[f-nsp] Foundry and Cisco UDLD different?

Chris Gauthier cgauthie at pcc.edu
Mon Jan 7 13:35:22 EST 2008


Thanks for all the answers, both public and private.  I have a better 
sense of UDLD now.  :)

Happy Monday,

Chris

Mike Allen wrote:
> UDLD is what you are enabling by using the link-keepalive commands.  
> It references Uni-Directional Link Detection, and this is incompatible 
> between vendors, as there is no universal standard.  There are some 
> options that may or may not work for you, depending on the interface 
> (media) type, such as LFS, RFN, or some tweaks that have been made to 
> LACP.  The basic problem that any of these solve is the one of a 
> single fiber failure in a multiple interface link.  Normal behavior in 
> the past would be for the link still recieving light (intact recieve 
> path) would stay up, even though the transmit side of that same link 
> was broken.  The fact that the link stays up prevents the switch from 
> failing over to a failover or redundant (trunk) link, and blackhole 
> traffic down a broken fiber when there are alternate paths available. 
> Hope that helps.
>  
> Mike
> On Jan 7, 2008 8:18 AM, Chris Gauthier <cgauthie at pcc.edu 
> <mailto:cgauthie at pcc.edu>> wrote:
>
>     Pardon my ignorance, but what is UDLD?
>
>     Chris
>
>
>     Andreas wrote:
>>     I would guess that they are incompatible the
>>     http://www.ietf.org/internet-drafts/draft-foschiano-udld-03.txt is
>>     preatty new and I guess that the "standards" for it isn't implemented
>>     correct in one of the platform. I  guess you could ask Foundry or Cisco
>>     if they do support UDLD between different vendor devices.
>>
>>     Regards Andreas
>>
>>
>>     On Mon, 2008-01-07 at 16:50 +0100, Christian Bering wrote:
>>       
>>>     Hi all,
>>>
>>>     Googling the archives I haven't been able to come up with an answer to
>>>     subj.
>>>
>>>     I am unable to establish UDLD between a Cisco 7600 and a Foundry MLX.
>>>     I have tried setting the Foundry values to what I think is default on
>>>     Cisco, but with no luck:
>>>
>>>     SSH at dr1.nybf#show <mailto:SSH at dr1.nybf#show> link-keep
>>>     Total link-keepalive enabled ports: 1
>>>     Keepalive Retries: 5    Keepalive Interval: 7 * 100 MilliSec.
>>>
>>>     Port    Physical Link   Link-keepalive  Logical link  
>>>     1/3     up              down            down          
>>>
>>>
>>>     cr1.hors#show udld tenGigabitEthernet 4/1
>>>
>>>     Interface Te4/1
>>>     ---
>>>     Port enable administrative configuration setting: Enabled
>>>     Port enable operational state: Enabled
>>>     Current bidirectional state: Unknown
>>>     Current operational state: Advertisement
>>>     Message interval: 7
>>>     Time out interval: 5
>>>     No neighbor cache information stored
>>>
>>>     Are they incompatible or am I just using wrong values?
>>>
>>>     Thanks,
>>>
>>>     Christian Bering
>>>
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>
>     -- 
>     Chris Gauthier, CCNA, Network+, A+
>     Network Administration Team
>     Portland Community College
>     Portland, Oregon
>
>     "For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return."
>     --Leonardo da Vinci
>
>
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>

-- 
Chris Gauthier, CCNA, Network+, A+
Network Administration Team
Portland Community College
Portland, Oregon

"For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return."
--Leonardo da Vinci

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