[j-nsp] OSPF NSSA Type 4 LSA generation behavior

[Adam]

Yes, because from the perspective of Area 0 route that was injected
into NSSA as Type7, appears to be injected by Area 0 ABR that
performed the 7-to-5 translation. So Type1 LSA with E-bit set provides
reachability within Area 0. Once this Type5 gets flooded into other
regular non-backbone areas, reachability is provided by generating
Type4 that guide routers how to get to the ASBR (which in fact is the
7-to-5 translator in this case).

On Tue, Apr 19, 2011 at 9:20 PM, Muruganandham M <sedhuanand at gmail.com> wrote:
> I think the behavior which you said is also not compliant with the RFC
> mentioned.
>
> However my opinion is that, the ABR who is doing the conversion will set the
> E bit in its router LSA on area 0; by seeing this router LSA the other ABRs
> connected to the Area 0 will generate the ASBR summary and flood it to their
> connected non-area-zero routers.
>
> I dont see a reason for the NSSA ABR to generate a type-4 LSA within Area 0.
>
> Please correct me if i am wrong.
>
> Thanks.
> Muruganandham
>
> On Tue, Apr 19, 2011 at 5:34 PM, Adam <adam.tajer at gmail.com> wrote:
>>
>> If I recall correctly, the ABR that translates Type7 into Type5
>> (highest RID) shows up in the backbone and other non-backbone areas as
>> ASBR, because it changes the Advertising router to itself while
>> performing translation from Type 7 and generating Type5 into Area 0.
>> So in areas other than the NSSA (where prefix was injected), you
>> should not see the "real" ASBR as Advertising Router, you should see
>> the ABR that performed the 7-to-5 translation listed in that field.
>>
>> Regards,
>> Adam
>>
>> On Tue, Apr 19, 2011 at 4:08 PM, Muruganandham M <sedhuanand at gmail.com>
>> wrote:
>> > Dear Experts,
>> >
>> >        As per RFC 3101, *The OSPF Not-So-Stubby Area (NSSA) Option*,
>> > listed
>> > in the Juniper supported standards,
>> >
>> > Since Type-5 AS-external-LSAs are not flooded
>> >   into NSSAs, NSSA border routers should not originate Type-4 summary-
>> >   LSAs into their NSSAs.  Also an NSSA's border routers never originate
>> >   Type-4 summary-LSAs for the NSSA's AS boundary routers, since Type-7
>> >   AS-external-LSAs are never flooded beyond the NSSA's border.
>> >
>> > This looks to be the same behavior in CISCO also.
>> >
>> > But JUNIPER router (ABR) does generate the ASBR summary (type 4) for
>> > the NSSA ASBR.  Is there any specific  reason for doing this
>> > implementation? Or Juniper follows any other RFC for this behavior?
>> >
>> > --
>> > Thanks
>> > Muruganandham M
>> > _______________________________________________
>> > juniper-nsp mailing list juniper-nsp at puck.nether.net
>> > https://puck.nether.net/mailman/listinfo/juniper-nsp
>> >
>
>
>
> --
> Thanks
> Muruganandham M