Conference netcad::hub_mgnt

3265.0. "Spanning Tree Problems on 900EF" by NETRIX::"[email protected]" (Steven Freke) Mon Feb 12 1996 07:35

Folks, 

I have a network setup more or less in the following way. A Gigaswitch with 2 
FGL card in it and 2 900EF'S. Each FGL card is connected in an FDDI ring to one
of the EFs. The EF's in turn are connected to a 900TM repeater by one of the 
ports out the front. None of the modules are using the backplane except the
900TM. 

The problem is:
The default cost for the bridge ports is 4, and when both bridges have the same 
cost, one goes into backup, and the other forwards as expected. The cost is then
changed to 2 on one of the EF's and the bridges maintain the same state, (one in
backup, and one in forwarding). The cost is then reverted back to 4 and then
the bridges get stuck in a preforwarding state. Noting happens. 
A network trace indicates that there are a lot of spanning tree packets flying
around, but nothing is established by the two bridges.

Firmware:
900EF V1.5.2
SCP V2.2
FGL V2.2
Hub900 V4.1.1

Any ideas would be greatly appreciatted. One more thing, the gigaswitch is 
acting as the route bridge all th time. The two FDDI rings appear to be in a 
stable state all the time.

Steven Freke
UK CSC
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