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Hi,

I have a strange problem with some stacks of 2950 switches running rapid
spanning-tree.

We have two stacks:
Stack 1 consists of two 2950 switches. Both switches are connected through
GBIC stacking modules.
Stack 2 consists of three 2950 switches. All connected through GBIC
stacking cables.

Both stacks are connected to the core through 1000sx uplinks on both the
top and bottom switch.

In the stack of two switches, rapid spanning tree will block the GBIC stack
port and forward to the core through the 1000sx uplink. As soon as 1 1000sx
uplink fails, the stack port starts forwarding from the upper to the lower
switch. Fine!

In the stack of three switches however, we see only the 1000sx uplinks on
the top and bottom switches forwarding, but the middle switch (without
1000sx of course) seems 'isolated', no traffic passing through from either
the top or bottom switch.

Is this a known issue or have we forgotten something on port configuration?

Silvan