We will be replacing our fault-tolerant CSS11506 with WS-X066-SLB-S-K9 modules. Can I put two of them in a single 6513 and configure them for failover? Or is there a limit to one module per chassis?
You can put both CSM-S in the same chassis if you want, and operate them as a FT pair. Actually, you can put up to four of them in a single chassis.