Newsgroups: comp.dcom.sys.cisco
Path: utzoo!utgpu!cunews!bnrgate!bwdls61!bwdls56!fortinp
From: fortinp@bwdls56.bnr.ca (Pierre Fortin)
Subject: Re: Funny Story
Message-ID: <1991Jun28.233723.10989@bwdls61.bnr.ca>
Sender: usenet@bwdls61.bnr.ca (Use Net)
Nntp-Posting-Host: bwdls56
Reply-To: fortinp@bwdls56.bnr.ca (Pierre Fortin)
Organization: Bell-Northern Research, Ottawa, Canada
References:  <1991Jun26.193714.26266@cirrus.com>
Date: Fri, 28 Jun 1991 23:37:23 GMT

In article <1991Jun26.193714.26266@cirrus.com>, tjt@cirrus.com (Tim Tessin) writes:
|> 
|> Subtitle: Gosh darn it Cisco, ya build these damn things too robustly!
|> 
[stuff deleted]
|> The Problem: crossed serial lines (Thanks Cisco Support!)
|> 
|> 
|> 	 ------         -----     t1     -----         ------
|> 	 |    |---   ---|CSU|------------|CSU|---------|    |
|> 	 |    |   \ /   -----            -----         |    |
|>       |AGS |    x                                   |CGS |
|> 	 |    |   / \   -----     t1     -----         |    |
|> 	 |    |---   ---|CSU|------------|CSU|---------|    |
|> 	 ------         -----            -----         ------
|> 

I had a similar situation here for a short time but my topology was a little 
more complex:
 
                                  |--R4----------------R5--|
         |--R1--\ /-----------R3--|                        |
         |       X                                         |
         |--R2--/ \------------------------------------R6--|

Mind you, there were actually multiple Ethernets involved and many more serial
links, but this triangle managed to get the packets through!!!!  The clue that 
something was wrong was a complaint about throughput in this section relative to 
the rest of the network (all T1 in the metro).  I found that some packets were
traversing the same link up to four times (twice in each direction) until they
managed to figure out how to get to the ultimate destination.  

So I agree:   too damn robust...   :^)

|> Who would ever suspect that this stuff would run for over 9 months and
|> 2 upgrades when the two ends of the serial lines aren't connected to their
|> respective networks.  The only reason it even broke at all was the fact that
|> in 8.2(4) the software pays attention to the appletalk addresses on the serial 
|> interfaces and the mismatched addresses prevented routing information from
|> being transmitted.  

Well, *I* believe you...

|> Hey Cisco, to heck with my expensive T1's.  I'm gonna
|> try plugging an interface card in to the 110v socket.  PG&E rates are much
|> better that Pac Bell.  Hmmm, Cisco routes over 15,000 watts per second....

Hey!  You weren't supposed to say anything about that...  cisco is still trying 
to figure out how to handle the influx of user generated watts which, in some
jurisdictions, may be flowed into the power grid...  The routing of these watts
is still not fully understood in the Opens and Shorts Power Flow (OSPF) protocol. 

Ooops, I think we both blew our non-disclosures.  
|> 
|> -- 
|> Tim Tessin 
|> tjt@cirrus.com
|> uunet!cirrus.com!tjt

-- 
Cheers,                      
Pierre Fortin       fortinp@bnr.ca         (613)763-2598