Bless you, Chuck! When the Old Ones return, you will spared!
Seriously, many thanks for this thread and your extensive experimentation...
I am now much smarter for it!!
Charles
""Chuck Larrieu"" <[EMAIL PROTECTED]> wrote in message
00a501c029d4$097bfca0$[EMAIL PROTECTED]">news:00a501c029d4$097bfca0$[EMAIL PROTECTED]...
>
> Can't sleep until I make some sense out of this one. After reading the
> many fine replies to my original study I came to believe there was a flaw
in
> my methodology. Tonight's results seem to indicate this was true.
>
> So... for testing purposes I now know another behaviour of OSPF. On
loopback
> interfaces, the default behavior is to treat the loopbacks as stub
networks,
> with a summary of /32 I followed the advice of one Mr. Clue Less, and
> configured all loopbacks as point-to-point networks. ( I should note here
> that it appears that one can not configure loopbacks as broadcast
networks,
> no matter what the circumstance )
>
> Here are the results, using standard configurations. This first result is
> with EIGRP and OSPF both configured more or less mimicking a real network.
>
> Router#
> Router#sh 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
>
> C 192.168.8.0/24 is directly connected, Loopback0
> C 192.168.9.0/24 is directly connected, Loopback1
> C 192.168.10.0/24 is directly connected, Loopback2
> C 192.168.11.0/24 is directly connected, Loopback3
> D 192.168.4.0/24 [90/2297856] via 192.168.254.2, 00:07:44, Serial0
> D 192.168.5.0/24 [90/2297856] via 192.168.254.2, 00:07:44, Serial0
> D 192.168.6.0/24 [90/2297856] via 192.168.254.2, 00:07:44, Serial0
> D 192.168.7.0/24 [90/2297856] via 192.168.254.2, 00:07:44, Serial0
> D 192.168.0.0/24 [90/2809856] via 192.168.254.2, 00:06:14, Serial0
> 192.168.254.0/30 is subnetted, 2 subnets
> D 192.168.254.4 [90/2681856] via 192.168.254.2, 00:07:45, Serial0
> C 192.168.254.0 is directly connected, Serial0
> D 192.168.1.0/24 [90/2809856] via 192.168.254.2, 00:06:14, Serial0
> D 192.168.2.0/24 [90/2809856] via 192.168.254.2, 00:06:15, Serial0
> D 192.168.3.0/24 [90/2809856] via 192.168.254.2, 00:06:15, Serial0
> Router#
> Router#
> Router#sh ip route ospf
>
> Router#sh ip route
>
> Notice that there are no OSPF routes in the RIB at all.
>
> Next, I changed the OSPF administrative distance to 85 ( a bit lower than
> the EIGRP default distance )
>
> Here is the resulting change in the routing table:
>
> Router#sh 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
>
> C 192.168.8.0/24 is directly connected, Loopback0
> C 192.168.9.0/24 is directly connected, Loopback1
> C 192.168.10.0/24 is directly connected, Loopback2
> C 192.168.11.0/24 is directly connected, Loopback3
> O IA 192.168.4.0/24 [85/65] via 192.168.254.2, 00:01:22, Serial0
> O IA 192.168.5.0/24 [85/65] via 192.168.254.2, 00:01:22, Serial0
> O IA 192.168.6.0/24 [85/65] via 192.168.254.2, 00:01:22, Serial0
> O IA 192.168.7.0/24 [85/65] via 192.168.254.2, 00:01:22, Serial0
> O IA 192.168.0.0/24 [85/129] via 192.168.254.2, 00:01:23, Serial0
> 192.168.254.0/30 is subnetted, 2 subnets
> O 192.168.254.4 [85/128] via 192.168.254.2, 00:01:23, Serial0
> C 192.168.254.0 is directly connected, Serial0
> O IA 192.168.1.0/24 [85/129] via 192.168.254.2, 00:01:23, Serial0
> O IA 192.168.2.0/24 [85/129] via 192.168.254.2, 00:01:24, Serial0
> O IA 192.168.3.0/24 [85/129] via 192.168.254.2, 00:01:24, Serial0
> Router#
>
> This is a lot cleaner than what I was showing the other night.
>
> So now - it looks like Mr Cthulu Not Dagon can indeed migrate his real
> network from EIGRP to OSPF with very little problem. There may some issues
> here and there with the way OSPF handles loopbacks, as one caveat. I sure
> like the idea that, if memory serves, Brian proposed - changing the admin
> distances of the protocols, but retaining the EIGRP configurations, so
that
> they would not have to be rebuilt should things go bad with the migration.
>
> I also imagine that one might consider planning redistribution if the
> network were large enough to have to be done in several stages over time.
>
> Once again, configs are available. E-mail me directly and I will send a
> file.
>
> Other points of minor interest. The distance command for the three routing
> protocols I looked at were a bit different - enough to be annoying. Eigrp
> syntax is distance eigrp [internal route value] [external route value]
while
> ospf is distance [admin distance ] more protocol behavior differences to
> keep in mind.
>
> Also, I am putting the router pod on line. Telnet to 64.220.150.9
password
> "hello" ( without the quotes ) for a look. User mode only
> All three routers are open - you will have to daisy chain your telnets.
What
> you will see is the result of the routing table after raising the eigrp
> default distance to 125 ( slightly higher than ospf's 110 )
>
> Can someone test this for me? Everything looks ok from this side. But I do
> not an outside account I can use to test from the internet side.
>
> Chuck
>
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