What is Shared Memory Communications over RDMA?

"Shared Memory Communication over RDMA (SMC-R) is a new sockets over RDMA communication protocol that allows existing sockets applications that exploit TCP to transparently benefit from RDMA for exchanging data over a RoCE network.

The exploitation of SMC-R is transparent to sockets applications. This means that no application change is required.

SMC-R provides host-to-host direct memory access without the traditional TCP/IP processing overhead.

In addition to transparent application exploitation of RDMA, the SMC-R protocol allows customers to benefit from InfiniBand technology by leveraging their existing 10GbE Ethernet infrastructure.

SMC-R also provides for critical qualities of services that are required by the Enterprise Data Center environment such as:

• When redundant network hardware paths are available, SMC-R offers both high availability and load balancing.

• SMC-R offers preservation of existing IP topology and IP security.

• SMC-R introduces minimal administrative and operational changes.

• SMC-R provides dynamic discovery of partner RDMA capabilities and dynamic setup of RDMA connections over RoCE fabrics.

SMC-R support is included as part of z/OS V2R1.

SMC-R exploitation in z/OS V2R1requires the 10GbE RoCE Express feature." (Linda Harrison, SMC-R RoCE FAQ Document, http://www-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/FQ131485)