STP issue

 Hi,
I have 3 switches connected in a full mesh at a Customer's site.

One Cisco 6500 switch and 2 NON CISCO switches. The NON CISCO switches have
each 4 physical connections with the 6500 and 2 between each others. the
issue
is the following:

The NON CISCO switches are supposed to form an etherchannel with the 6500,
but
they neither support LACP nor PAGP. Thus the only left etherchannel method is
on.

On the catalyst 6500 the configuration for the etherchannel is correct.

The Loop occurs when my customer misconfigures the etherchannel from the NON
CISCO switches side.

We end up having etherchannel config from one end (6500) and normal links from
the NON CISCO switches end.

Since the etherchannel ports on the 6500 will have the same parameters, all
the NON CISCO ports will end up forwarding and an STP loop is formed causing
the network to go down.

Now etherchannel guard is enabled but it's not putting the ports into error
disable mode on the 6500 ( I guess because of compatibility between Cisco and
Non Cisco Switches).

Is there any way in case the customer misconfigures the NON CISCO switches to
prevent a loop ?

Thx,
Hadi
Received on Wed Oct 14 2009 - 20:43:56 ART