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rfc:rfc6172

Internet Engineering Task Force (IETF) D. Black Request for Comments: 6172 EMC Updates: 4172 D. Peterson Category: Standards Track Brocade ISSN: 2070-1721 March 2011

     Deprecation of the Internet Fibre Channel Protocol (iFCP)
                      Address Translation Mode

Abstract

 Changes to Fibre Channel have caused the specification of the
 Internet Fibre Channel Protocol (iFCP) address translation mode to
 become incorrect.  Due to the absence of usage of iFCP address
 translation mode, it is deprecated by this document.  iFCP address
 transparent mode remains correctly specified.
 iFCP address transparent mode has been implemented and is in current
 use; therefore, it is not affected by this document.
 This document also records the state of Protocol Number 133, which
 was allocated for a pre-standard version of the Fibre Channel
 Internet Protocol (FCIP).

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc6172.

Black & Peterson Standards Track [Page 1] RFC 6172 iFCP and Protocol 133 Updates March 2011

Copyright Notice

 Copyright (c) 2011 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (http://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Table of Contents

 1. Introduction...................................................3
 2. Conventions Used in This Document..............................3
 3. iFCP Address Translation Mode..................................3
    3.1. Problem Discussion........................................4
    3.2. iFCP Address Translation Mode Deprecation.................4
 4. FCIP and Protocol Number 133...................................5
 5. Security Considerations........................................5
 6. IANA Considerations............................................5
 7. Conclusions....................................................5
 8. References.....................................................5
    8.1. Normative References......................................5
    8.2. Informative References....................................6
 9. Acknowledgments ...............................................6

Black & Peterson Standards Track [Page 2] RFC 6172 iFCP and Protocol 133 Updates March 2011

1. Introduction

 See Section 3 of [RFC4172] for introductory material on Fibre Channel
 concepts.
 The Internet Fibre Channel Protocol (iFCP) [RFC4172] operates in two
 modes with respect to Fibre Channel N_PORT fabric addresses (24-bit
 N_PORT_IDs): address transparent mode and address translation mode
 (both modes are specified in [RFC4172]):
 o  Address transparent mode is a pass-through mode that preserves
    Fibre Channel N_PORT fabric addresses.
 o  Address translation mode is a Fibre Channel analog to Network
    Address Translation (NAT) in which iFCP gateways change Fibre
    Channel N_PORT fabric addresses at the boundary between Fibre
    Channel and the Internet.  Both the source (S_ID) and destination
    (D_ID) N_PORT fabric addresses may be changed by the iFCP
    gateways.
 This document deprecates iFCP address translation mode because the
 specification has not tracked changes in Fibre Channel and because
 there are no known implementations.
 Protocol Number 133 was allocated for a pre-standard version of the
 Fibre Channel Internet Protocol (FCIP) that encapsulated FC frames
 directly in IP packets.  That protocol number is not used by the
 standard FCIP protocol [RFC3821] [FC-BB-3], but implementations of
 the pre-standard protocol were deployed.  Therefore, this document
 makes no change to the current allocation of Protocol Number 133.

2. Conventions Used in This Document

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
 document are to be interpreted as described in [RFC2119].

3. iFCP Address Translation Mode

 iFCP address translation mode has to translate addresses embedded in
 transmitted data.  This is analogous to NAT translation of IP
 addresses embedded in IP packets.  Fibre Channel restricts the
 occurrence of embedded fabric addresses to control messages (frames);
 N_PORTs send and receive two types of control frames that may contain
 embedded fabric addresses:

Black & Peterson Standards Track [Page 3] RFC 6172 iFCP and Protocol 133 Updates March 2011

 o  Extended Link Services (ELSs); and
 o  FC-4 Link Services (FC-4 LSs) for the Small Computer System
    Interface (SCSI) over Fibre Channel Protocol (FCP).
 The embedded fabric address translations for N_PORT control frames
 are specified in Section 7.3 of [RFC4172].  These translations were
 correct as specified for Fibre Channel as of approximately 2003,
 based on the [FC-FS] standard for ELSs and the [FCP] standard for FCP
 FC-4 LSs.

3.1. Problem Discussion

 Significant changes have been made to FC control frames since the
 iFCP specification [RFC4172] was published; the currently applicable
 FC standards are [FC-LS] and [FCP-3], and additional changes are
 forthcoming in the [FC-LS-2] and [FCP-4] standards projects, which
 are nearing completion.  These changes have caused Section 7.3 of
 [RFC4172] to become incorrect.
 Actual iFCP deployment has diverged significantly from that
 anticipated during the development of [RFC4172].  All deployments of
 iFCP known to the authors of this document use iFCP address
 transparent mode and are used only for FC inter-switch links.  iFCP
 address translation mode as specified in [RFC4172] cannot be used for
 FC inter-switch links because the necessary embedded fabric address
 translations for FC inter-switch control messages (Switch Fabric
 Internal Link Services (ILSs)) have not been specified.

