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
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