Guess the web ate half the diagram but well...Five Levels from Top to Bottom:
2-Layer 2Switch--Tie Between 2 Cores and Firewall
3-Two Main Cores--Pruned Layer 2 Port-Channeled Trunks carry Layer 3 Traffic(Platforms won't support sub-interfaces for integrated vrf configuration)
4-Layer 3 Distribution Points(layer 3 devices separating key sections)--again pruned Layer 2 Port Channels
5-Access Switches-Layer 2 Trunks to End users.
Specific question is unique to the links between Levels 2 and 3(Layer2 Switch To Two Cores Connection)
Now supposing that spanning-tree protocol is running between the three devices in a triangle(Layer2 Switch the Vertex), and that Cores A and B are running GLBP protocol to service some subnets(approximately vlans) which,(due to transitional inconvenience) have to be routed from the Core instead of the Sectional Distribution points(Level4 Switches) devices; What device needs to be set up as the SPANNING-TREE ROOT(r-pvst), thus
letting GLBP to properly load balance between the two Core Devices?
Keep in Mind Both Cores are connected to each other, and then to the layer 2 switch.
I need to get independent opinions so as to reduce the chance of misconfiguration mishaps, since whatever I set up is gonna be pretty much it, and I will be expected to clean up any projected messes depending on what I opt for.
As I post the question I will take the liberty to revisit the GLBP white papers on Cisco and perhaps something about RSTP to go along. Any input is much appreciated.