User Manual

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No.
Port 1 to Port N, N is based on the total port number.
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Role
This field shows the role of the STP port.
Root: This is the root port, which is connected to the Root Bridge with the lowest cost.
Designated: This is the designated port, which can send the best BPDU on the segment to other
connected nodes.
Alternate: This is the alternate port, which is blocked. This port can still receive useful BPDU from
another bridge. When it receives a useful BPDU, it will help to forward it on the segment.
Backup: This is the backup port, which is blocked. It corresponds with “Alternate Port” to the
blocking state. This port also receives useful BPDU, but the BPDU is from the same bridge. When it
receives a useful BPDU, it will help to forward it on the segment.
Disabled: The port is not linked up.
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Path State
This field shows the path state of this STP port.
Discarding: The port state can be “Disabled”, “Blocking”, or “Listening”. The incoming frames are
dropped and learning MAC addresses are stopped.
Learning: The port is learning MAC addresses, but the incoming frames are dropped.
Forwarding: The port in the forwarding state forwards the incoming frames based on the learned
MAC address table.
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Port Cost
This is the cost from the port to the Root Bridge. Spanning-tree Protocol assumes the path cost is
determined by the access speeds of the links. The default RSTP path cost is shown in the following
table:
Speed
RSTP Path Cost
Speed
RSTP Path Cost
4 Mbps
5,000,000
1000 Mbps (1 Gbps)
20,000
10 Mbps
2,000,000
2000 Mbps (2 Gbps)
10,000
16 Mbps
1,250,000
10000 Mbps (10 Gbps)
2,000
100 Mbps
200,000
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Port Priority
The Port Priority is used to determine the Root Port on a non-root bridge. The port with the lowest
Port Priority value gets the higher priority.