H3C MSTP Configuration

[AtticaNet]

Hello,

I would like to know on the H3C switches when configuring the MSTP, what does the following settings mean:

#

stp region-configuration
 region-name mstp-vrrp
 instance 1 vlan 1
 instance 2 vlan 33
 active region-configuration
#
 stp instance 0 priority 0
 stp instance 1 priority 0
 stp instance 2 priority 0
 stp enable

Specifically what does priority 0 mean? I have seen some other switches in the same network that have the same ring topology yet the stp instance 0 is set to priority 4096 and the instance 1 and instance 2 are not even configured.

Regards.

[Richard Brodie_1]

It's the bridge priority for that instance, so the switch is intended to be root for that instance. The default is 32768, and it's often (e.g. on Procurve) configured in steps of 4096, so 4096 would be the backup root.

On the Procurve if it's set to 8 (=32768 actual value) it's not shown in the configuraiton. I guess the same applies here.

[AtticaNet]

Hello Richard,

Thank you for the clarification. Now what happens if on the other switches I have the same MSTP priority configuration? My understanding is that in order to determine the STP root the priority is compared between the bridges (switches) and if the priority is the same then the MAC address is used to determine the root. Is this correct? In any case there should always be a STP root on the network, right?