[T11.3] FC-LS/FCP-4: Proposed REC behavior

Bob.Nixon at Emulex.Com Bob.Nixon at Emulex.Com
Thu Aug 31 09:00:43 PDT 2006


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Rather than say who shall do it, we should simply say what it shall be.
Unless we excuse either side explicitly (which we should not do) then the
sender is required to get it right, and the receiver is required to protect
itself.  In the first paragraph of the description, change
The S_ID specified in the Payload of the request Sequence may differ from
address identifiers of both the source and destination of the REC request
itself
to
The S_ID specified in the Exchange originator S_ID field of the Payload of
the request Sequence shall be the same as either the S_ID or the D_ID in the
Frame Header of the request Sequence.
   - bob
-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org]On Behalf Of David Peterson
Sent: Thursday, August 31, 2006 8:21 AM
To: t10 at t10.org; t11_3 at mail.t11.org
Subject: RE: [T11.3] FC-LS/FCP-4: Proposed REC behavior
Howdy Roger,
Don't see how your proposed change allows existing implementations to remain
compliant either.
Per your proposed change, it still implies the recipient FCP_Port needs to
verify that the FC header S_ID field value is a valid address identifier for
the target Exchange.
In other words, without checking FC header S_ID field value, how can the
recipient FCP_Port verify that the REC was issued by the Originator Nx_Port
or Responder Nx_Port of the target Exchange?
Not quite enough teeth for me. I'm looking to enforce that REC is not
processed via a 3rd party request.
Also note that FCP-4 already contains changes to PRLI (i.e., the
REC_SUPPORTED bit). 
Thanks...Dave
(no disclaimer)
  _____  
From: Roger Hathorn [mailto:rhathorn at us.ibm.com] 
Sent: Wednesday, August 30, 2006 3:53 PM
To: David Peterson
Cc: t10 at t10.org; t11_3 at mail.t11.org
Subject: Re: [T11.3] FC-LS/FCP-4: Proposed REC behavior
I suggest that the proposed text: 
A Read Exchange Consise Request shall only be accepted if the Originator
Nx_Port or the Responder Nx_Port of the target Exchange makes the request
be changed to:
"A Read Exchange Consise Request shall only be issued by the Originator
Nx_Port or the Responder Nx_Port of the target Exchange."
to allow existing implementations to remain compliant. The text, as proposed,
indicated that the recipient has to somehow check this. 
Roger G. Hathorn
Senior Engineer, Storage Systems Development
IBM Systems and Technology Group
Tel: 520-799-5950 (T/L: 321-5950)
Pager: 520-446-2741 or 
http://www.arch.com/cgi-bin/wwwpreproc.exe?PIN=5204462741 
Inactive hide details for "David Peterson" '
src="cid:918214815 at 31082006-1256" width=16 border=0>"David Peterson"
<David.Peterson at mcdata.com>
	"David Peterson" <David.Peterson at mcdata.com> 
Sent by: t11_3-bounces at listserve.com 
	08/30/2006 10:29 AM
To
<t10 at t10.org>, <t11_3 at mail.t11.org>	
cc
Subject
[T11.3] FC-LS/FCP-4: Proposed REC behavior	
Howdy,
To remove the ability for a third party to issue an REC, here is the proposed
text for FC-LS: 
4.2.42.1 Description
This ELS shall be used only for purposes specific to an FC-4. The REC (Read
Exchange Concise) Extended Link Service requests an Nx_Port to return
Exchange information for the RX_ID and OX_ID originated by the S_ID specified
in the Payload of the request Sequence. The S_ID specified in the Payload of
the request Sequence may differ from address identifiers of both the source
and destination of the REC request itself. A Read Exchange Consise Request
shall only be accepted if the Originator Nx_Port or the Responder Nx_Port of
the target Exchange makes the request. The specification of OX_ID and RX_ID
shall be provided for the destination Nx_Port to locate the status
information requested. A Responder destination Nx_Port shall use the RX_ID
and verify that the OX_ID is consistent, unless the RX_ID is unassigned
(i.e., RX_ID = FFFFh). If the RX_ID is unassigned in the request, the
Responder shall identify the Exchange by means of the S_ID specified in the
Payload of the request Sequence and OX_ID. An Originator Nx_Port shall use
the OX_ID and verify that the RX_ID is consistent.
Please review the proposed text and be ready for a vote at the October T11
FC-LS working group meeting.
Thanks...Dave
(no disclaimer)
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