Re: LSA Type 4 again

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
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\Recommended%20Reading\Books\Cisco%20press\Jeff%20Doyle 
> \CCIE_Professional_Development_Routing_TCPIP 
> ,_Volume_I,_Second_Edition.chm::/1587052024/ 
> ch08lev1sec1.html#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
>
>
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