H. Ohta Internet Draft NTT Document: draft-ohta-mpls-label-value-01.txt Expires: August 2002 February 2002 Use of a reserved label value defined in RFC 3032 for MPLS OAM functions Status of this Memo Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. This document requests IANA to allocate a label value. Distribution of this memo is unlimited. This document is an Internet-Draft and is subject to all provisions of Section 10 of RFC2026 except that the right to produce derivative works is not granted. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract This document describes use of an MPLS reserved label value for identification of user-plane MPLS OAM packets as described in the ITU-T draft Recommendation Y.1711, and makes a request to IANA for allocation of a reserved label for this purpose. Ohta Informational - Expires August 2002 1 Use of a reserved label value defined in RFC 3032 Feb 2002 for MPLS OAM functions 1. Introduction This document describes use of an MPLS reserved label value for identification of user-plane MPLS OAM packets as described in the ITU-T draft Recommendation Y.1711 (on MPLS OAM functions) and makes a request to IANA for allocation of a reserved label for this purpose. 2. OAM functions MPLS OAM (Operation and Maintenance) provide necessary tools for network operators to operate and maintain the networks. MPLS OAM functionality is required at the MPLS layer, and more specifically at each MPLS level, independent of OAM functionality provided by the lower layers (SONET/SDH, etc.). The objectives of the OAM functions include the followings: - Defect and failure detection: Defect/failures affecting the transport of user information are detected by continuous or periodic checking. As a result, maintenance event information or various alarms will be produced. - Reporting the defect/failure information: Defect information is given to other management entities (e.g. Operation Support System) in order to provide the appropriate indications to the maintenance staff for maintaining the Quality of Service (QoS) level offered to customers. - Defect/failure localization: Determination by internal or external test systems of a failed entity is performed if defect information is insufficient. - Performance monitoring: Performance (packet losses, transfer delay, bit errors, etc.) of the user information transport is measured in order to estimate the transport integrity. Related work in IETF can be found in [1], [2], [3]. 3. MPLS OAM work in ITU-T SG13 ITU-T Study Group 13, Question 3/13 is progressing work on user-plane MPLS OAM and has produced the following documents: (1) Approved Recommendation Y.1710 (Requirements for OAM functionality for MPLS networks) [4] (2) Draft Recommendation Y.1711 (OAM mechanisms for MPLS networks)[5] (3) Draft Recommendation Y.1720 (MPLS Protection Switching)[6] which relies on OAM mechanisms in Y.1711. Please note that we are planning to put the document (2) above into the approval process in the middle of February. The user-plane MPLS Ohta Informational - Expires August 2002 2 Use of a reserved label value defined in RFC 3032 Feb 2002 for MPLS OAM functions OAM mechanisms[5] relies on the use of a special label called 'OAM Alert Label'. Study Group 13 has tentatively decided to use one of the reserved label values defined in RFC 3032(MPLS label stack encoding)[7] to differentiate OAM packets from the normal user packets. A value of 14 has been proposed for this purpose. IANA is requested to consider if the use of this value is acceptable. Should the said value not be acceptable by IANA, Study Group 13 is ready to accept another reserved label value (as per IANA's recommendation). Study group 13 appreciates if IANA advises the author of any problem with the use of this value no later than April 30, 2002. Extracts from draft Recommendation Y.1711 follow: "1 Introduction This Recommendation provides mechanisms for user-plane OAM (Operation and Maintenance) functionality in MPLS networks according to the requirements and principles given in Recommendation Y.1710. It is recognized that OAM functionality is important in public networks for ease of network operation, for verifying network performance and to reduce operational costs. OAM functionality is especially important for networks, which are required to deliver (and hence be measurable against) QoS (Quality of Service) and availability performance parameters/objectives." " 5.1 Identification of OAM packets from normal user-plane traffic The label structure defined in [7] indicates a single label field of 20 bits. Some label field values have already been reserved for special functions[7]. This Recommendation introduces a new globally reserved label value, herein referred to as the 'OAM Alert Label'. The recommended numerical value of the OAM Alert Label is 14." Further information can be obtained from the author. 4. IANA considerations It is requested that the IANA consider if the use of the MPLS reserved label value of 14 as the 'OAM Alert Label' is acceptable. If it is acceptable, it is requested that the use of this value is officially assigned. Study group 13 appreciates if IANA will advise the author of any problem with the use of this value, and if necessary recommends an alternative reserved label value no later than April 30, 2002. . Ohta Informational - Expires August 2002 3 Use of a reserved label value defined in RFC 3032 Feb 2002 for MPLS OAM functions 5. References [1] Neil Harrison et. al. "Requirements for OAM in MPLS Networks", IETF Work in progress, draft-harrison-mpls-oam-req-01.txt, December 2001 [2] David Allan et. al. " A Framework for MPLS User Plane OAM", IETF Work in progress, draft-allan-mpls-oam-frmwk-01.txt, November 2001 [3] Mina Azad et. al. " MPLS user-plane OAM messaging", IETF Work in progress, draft-azad-mpls-oam-messaging-01.txt, December 2001 [4] ITU-T recommendation Y.1710, "Requirements for OAM functionality for MPLS networks" Caracas, Venezuela, May 2001 [5] ITU-T draft recommendation Y.1711, "OAM mechanism for MPLS networks", Geneva, Switzerland, February 2002 [6] ITU-T draft recommendation Y.1720, "Protection switching for MPLS networks", Caracas, Venezuela, May 2001 [7] IETF, RFC 3032, MPLS label stack encoding, Category: Standards Track, January 2001. 6. Author's Address Hiroshi OHTA NTT 3-9-11 Midori-Cho, Musashino-Shi Tokyo 180-8585 Japan Tel: +81 422 59 3617 Fax: +81 422 59 3782 Email: ohta.hiroshi@lab.ntt.co.jp Ohta Informational - Expires August 2002 4