Re: ATT bit

From: Sameh El Tawil (eltawil@free.fr)
Date: Tue Oct 05 2004 - 18:00:54 GMT-3


James,
Actually no adjacency comes up of any kind.. Fortunately I have not erased
the configs. Let me show you :

                                   2610 eth0/0 ---- 2612 eth0/0

2610 Config:
-----------------
interface Ethernet0/0
 ip address 172.16.19.3 255.255.255.0
 ip router isis
 half-duplex
!
interface Serial0/0
 no ip address
 ip router isis
 no fair-queue
!
interface BRI0/0
 no ip address
 shutdown
!
router isis
 net 00.0002.0008.213c.8c80.00
 metric-style wide
 log-adjacency-changes
!

2612 Config:
-------------
interface Ethernet0/0
 ip address 172.16.18.15 255.255.255.0
 ip router isis
 half-duplex
!
interface Serial0/0
 no ip address
 ip router isis
 shutdown
 no fair-queue
!
interface TokenRing0/0
 no ip address
 shutdown
 ring-speed 16
!
interface BRI0/0
 no ip address
 encapsulation hdlc
 shutdown
!
router isis
 net 00.0002.00b0.6426.3f20.00
 metric-style wide
 log-adjacency-changes
!
----------------------------------------
Apparently no adjacency is coming up:
----------------------------------------
2610#sh clns ne

2610#
---------------------------------
A debug isis adj shows you why:
---------------------------------

2610#debug isis adj
IS-IS Adjacency related packets debugging is on
2610#
*Mar 1 00:12:39: ISIS-Adj: Rec L1 IIH from 00b0.6426.3f20 (Ethernet0/0),
cir type L1L2, cir id 00B0.6426.3F20.02, length 1497
*Mar 1 00:12:39: ISIS-Adj: No usable IP interface addresses in LAN IIH from
Ethernet0/0
2610#

----- Original Message -----
From: "James" <james@towardex.com>
To: "Sameh El Tawil" <eltawil@free.fr>
Cc: <gladston@br.ibm.com>; <ccielab@groupstudy.com>
Sent: Tuesday, October 05, 2004 10:27 PM
Subject: Re: ATT bit

> On Tue, Oct 05, 2004 at 06:12:10PM +0200, Sameh El Tawil wrote:
> > I have seen the same thing when I was testing ISIS in my lab. The
attached
> > bit is taken into consideration and generates the default route by
default.
> > There is no need to enable CLNS routing.
> >
> > My guess is that the ISIS implementation has evolved a lot since the
Doyle
> > book was published. This is not the only thing that doesn't tally.
> >
> > Another example is the statement that ISIS adjacencies do not take into
> > consideration the interface IP addresses. ISIS adjacencies DO take the
> > configured interface IP address into account. If you try to bring up an
ISIS
> > adjacency with a neighbor that is not part of the locally configured
subnet,
> > it won't come up.
>
> Hmm are you sure? Does IP ISIS not come up, but does CLNS maintain adj?
>
> Just asking/curious...
>
> -J
>
> --
> James Jun TowardEX
Technologies, Inc.
> Technical Lead Network Design, Consulting, IT
Outsourcing
> james@towardex.com Boston-based Colocation & Bandwidth
Services
> cell: 1(978)-394-2867 web: http://www.towardex.com , noc:
www.twdx.net
>
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