On 5/16/06, Raja Subramanian <[EMAIL PROTECTED]> wrote:
...
In my current setup it seems that my switch does not permit
the same MAC ID (of my router NIC) to appear on different
VLANs.  So long as I have only one vlan interface up at any
given time, everything works perfectly.

Right.  The 802.1Q spec for ethernet vlans did not specify whether the
spanning tree was per-VLAN or shared among them.  As a result, many
(most?) vendors just used a single tree, which breaks setups where the
(active) port to use for a given device can vary by VLAN.  Check the
documentation, particularly the documentation for the firmware
patches, for a configuration switch that enables something like
"spanning tree per VLAN" and enable it.

(I recall hitting this back in, uh, 1999 or so while working with a
bunch of 3com switches at a previous job.  3com ended up releasing
firmware upgrades that added such a configuration option, but man was
it frustrating trying to figure out why it wasn't working.  The
doubly-connected device would only be able to see the first VLAN that
it sent out on...)


Philip Guenther

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