From: nikolai (niko@4ovek.com)
Date: Thu Aug 10 2006 - 21:05:02 ART
I understand that, but the issue here is that one ABR pushes the single
Type-5 received from the other ABR (higher RID) in its the routing
table, while the other ABR installs both Type-7 in its RID (the desired
result) as well as translates Type-7 from the NSSA to Type-5 for Area 0.
FYI, both ABRs have the NSSA configured as "no-summary" in order to
generate defaults.
Thanks,
Nikolai
Victor Cappuccio wrote:
> What you see is a normal operation defined in this RFC
> http://www.faqs.org/rfcs/rfc1587.html
>
> 4.1 Translating Type-7 LSAs Into Type-5 LSAs
>
> This step is performed as part of the NSSA's Dijkstra calculation
> after type-5 and type-7 routes have been calculated. If the
> calculating router is not an area border router this translation
> algorithm should be skipped. All reachable area border routers in
> the NSSA should now be examined noting the one with the highest
> router ID. If this router has the highest router ID, it will be the
> one translating type-7 LSAs into type-5 LSAs for the NSSA, otherwise
> the translation algorithm should not be performed.
>
> HTH
> Victor.-
>
> -----Mensaje original-----
> De: nobody@groupstudy.com [mailto:nobody@groupstudy.com] En nombre de
> nikolai
> Enviado el: Jueves, 10 de Agosto de 2006 05:25 p.m.
> Para: Cisco certification
> Asunto: OSPF NSSA issue
>
> I have an interesting OSPF NSSA issue. Two routers, both ABRs (Area 0
> and NSSA no-summary), are receiving the same prefix as Type-7 from two
> ASBRs in the NSSA area. Both ABRs have the prefix as two Type-7s from
> both ASBRs, and a single Type-5 from only one ABR in their OSPF LSA dB.
>
> However, the ABR advertising the Type-5 has both Type-7s in its RIB,
> while the other ABR has only the single Type-5 in its RIB. Please see
> http://nikolai.pastebin.ca/125715 for more details.
>
> My objective was to get both paths to the prefix in the RIB as ECMP, and
> I was able to achieve that by turning the NSSA into a regular area, thus
> eliminating the Type-7 Externals, and dealing with Type-5 only. However,
> would love to go back to NSSA no-summary, if possible.
>
> Thanks for the help,
>
> -- nikolai
>
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