MPLS-TP OAM ACh Type: Allocation of a Generic Associated Channel Type for ITU-T MPLS Transport Profile Operation, Maintenance, and Administration (MPLS-TP OAM)
IANA assigns a G-ACh Type for ITU-T G.8113.1 OAM messages in MPLS-TP, with an IESG note that the IETF does not endorse it.
Betts, M., "Allocation of a Generic Associated Channel Type for ITU-T MPLS Transport Profile Operation, Maintenance, and Administration (MPLS-TP OAM)", RFC 6671, DOI 10.17487/RFC6671, November 2012, <https://www.rfc-editor.org/info/rfc6671>.
@misc{rfc6671,
series = {Request for Comments},
number = 6671,
howpublished = {RFC 6671},
publisher = {RFC Editor},
doi = {10.17487/RFC6671},
url = {https://www.rfc-editor.org/info/rfc6671},
author = {M. Betts},
title = {{Allocation of a Generic Associated Channel Type for ITU-T MPLS Transport Profile Operation, Maintenance, and Administration (MPLS-TP OAM)}},
pagetotal = 5,
year = 2012,
month = nov,
} RFC text
Contents
Internet Engineering Task Force (IETF) M. Betts
Request for Comments: 6671 ZTE
Category: Informational November 2012
ISSN: 2070-1721
Allocation of a Generic Associated Channel Type for ITU-T
MPLS Transport Profile Operation, Maintenance, and Administration
(MPLS-TP OAM)
Abstract
This document assigns a Generic Associated Channel (G-ACh) Type for
carrying ITU-T MPLS Transport Profile Operations, Administration, and
Management (MPLS-TP OAM) messages in the MPLS Generic Associated
Channel.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see 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/rfc6671.
IESG Note
The IESG notes that the IETF has developed a set of OAM tools for
MPLS-TP that have been published as Standards Track RFCs. A list of
the relevant RFCs can be found in RFC 6669. The approval of this
document and the assignment of an ACh Type does not constitute
endorsement by the IETF of the alternate MPLS-TP OAM documented in
G.8113.1. The IESG recommends instead that the RFCs noted above
should be implemented.
Copyright Notice
Copyright (c) 2012 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.
1. Introduction
The Transport Profile of MPLS (MPLS-TP) defined in [RFC5654] is a
profile of MPLS technology for use in packet transport networks. The
MPLS-TP profile includes a set of Operations, Administration, and
Management (OAM) tools defined by the IETF [RFC6669] that are used to
meet the OAM functional requirements defined in [RFC5860].
ITU-T Recommendation [G.8113.1] documents MPLS-TP OAM. This
Recommendation builds upon Ethernet OAM as documented in [Y.1731].
The messages in [G.8113.1] are defined to be carried in a new Generic
Associated Channel (G-ACh) Type in the MPLS Generic Associated
Channel. In order to carry these messages in an interoperable
fashion, a Generic Associated Channel Type from the IANA maintained
registry "Pseudowire Associated Channel Types" is to be used.
To fulfill the request from ITU-T SG15 in [LS370] and to allow
deployment of the [G.8113.1] OAM solution without using an
experimental G-ACh Type, IANA has assigned a G-ACh Type <0x8902> for
use by the ITU-T for [G.8113.1]. This G-ACh Type is known as the
"G.8113.1 OAM G-ACh Type".
A number of experts in the IETF do not consider that the development
or deployment of a second protocol solution within the same
architectural problem space is necessary or advisable [RFC6670].
2. Conventions Used in This Document
2.1. Requirements Notation
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. Scope of the G.8113.1 OAM G-ACh Type
The G-ACh Type assigned by this document MUST only be used for OAM
messages, as defined in the ITU-T Recommendation [G.8113.1], carried
in the G-ACh. The OAM messages and procedures carried behind this
G-ACh Type are restricted to only those that address the OAM
functional requirements defined in [RFC5860]. Other message types
MUST NOT be carried behind this G-ACh Type.
All ITU-T Recommendations are subject to updates by errata,
corrigenda, amendments, or complete revisions. In any update of
[G.8113.1], the G-ACh Type assigned by this document MUST NOT be used
for any functions not identified as OAM functional requirements in
[RFC5860]. An update of [G.8113.1] may use the G-ACh Type assigned
by this document to support the OAM functions identified in
[RFC5860]. When an amendment or complete revision of G.8113.1 is
approved, the reference to [G.8113.1], provided in this document,
should be updated to show the approval date of the new version.
The G-ACh Type assigned by this document may be used on any transport
construct that uses the G-ACh, e.g., MPLS-TP Sections, MPLS-TP LSPs,
or PWs as described in [G.8113.1].
