Network Working Group J. Dong Internet-Draft M. Chen Intended status: Standards Track Huawei Technologies Expires: August 29, 2013 February 25, 2013 Distribution of MPLS Traffic Engineering (TE) LSP State using BGP draft-dong-idr-te-lsp-distribution-01 Abstract This document describes a mechanism to collect the Traffic Engineering (TE) LSP information using BGP. Such information can be used by external components for path reoptimization, service placement and network visualization. Requirements Language 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 [RFC2119]. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on August 29, 2013. Copyright Notice Copyright (c) 2013 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 Dong & Chen Expires August 29, 2013 [Page 1]
Internet-Draft MPLS TE LSP State Distribution using BGP February 2013 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. Carrying LSP State Information in BGP . . . . . . . . . . . . . 4 2.1. LSP Identifier Inforation . . . . . . . . . . . . . . . . . 4 2.2. LSP State Attribute . . . . . . . . . . . . . . . . . . . . 6 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7 6.2. Informative References . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Dong & Chen Expires August 29, 2013 [Page 2]
Internet-Draft MPLS TE LSP State Distribution using BGP February 2013 1. Introduction In some network environments, the states of established Multi- Protocol Label Switching (MPLS) Traffic Engineering (TE) Label Switched Paths (LSPs) in the network are required by some components external to the network domain. Usually this information is directly maintained by the ingress Label Edge Routers (LERs) of the MPLS TE LSPs. One example of using the LSP information is stateful Path Computation Element (PCE) [I-D.ietf-pce-stateful-pce], which could provide benefits in path reoptimization . While some extensions are proposed in Path Computation Element Communication Protocol (PCEP) for the Path Computation Clients (PCCs) to report the LSP states to the PCE, this mechanism may not be applicable in a management-based PCE architecture as specified in section 5.5 of [RFC4655]. As illustrated in the figure below, the PCC is not an LSR in the routing domain, thus the head-end nodes of the TE-LSP may not implement the PCEP protocol. In this case some general mechanism to collect the TE-LSP states from the ingress LERs is needed. This document proposes an LSP state collection mechanism complementary to the mechanism defined in [I-D.ietf-pce-stateful-pce]. ----------- | ----- | Service | | TED |<-+-----------> Request | ----- | TED synchronization | | | | mechanism (for example, v | | | routing protocol) ------------- Request/ | v | | | Response| ----- | | NMS |<--------+> | PCE | | | | | ----- | ------------- ----------- Service | Request | v ---------- Signaling ---------- | Head-End | Protocol | Adjacent | | Node |<---------->| Node | ---------- ---------- Figure 1. Management-Based PCE Usage In networks with composite PCE nodes as specified in section 5.1 of [RFC4655], the PCE is implemented on several routers in the network, and the PCCs in the network can use the mechanism described in [I-D.ietf-pce-stateful-pce] to report the LSP information to the PCE Dong & Chen Expires August 29, 2013 [Page 3]
Internet-Draft MPLS TE LSP State Distribution using BGP February 2013 nodes. An external component may further need to collect the LSP information from all the PCEs in the network to get a global view of the LSP states in the network. In some networks, a centralized controller is used for service placement. Obtaining the TE LSP state information is quite important for making appropriate service placement decisions with the purpose of both meeting the application's requirements and utilizing the network resource efficiently. The Network Management System (NMS) may need to provide global visibility of the TE LSPs in the network as part of the network visualization function. BGP has been extended to distribute link-state and traffic engineering information and share with some external components [I-D.ietf-idr-ls-distribution]. Using the same protocol to collect other network layer information would be desired by the external components, which avoids introducing multiple protocols for network information collection. This document describes a mechanism to distribute the TE LSP information to external components using BGP. 2. Carrying LSP State Information in BGP 2.1. LSP Identifier Inforation The TE LSP Identifier information is advertised in BGP UPDATE messages using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes [RFC4760]. The "Link State NLRI" defined in [I-D.ietf-idr-ls-distribution] is extended to carry the TE LSP information. BGP speakers that wish to exchange TE LSP information MUST use the BGP Multiprotocol Extensions Capability Code (1) to advertise the corresponding (AFI, SAFI) pair, as specified in [RFC4760]. The format of the Link State NLRI is shown in the following figure. Dong & Chen Expires August 29, 2013 [Page 4]
Internet-Draft MPLS TE LSP State Distribution using BGP February 2013 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NLRI Type | Total NLRI Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link State NLRI (variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2. Link State NLRI Format Two new "NLRI Type" are defined for TE LSP Identifier Information as following: o NLRI Type = 5: IPv4 LSP NLRI o NLRI-Type = 6: IPv6 LSP NLRI If the NLRI Type value is set to 5, the Link State NLRI field is the IPv4-LSP-IDENTIFER structured as below: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Tunnel Sender Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tunnel ID | LSP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Tunnel End-point Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3. IPv4-LSP-IDENTIFIER If the NLRI Type value is set to 6, the Link State NLRI field is the IPv6-LSP-IDENTIFIER structured as below: Dong & Chen Expires August 29, 2013 [Page 5]
Internet-Draft MPLS TE LSP State Distribution using BGP February 2013 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | IPv6 Tunnel Sender Address | + (16 octets) + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tunnel ID | LSP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | IPv6 Tunnel End-point Address | + (16 octets) + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4. IPv6-LSP-IDENTIFIER The fields in the IPv4-LSP-IDENTIFIER and IPv6-LSP-IDENTIFIER are the same as specified in [RFC3209]. 2.2. LSP State Attribute The LSP State Attribute is an optional non-transitive BGP attribute which is used to describe the characteristics of the LSPs. The LSP State Attribute consists of a set of objects defined in [RFC3209], [RFC3473] and [RFC5440] . This Attribute SHOULD only be used with IPv4/IPv6 LSP NLRI. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Objects (variable) ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5. LSP State Attribute Currently the Objects that can be carried in the LSP State Attribute include: Dong & Chen Expires August 29, 2013 [Page 6]
Internet-Draft MPLS TE LSP State Distribution using BGP February 2013 o LSP Attributes (LSPA) Object o Explicit Route Object (ERO) o Record Route Object (RRO) o BANDWIDTH Object o METRIC Object o Protection Object o Admin Status Object Other objects may also be carried in the LSP State Attribute, which would be specified in a future version. 3. IANA Considerations IANA needs to assign an new code point for the LSP State Attribute from the "BGP Path Attributes" registry. 4. Security Considerations TBD 5. Acknowledgements TBD 6. References 6.1. Normative References [I-D.ietf-idr-ls-distribution] Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and TE Information using BGP", draft-ietf-idr-ls-distribution-01 (work in progress), October 2012. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., Dong & Chen Expires August 29, 2013 [Page 7]
Internet-Draft MPLS TE LSP State Distribution using BGP February 2013 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 4760, January 2007. [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. 6.2. Informative References [I-D.ietf-pce-stateful-pce] Crabbe, E., Medved, J., Minei, I., and R. Varga, "PCEP Extensions for Stateful PCE", draft-ietf-pce-stateful-pce-02 (work in progress), October 2012. [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. Authors' Addresses Jie Dong Huawei Technologies Huawei Building, No. 156 Beiqing Rd. Beijing 100095 China Email: jie.dong@huawei.com Mach(Guoyi) Chen Huawei Technologies Huawei Building, No. 156 Beiqing Rd. Beijing 100095 China Email: mach.chen@huawei.com Dong & Chen Expires August 29, 2013 [Page 8]