I am struggling with a couple of people on designing a new campus in regards to layer 2 and spanning tree. We have an established distributino layer with dual 6509 chassis that are innerconnected with a layer 2 trunk. The access closets are dual connected, one to each distribution switch. Where i am struggling is with their decision to have the voice and data vlans from each access switch trunked between on the inner connect between the two distribution switches, as well as the two uplinks from the access switch. Each vlan is unique per closet so they do not reside in other access switches in the campus. Currently one of the two uplinks is blocking on STP at the access switch. Their arguement is that since it is Rapid PVST that this is an ok design give the recovery would be 200ms in the event the non blocking uplink fails and the blocked uplink starts to forward the VLAN traffic. My thought process is to remove the VLANs between the distribution innerconnection and thereby have no need for any blocking and STP setup as a safeguard. I have yet to find any design guides that recommend having an active STP in the dist/access layer. We are running IP phones in this model and my concern is how they will react in the desing with Rapid PVST actively blocking. Layer 3 routing is on both dist switches with HSRP.
Am i missing something with their design?
Okay so the links are trunk links.
Yes i was suggesting running Rapid-PVST+ and having one of the uplinks blocked by STP. Failover time for a major failure with Rapid-PVST+ is about 1 - 2seconds but i would suggest testing. If these times are not good enough for your VOIP setup then yes the only other way would be to remove the vlan from the distro interconnect and have both uplinks forwarding.
Quicker failover then Rapid-PVST+ can b achieved with EIGRP/OSPF but as we have already discussed this cannot be done within your network at present.