My customer have a redundancy supervisor engine 2 fail on the Cat 6509. Now the new claimed engine need to be replaced to it. The supervisor engine is with a MSFC2 and PFC2. The software version of the active engine is c6sup22-dsv-mz.121-26.E2. No CatOS installed. I have searched the upgrade process on Cisco but I cannot find a guideline for installing a redundancy supervisor engine without network downtime. Does anyone know about this? Thanks for your help!