Re: Connection Startup

On Friday, October 3, 2003, at 03:16 PM, Jim Pinkerton wrote:

> Note that iSER essentially uses the same boot start mechanism - send a
> bit of data, agree on configuration, and then enable RDMA - the only
> difference is that iSER exchanged the information as part of *their*
> record delineation mechanism, and this proposal defines it within MPA
> (i.e. LLP) to make it possible to delineate config information record
> boundary independent of application protocol.


But iSCSI negotiations are only defined over TCP, hardly LLP neutral.

When/if iSCSI/SCTP is defined (as it should have been) the ULP would
have to engage in different interactions to negotiate depending on
which LLP was in use. The bottom line is that TCP exchanges bytes
while SCTP exchanges messages.

If you are developing an RDMA specific application then the message
orientation is closer to how you will be working once RDMA is 
established.
So having a message-oriented negotiation standard available as an
option is a major benefit. It lets the entire application be coded
at a "message" layer, not mixing byte streams and messages.

It's really early in the process to come to any final conclusions
about what is "normal" for RDMA applications. The app developers
that I have talked with have had no interest in adding iSER like
capabilities to the DAT API.

But in any case, I believe we are in full agreement that *both*
models need to be supported. Which just disagree over which one
should be viewed as "normal".


Caitlin Bestler - [email protected] - http://asomi.com/