interface in area 0 and one interface in area 10.

Virtual links are used when there is no physical connection to area 0. See this attached doc for more details


Note that virtual links are not good design. They are usually used as a temporary stop gap.


paul.matthews Fri, 09/26/2008 - 06:30
User Badges:
  • Silver, 250 points or more

Your question is not totally clear. The basic OSPF rule is that all areas shall be connected to the backbone. If you have an area that does not have a direct connection to the backbone, to allow connectivity to other areas you would need to configure a virtual link.

The rule of thumb for virtual links? They are for emergencies, temporary use or for people that cannot design networks.


This Discussion