STP (Spanning Tree Protocol) Port Status

Port Number

The LAN port ID

Path Cost

The Spanning-Tree Protocol uses port path costs to

 

determine which port to select as a forwarding port.

 

You should assign lower numbers to ports attached

 

to faster media (such as full duplex), and higher

 

numbers to ports attached to slower media. The

 

possible range is 1 to 65535. The recommended path

 

cost is 1000 ¡Ò LAN speed in megabits per second.

Priority

The port (physical or logical) with the lowest priority

 

value has the highest priority and forwards the

 

spanning-tree frames. The possible priority range is 0

 

through 255 (decimal). The default is 128. If all ports

 

have the same priority value, the lowest port number

 

forwards the spanning-tree frames.

Port Status

Ports which are enabled can be in one of the follow-

 

ing states:

 

Listening : Switches send messages to one another

 

to establish the network topology and the optimal

 

paths to the different segments of the network. Other

 

data is not transmitted.

 

Blocking : The switch enters the Blocking State if a

 

path with higher priority is found to exist during the

 

Listening State. Normal data is not transmitted.

 

Learning : The switch enters the Learning State if no

 

path with a higher priority is found during the

 

Listening State. Learned entries are entered in the

 

Unicast Destination Forwarding Table. Normal data

 

is not transmitted.

 

Forwarding : The switch enters the Forwarding State

 

after having been in the Learning State for a pre-

 

defined time period. Normal data is transmitted.

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Image 53
Xerox KS-801 LAN port ID, Ports which are enabled can be in one of the follow, Ing states, Data is not transmitted