3.2. iFCP Address Translation Mode Deprecation

 For the reasons described above, it is prudent to deprecate iFCP
 address translation mode in preference to updating it to the current
 state of Fibre Channel standards.  Updating iFCP address translation
 mode would create a continuing requirement to update an unused
 protocol mode to match future changes to FC control frames.
 Therefore, this document deprecates iFCP address translation mode:
 o  iFCP address translation mode [RFC4172] SHOULD NOT be implemented
    and SHOULD NOT be used.
 o  The status of [RFC4172] remains Proposed Standard RFC in order to
    retain the specification of iFCP address transparent mode.
 o  The [RFC4172] specification of iFCP address translation mode
    should be treated as Historic [RFC2026].

Black & Peterson Standards Track [Page 4] RFC 6172 iFCP and Protocol 133 Updates March 2011

4. FCIP and Protocol Number 133

 Protocol Number 133 was allocated for Fibre Channel (FC) [IANA-IP]
 and used by a pre-standard version of the FCIP protocol that
 encapsulates FC frames directly in IP packets.  The standard FCIP
 protocol [RFC3821] [FC-BB-3] encapsulates FC frames in TCP and hence
 does not use Protocol Number 133, but implementations of the pre-
 standard version of the FCIP protocol were deployed [MR].  Based on
 this deployment, the protocol number needs to remain allocated.

5. Security Considerations

 The security considerations for iFCP continue to apply; see Section
 10 of [RFC4172].

6. IANA Considerations

 IANA has added this document as a supplemental reference for the
 allocation of Protocol Number 133 but hasn't changed that allocation.

7. Conclusions

 For the reasons described in this document, iFCP Address Translation
 mode is deprecated, and the allocation of Protocol Number 133 remains
 unchanged at this time.

8. References

8.1. Normative References

 [FC-FS]   Fibre Channel Framing and Signaling Interface (FC-FS), ANSI
           INCITS 373-2003, October 2003.
 [FC-LS]   Fibre Channel - Link Services (FC-LS), ANSI INCITS
           433-2007, July 2007.
 [FCP]     Fibre Channel Protocol (FCP), ANSI INCITS 269-1996, April
           1996.
 [FCP-3]   Fibre Channel Protocol - 3 (FCP-3), ISO/IEC 14776-223:2008,
           June 2008.
 [IANA-IP] Assigned Internet Protocol Numbers, IANA Registry,
           http://www.iana.org, visited October 2010.
 [RFC2026] Bradner, S., "The Internet Standards Process -- Revision
           3", BCP 9, RFC 2026, October 1996.

Black & Peterson Standards Track [Page 5] RFC 6172 iFCP and Protocol 133 Updates March 2011

 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
           Requirement Levels", BCP 14, RFC 2119, March 1997.
 [RFC4172] Monia, C., Mullendore, R., Travostino, F., Jeong, W., and
           M. Edwards, "iFCP - A Protocol for Internet Fibre Channel
           Storage Networking", RFC 4172, September 2005.

8.2. Informative References

 [FC-BB-3] Fibre Channel Backbone - 3 (FC-BB-3), ANSI INCITS 414-2006,
           July 2006.
 [FC-LS-2] Fibre Channel - Link Services - 2 (FC-LS-2), INCITS Project
           2103-D, Technical Committee T11 (www.t11.org).
 [FCP-4]   Fibre Channel Protocol - 4 (FCP-4), INCITS Project 1828-D,
           Technical Committee T10 (www.t10.org).
 [MR]      Rajagopal, M., Private email communication, June 2009.
 [RFC3821] Rajagopal, M., Rodriguez, E., and R. Weber, "Fibre Channel
           Over TCP/IP (FCIP)", RFC 3821, July 2004.

9. Acknowledgments

 The authors would like to thank Tom Talpey, David Harrington, Joe
 Touch, Paul Hoffman, and Pekka Savola for helpful comments on this
 document.

Authors' Addresses

 David L. Black
 EMC Corporation
 176 South Street
 Hopkinton, MA 01748
 Phone: +1 (508) 293-7953
 EMail: david.black@emc.com
 David Peterson
 Brocade Communications
 6000 Nathan Lane North
 Plymouth, MN 55442
 Phone: +1 (612) 802-3299
 EMail: david.peterson@brocade.com

Black & Peterson Standards Track [Page 6]

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