[rescue] Cisco Weirdness

Jonathan Sadler sadler at homesys.org
Sat Dec 20 18:08:12 CST 2003

On Thu, 20 Nov 2003 21:15:42 -0500, Thomas Gallaway opined:
> I rescued a cisco 2900-XL out of a dumpster.

> So the switch works, I can plug in stuff but here is my problem. Not
> every NIC or  switch I connect works. This is total random. I am able
> to connect a sun nic, a switch and a wireless access point too it but
> an PC's nic or another switch/hub will not get a link. I tried all
> ports and different cables and did not seem to find  anything usefull. 
> I was able to upload the latest IOS image to it but that did not fix
> it. It does not seem that the switch really is bad as I can connect
> to every port and telnet into the switch.  It is just that I can not
> plug everything into it.

Two thoughts:
1. Back when these devices first came out, the whole auto-negotiation
   thing for Ethernet (10/100, Full/Half Duplex) was poorly specified,
   and a number of devices didn't implement it correctly.  Just talk
   to the guys at the UNH Ethernet Test lab (something I get to do as
   a part of my day job :^) and you'll get the picture about how bad
   it really was.  Without pointing fingers, I can say that the company
   with the "bay bridge"-like logo is one of the known culprits.  The
   common workaround is to manually configure speed and duplex.

2. It could be a Ethernet cross-over cable thing...

Hope this helps,

Jonathan Sadler

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