Re: LSA Type 4 again

Rick,
Actually I did lab it and it was not permitted,

R1---area 1--- R2 ---area 0 --- R3 --area 0--- R4--- area 2--- R5

area 0 backbone
area 1 normal area
area 2 is nssa

R5 ASBR

on R1 I cannot see the LSA type 4.

Regards,
Molomo

On Sun, Sep 6, 2009 at 4:43 PM, Rick Mur <rmur_at_ipexpert.com> wrote:

> It could be allowed in the NSSA area, but it would have no use.
> You are correct, the ABR generates a type 4 LSA, when it sees type 5 LSA's
> indeed to describe the location of the ASBR.
>
> Try to lab it up. Create a topology, insert some external routes in OSPF
> and issue a 'show ip ospf database' on a router within the NSSA and see if
> you have a type-4 in your database. It's always good to see the theory
being
> confirmed in a lab, at least that is what helps me to understand and
> remember the theory.
>
>
> --
> Regards,
>
> Rick Mur
> CCIE2 #21946 (R&S / Service Provider)
> Sr. Support Engineer  IPexpert, Inc.
> URL: http://www.IPexpert.com <http://www.ipexpert.com/>
>
>
> On 6 sep 2009, at 16:27, Molomo wrote:
>
> Experts,
>>
>> Jeff Doyle says LSA type 4 is allowed in nssa area ( see table below). I
>> would have thought that since LSA 5 is not permitted then no need to
>> generate LSA 4.
>>
>> My understanding is , ABR generates LSA 4 based on the type 5, to describe
>> the position of the ASBR.
>>
>>
>> Or am I missing something here?
>>
>>
>> I have also seen this in Quick Reference Sheet by Anthony Sequeira.
>>
>>
>>
>>
>> Table 8-5. LSA types allowed per area type.
>>
>> Area Type
>>
>> 1&2
>>
>> 3
>>
>> 4
>>
>> 5
>>
>> 7
>>
>> Backbone (area 0)
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> No
>>
>> Non-backbone, non-stub
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> No
>>
>> Stub
>>
>> Yes
>>
>> Yes
>>
>> No
>>
>> No
>>
>> No
>>
>> Totally stubby
>>
>> Yes
>>
>>
No[*]<mk:@MSITStore:C:\Documents%20and%20Settings\user\Desktop\R&S%20CCIE\Rec
ommended%20Reading\Books\Cisco%20press\Jeff%20Doyle\CCIE_Professional_Develop
ment_Routing_TCPIP,_Volume_I,_Second_Edition.chm::/1587052024/ch08lev1sec1.ht
ml#ch08tn01>
>>
>>
>> No
>>
>> No
>>
>> No
>>
>> Not-so-stubby
>>
>> Yes
>>
>> Yes
>>
>> Yes
>>
>> No
>>
>> Yes
>>
>> [*] Except for a single type 3 LSA per ABR, advertising the default route
>>
>>
>>
>> Regards,
>>
>> Molomo
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
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Received on Sun Sep 06 2009 - 16:50:58 ART