GE ML1200 instruction manual Example 13-2 Reviewing the Rstp port parameters

RAPID SPANNING TREE PROTOCOL CHAPTER 13: RAPID SPANNING TREE PROTOCOL

•Bridge Max Age: This is the maximum time a message with STP information is allowed by the switch before the switch discards the information and updates the address table again. Values range from 6 to 40 seconds with a default value of 20.

•Root Port: Indicates the port number, which is elected as the root port of the switch. A root port of "0" indicates STP is disabled.

•Root Path Cost: A path cost is assigned to individual ports for the switch to determine which ports are the forwarding points. A higher cost means more loops; a lower cost means fewer loops. More loops equal more traffic and a tree which takes a long time to converge, resulting in a slower system.

•Designated Root: Shows the MAC address of the bridge in the network elected or designated as the root bridge.

•Designated Root Priority: Shows the designated root bridge's priority. The default value is 0.

•Root Bridge Forward Delay: Indicates the designated root bridge's forward delay. This is the time the switch waits before it switches from the listening to the forwarding state. This value can be set between 4 to 30 seconds, with a default of 15.

•Root Bridge Hello Time: Indicates the designated root bridge's hello time. Hello information is sent out every 2 seconds.

•Root Bridge Max Age: Indicates the designated root bridge's maximum age, after which it discards the information as being old and receives new updates.

•Topology Change Count: Since the last reboot, the number of times the topology has changed. Use this in conjunction with "show uptime" to find the frequency of the topology changes.

•Time Since topology Change: The number of seconds since the last topology change.

The variables listed by the show stp ports command are:

•Port#: Indicates the port number. The value ranges from 1 to the maximum number of ports in the switch.

•Type: Indicates the type of port. TP indicates twisted pair.

•Priority: STP uses this to determine which ports are used for forwarding. Lower numbers indicate higher priority. The values range from 0 to 255, with a default of 128.

Example 13-2: Reviewing the RSTP port parameters

ML1200(rstp)##show stp ports

RSTP Port Configuration

-------------------------------------------------------------------------------

Port# Type Priority Path Cost State Des. BridgeDes. Port

-------------------------------------------------------------------------------

01	TP(10/100)		128	2000000	Disabled	00:01
02	TP(10/100)		128	2000000	Disabled	00:02
03	100MB	Fiber	128	200000	Disabled	00:03
04	100MB	Fiber	128	200000	Disabled	00:04

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