Transit Area

Hi!

 

According to the CoD virtual link video, when describing the transit area for the virtual link between router 1 and router 4, it is said that area 0 is the transit area?  I thought area 2 would be the transit area for the virtual link since that is where the virtual link is spanning to reach the backbone area.  I understand that filtering and stub area designs are not allowed when using virtual links but area 0 is not being used as the transit area for the virtual link, area 2 is the transit area.  Can someone clarify this please.

Thanks

Erick

Comments

  • Nevermind.

     

    After a good night sleep and a strong cup of coffee, I believe the light bulb has come on.  If I am wrong, please correct me. 

    In order for inter-area routing to occur, all traffic must flow through area 0.  When the link between router 2 and router 5 broke, this effectively made area 0 a stub network meaning there is only one entry in and one entry out of the area.  When the virtual link between router 1 and router 4 was created, this effectively made area 0 a transit area again allowing inter-area routing and full database reachability.  So traffic that used to flow from router one to router 3 to router 2 and then into the backbone area is now flowing over the virtual link between router 1 and 4 to reach the backbone area. [Y]

    Erick

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