NFS Over TCP

The default transport protocol for the NFS protocol was changed to the Transport Control Protocol (TCP) in the Solaris 2.5 release. TCP helps performance on slow networks and wide area networks. TCP also provides congestion control and error recovery. NFS over TCP works with version 2, version 3, and version 4. Prior to the Solaris 2.5 release, the default NFS protocol was User Datagram Protocol (UDP).

Starting in the Solaris 10 release, if RDMA for InfiniBand is available, RDMA is the default transport protocol for NFS. For more information, see NFS Over RDMA. Note, however, that if you use the proto=tcp mount option, NFS mounts are forced to use TCP only.