Planned contrib/rdma import

[Kip Macy]

I received the following question in a private e-mail that I think
others might be asking.

>  what is RDMA and ipwarp ? google didn't help much here :(

RDMA in general is the ability to directly DMA to and from the memory
of a remote host. In this particular context it is the ability to do
so with authentication and access checking and thus does *not* cover
firewire or countless other means by which one could trivially do
memory to memory transfers.

The two transports that allow this are infiniband and iwarp.
Infiniband is a link layer transport. Iwarp uses TCP as the underlying
transport. For more details you can see the RFCs and the consortium
website.

4296 The Architecture of Direct Data Placement (DDP) and Remote Direct
     Memory Access (RDMA) on Internet Protocols. S. Bailey, T. Talpey.
     December 2005. (Format: TXT=43907 bytes) (Status: INFORMATIONAL)

4297 Remote Direct Memory Access (RDMA) over IP Problem Statement. A.
     Romanow, J. Mogul, T. Talpey, S. Bailey. December 2005. (Format:
     TXT=48514 bytes) (Status: INFORMATIONAL)

5040 A Remote Direct Memory Access Protocol Specification. R. Recio,
     B. Metzler, P. Culley, J. Hilland, D. Garcia. October 2007. (Format:
     TXT=142247 bytes) (Status: PROPOSED STANDARD)


http://www.rdmaconsortium.org/home