Specifying the interval between BPDU transmissions

Syntax:

spanning-tree port-list hello-time [global | 1 - 10]

When the switch is the CIST root, this parameter specifies the interval (in seconds) between periodic BPDU transmissions by the designated ports. This interval also applies to all ports in all switches downstream from each port in the port-list.

A setting of global indicates that the ports in port-list on the CIST root are using the value set by the global spanning tree hello-time value.

When a given switch X is not the CIST root, the per-port hello-time for all active ports on switch X is propagated from the CIST root, and is the same as the hello-time in use on the CIST root port in the currently active path from switch X to the CIST root. When switch X is not the CIST root, then the upstream CIST root's port hello-time setting overrides the hello-time setting configured on switch X.

Default Per-Port setting: Use Global.

Default Global Hello-Time: 2.