PLANET GSW-1602SF - Manual (Page 83)

User’s Manual of GSW-1602SF / GSW-2404SF
You can modify each port state by using management software. When you enable STP, every port on every switch in the
network goes through the blocking state and then transitions through the states of listening and learning at power up. If
properly configured, each port stabilizes to the forwarding or blocking state. No packets (except BPDUs) are forwarded
from, or received by, STP enabled ports until the forwarding state is enabled for that port.
STP Parameters
STP Operation Levels
The Switch allows for two levels of operation: the switch level and the port level. The switch level forms a spanning tree
consisting of links between one or more switches. The port level constructs a spanning tree consisting of groups of one or
more ports. The STP operates in much the same way for both levels.
On the switch level, STP calculates the Bridge Identifier for each switch and then sets the Root Bridge
and the Designated Bridges.
On the port level, STP sets the Root Port and the Designated Ports.
The following are the user-configurable STP parameters for the switch level:
Parameter Description Default Value
Bridge Identifier
(Not user configurable except by
setting priority below)
A combination of the User-set priority and the
switch’s MAC address.
The Bridge Identifier consists of two parts:
a 16-bit priority and a 48-bit Ethernet MAC
address 32768 + MAC
32768 + MAC
Priority A relative priority for each switch – lower
numbers give a higher priority and a greater
chance of a given switch being elected as the
root bridge
32768
Hello Time The length of time between broadcasts of the
hello message by the switch
2 seconds
Maximum Age Timer Measures the age of a received BPDU for a port
and ensures that the BPDU is discarded when
its age exceeds the value of the maximum age
timer.
20 seconds
Forward Delay Timer The amount time spent by a port in the learning
and listening states waiting for a
BPDU that may return the port to the blocking
state.
15 seconds
-77-