I have connected a Cisco 4500 series switch to a Cisco 6509 (allow all vlans), the switch all ready had a connection to another switch Cisco 3750 (allow all vlans). Spanning tree has blocked the connection to the Cisco 6509. I want to shut down the trunk ports going from the 4500 to the 3750 so the 4500 traffic will all go through the Cisco 6509 (root bridge). All devices have been taken off of the 3750 and placed on the 4500 so traffic is going from the 4500 through the 3750 out to the router and to the external network. I'm wanting to know how long it will take for spanning tree to unblock the ports on the 4500 going to the 6509 after I shutdown the ports on on the 4500 going to the 3750.