ISIS Level 2 routers under the same area

Hi all,

   I have a question regarding to ISIS routing. As per my understanding, a level 2 ISIS router will have level 2 adjacency to level 2 routers. THe word level 2 adjacency as i knew is adjacency between IS in different area. My question is : Is it a common situation to have several level 2 ISIS routers under the same area ? What is the benefit and drawbacks to have this scenario ?

 

regards

 

 

Comments

  • I have seen this as a common design practice 1 L2 area for multiple routers..
    It is not uncommon to have a large number of routers in the same area to
    allow for optimal routing. For TE it is easier to have a single area and ISIS
    scales to very large numbers of routers in a single area.

    It would be no different that multiple routers in an OSPF area.

    Regards
    Kevin

    On Wed, Mar 25, 2009 at 7:42 AM, menotii wrote:
    > Hi all,
    >
    >    I have a question regarding to ISIS routing. As per my understanding, a
    > level 2 ISIS router will have level 2 adjacency to level 2 routers. THe word
    > level 2 adjacency as i knew is adjacency between IS in different area. My
    > question is : Is it a common situation to have several level 2 ISIS routers
    > under the same area ? What is the benefit and drawbacks to have this
    > scenario ?
    >
    >
    >
    > regards
    >
    >
    >
    >
    >
    >
    > Internetwork Expert - The Industry Leader in CCIE Preparation
    > http://www.internetworkexpert.com
    >
    > Subscription information may be found at:
    > http://www.ieoc.com/forums/ForumSubscriptions.aspx
    >
  • Hi Kevin,

      THanks for the anwer. Anyhow, what is the type of adjacency in this "backbone" area ? Is it level 1 adjacency between L2 ISs or still level 2 adjacency between those L2 ISs

     

    regards

     

  • L2

    regards
    Kevin

    On Wed, Mar 25, 2009 at 8:02 AM, menotii wrote:
    > Hi Kevin,
    >
    >   THanks for the anwer. Anyhow, what is the type of adjacency in this
    > "backbone" area ? Is it level 1 adjacency between L2 ISs or still level 2
    > adjacency between those L2 ISs
    >
    >
    >
    > regards
    >
    >
    >
    >
    > Internetwork Expert - The Industry Leader in CCIE Preparation
    > http://www.internetworkexpert.com
    >
    > Subscription information may be found at:
    > http://www.ieoc.com/forums/ForumSubscriptions.aspx
    >
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