[openib-general] [PATCH] [CM] add private data comparison tomatch REQs with listens

[Fab Tillier]

> From: Caitlin Bestler [mailto:caitlinb at broadcom.com]
> Sent: Friday, December 02, 2005 4:06 PM
> 
> Socket listen semantics have nothing to do with Ethernet.
> They are Unix/POSIX. In fact a major point of socket semantics
> is that they worked over multiple networks.

The IB CM doesn't provide socket semantics.  Period, end of story.  Providing
socket semantics is higher level functionality (the CMA), and outside the scope
of the IB CM and this email thread.

> Sockets are part of the problem when it comes to transferring
> data once a connection is established, which is why we have
> QPs and CQs.

Irrelevant.

> But there is a very simple transport neutral definition of
> passive side connectin setup. The server issues a listen.
> The server receives connection requests. The service can
> optionally hand off the connection request, accept it
> or reject it.

There is no notion of per-request handoff in IB - you either accept or reject -
that's it.  The reject can cause a redirect, but that requires a new connection
request from the client.

> That model is a natural extension of both TCP connection
> setup and the InfiniBand CM. 

How does the IB CM protocol support hand off?

> It allows the server to deal
> with destination multiplexing. DAPL and IT-API both already
> work this way.
> 
> Are you opposed to transport neutral connection establishment?

I don't give a hoot about transport neutral connection establishment, DAPL, or
IT-API in the scope of this email thread.  They just aren't relevant whatsoever.
This thread is about adding private data comparison functionality to the IB CM.
The IB CM is the module to which the CMA interfaces.  The CMA is a separate
module providing higher level functionality, and is designed to provide
transport neutral connection establishment, specifically IP addressing over IB.

As Sean originally stated in the mail that started this thread, the CMA will
make use of the private data comparison functionality.  Adding this
functionality to the IB CM is simpler than implementing it in the CMA while at
the same time providing additional flexibility to future users of the IB CM that
wish to have similar functionality.

- Fab