3.14.1 STP Bridge Configuration

Use this command to configure STP protocol version, bridge priority, the interval between sending STP BPDU's, the delay used by STP Bridges to transit root and designated ports to forwarding, the maximum age of the information transmitted by the bridge when it is the root bridge, hop count range, and the maximum number of transmitted BPDUs per second.

Command Syntax:

Basic STP global setting commands:

spanning-tree mode { stp | rstp | mstp }
spanning-tree mst <instance> priority <prio>
spanning-tree mst hello-time <hellotime>
spanning-tree mst forward-time <fwdtime>
spanning-tree mst max-age <maxage> [ forward-time <fwdtime> ]
spanning-tree mst max-hops <max_hops>
spanning-tree transmit hold-count <holdcount>

Advanced STP global setting commands:

spanning-tree edge bpdu-filter 
spanning-tree edge bpdu-guard 
spanning-tree recovery interval <interval>

Table 3-70. Command Description
	Argument	Description
Parameter	`<instance>`	STP bridge instance. Must be 0 (zero) for CIST.
	`priority <prio>`	Bridge Priority. Supported values are 0–61440. Only values divisible by 4096 are allowed. For example, 4096, 8192, and so on. Default value is 32768
	`<hellotime>`	Interval between sending STP BPDUs. Valid values are 1-10 seconds. Default value is 2 seconds.
	`<fwdtime>`	Forward delay used by STP Bridges to transit Root and Designated Ports to Forwarding. Valid values range from 4–30 seconds. Default value is 15.
	`<maxage>`	Maximum age of the information transmitted by the Bridge when it is a Root Bridge. Valid values ranage from 6–40 seconds. Default value is 20.
	`<maxhops>`	Defines how many bridges a root bridge can distribute its BPDU information. Valid values ranage from 6–40 hops. Default value is 20.
	`<holdcount>`	Number of BPDUs a bridge port can send per second. Valid values ranage from 1–10 BPDUs per second. Default value is 6.
	`<interval>`	Time to pass before a port in error-disabled state can be enabled. Valid values ranage from 30–86400 seconds (24 hours). Default is port error recovery disabled.
Default	N.A
Mode	Global Configuration mode
Usage	Configure STP system settings. To revert to the default, use the ‘no’ version of the command.
Example	Example 1: Configure STP settings. `# configure terminal (config)# spanning-tree mode mstp (config)# spanning-tree mst 0 priority 36864 (config)# spanning-tree mst hello-time 3 (config)# spanning-tree mst max-age 25 forward-time 16 (config)# spanning-tree mst max-hops 25 (config)# spanning-tree transmit hold-count 7 (config)# spanning-tree edge bpdu-filter (config)# spanning-tree edge bpdu-guard (config)# spanning-tree recovery interval 120`