Interlogix IFS NS3550-24T/4S, User Manual

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User’s Manual of NS3550-24T/4S
135
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
The following are the user-configurable STP parameters for the port or port group level:
Variable Description Default Value
Port Priority
A relative priority for each
port –lower numbers give a higher priority
and a greater chance of a given port being
elected as the root port 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
Default Spanning-Tree Configuration
Feature Default Value
Enable state STP disabled for all ports
Port priority 128
Port cost 0
Bridge Priority 32,768
User-Changeable STA Parameters
The Switch’s factory default setting should cover the majority of installations. However, it is suggested to keep the default settings
as set at the factory; unless, it is absolutely necessary. The user changeable parameters in the Switch are as follows:
Priority
– A Priority for the switch can be set from 0 to 65535. 0 is equal to the highest Priority.
Hello Time
– The Hello Time can be from 1 to 10 seconds. This is the interval between two transmissions of BPDU packets sent
by the Root Bridge to tell all other Switches that it is indeed the Root Bridge. If you set a Hello Time for your Switch, and it is not
the Root Bridge, the set Hello Time will be used if and when your Switch becomes the Root Bridge.
The Hello Time cannot be longer than the Max. Age. Otherwise, a configuration error will
occur.
Max. Age
– The Max Age can be from 6 to 40 seconds. At the end of the Max Age, if a BPDU has still not been received from the
Root Bridge, your Switch will start sending its own BPDU to all other Switches for permission to become the Root Bridge. If it turns