October 31, 2003
SDP Frequently Asked Questions
Q1. What is SDP?
SDP stands for "Sockets Direct Protocol". As the name indicates, it is a wire
protocol for direct communication between RDMA hardware and the application
“sockets layer” that enables applications to directly benefit from the
performance benefits derived from RDMA technology.
Q2. What are “sockets”?
Sockets are a standard programming interface used to communicate with TCP/IP
Q3. What is the purpose of
SDP enables Internet applications to transparently take advantage of the
performance advantages of the RDMA (Remote Direct Memory Access) protocol suite
Q4. What are the
advantages of SDP?
SDP enables internet applications to take advantage of the low-latency,
high-bandwidth performance benefits of RDMA, including Direct Data Placement and
Q5. What is SDP replacing?
SDP emulates sockets streaming semantics over the RDMA interface. It does
not replace any component, but instead emulates sockets semantics to allow
applications to gain the performance benefits of RDMA without changing any
application code which relies on sockets today.
Q6. How is WSD related to
WinSock Direct Protocol (WSD, a.k.a. WSDP) is the predecessor to SDP.
Support for WSD is currently shipping in Microsoft Server Operating Systems.
Q7. Is the RDMA Consortium
planning any additional specifications?
No, the SDP specification is the final specification produced by the RDMA
Consortium. The delivery of iSER, SDP, the RDMA wire-protocol suite and the
Verbs Specifications complete the family of protocols necessary to enable
deployment of RDMA based networking, Inter-Process Communication (IPC), and
Q8. What is the plan for
the RDMAC now that the specs are complete?
The consortium members will continue to address Errata for the RDMA Consortium
specifications. The members of the RDMAC will continue to work with the
IETF on approval of the RDMA suite of specifications.
Q9. Will the SDP
specification be submitted to the IETF?
Yes, the RDMAC will submit the SDP specification to the IETF as a proposed
informational RFC to increase familiarity of the SDP protocol with the IETF.
Q10. When will RNIC hardware become available?
Specific details on availability of RNIC hardware need to come from RNIC
vendors. In general, we expect RDMA solutions to be available in 2004.
Q11. When will operating systems support SDP?
Specific details on availability of SDP need to come from OS vendors.
Q12. Who should customers contact for information
on RDMA products?
Customers should contact their respective vendors.
Q13. Where can I get additional information on the
RDMA protocol and SDP?
Additional information is available at the RDMA Consortium website which is
located at www.rdmaconsortium.org.