RE: igrp: advertise loopbacks as subnets?

From: John.K.Feuerherd@xxxxxxxxxxxxxx
Date: Thu Aug 09 2001 - 01:18:52 GMT-3


   
Daniel,
Remember that IGRP will perform subnet hiding, or summarization at network
boundaries.

In this example the updates are going out SE0 which is on the 10.1.8.0/24
network. IGRP will summarize all networks that are not part of the
10.x.x.x/24 class into "system" routes out that interface. So that is why
you are see the 172.27.0.0 and the 15.0.0.0 entries in the update, they are
being summarized.

JF

-----Original Message-----
From: Daniel C. Young [mailto:danyoung99@mediaone.net]
Sent: Wednesday, August 08, 2001 8:23 PM
To: ccielab@groupstudy.com
Subject: igrp: advertise loopbacks as subnets?

Group,

Does IGRP advertise loopbacks or ethernet segments as network summaries
only? With token ring it seems to advertise the subnet just fine. I have the
following configuration:

interface Loopback0
 ip address 15.15.8.8 255.255.255.0
!
interface Ethernet0
 ip address 172.27.1.1 255.255.255.0
 no keepalive
!
interface Ethernet1
 ip address 172.27.2.1 255.255.255.0
 no keepalive
!
interface Serial0
 ip address 10.1.10.8 255.255.255.0
!
interface TokenRing0
 ip address 10.2.1.1 255.255.255.0
 ring-speed 16
!
interface TokenRing1
 ip address 10.3.1.1 255.255.255.0
 ring-speed 16
!
router igrp 1
 passive-interface Ethernet0
 passive-interface Ethernet1
 passive-interface Loopback0
 passive-interface TokenRing0
 passive-interface TokenRing1
 network 10.0.0.0
 network 15.0.0.0
 network 172.27.0.0

As you can see, IGRP is advertising the TR interfaces as subnets, but only
classful network summaries for the ethernet and loopbacks. The remote router
is not receiving the route for the loopback address as well.

06:14:50: IGRP: sending update to 255.255.255.255 via Serial0 (10.1.10.8)
06:14:50: subnet 10.3.1.0, metric=688
06:14:50: subnet 10.2.1.0, metric=688
06:14:50: network 172.27.0.0, metric=1100
06:14:50: network 15.0.0.0, metric=501
06:14:50: IGRP: Update contains 2 interior, 2 system, and 0 exterior routes.
06:14:50: IGRP: Total routes in update: 406:17:50: IGRP: received update
from 10.1.10.6 on Serial0

Am I missing something obvious?

Please help.

Daniel C. Young
Sr. Network Engineer
(909) 221-1928 Direct
dan.young@sbc.com

SBC Internet Data Center
2681 Kelvin Ave.
Irvine, CA 92614
(949) 221-1900 Main
(949) 221-1978 Fax
**Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html



This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:31:47 GMT-3