Users Guide

spanning-tree 0
Assigns a Layer 2 interface to STP instance 0 and congures a port cost or port priority, or enables loop guard, root guard, or the
Portfast feature on the interface.
Syntax
spanning-tree stp-id {cost cost | {loopguard | rootguard} | portfast
[bpduguard [shutdown-on-violation]] | priority priority}
To disable Spanning Tree group on an interface, use the no spanning-tree stp-id {cost cost |
{loopguard | rootguard} | portfast [bpduguard [shutdown-on-violation]] |
priority priority} command.
Parameters
stp-id Enter the STP instance ID. The range is 0.
cost cost Enter the keyword cost followed by a number as the cost. The range is 1 to
65535. The defaults are:
• 100 Mb/s Ethernet interface = 19.
• 1-Gigabit Ethernet interface = 4.
• 10-Gigabit Ethernet interface = 2.
• Port Channel interface with 100 Mb/s Ethernet = 18.
• Port Channel interface with 1-Gigabit Ethernet = 3.
• Port Channel interface with 10-Gigabit Ethernet = 1.
loopguard (C-, S-, and E-Series TeraScale and S4810 only) Enter the keyword loopguard to
enable STP loop guard on a port or port-channel interface.
rootguard (C-, S-, and E-Series TeraScale and S4810 only) Enter the keyword rootguard to
enable STP root guard on a port or port-channel interface.
portfast [bpduguard
[shutdown-on-viol
ation]]
Enter the keyword portfast to enable Portfast to move the interface into
Forwarding mode immediately after the root fails.
Enter the optional keyword bpduguard to disable the port when it receives a
BPDU.
Enter the optional keyword shutdown-on-violation to hardware disable an
interface when a BPDU is received and the port is disabled.
priority priority Enter keyword priority followed by a number as the priority. The range is zero
(0) to 15. The default is 8.
Defaults cost = depends on the interface type; priority = 8
Command Modes INTERFACE
Command History
Version 8.3.10.1 Introduced the loopguard and rootguard options on the S4810.
Version 8.4.2.1 Introduced the loopguard and rootguard options on the E-Series TeraScale,
C-Series, and S-Series.
Version 8.3.7.0 Introduced on the S4810.
Version 8.2.1.0 Introduced the shutdown-on-violation option.
Version 7.7.1.0 Introduced on the S-Series.
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Spanning Tree Protocol (STP)