spanning tree question

[g.hammond]

I want to change the spanning tree root on several vlans on my network. My question is, will this cause STP to recalculate for the entire network, which can cause the network to slow down or will it only affect the vlans that I am changing? I want to make sure I am not going to impact anything on the network.

[lgijssel]

When executed properly, this will only affect the vlans that you wish to change. Use the folllowing command to change spanning tree prio on a vlan:

spanning-tree vlan xx priority 4096 (or a multiple of 4096 for less priority)

Be aware that there is always a risk of unexpected disruptions when you do this. The vlans that you change may still carry user traffic altough there are no users on it. If your topology and traffic flow are not exactly as you assume they are, more vlans may be affected. It is therefore not advisable to alter this setting during peak-hours.

Regards,

Leo

[groupcisco]

Hi,

Are there any loops in your network, If you are sure that there are no loops in your network, you can change the STP root, and it will not cause any problems. Incase there are any loops in your network, then the VLANS for what you change will get affected, if it changes the topology.

Rgds,

Naveen B