Subject: [rddp] Intent of statement

From: "bbr" <[email-masked]>
Date: Mon, 7 May 2007 18:51:58 -0400

Page 36 of draft 07 or RDMAP states that:

HdrCt: 3 bits. 

Header control bits: 

* M: bit 16. DDP Segment Length valid. See Figure 10 for when this bit
SHOULD be set. 

* D: bit 17. DDP Header Included. See Figure 10 for when this bit SHOULD be
set. 

* R: bit 18. RDMAP Header Included. See Figure 10 for when this bit SHOULD
be set.

The SHOULD statements in this text indicate that these items are optional.
However, in reading the text it appears that the intent may have been that
these statements are just incorrectly capitalized "should" statements and
best understood as:

HdrCt: 3 bits. 

Header control bits: 

* M: bit 16. DDP Segment Length valid. See Figure 10 for when to set this
bit. 

* D: bit 17. DDP Header Included. See Figure 10 for when to set this bit.

* R: bit 18. RDMAP Header Included. See Figure 10 for when to set this bit.

The implication of this would be, for instance, that an implementation MUST
set the R bit and return the received RDMA header when generating a
terminate for a read request that generated a remote protection error due to
an invalid Stag.

A literal reading of the current wording (with SHOULD) leaves a somewhat
conflicted state in which figure 10 states that the RDMA header is required
but that it is not necessary to set the R bit.

Unless instructed otherwise I am going to assume that the SHOULD in HdrCt is
not really normative. 

Hope someone is still reading this reflector..

 

Barry Reinhold

(603) 868-8411

 <mailto:[email-masked]> [email-masked]

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