From: Nigel Taylor (nigel_taylor@xxxxxxxxxxx)
Date: Wed Apr 04 2001 - 04:40:36 GMT-3
Ramesh,
Let's see if I'm also getting confused as I get closer as
well.. See Inline.
----- Original Message -----
From: Ramesh Ramasamy <ramesh_ramasamy@hotmail.com>
To: <ccielab@groupstudy.com>
Sent: Wednesday, April 04, 2001 2:45 AM
Subject: ospf-igrp-2 redis-doubts
> Hi All,
> As am getting closer to the lab - am getting more confused I think. Need
> your help with these doubts pls.....
> Thanks,
> RR.
>
> Redistribution Question--1
> IS THIS POSSIBLE?:
> ---------------------------
> scenario: ospf backbone - asbr with area0 and 1 with igrp.
> task : do mutual redistribution and send a def.router to igrp only rtr.
> Assumptions - the regular ones .........no static routes...etc.,
> ... AND--you dont have a (non-ospf) classful subnet - on your network.
> 1.You have to send default route into igrp from an ASBR to a
> remote router only running IGRP.
> 2.Redistributing router is having area 0 and area x and igrp.
> I tried using the following on the asbr:
> acl 1 permit 0.0.0.0 -- and then a
> distribute list out 1 serial 0 -- connecting the remote igrp rtr.
> I didnt see the default route on the igrp router.
> CAN SOMEONE CONFIRM THAT THIS WILL / WILL NOT WORK FOR IGRP? PLS
> my reasoning:
> -------------
> igrp - so no default-info originate;
> choice of ip default network - is not there since there is no classful
> subnets (non-ospf) anywhere in the scenario
NT: Good points..! Once we agree that igrp doesn't know how to interpret
0.0.0.0, then we agree
that a redistributed default-route won't work either. based on the points
you've already identified I
would say that the only options left here is summarization of the ospf
domain to the classful boundary
which igrp should learn.
>
> Redistribution Question--2:
NT: Since igrp has a lower AD than ospf why even bother filtering what
routes ospf gets from igrp. Also why the need for the "distance" command.
This typically used in a scanerio with multiple point of redistribution to
allow redundant route infomation to exist in the network.
Depending on the specifics of the connection, using the ip split-horizion on
the interface connecting the
igrp router should eliminate any possible routing loops. Also, what is the
exact (E2) route being picked up
by ospf...?
> ---------------------------
> Same scenario - if you are given a non-ospf classful network and
> do a 'ip default network a.b.c.0' - i got the default route as
> i wanted. But I had a distribute-list to filter the igrp learnt
> routes to be permited to go to ospf. And THIS stopped the
> 154.14.0.0 - E2 routes from appearing in the ospf routers...??WHY?
> !
> router ospf 1
> redistribute connected metric 1 subnets route-map looponly
> redistribute igrp 1 metric 150 subnets
> passive-interface Serial0
> network 145.2.28.0 0.0.3.255 area 0
> network 145.2.32.0 0.0.0.3 area 5
> distribute-list 34 out igrp 1<---got out of this by removing this.
> !
> router igrp 1
> redistribute ospf 1
> passive-interface BRI0
> passive-interface Ethernet0
> passive-interface Loopback0
> network 145.2.0.0
> default-metric 8000 100 255 1 1500
> distance 120
> !
> ip classless
> ip default-network a.b.c.0
> access-list 10 permit 145.2.3.0 0.0.0.255
> access-list 10 permit 145.2.192.0 0.0.0.255
> access-list 34 permit 145.2.4.0 0.0.0.255
> access-list 34 permit 154.14.0.0 0.0.0.255
> Pls correct if am wrong in this:
> classful-Class B -igrp - with vlsm subnets inside their domain -
> when connected through /24 ip add to a classless - ospf - is sending
> only /16 of the Class B network through IGRP adhering to its nature.
> When this /16 needs to be sent back to rest of network - as long as
> we dont have overlaps of the same network AND we have specific routes
> to other /24 /xx of the same Class B network - we should not have
> reachability problems - provided our configs are fine!
> Your feedback is appreciated.
NT: sounds good to me.....:-)
>
> Thanks,
> RR.
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