[f-nsp] FESX spanning-tree path cost success?

[Chris Marlatt]

Jonathan Brashear wrote:
> Our DC has had intermittent issues over the past year with spanning-tree loops with customers who have multiple uplinks to our switch fabric.  We've explored a few different options with limited to no success(such as bpdu guard, stp-protect, etc.), but currently we're considering setting manual path costs on ports as a way to help avoid the loops & subsequent cpu spikes we've dealt with.  Has anyone deployed manual path costs for customers with multiple uplinks(either to the same switch or multiple switches), and if so what success/problems have you had with its implementation?  I'd prefer the info be from the FastIron environment, but any Foundry-related discussion would be appreciated.
> 

I've had relatively good success using pvst mode and multiple paths on 
both the FESX and RX line. Even when using other switch vendors at the 
edge it seems to work well. Setting the cost has seemed to work well too 
- although I typically set those at the edge. Per their manual the 
interfaces default into an mstp mode and can under certain circumstance 
switch to pvst, setting it expressly as "pvst-mode" on the interface 
helps mitigate looping and other "weirdness" in my experience.

Regards,

	Chris