Michale,
I have dot1q trunks running across Cisco MDF switches and Nortel IDF
switches. We found that Cisco and Nortel run two different versions of
Spanning Tree, both of which are 802.1q compliant. The difference between
the two is that Cisco's portfast feature, and Nortel's faststart feature are
different, where portfast has a default forward delay of 15 seconds, and
faststart doesn't implement the forward delay feature.
This resulted in a huge amount of TCN's (topology change notifications),
particularly in the morning, when all end users are booting up their pc's
and changing to 'forwarding' mode in spanning tree. As a result, we opened
a ticket with Nortel, and they agreed to add forward delay to their
switching code to correct this problem.
I would check the STP documentation on both vendors, and determine if all
the default values are the same, what the default root bridge priority
number is with both vendors, who you have configured as your root bridge,
etc. I would even plug a sniffer in and capture some traffic... Draw out a
spanning tree diagram, and document your root bridge, and the subsequent
switches in the spanning tree. Those are just some suggestions... Hope you
find some results.
Chris
>From: [EMAIL PROTECTED]
>Reply-To: [EMAIL PROTECTED]
>To: [EMAIL PROTECTED]
>Subject: Cisco to 3Com Dot1Q trunks and VLANs
>Date: Thu, 11 Jan 2001 13:02:56 -0600
>
>I have the opportunity to create this cross platform network and am looking
>for
>information other than the standard documentation from Cisco and 3Com to
>accomplish this task. The dot1Q trunks appear to be functioning correctly
>between the Cisco 6509 and the 3Com 3300, but the VLANs are not performing
>optimally. Any helpful information or pointers to sites with information
>would
>be greatly appreciated.
>
>Mike
>
>
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