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Re: Problems connectivity GE on Foundry BigIron to Cisco 2950T

  • From: Martin Hannigan
  • Date: Sun Jan 15 20:49:37 2006

> 
> 
> Hi Randy,
> 
> On Sun, 15 Jan 2006 11:10:04 -1000
> Randy Bush <randy@psg.com> wrote:
> 
> > 
> > > You are using a crossover cable right?
> > >> I'm having a right mare trying to get a Foundry BigIron to 
> > >> connect up to a cisco 2950T, via Gigabit copper.
> > 
> > i was under the impression that gige spec handled crossover
> > automagically
> > 
> 
> According to "Ethernet, The Definitive Guide", that feature is an
> optional part of the spec.
> 
> One thing I've heard people encounter is that if they use a cross-over
> cable, which probably really implies a 100BASE-TX cross-over, then the
> ports only go to 100Mbps. A Gig-E rated straight through, in conjunction

And a GE rated cable is CAT5. Non transmission is using multi mode
and all long haul transmission uses single mode. If you review the
gig spec, it was designed for CAT5. Regardless, I always use CAT6
and I stick with the standard ethernet caps although I tend to go
upscale on the caps and the compresssion tools i.e. calibrateable
and matching to caps. For example, at mumble carrier, we spent weeks
in the labs qualifying cable, caps, and crimpers - copper and 
coax - and then making it a systemwide standard for techs and vendors.

Funny story though. Mumblecarrier had people walking by tugging on 
the new ds3 installations and they started falling out. The center
managers started mailing each other and then all of a sudden the 
freakin' things were falling out all over the country. I went out
to one of the datacenters, jacked up the test gear, and started 
looking at it. While I was sitting there being stumped as to what 
was happening, I watched no less than ten people walk by and tug
on the cross connects. The next day, same thing and they'd look
at me and go "SEE!!! THEY FALL OUT!!!!!". 

What had happened was mass cable hysteria. Once the center managers
started telling each other to "pull on the xcons" they all started
being stressed and then they had every tech pulling on them and 
if you pull on it enough - it will fall out. 

Thank you for allowing me that off topic spew. :-)

-M<




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