From: richard.harvey@nbs.nhs.uk
Date: Thu Jul 28 2005 - 05:19:13 GMT-3
As I understand it, the autonegotiation mechanism (on by default) for a GigE port will pick up on simple layer 1 problems such as one side of the link being manually disconnnected.
UDLD will pick up on more subtle problems at layer-2 where the actual frames are only passing in one direction (due to fibre cable degradation etc). I have seen UDLD successfully shut down poor fibre connections that were later tested to be faulty.
Richard Harvey
-----Original Message-----
From: MIME :caccamucca@hotmail.com Sent: 28 July 2005 00:25
To: eward15@juno.com; nelsnjr@cox.net
Cc: John.Sheahan@priceline.com; ccielab@groupstudy.com
Subject: Re: UDLD
You must have UDLD configured on BOTH sides to work.
>From: "Eugene Ward" <eward15@juno.com>
>Reply-To: "Eugene Ward" <eward15@juno.com>
>To: nelsnjr@cox.net
>CC: John.Sheahan@priceline.com, ccielab@groupstudy.com
>Subject: Re: UDLD
>Date: Wed, 27 Jul 2005 23:15:32 GMT
>
>Bob,
>
>I thought that if a layer 1 problem occurred (fiber break on one side), >that the port would transition down as expected. I also thought UDLD was >used when the Layer 1 is up and Layer 2 is transmitting in one direction. >Any thoughts?
>
>Eugene Ward
>
>-----------------------------------------------------------------------
>
>
>John:
>
>Thanks for the reply. I tried your suggestion, but I still get the same
>results.
>I used the udld reset command and got the reply that no ports were disabled
>by UDLD.
> cat3550-1#udld reset
> No ports are disabled by UDLD.
>
>Bob
>
>----- Original Message -----
>From: "Sheahan, John" <John.Sheahan@priceline.com>
>To: "Bob Nelson" <nelsnjr@cox.net>; <ccielab@groupstudy.com&g
>t;
>Sent: Wednesday, July 27, 2005 1:13 PM
>Subject: RE: UDLD
>
>
>UDLD ensures the port disables when one piece of fiber is disconnected.
>What you might want to do is disable UDLD and try the same experiment.
>You might then see the port stay active longer than with UDLD enabled.
>
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>Bob Nelson
>Sent: Wednesday, July 27, 2005 3:40 PM
>To: ccielab@groupstudy.com
>Subject: UDLD
>
>Wondering if any has been able to test UDLD shutting down an interface
>on
>fiber ports.
>I have it configured and it says enabled, but when I pull one-half of
>the
>connection
>to the switch, the port just goes down normally.
>
>I have tried both normal and aggressive modes and have even tried
>reversing
>the transmit and receive plugs, but the port seems to just go down
>normally
>with no indication of UDLD involvement.
>
>Any ideas?
>
>Thanks
>
>Bob
>
>_____
>
>___________________________________________________________________
>Try Juno Platinum for Free! Then, only $9.95/month!
>Unlimited Internet Access with 250MB of Email Storage.
>Visit http://www.juno.com/value to sign up today!
>
>_______________________________________________________________________
>Subscription information may be found at:
>http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Sun Sep 04 2005 - 17:00:31 GMT-3