From: shiran guez (shiranp3@gmail.com)
Date: Thu Sep 13 2007 - 06:42:46 ART
well it is actually very simple,
the database is divide in such a way that you can see the the LSA that where
received in a real structured manner
mean you will see the LSA type and area it is related to in the title and
bellow the title what are the received updates for that LSA.
and how do you know the type of the area you are in well to know that you
need to understand the OSPF concept and know that for example if you see LSA
type 7 then you are in NSSA area and if you see an area that have only LSA
type 1 (*and you have a neighbor relationship*) it mean that you are in a No
DR/BDR ospf mode and you probably in a stub or even totally stuby area.
LSA 1 is router advertisement - each router in OSPF generate it
LSA 2 is network advertisement - only DR generate it for example in point to
point envio there is not DR/BDR relation so there is no LSA 2
LSA 3 is a summary advertisement - only ABR generate it because the OSPF is
a link state protocol each member of the OSPF are must have the
same OSPF DB, the multi area concept solve the need to have a very large
and unnecessary update in the DB
LSA 4 is little confusing it is specific advertisement generated by the ABR
to specify the location of the ASBR
LSA 5 is generated by the ASBR
LSA 6 is related to OSPF ver 3 as i recall
LSA 7 is the same as 5 but in a NSSA area
the rest I do not remember and I think the rest are not actually relevant
that much.
there is a lot more to it then what I have specified but I think it is a
start.
as a general note you must know OSPF end to end to pass the CCIE and I think
all will agree with me on that.
I hope this was a little helpful
On 9/13/07, John Hooper <homith@homith.com> wrote:
>
> G'Day Group,
> Just a question regarding the command "show ip ospf
> database". If I was given an output from "show ip ospf database" and asked
> to
> explain what area the router is in and what type of area is, I can work
> out
> what ospf area the router is in but I am confused on how to work out the
> area
> type it is (eg is it a standard OSPF area, or stub or totally stubby, etc
> ..)
> If anyone can point me in the right direction I know I am just missing
> something here in my head :)
>
> Cheers
>
> John
>
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-- Shiran Guez MCSE CCNP NCE1 http://cciep3.blogspot.com
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