User`s manual

Configuring the Spanning Tree Protocol
Console version
The Switch implements the IEEE Spanning Tree Protocol to detect and preserve an active bridged local area
network topology.
Spanning tree blocks certain ports to prevent bandwidth-sapping traffic loops while preserving fault tolerance by
maintaining a redundant bridge path as backup. If the first bridge path should fail, the secondary bridge path
takes over.
To set the parameters for spanning tree, select Spanning Tree from the Console Main Menu. The Spanning
Tree screen appears. Make your entries as described in the steps below.
Enter a Port Number. You can enter a single number, multiple individual numbers or a range of numbers
in the Port Number field. Use a dash to separate numbers in a range. Use commas to separate individual
numbers or more than one range of numbers, for example: 1-3,5,9,12-15. Fast Ethernet ports are
numbered from 1 through 24. If installed, Gigabit uplink modules are numbered 25 and 26.
1.
Select enable or disable in the Spanning Tree field to select whether you want the Switch to use the
Spanning Tree Protocol.
2.
Enter a value from 0-65535 in the Bridge Priority field to influence the choice of this Switch as the root
bridge of the spanning tree. The lower the number, the more likely this Switch is used as the root. A 0, as
shown in the screen above, means the ports entered are always the root of the tree. The default is 32768.
3.
In Hello Time, enter the time interval between issuing configuration Bridge Protocol Data Units (BPDU).
Bridges (switches) use BPDUs to calculate the spanning tree. Hello time can range from 100-1000 in
10ms units (1-10 seconds in 1/100-second increments). It is usually sufficient to use a whole number. The
default is 200ms or 2 seconds.
4.
In Max Age, enter the time period after which received protocol information is discarded. The Switch
stores received and calculated BPDU parameters in memory. The stored configuration information for
each port is discarded if no update activity has occurred when this limit is reached. Maximum age can
range from 600-4000 in 10ms units (6-40 seconds in 1/100-second increments).
5.
In Forward Delay, enter the amount of time the spanning tree algorithm spends in each intermediate port
state during a transition from blocking to forwarding. The default is 15 seconds. This value is also used as
a short aging time value for all dynamic MAC entries in the address tables, during a topology change of
the active bridged local area network, as specified by the root bridge. Forward delay can range from
400-3000, in 10ms units (4-30 seconds in 1/100-second increments).
6.
Use Port Enable to enable or disable a port.7.
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