Well, I couldn't resist. I had the router pod set up for a RIP to EIGRP
migration test yesterday. I am not sure that the results will soothe your
concerns, Mr. Cthulu.
I would post configurations, but the file size exceeds what Paul allows.
Those who are interested, contact me off line, and I will send you a text
file with configurations and routing tables.
Following is a routing table resulting from placing OSPF onto a router
already running EIGRP. Note that OSPF routes with a mask of /32 are being
placed into the routing table. I am not sure why this is happening. Several
tweaks have failed to eliminate these routes. Nor did changing the EIGRP
distance to 115 ( higher than OSPF's 110 ) eliminate EIGRP routes from the
routing table.
So now I have to wonder what is happening.
If no one has a quick and good explanation, I'll try to post configs and
fool with this some more. Possibly I can place the routers on line and let
folks poke around
Look forward to some more discussion. Customer visits tomorrow, so I won't
be back on line until very late in the day.
Chuck
Router# show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter
area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
192.168.8.0/24 is variably subnetted, 2 subnets, 2 masks
D 192.168.8.0/24 [90/2809856] via 192.168.254.5, 23:15:32, Serial1
O IA 192.168.8.1/32 [110/129] via 192.168.254.5, 00:05:44, Serial1
192.168.9.0/24 is variably subnetted, 2 subnets, 2 masks
O IA 192.168.9.1/32 [110/129] via 192.168.254.5, 00:05:45, Serial1
D 192.168.9.0/24 [90/2809856] via 192.168.254.5, 23:15:32, Serial1
192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
D 192.168.10.0/24 [90/2809856] via 192.168.254.5, 23:15:33, Serial1
O IA 192.168.10.1/32 [110/129] via 192.168.254.5, 00:05:46, Serial1
192.168.11.0/24 is variably subnetted, 2 subnets, 2 masks
O IA 192.168.11.1/32 [110/129] via 192.168.254.5, 00:05:46, Serial1
D 192.168.11.0/24 [90/2809856] via 192.168.254.5, 23:15:33, Serial1
192.168.4.0/24 is variably subnetted, 2 subnets, 2 masks
D 192.168.4.0/24 [90/2297856] via 192.168.254.5, 23:15:34, Serial1
O IA 192.168.4.1/32 [110/65] via 192.168.254.5, 00:05:47, Serial1
192.168.5.0/24 is variably subnetted, 2 subnets, 2 masks
O IA 192.168.5.1/32 [110/65] via 192.168.254.5, 00:05:47, Serial1
D 192.168.5.0/24 [90/2297856] via 192.168.254.5, 23:15:34, Serial1
192.168.6.0/24 is variably subnetted, 2 subnets, 2 masks
D 192.168.6.0/24 [90/2297856] via 192.168.254.5, 23:15:34, Serial1
O IA 192.168.6.1/32 [110/65] via 192.168.254.5, 00:05:47, Serial1
192.168.7.0/24 is variably subnetted, 2 subnets, 2 masks
O IA 192.168.7.1/32 [110/65] via 192.168.254.5, 00:05:47, Serial1
D 192.168.7.0/24 [90/2297856] via 192.168.254.5, 23:15:34, Serial1
C 192.168.0.0/24 is directly connected, Loopback0
192.168.254.0/24 is variably subnetted, 3 subnets, 2 masks
C 192.168.254.4/30 is directly connected, Serial1
D 192.168.254.0/24 is a summary, 23:15:36, Null0
D 192.168.254.0/30 [90/2681856] via 192.168.254.5, 23:15:35, Serial1
C 192.168.1.0/24 is directly connected, Loopback1
C 192.168.2.0/24 is directly connected, Loopback2
C 192.168.3.0/24 is directly connected, Loopback3
Router#
Router#
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of
Cthulu, CCIE Candidate It's Not Dagon
Sent: Tuesday, September 26, 2000 11:29 AM
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Subject: Re: Migrating from EIGRP to OSPF
Hey, Brian,
Thanks for the info. I have some comments/clarification.
>EIGRP carries a lower administrative distance vs. EIGRP.
CR: You mean EIGRP (90) has a lower AD than OSPF (110)?
So you can
>basically turn up OSPF on your routers, and then when it all looks kosher,
>what I would do is raise the administrative distance of EIGRP above
>OSPF..........this will cause the EIGRP routes to phase out and OSPF to
>be used. If it all goes crazy........you can revert by simply moving
>EIGRP back to the default administrative distance. If you were to have
>cleared out your EIGRP config......it would be difficult to put things
>back..........
CR: That is an excellent suggestion! It would be easy to write a script
that lower/raise as needed. Thank you!
>Ok, why would a more specific route be inserted in OSPF vs. EIGRP? If you
>deploy your OSPF to match that of your EIGRP, this should not
>happen.......its definitly avoidable.
CR: I was not clear on this. What I meant to say was that if EIGRP has a
more specific/longest match route than OSPF (or vice versa), that route will
be inserted in the routing table rather than the OSPF route. Recalling past
groupstudy discussions, a learned route gets inserted in the routing table
in order of preference of:
1. Most specific/longest match
2. administrative distance
3. cost (metrics)
I had a situation where a more specific EIGRP route stayed in the routing
table even though adjustments has been made to prefer OSPF. For example, if
you enter a network 1.1.1.1 0.0.0.0 area 0 command under OSPF, the mask that
gets advertised with this route by OSPF is whatever mask you have on the
interface. Another thing is that if you advertise loopback interfaces, OSPF
treats them as stub hosts (with a /32 mask); therfore, the route from OSPF
will be inserted in the routing table as it is more specific/longest match,
rather than the same route learned from EIGRP with its lower administrative
distance. These are the types of problems I want to minimize.
Many thanks, Brian, for the suggestions and feedback!
Charles
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
Share information about yourself, create your own public profile at
http://profiles.msn.com.
**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
_________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
_________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
