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Small Computer Systems Interface (SCSI) Command Ordering Considerations with iSCSI (RFC3783)

IP.com Disclosure Number: IPCOM000028614D
Original Publication Date: 2004-May-01
Included in the Prior Art Database: 2004-May-25
Document File: 15 page(s) / 32K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M. Chadalapaka: AUTHOR [+2]

Abstract

Internet Small Computer Systems Interface (iSCSI) is a Small Computer Systems Interface (SCSI) transport protocol designed to run on top of TCP. The iSCSI session abstraction is equivalent to the classic SCSI "I_T nexus", which represents the logical relationship between an Initiator and a Target (I and T) required in order to communicate via the SCSI family of protocols. The iSCSI session provides an ordered command delivery from the SCSI initiator to the SCSI target. This document goes into the design considerations that led to the iSCSI session model as it is defined today, relates the SCSI command ordering features defined in T10 specifications to the iSCSI concepts, and finally provides guidance to system designers on how true command ordering solutions can be built based on iSCSI.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 9% of the total text.

Network Working Group                                     M. Chadalapaka

Request for Comments: 3783                                    R. Elliott

Category: Informational                              Hewlett-Packard Co.

                                                                May 2004

                Small Computer Systems Interface (SCSI)

               Command Ordering Considerations with iSCSI

Status of this Memo

   This memo provides information for the Internet community.  It does

   not specify an Internet standard of any kind.  Distribution of this

   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract

   Internet Small Computer Systems Interface (iSCSI) is a Small Computer

   Systems Interface (SCSI) transport protocol designed to run on top of

   TCP.  The iSCSI session abstraction is equivalent to the classic SCSI

   "I_T nexus", which represents the logical relationship between an

   Initiator and a Target (I and T) required in order to communicate via

   the SCSI family of protocols.  The iSCSI session provides an ordered

   command delivery from the SCSI initiator to the SCSI target.  This

   document goes into the design considerations that led to the iSCSI

   session model as it is defined today, relates the SCSI command

   ordering features defined in T10 specifications to the iSCSI

   concepts, and finally provides guidance to system designers on how

   true command ordering solutions can be built based on iSCSI.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2

   2.  Definitions and Acronyms . . . . . . . . . . . . . . . . . . .  3

       2.1.  Definitions. . . . . . . . . . . . . . . . . . . . . . .  3

       2.2.  Acronyms . . . . . . . . . . . . . . . . . . . . . . . .  4

   3.  Overview of the iSCSI Protocol . . . . . . . . . . . . . . . .  4

       3.1.  Protocol Mapping Description . . . . . . . . . . . . . .  4

       3.2.  The I_T Nexus Model. . . . . . . . . . . . . . . . . . .  5

       3.3.  Ordered Command Delivery . . . . . . . . . . . . . . . .  6

             3.3.1.  Questions. . . . . . . . . . . . . . . . . . . .  6

             3.3.2.  The Session Guarantee. . . . . . . . . . . . . .  6

             3.3.3.  Ordering Onus. . . . . . . . . . . . . . . . . .  7

             3.3.4.  Design Intent. . . . . . . . . . . . . . . . . .  7

Chadalapaka & Elliott        Informational                      [Page 1]

RFC 3783                    Command Ordering                    May 2004

   4.  The Command Ordering...