Re: Etherchannel misconfig guard

If I remember correctly it only detects if you're negotiating and the
other end is in the wrong channel group. The problem with removing the
channel group and statically setting it on the other end is that there is
no way for the switch to know that this is incorrect. If etherchannel is
set statically on the other end and negotiation is turned off it looks the
same as when etherchannel is not configured at all. Also, there are
several devices which can channel but cannot negotiate.

From:
Dimitar Mojsovski <dimitar.mojsovski_at_gmail.com>
To:
ccielab_at_groupstudy.com
Date:
11/22/2009 11:41 AM
Subject:
Etherchannel misconfig guard
Sent by:
<nobody_at_groupstudy.com>

Hello !

Does anyone have any experience with the Etherchannel guard misconfig
feature ?

I have a setup with 2xCat6500 running in VSS and I have a a Cat2960
connecting to both VSS nodes. Naturally, I bundle the ports to a
port-channel and create a trunk. All is working fine.
At this point I try to test the Etherchannel guard and see what happens.
I deliberately misconfigure the 2960 interfaces (set them to default
with no channel-group), and wait for some (about 5 mins) and I see no
sign of the Etherchannel Misconfig detection. Instead, a bridging loop
occured - which is expected to happen without this feature.

I am able to kind-of escape this problem by negotiating the etherchannel
(auto/desirable), but this is not what I'm trying to accomplish.

Cisco documentation doesen't help me much
Cat6500 etherchannel config guide warns about misconfig, but states no
measure to avoid.
Cat6500 spanning-tree config guide only says this feature exists and
detects misconfigured etherchannels. On most switches it seems to be
enabled by default. On my 6500 it was not.

Thanx

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Received on Sun Nov 22 2009 - 18:03:12 ART