The decision process for putting a route in the table is (roughly from my poor memory so correct at will) is: 1. most specific/longest match 2. AD 3. metrics/cost stuff 4. lunar alignment (just kidding, I forgot this one) So, since OSPF will always advertise loopbacks with a /32, they will almost always be inserted in the table even if EIGRP is advertising the same network and has a lower AD. HTH, CHarles >From: Brian <[EMAIL PROTECTED]> >To: Chuck Larrieu <[EMAIL PROTECTED]> >CC: "Cthulu, CCIE Candidate It's Not Dagon" <[EMAIL PROTECTED]>, > [EMAIL PROTECTED] >Subject: RE: Migrating from EIGRP to OSPF - Bad News! >Date: Wed, 27 Sep 2000 08:27:26 -0500 (CDT) > > >The /32's are those the loopbacks? > >raising the EIGRP AD should work, it may take some time for the route to >be invalidated though. > >Brian > > >On Tue, 26 Sep 2000, Chuck Larrieu wrote: > > > 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] > > > >----------------------------------------------- >Brian Feeny, CCNA, CCDA [EMAIL PROTECTED] >Network Administrator >ShreveNet Inc. (ASN 11881) > _________________________________________________________________________ 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]
RE: Migrating from EIGRP to OSPF - Bad News!
Cthulu, CCIE Candidate It's Not Dagon Wed, 27 Sep 2000 07:40:44 -0700
- RE: Migrating from EIGRP to OSPF - B... Phil Barker
- RE: Migrating from EIGRP to OSP... Cthulu, CCIE Candidate It's Not Dagon
- RE: Migrating from EIGRP to OSP... jenny . mcleod
- RE: Migrating from EIGRP to OSP... Nicholas Monjo
- RE: Migrating from EIGRP to OSP... Lauren_Dygowski
