ES-2048 User’s Guide
Chapter 33 Configuration Mode Commands 251
33.3 Enabling STP
Use the spanning-tree commands to enable and configure STP on the switch.
Syntax:
spanning-tree
spanning-tree priority <0-61440>
spanning-tree hello-time <1-10> maximum-age <6-40> forward-delay <4-30>
spanning-tree <port-list> path-cost <1-65535>
spanning-tree <port-list> priority <0-255>
where
spanning-tree
= Enables STP on the switch.
priority <0-61440>
= Specifies the bridge priority for the switch. The lower the
numeric value you assign, the higher the priority for this bridge.
Bridge priority is used in determining the root switch, root port
and designated port. The switch with the highest priority
(lowest numeric value) becomes the STP root switch. If all
switches have the same priority, the switch with the lowest
MAC address will then become the root switch.
Bridge Priority determines the root bridge, which in turn
determines Hello Time, Max Age and Forwarding Delay.
hello-time <1-10>
= Specifies the time interval in seconds between BPDU (Bridge
Protocol Data Units) configuration message generations by the
root switch.
maximum-age <6-40>
= Specifies the maximum time (in seconds) a switch can wait
without receiving a BPDU before attempting to reconfigure. All
switch ports (except for designated ports) should receive
BPDUs at regular intervals. Any port that ages out STP
information (provided in the last BPDU) becomes the
designated port for the attached LAN. If it is a root port, a new
root port is selected from among the switch ports attached to the
network.
forward-delay <4-
30>
= Specifies the maximum time (in seconds) a switch will wait
before changing states. This delay is required because every
switch must receive information about topology changes before
it starts to forward frames. In addition, each port needs time to
listen for conflicting information that would make it return to a
blocking state; otherwise, temporary data loops might result.
