[c-nsp] remove spanning-tree without being service effecting

[Friedrich, Gregor]

Hi James,

I think it's a design problem.  Ethernet L2 ring sounds bad to me. Especially  multi-vendor  rings  are not a good idea.  
What about to replace the Brocade stuff with cisco, there are only 2 in your ring?   Or do you really need a L2 ring, why not L3 with routing protocol?  Or cloud you filter spanning tree facing to the customer, at least.   That is best practise. 

 Also REP would work better, but has to be  tested  in  lab of course! 

Thanks Gregor