<div>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.
</div>
<div> </div>
<div>Mike<br></div>
<div class="gmail_quote">On Jan 7, 2008 8:18 AM, Chris Gauthier <<a href="mailto:cgauthie@pcc.edu">cgauthie@pcc.edu</a>> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div text="#000000" bgcolor="#ffffff">Pardon my ignorance, but what is UDLD?<br><br>Chris
<div>
<div></div>
<div class="Wj3C7c"><br><br>Andreas wrote:
<blockquote type="cite"><pre>I would guess that they are incompatible the
<a href="http://www.ietf.org/internet-drafts/draft-foschiano-udld-03.txt" target="_blank">http://www.ietf.org/internet-drafts/draft-foschiano-udld-03.txt</a> 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:
</pre>
<blockquote type="cite"><pre>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:
<a href="mailto:SSH@dr1.nybf#show" target="_blank">SSH@dr1.nybf#show</a> 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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</pre></blockquote><br></div></div><pre cols="72">--
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."
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