From: ccie2be (ccie2be@nyc.rr.com)
Date: Wed Aug 06 2003 - 13:38:18 GMT-3
Hey Joe,
I would gladly send all that output if I could simly do a cut and paste but
unfortunately I'm not set up (long story- don't ask) to do that.
However, this is very easy to duplicate if you're so inclined.
Here are the configs:
R2 R3
int lo0
ip addr 192.168.2.2/24 ip addr
192.168.3.3/24
int e0
ip addr 172.16.2.2/24
int s0
encap frame relay
ip addr 172.16.100.2/24 ip addr
172.16.100.3/24
fram map ip 172.16.100.3 233 broad fram map ip 172.16.100.2 322
broad
no fram inverse-arp
ip os net point-to-multipoint ip os net
non-broadcast
router ospf 1
net 192.168.2.0 0.0.0.255 area 0 net 192.168.3.0
0.0.0.255 area 0
net 172.16.100.0 0.0.0.255 area 0 net 172.16.100.0
0.0.0.255 area 0
net 172.16.2.0 0.0.0.255 area 2
Except for the few differences shown above in addressing, dlci's, the
config's are the same for both routers. If you'd like to see some
interesting stuff, turn on debug ip os adj and then do things like manually
change the router-id on R2 so that it's rid is than R3's. Clear the ospf
process on 1 router at a time and watch the exchange of ospf packets. Add a
3rd router, R1 and config it the same making sure it has a lower rid than
R2, say, 192.168.1.1/24. And, then observe what routes show up in the route
tables of all 3 routers. But, start off with R3 being the DR and then try
to change the DR to R2 by changing it's rid, 1st by changing the ip addr of
the loopback and then by adding the router-id command.
The result, I'm sure will surprise you.
----- Original Message -----
From: "Joe Martin" <jmartin@capitalpremium.net>
To: "ccie2be" <ccie2be@nyc.rr.com>
Sent: Wednesday, August 06, 2003 10:29 AM
Subject: RE: Surprise Result -- OSPF nei are adjacent but don't exchange
link states
> Raj,
>
> Send your configs and a sh ip ospf nei and a sh ip ospf database.
>
> Thanks,
>
> Joe Martin
> CCIE #12035
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> ccie2be
> Sent: August 06, 2003 7:10 AM
> To: Group Study
> Subject: Surprise Result -- OSPF nei are adjacent but don't exchange
> link states
>
>
> Good Morning,
>
> I just configured 2 ospf routers with different ospf net types
>
> On R2's s0, I configured p2m.
>
> On R3's s0, I left it at default (non-broadcast for physical F/R).
>
> Result:
>
> There was an election for the DR (R2 won - it had the higher router-id).
>
> R2 and R3 became adjacent and exchanged the link state database, but, R2
and
> R3 didn't add any of the routes to the route table that they had learned
> from
> each other. Note: a check of the ospf link state database on R3 showed
> that
> it had learned of all the routes from R2 and vice versa.
>
> When I change R3's s0 back to ospf net type, the route tables on both R2
and
> R3 both show all the routes that were exchanged.
>
> Questions:
>
> Why do R2 and R3 become adjacent even though they have different ospf net
> types?
>
> Why is there a DR/BDR election between R2 and R3 when R3 has an ospf net
> type
> of "non-broadcast"?
>
> Why doesn't R3 add the routes it learns from R2 if it's adjacent to R2?
>
> I thought that that R2 and R3 wouldn't become adjacent since they had
> different net types but if they did become adjacent, then they would add
the
> routes they learned from each other. Is this behavior to be expected or
is
> there something else going on?
>
> Thanks in advance, Raj
>
>
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