I cannot find a great deal of documentation about exactly how the pathcost method operates.
We have a 6509 connecting to a 4006 which in turn connects to several 3550's. The 6509 and the 4006 are in the same MST domain and the 4006/3550's are in a PVST domain.
As far as I can tell, the 6509 default pathcost method is long, whereas the 4006 and 3550 defaults are short. This causes the 4006 to report 'Configured Pathcost method is short (Operational value is long)', however the 3550's report the use of short.
I have three questions;
1. How does the 4006 detect the operational mode for pathcost? Does it simply revert to this method if it detects a larger pathcost number being used?
2. Is the same pathcost method used globally on the switch, or can it perform long method with the 6509 and short with the 3550's?
3. Can a mis-match of pathcost methods cause the 4006 to wrongly detect the spanning-tree type used by the 6509 (if they both reboot at the same time, we see this problem).
Essentially, I would like to know whether forcing the default pathcost method on the 4006 to be long will a) Resolve the incorrect spanning tree type detection. b) Continue to operate in short mode with the 3550s.
Many thanks in advance,