Subject: [nfsv4] Ben Campbell's No Objection on draft-ietf-nfsv4-rpcrdma-bidirection-07: (with COMMENT)

From: Ben Campbell <[email-masked]>
Date: Wed, 01 Mar 2017 15:23:48 -0800

Ben Campbell has entered the following ballot position for
draft-ietf-nfsv4-rpcrdma-bidirection-07: No Objection

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COMMENT:
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Some minor comments:

-4.1: This is the first mention of "credits", and there is no definition.
I realize that the term is defined in the reference from the previous
section. It would be helpful to mention that in the context of that
reference.
--  Are there any head-of-line-blocking issues introduced by
bidirectional transactions? For example, can a reply get stuck behind
requests that are blocked by flow control?

-5.4, 4th paragraph, last sentence: Can a reverse requestor reasonably
give up or time out, rather than wait "indefinitely"?

-8:  This implies that reverse direction transactions do not change
anything.If that is the case, please say so explicitly. For example, Is
there any change to authentication for reverse calls? I am not an expert
in direct memory access transport protocols; are there every situation
where authentication depends on an initial request from the client?

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From: Chuck Lever <[email-masked]>
Date: Thu, 2 Mar 2017 12:18:23 -0800

> On Mar 1, 2017, at 3:23 PM, Ben Campbell <[email-masked]> wrote:
> 

I can add that.

> requests that are blocked by flow control?

Head-of-line-blocking issues that affect one direction
should have no impact on the other direction because the
two directions have independent credit accounting
mechanisms.

> give up or time out, rather than wait "indefinitely"?

Yes, a timeout is a reasonable response to this situation.
I can soften this sentence to include that possibility.

> there any change to authentication for reverse calls?

Reverse calls would make use of a separate authentication
mechanism and credentials, but would otherwise operate in
the same fashion as requests in the forward direction. I
can add a sentence that states this.

> I am not an expert

The authentication mechanisms are handled by the RPC layer.
There is no authentication (or integrity or confidentiality
protection) in RPC transports, whose only responsibility is
moving bytes. I can add an introductory sentence that states
this.

--
Chuck Lever

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From: "Ben Campbell" <[email-masked]>
Date: Thu, 02 Mar 2017 14:20:42 -0600

Thanks for the response. That all sounds good.

Thanks!

Ben.