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Forum Replies

  1. Hi Rene,

    In regards to:
    <h3>OSPF NSSA ASBR and ABR</h3>
    You say: “When an OSPF NSSA router is both ASBR and ABR then it can flood LSA type 7 or LSA type 5 directly in another area. For this reason, the P-bit will be disabled on type 7 LSAs.”

    I feel i am missing something here.

    When you make R2 both ABR and ASBR by redistributing R2’s loopback , you say the conversion from 7 to 5 does not happen.

    But Still R1 gets the type 5 for the loopback from R2?

    I mean, if the P bit is not set, then how can this redistributed loopback on R2 make it to R1 as a type5?

    What i

    ... Continue reading in our forum

  2. Hi Edwin,

    In case anyone else reads this, we are talking about this post right:


    You are correct. In this example, R2 will create a LSA type 5 directly which R1 can learn and a LSA type 7 that R4 will learn. There’s no need to create a LSA type 7 and then translate it into a type 5, that’s why the P-bit is disabled.


  3. Pradeep,
    I assume you mean the following command
    translate type7 suppress-fa

    To answer this question, you first need to understand how a Type-5 External advertisement changes when it is translated by an NSSA ABR. When an LSA Type-7 to Type-5 translation occurs (only an NSSA ABR can do this), two properties change: 1) The advertising router and 2) The Forwarding Address.

    Regular Type 5 LSA
    In a regular (not translated) Type-5 LSA, the Advertising router is the ASBR itself, and the Forwarding Address is

    Regular Type 5 LSA

    LS Type: AS External Link
    ... Continue reading in our forum

  4. Hi Rene, The “P” bit now has a spot where the “NP” was in Wireshark, on the top of the section it’s actually called Propagate. Just an FYI

    Great Practice Site, I passed my CCIE Route Switch two months ago…


  5. Hi Rene,

    Will the forwarding address be changed when ABR summarize the external route to other areas?

    I thought Forwarding Address will be always ASBR address and Advertising router field will be changed.

    But below point confused me.

    To reach we have to use forward address R1 will use both R2 and R3 to reach this network:

    R1#show ip route
    Routing entry for
      Known via "ospf 1", distance 110, metric 20, type extern 2, forward metric 3
      Last update from on FastEthernet0/1, 00:00:22 ago
      Routing Descriptor
    ... Continue reading in our forum

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