Product guide

Spanning-Tree Operation
802.1D Spanning-Tree Protocol (STP) on 5300xl, 3400cl and 6400cl Switches
Note When you add a port to a trunk, the port takes on the STP mode configured
for the trunk, regardless of which STP mode was configured on the port before
it was added to the trunk. Thus, all ports belonging to a trunk configured with
Uplink in the STP Mode field will operate in the fast-uplink mode. (If you remove
a port from a trunk, the port reverts to the STP Mode setting it had before you
added the port to the trunk.)
To use fast uplink over a trunk, you must:
1. Create the trunk.
2. Configure the trunk for fast uplink in the same way that you would
configure an individual port for fast uplink.
When you first create a port trunk, its STP Mode setting will be
Norm, regardless
of whether one or more ports in the trunk are set to fast uplink (Mode =
Uplink).
You must still specifically configure the trunk Mode setting to
Uplink. Similarly,
if you eliminate a trunk, the Mode setting on the individual ports in the trunk
will return to their previous settings.
For Troubleshooting Information on Fast Uplink. Refer to the section
titled “Spanning-Tree Protocol (STP) and Fast-Uplink Problems” in appendix
C, “Troubleshooting” in the Management and Configuration Guide for your
switch.
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