Re: [nsp] MM/SM gbics/cables

From: Robert E. Seastrom (rs@seastrom.com)
Date: Fri Nov 16 2001 - 10:29:22 EST


You're probably overdriving the receivers. Put in a 5 dB attenuator
on each direction (or on transmit on both ends) and see if that works.
At gige speeds, you should be able to go reasonable distances with LX
gbics on MM glass.

                                        ---Rob

Mikael Abrahamsson <swmike@swm.pp.se> writes:

> I'm trying to figure out if Singlemode (LX) GBICS will work using
> Multimode cabling.
>
> Experiences so far are that if I insert MM cables into LX gbics then I do
> not get link. If I unplug the MM connector a few millimeters in one or
> both ends, then I get a link and I seem to be able to transfer data
> correctly. So far I have not seen any CRC errors on the link in question.
> (100.000 packets tested so far).
>
> The cable I'm using is only 5 meters, I'm going to try with a 100 meter
> cable later on.
>
> Does anyone KNOW if this is a setup that should work? I talked to one
> person who said that SM gbics are supposed to work the same distance in MM
> cabling as the MM gbics, ie around 500-1000 meters or so, but I have not
> heard this before.
>
> I have two reasons for this, first of all I want to know in case I ever
> have to do an emergency patch somewhere and I only happen to have MM
> cabling available. Secondly I have a case where I need to do a temporary
> setup and I only have long MM cabling and we do not use MM gbics but have
> plenty of SM gbics.
>
> SM=singlemode=LX
> MM=multimode=SX
>
> --
> Mikael Abrahamsson email: swmike@swm.pp.se



This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:54 EDT