Intel® NetStructure™ 6000 Switch

C H A P T E R 5
Managing the Switch
The Spanning Tree protocol:
• Assigns a unique address to each switch (usually the MAC
address of the Control Processor).
• Assigns a priority value to each switch.
• Selects a root switch. This is the starting point for the Spanning
Tree.
• Assigns a unique address to each port on each switch.
• Calculates a path cost for each port on each switch.
• Assigns the root port of the switch based on path cost.
To configure the Spanning Tree protocol
1 The Root Switch
The bridge with the lowest identifier (usually the MAC address) is the
root switch. The MAC address is assigned when the IP address is
assigned for the switch.
2 Assign the Switch’s Priority.
Type the privileged set spantree priority value command. The range
is from 0 to 65,335. The default is 32,768.
6000 Switch>set spantree priority 1
3 Assign the Root Port.
Type the set spantree portpri port_number value command to
assign a priority value to a port. The range is from 1 to 255. The
default is 128.
After the root switch is selected, the other switches determine which
port is the most cost-effective path to the root switch. This port
becomes the root port.
The command line below sets the priority of port 3 to 1.
6000 Switch>set spantree portpri 3 1
4 Set the Port Cost.
Finally, the Spanning Tree protocol detects the switch and switch
ports that have access to the root. The bridge then enables those ports
to be used for forwarding packets and disables others ports to prevent
loops. These disabled ports are kept in backup mode in case a primary
port or link fails.
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