Mohamed,
You cannot do a MSP1+1 on a Gig port on any SONET/SDH box. Because MSP1+1 is a SONET/SDH protection switching scheme. It is not an enterprise/data switching scheme. I do not know what the client equipment is you are connecting this to but I am pretty sure it does not support MSP1+1 on Gig ports.
On the other hand an alternative is to use SDH ports on the client equipment and connect to the 15600 with SDH signals. This will support MSP1+1. Inside the SDH signal you can have the VC4-8C and the client can put data inside the VC4-8C.
The Client side port would require a pair of STM16 POS/Optical interfaces which would connect to the 15600. These ports can be setup to do MSP1+1 between the 15600 and the client.
Mike Dooley
Cisco Optical TAC
