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

David Peterson David.Peterson at mcdata.com
Thu Aug 31 08:20:45 PDT 2006


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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 
	 "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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