RE: UDLD recommendations

As I stated, UDLD aggressive mode has disabled non-one way links, esp with copper... its off in my networks... sorry

-----Original Message-----
From: Carlos G Mendioroz [mailto:tron_at_huapi.ba.ar]
Sent: Sunday, September 11, 2011 9:56 AM
To: Joseph L. Brunner
Cc: Atle Xrn Hardarson; Ccielab_at_groupstudy.com
Subject: Re: UDLD recommendations

Joseph,
I don't think the physician metaphor applies, or else, you'd rather do
the IP routing on all the networks by hand ???
The time it takes for a human to react to an event is HUGE compared to
an automatic procedure. I guess we all agree on that.

What IMHO is important in your argument is that UDLD is not dependable.
I have no direct experience to such faults, anyone else care to comment?

-Carlos

Joseph L. Brunner @ 11/09/2011 06:01 -0300 dixit:
>> Surely, in a critical, redundant environment one would configure aggressive mode instead of normal mode?
>
> No because taking a whole link down is a major event in a production network. Your network should get the alerts to peoples smartphones/screens who can fix the issue and determine if further action is required before taking a link down and re-routing traffic to a different layer 2 path.
>
> Also, UDLD is not always very accurate - so you may not want to trust it... I have had it fail on copper many times and think the link was unidirectional, simply because of poor copper links, etc.
>
> You're missing the fact the UDLD feature is not as good at detecting an issue as a qualified person responding to an alert...
>
> "Would you want UDLD to perform brain surgery on your child or a skilled physician?
>
> -Joe
>
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Atle Xrn Hardarson
> Sent: Saturday, September 10, 2011 9:22 AM
> To: Ccielab_at_groupstudy.com
> Subject: UDLD recommendations
>
> Hi guys
>
> I was reading up on UDLD, and I have always wondered why Cisco recommends
> normal mode for UDLD, and not aggressive mode?
> Surely, in a critical, redundant environment one would configure aggressive
> mode instead of normal mode?
> Personally, I would much rather see my network loose a link with UDLD
> shutdown of a port, than causing a potential bridging loop in the entire L2
> domain.
>
> Can anyone shed some light on this? What am I missing?
>
> Atle
>
>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net