GE GE-DS-242-POE, User Manual

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Chapter 4: Web-Based Management
GE-DS-242-PoE Managed Ethernet Switch User Manual 73
NOTE: 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:
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
The following are the user-configurable STP parameters for the port or port group
level:
PARAMETER DESCRIPTION DEFAULT VALUE
Port 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.
128
Port Cost
A value used by STP to evaluate paths - STP
calculates path costs and selects the path with the
minimum cost as the active path.
200,000-100Mbps
Fast Ethernet ports
20,000-1000Mbps
Gigabit Ethernet ports
0 - Auto