Product guide

Spanning-Tree Operation
802.1D Spanning-Tree Protocol (STP) on 5300xl, 3400cl and 6400cl Switches
state, the server access will fail. To provide support for this end node behavior,
the switches covered by this manual offer a configuration mode, called “Fast
Mode”, that causes the switch port to skip the standard STP start-up sequence
and put the port directly into the “Forwarding” state, thus allowing the server
access request to be forwarded when the end node needs it.
If you encounter end nodes that repeatedly indicate server access failure when
attempting to bring up their network connection, and you have enabled STP
on the switch, try changing the configuration of the switch ports associated
with those end nodes to STP Fast Mode.
Caution The Fast Mode configuration should be used only on switch ports connected
to end nodes. Changing the Mode to Fast on ports connected to hubs, switches,
or routers may cause loops in your network that STP may not be able to
immediately detect, in all cases. This will cause temporary loops in your
network. After the fast start-up sequence, though, the switch ports operate
according to the STP standard, and will adjust their state to eliminate continu-
ing network loops.
To Enable or Disable Fast Mode for a Switch Port: You can use either
the CLI or the menu interface to toggle between STP Fast mode and STP
Normal mode. (To use the menu interface, see “Menu: Configuring 802.1D
STP” on page 6-22.)
Syntax: spanning-tree < port-list > mode <fast | norm>
For example, to configure Fast mode for ports C1-C3 and C5:
ProCurve(config)# spanning-tree c1-c3,c5 mode fast
Fast-Uplink Spanning Tree Protocol (STP)
Fast-Uplink STP is an option added to the switch’s 802.1D STP to improve the
recovery (convergence) time in wiring closet switches with redundant
uplinks. Specifically, a switch having redundant links toward the root device
can decrease the convergence time (or failover) to a new uplink (STP root)
port to as little as ten seconds. To realize this performance, the switch must be:
■ Used as a wiring closet switch (also termed an edge switch or a leaf
switch).
■ Configured for fast-uplink STP mode on two or more ports intended for
redundancy in the direction of the root switch, so that at any time only
one of the redundant ports is expected to be in the forwarding state.
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