Re: UDLD recommendations

I've seen the same with media converters.

Sent from handheld

On Sep 11, 2011, at 10:49 AM, "Joseph L. Brunner" <joe_at_affirmedsystems.com> wrote:

> 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
>>
>>
>> Blogs and organic groups at http://www.ccie.net
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>>
>>
>>
>
> --
> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
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Received on Sun Sep 11 2011 - 18:41:39 ART