[openib-general] Re: [PATCH] CMA: allow/require bind beforeconnect

[Sean Hefty]

>On IB, it also maps ports to service IDs.
>
>This argues that the port values are within the scope of the CMA
>and that the active side behavior should be changed.

The passive side maps the source port, and the active side maps the destination
port.  So, a port assignment is only needed on the passive side.  Although, if
code needs to be there to support listens that don't care which port they listen
on, then using it on the active side isn't any more difficult.

An application wants to connect to some server, and doesn't care what port
number is used.  Why does it care that the source port assignment is unique?
And how unique is unique?  System wide?  Within the RDMA CM?  Within all of TCP?
Within all TCP ports over a specific IP address?  Within the RDMA CM within its
TCP space over a specific IP address?  Etc.

What scope is needed, and why?  SDP has its own address family.  Does this give
it its own port space, or does it need to share it?

- Sean