enabling "spanning-tree extend system-id" to running network disruptive???

[will]

Hi, I have about 20 vlans running on a 6509 pair at the core of network. This core switch pair is acting as root bridge for STP. Someone didn't enable extended vlans when setting up switch. Current spanning tree configuration looks like this:

spanning-tree mode pvst

spanning-tree portfast edge bpduguard

I need to enable: spanning-tree extend system-id

Will this recalculate spanning tree on all links, or cause outages on any ports not configured for portfast? Or outages on those possibly configured as portfast access ports?

thx,

Will

[Reza Sharifi]

Hi,

According to the command reference guide:

Enabling or disabling the extended-system ID  updates the bridge IDs of all active Spanning Tree Protocol (STP)  instances, which might change the spanning-tree topology.

So, to be sure, you may want to have a short outage window to make sure everything is fine after enabling it.

here is the link to the command reference guide for the 6500 series.

http://www.cisco.com/en/US/docs/ios/lanswitch/command/reference/lsw_s2.html#wp1110581

HTH