in this case definitely. No adjacency formed because the ip address was duplicate. Once I sorted this problem then the adjacency came in so in this scenario I would definitely say that Jeff Doyle is wrong. -----Original Message----- From: tom cheung [mailto:[EMAIL PROTECTED]] Sent: 14 April 2001 15:02 To: [EMAIL PROTECTED] Subject: RE: Unusual Aspect of a duplicate IP Address According to Doyle's book Pp 648: "An interesting side effect of the fact that ISIS is a CLNS protocol is that the IP addresses of neighboring routers have NO INFLUNECE ON THE FORMATION OF ADJANCIES......... another result is that two interfaces with IP addresses from completely different subnets can become adjacnet." Is Jeff Doyle wrong? >From: "McCallum, Robert" >To: 'tom cheung' >Subject: RE: Unusual Aspect of a duplicate IP Address >Date: Sat, 14 Apr 2001 10:38:15 +0100 > >EEEEEEHHHHH ! WRONG!!!! > >-----Original Message----- >From: tom cheung [mailto:[EMAIL PROTECTED]] >Sent: 12 April 2001 19:09 >To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; >[EMAIL PROTECTED] >Subject: Re: Unusual Aspect of a duplicate IP Address > > >ISIS uses CLNS to form adjancies. IP has nothing to do with it. It'll >form > >adjancies, if I'm not mistaken, even when router A and B are on different >subnets. > > > >From: "McCallum, Robert" > >Reply-To: "McCallum, Robert" > >To: "'Ccielab' (E-mail)" , > >"Cisco@Groupstudy. Com (E-mail)" > >Subject: Unusual Aspect of a duplicate IP Address > >Date: Thu, 12 Apr 2001 16:59:32 +0100 > > > >Here is a scenario which caught me out BIG time in a real life situation > >using ISIS. > > > >To make it easier > > > >Router A has a serial connection to Router B > > > > > >Everything is up layer 1 & 2i.e CDP can indeed see Router B if you are on > >Router A and vice versa. Router B can't see any routes from Router A or > >beyond. > > > >NOW Routers A serial 0's ip address is 172.16.130.5, Routers B serial >0's > >ip address is 172.16.130.5. > > > >Spot the deliberate mistake. > > > >Although you say AHA he has the same ip address on the serial >connections. > >SO, quite rightly ISIS says, go away I will never make an adjacency with > >myself !!!! :-( > > > >However, it took me quite a while to discover that these IP addresses >were > >indeed duplicated. > > > >REASON or should I make it a question? I think question would be better. > > > >Q: What do you think would happen if I was on Router A and telnetted to > >172.16.130.5, would I telnet to Router A or B. :-> > > > >A: This is why it took me a while to realise this. I started debugging > >adjacencies, blaming a new controller card which was the first time I had > >used this in ISIS, everything bar the easy problem. Mental Note for me > >here > >is don't dive in head first, always fault find the layers and remember >this > >fault because it is nasty!!!! :- > > >What made it worse was the customer sitting over my shoulder saying WHY > >isn't this working, I knew we shouldn't have bought those new fangled > >router > >things!!!!! > > > >Oh the joys of life!!!! >_________________________________________________________________ >Get your FREE download of MSN Explorer at http://explorer.msn.com > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=707&t=707 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
