Network Working Group Han Li Internet Draft China Mobile Updates (if published): RFC5586 Intended status: Standards Track Luca Martini Cisco System Jia He Huawei Feng Huang Alcatel-Lucent Expires: March 2011 September 14, 2010 Using the Generic Associated Channel Label for Pseudowire in MPLS-TP draft-lm-pwe3-mpls-tp-gal-in-pw-00.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. 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. 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." 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Abstract This document describes the requirements for using the Generic Associated Channel Label (GAL) in Pseudowires (PWs) in MPLS-TP networks, and provides an update to the description of GAL usage in [RFC5586] by removing the restriction that is imposed on using GAL for PWs especially in MPLS-TP environments. . Table of Contents 1. Introduction................................................2 2. Conventions used in this document...........................3 2.1. Terminology............................................3 3. GAL Usage for MPLS-TP PW....................................3 4. Security Considerations.....................................4 5. IANA Considerations.........................................4 6. Acknowledgments.............................................5 7. References..................................................5 7.1. Normative References...................................5 7.2. Informative References.................................5 8. Authors' Addresses..........................................5 1. Introduction [RFC5586] generalizes the associated control channel mechanism of [RFC5085] to be used for Sections, Label Switched Paths (LSPs), and Pseudowires (PWs) in MPLS networks. [RFC5085] defines the Associated Channel Header (ACH), and [RFC5586] generalizes this for use in the Generic Associated Channel (G-ACh). [RFC5586] defines a generalized label-based exception mechanism using the Generic Associated Channel Label (GAL) to work together with the ACH for use with LSPs but places restrictions on GAL usage with PWs. This document removes the restriction imposed by [RFC5586]. H. Li et al. Expires March 14, 2011 [Page 2] Internet-Draft Using GAL in MPLS-TP PW September 2010 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 [RFC 2119]. 2.1. Terminology ACH Associated Channel Header CW Control Word G-ACh Generic Associated Channel GAL G-ACh Label MPLS-TP MPLS Transport Profile OAM Operation, Administration, and Maintenance 3. GAL Usage for MPLS-TP PW According to the MPLS-TP requirement document [RFC5654], it is necessary that MPLS-TP mechanisms and capabilities be able to interoperate with the existing IETF MPLS [RFC3031] and IETF PWE3 [RFC3985] architectures appropriate. [RFC5586] differentiates between the usage of the GAL with PWs in MPLS and MPLS-TP environments in section 4.2 as follows: In MPLS-TP, the GAL MUST be used with packets on a G-ACh on LSPs, Concatenated Segments of LSPs, and with Sections, and MUST NOT be used with PWs. This indicates that the GAL can be used for MPLS-TP LSPs and Sections, but not for PWs using an MPLS-TP PSN. However, there is no restriction imposed on the usage of the GAL in MPLS PWs, which is described immediately afterwards in the same section of [RFC5586] (Section 4.2): However, in other MPLS environments, this document places no restrictions on where the GAL may appear within the label stack or its use with PWs. The inconsistency between the usage of the GAL with MPLS PWs and MPLS-TP PWs may cause unnecessary implementation differences and is in disagreement with the MPLS-TP requirements. H. Li et al. Expires March 14, 2011 [Page 3] Internet-Draft Using GAL in MPLS-TP PW September 2010 Therefore, this document specifies that the GAL can be used with packets on a G-ACh on LSPs, Concatenated Segments of LSPs, Sections, and PWs in both MPLS and MPLS-TP environments without discrimination. [RFC5586] is updated by removing the restrictions on using GAL for PW as follows: - Section 1 (Introduction) in [RFC5586], the original text: The GAL mechanism is defined to work together with the ACH for LSPs and MPLS Sections. is replaced by: The GAL mechanism is defined to work together with the ACH for LSPs and MPLS Sections, and for PWs. - Section 4.2. (GAL Applicability and Usage) in [RFC5586], the original text: In MPLS-TP, the GAL MUST be used with packets on a G-ACh on LSPs, Concatenated Segments of LSPs, and with Sections, and MUST NOT be used with PWs. It MUST always be at the bottom of the label stack (i.e., S bit set to 1). However, in other MPLS environments, this document places no restrictions on where the GAL may appear within the label stack or its use with PWs. is replaced by: In MPLS-TP, the GAL MUST be used with packets on a G-ACh on LSPs, Concatenated Segments of LSPs, and with Sections, and MAY be used with PWs. It MUST always be at the bottom of the label stack (i.e., S bit set to 1). However, in other MPLS environments, this document places no restrictions on where the GAL may appear within the label stack. 4. Security Considerations No further security considerations than [RFC5586]. 5. IANA Considerations There are no IANA actions required. H. Li et al. Expires March 14, 2011 [Page 4] Internet-Draft Using GAL in MPLS-TP PW September 2010 6. Acknowledgments The authors would like to thank Luyuan Fang, Adrian Farrel, Haiyan Zhang, Guanghui Sun, Italo Busi, Matthew Bocci for their contributions to this work. The authors would also like to thank the authors of [RFC5586] and people who were involved in the development of [RFC5586]. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. [RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to-Edge (PWE3) Architecture", RFC 3985, March 2005. [RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic Associated Channel", RFC5586, June 2009 7.2. Informative References [RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires", RFC 5085, December 2007. [RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and S. Ueno, "Requirements of an MPLS Transport Profile", RFC 5654, September 2009. 8. Authors' Addresses Han Li China Mobile Communications Corporation Email: lihan@chinamobile.com H. Li et al. Expires March 14, 2011 [Page 5] Internet-Draft Using GAL in MPLS-TP PW September 2010 Luca Martini Cisco Systems, Inc. Email: lmartini@cisco.com Jia He Huawei Technologies Co., Ltd. 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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. H. Li et al. Expires March 14, 2011 [Page 7]