Interlogix NS3502-8P-2S User Manual - Manual (Page 145)

IFS NS3502-8P-2S User Manual
145
2. 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