Will I still need OSA once I exploit SMC-R using the 10 GbE RoCE Express feature?

"Yes, the SMC-R protocol leverages your existing IP topology and the TCP/IP connection to control your SMC-R connectivity.

Therefore you will still need to establish a standard TCP/IP connection over a QDIO OSA port and an Ethernet network to the peer. SMC-R uses this TCP connection to determine eligibility to exploit the RoCE fabric and then to build a point-to-point SMC-R link for the data flow over the RDMA connection path.

The SMC-R link is built for the first eligible connection between two RoCE-enabled partners and the same link can be reused for subsequent TCP connections between the same peer hosts.

TCP/IP is used not only to establish the TCP/IP and RDMA connections, but also for Keepalive functions and to terminate the TCP and the associated RDMA connections.

The standard TCP/IP path over the QDIO OSA port need not be dedicated to RDMA usage; it can be used simultaneously for other, non-RDMA traffic.

The QDIO OSA port can be attached to either a 10 Gigabit Ethernet or a 1 Gigabit Ethernet network." (Linda Harrison, SMC-R RoCE FAQ Document, http://www-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/FQ131485)