13–6 MULTILINK ML1200 MANAGED FIELD SWITCH – INSTRUCTION MANUAL
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. Bridge Des. 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
