Document: draft-ietf-nfsv4-rpcrdma-07.txt

Reviewer:		Eric Gray
Review Date:	03/17/2008

Summary:

This document is nearly ready to publish as a Proposed Standard RFC. 

COMMENTS/QUESTIONS
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In the first paragraph of section 3, there is some text about the fact that the RDMA header is analogous to record marking, as used for RPC over TCP, but is more extensive, because "RDMA transports support several modes of data transfer" and we want to allow the client and server to use efficient transfer modes.

Is the transfer mode negotiable between the client and server, or are more efficient modes simply well enough defined that either could make this decision on its own?
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In the last paragraph before section 3.1, you include this
(paraphrased) text:

"An upper layer may [...] define an exchange to dynamically  enable RPC/RDMA on an existing RPC association.  Any such  exchange must be carefully architected so as to prevent any  ambiguity as to the framing in use for each side of the  connection."

This does not look like the sort of statement we should be making in a proposed standard.  The entire (paraphrased) quote above - especially the phrase "must be carefully architected" - is at least a little too vague.  Does this specification (or another) provide support for this as an option?  Are there pre-conditions and signaling needs at the higher layer?  Or, is it enough simply to say that the same approach must be consistently used within any single message?

It sounds like this is something that needs to be defined at a specific level (such as at the application level) and that entities at that level need to ensure that specific things are correctly handled.  In this case, I'm being vague because I don't know the protocols involved well enough to be more specific about what "specific things" and "correctly handled"
mean - but I strongly suspect that "carefully architected"
doesn't cover it.

My suggestion is to remove (or rephrase) the last 3 sentences in that paragraph, including the two paraphrased above and the one that follows them.