4. Security Considerations
As noted in [RFC5586], when new G-ACh Types are defined, the
"security considerations MUST be described in the relevant associated
channel type specification". The IETF takes this opportunity to
remind the ITU-T of the need to describe security considerations in
[G.8113.1].
5. IANA Considerations
IANA maintains the "Pseudowire Associated Channel Types" sub-registry
of the "Pseudowire Name Spaces (PWE3)" registry.
IANA has allocated a new G-ACh Type as follows:
Value Description TLV Follows Reference
----------- ----------------------- ----------- ---------
0x8902 G.8113.1 OAM No [RFC6671]
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed.,
"MPLS Generic Associated Channel", RFC 5586, June 2009.
[RFC5654] Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed.,
Sprecher, N., and S. Ueno, "Requirements of an MPLS
Transport Profile", RFC 5654, September 2009.
[RFC5860] Vigoureux, M., Ed., Ward, D., Ed., and M. Betts, Ed.,
"Requirements for Operations, Administration, and
Maintenance (OAM) in MPLS Transport Networks", RFC 5860,
May 2010.
[G.8113.1] ITU-T Recommendation G.8113.1/Y.1372.1, "Operations,
Administration and Maintenance mechanism for MPLS-TP in
Packet Transport Network (PTN)", 11/2012,
http://www.itu.int/rec/T-REC-G.8113.1/en.
[Y.1731] ITU-T Recommendation G.8013/Y.1731, "OAM functions and
mechanisms for Ethernet based networks" 07/2011 as updated
by Corrigendum 1, 10/2011, and Amendment 1, 05/2012,
http://www.itu.int/rec/T-REC-G.8013/en.
6.2. Informative References
[LS370] "Liaison Statement: LS370 - Current status of
Recommendation ITU-T G.8113.1/Y.1372.1, Operations,
Administration and Maintenance mechanism for MPLS-TP in
Packet Transport Network (PTN)", January 2012,
https://datatracker.ietf.org/liaison/1125/.
[RFC6669] Sprecher, N. and L. Fang, "An Overview of the Operations,
Administration, and Maintenance (OAM) Tool Set for MPLS-
Based Transport Networks", RFC 6669, July 2012.
[RFC6670] Sprecher, N. and KY. Hong, "The Reasons for Selecting a
Single Solution for MPLS Transport Profile (MPLS-TP)
Operations, Administration, and Maintenance (OAM)", RFC
6670, July 2012.
Author's Address
Malcolm Betts
ZTE
EMail: malcolm.betts@zte.com.cn
AI ELI5
On this page
§1Why a G-ACh Type Was Needed
The Transport Profile of MPLS (MPLS-TP, RFC 5654) is a profile of MPLS for packet transport networks. Its OAM (Operations, Administration, and Maintenance) tool set is defined by the IETF in RFC 6669. ITU-T Recommendation G.8113.1 documents a separate MPLS-TP OAM that builds on Ethernet OAM (Y.1731).
Its messages are carried in a new type of the MPLS Generic Associated Channel. To fulfill a request from ITU-T SG15 and to allow deployment without an experimental G-ACh Type, IANA assigned 0x8902. The RFC also notes that a number of IETF experts do not consider a second protocol solution in the same problem space necessary or advisable (RFC 6670).
Another group wrote its own maintenance messages and needed an official lane number for them. IANA gave one, though some experts thought one set of messages was enough.
§2Scope of the Assigned Type
The type MUST only be used for OAM messages defined in G.8113.1 and carried in the G-ACh. The messages and procedures behind it are restricted to those that address the OAM functional requirements of RFC 5860. Other message types MUST NOT be carried behind it.
If G.8113.1 is updated, the type must still not be used for functions outside those requirements. The type may be used on any transport construct that uses the G-ACh, such as MPLS-TP Sections, LSPs or pseudowires.
The lane is only for maintenance messages. Nobody may send other kinds of traffic down it.
§3The IANA Allocation, IESG Note and Security
IANA maintains the "Pseudowire Associated Channel Types" sub-registry. The new entry is value 0x8902, description G.8113.1 OAM, TLV Follows: No, reference RFC 6671.
The IESG note says that approval of the document and the assignment do not constitute endorsement of the alternate MPLS-TP OAM in G.8113.1, and recommends instead that the Standards Track RFCs listed in RFC 6669 be implemented. For security, the RFC reminds the ITU-T that RFC 5586 requires security considerations to be described for each new associated channel type, and asks that they be described in G.8113.1.
The lane number is written in the official list. A note says it is there as a courtesy, and the IETF would rather people use its own messages.
- 0x8902G.8113.1 OAM — TLV Follows: No. Reference RFC 6671.