Network Working Group J. Dong Internet-Draft M. Chen Intended status: Standards Track Huawei Technologies Expires: January 5, 2015 H. Gredler Juniper Networks, Inc. S. Previdi Cisco Systems, Inc. J. Tantsura Ericsson July 4, 2014 Distribution of MPLS Traffic Engineering (TE) LSP State using BGP draft-ietf-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 January 5, 2015. Dong, et al. Expires January 5, 2015 [Page 1] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 Copyright Notice Copyright (c) 2014 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Carrying LSP State Information in BGP . . . . . . . . . . . . 4 2.1. LSP Identifier Information . . . . . . . . . . . . . . . 4 2.2. LSP State Information . . . . . . . . . . . . . . . . . . 5 3. Operational Considerations . . . . . . . . . . . . . . . . . 7 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References . . . . . . . . . . . . . . . . . . 7 7.2. Informative References . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 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 Dong, et al. Expires January 5, 2015 [Page 2] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 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 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 multi-area or multi-AS scenarios, each area or AS can have a child PCE to collect the LSP states of its own domain, in addition a parent PCE needs to collect the LSP information from multiple child PCEs to obtain a global view of LSPs inside and across the domains involved. In another network scenario, 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. Dong, et al. Expires January 5, 2015 [Page 3] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 BGP has been extended to distribute link-state and traffic engineering information to some external components [I-D.ietf-idr-ls-distribution]. Using the same protocol to collect other network layer information would be desirable for 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 Information 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 Identifier 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 "Link State NLRI" is defined in [I-D.ietf-idr-ls-distribution]. Two new "NLRI Type" are defined for TE LSP Identifier Information as following: o NLRI Type = 5: IPv4 TE LSP NLRI o NLRI-Type = 6: IPv6 TE LSP NLRI The IPv4 TE LSP NLRI (NLRI Type = 5) is shown in the following figure: 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 +-+-+-+-+-+-+-+-+ | Protocol-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identifier | | (64 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Tunnel Sender Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tunnel ID | LSP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Tunnel End-point Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2. IPv4 TE LSP NLRI Dong, et al. Expires January 5, 2015 [Page 4] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 The IPv6 TE LSP NLRI (NLRI Type = 6) is shown in the following figure: 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 +-+-+-+-+-+-+-+-+ | Protocol-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identifier | | (64 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | IPv6 Tunnel Sender Address | + (16 octets) + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tunnel ID | LSP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | IPv6 Tunnel End-point Address | + (16 octets) + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3. IPv6 TE LSP NLRI For IPv4 TE LSP NLRI and IPv6 TE LSP NLRI, the Protocol-ID field is set to 6, which indicates that the NLRI information has been sourced by RSVP-TE. The Identifier field is used to discriminate between instances with different LSP technology - e.g. one identifier can identify the instance for packet path, and another one is to identify the instance of optical path. The other fields in the IPv4 TE LSP NLRI and IPv6 TE LSP NLRI are the same as specified in [RFC3209]. 2.2. LSP State Information The LSP State TLV is used to describe the characteristics of the TE LSPs, which is carried in the optional non-transitive BGP Attribute "LINK_STATE Attribute" defined in [I-D.ietf-idr-ls-distribution]. Dong, et al. Expires January 5, 2015 [Page 5] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 The "Value" field of the LSP State TLV corresponds to the format and semantics of a set of objects defined in [RFC3209], [RFC3473] and other extensions for TE LSPs. Rather than replicating all RSVP-TE related objects in this document, the semantics and encodings of existing TE LSP objects are re-used. Hence all TE LSP objects are regarded as sub-TLVs. The LSP State TLV SHOULD only be used with IPv4/IPv6 TE 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ TE LSP Objects (variable) ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4. LSP State TLV Currently the TE LSP Objects that can be carried in the LSP State TLV include: o SENDER_TSPEC and FLOW_SPEC [RFC2205] o SESSION_ATTRIBUTE [RFC3209] o Explicit Route Object (ERO) [RFC3209] o Record Route Object (RRO) [RFC3209] o FAST_REROUTE Object [RFC4090] o DETOUR Object [RFC4090] o EXCLUDE_ROUTE Object (XRO) [RFC4874] o SECONDARY_EXPLICIT_ROUTE Object (SERO) [RFC4873] o SECONDARY_RECORD_ROUTE (SRRO) [RFC4873] o LSP_ATTRIBUTES Object [RFC5420] o LSP_REQUIRED_ATTRIBUTES Object [RFC5420] o PROTECTION Object [RFC3473][RFC4872][RFC4873] o ASSOCIATION Object [RFC4872] Dong, et al. Expires January 5, 2015 [Page 6] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 o PRIMARY_PATH_ROUTE Object [RFC4872] o ADMIN_STATUS Object [RFC3473] o BANDWIDTH Object [RFC5440] o METRIC Object [RFC5440] Other TE LSP objects which reflect specific state or attribute of the LSP may also be carried in the LSP state TLV, which is for further study. 3. Operational Considerations The Existing BGP operational procedures apply to this document. No new operation procedures are defined in this document. The operational considerations as specified in [I-D.ietf-idr-ls-distribution] apply to this document . 4. IANA Considerations IANA needs to assign two code points for "IPv4 TE LSP NLRI" and "IPv6 TE LSP NLRI" from the BGP-LS registry of NLRI Types. IANA needs to assign one Protocol-ID for "RSVP-TE" from the BGP-LS registry of Protocol-IDs. IANA needs to assign one new TLV type for "LSP State TLV" from the registry of BGP-LS Attribute TLVs. 5. Security Considerations Procedures and protocol extensions defined in this document do not affect the BGP security model. See [RFC6952] for details. 6. Acknowledgements The authors would like to thank Dhruv Dhody and Mohammed Abdul Aziz Khalid for their review and valuable comments. 7. References 7.1. Normative References Dong, et al. Expires January 5, 2015 [Page 7] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 [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-05 (work in progress), May 2014. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 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. [RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May 2005. [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 4760, January 2007. [RFC4872] Lang, J., Rekhter, Y., and D. Papadimitriou, "RSVP-TE Extensions in Support of End-to-End Generalized Multi- Protocol Label Switching (GMPLS) Recovery", RFC 4872, May 2007. [RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel, "GMPLS Segment Recovery", RFC 4873, May 2007. [RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes - Extension to Resource ReserVation Protocol-Traffic Engineering (RSVP-TE)", RFC 4874, April 2007. [RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A. Ayyangarps, "Encoding of Attributes for MPLS LSP Establishment Using Resource Reservation Protocol Traffic Engineering (RSVP-TE)", RFC 5420, February 2009. Dong, et al. Expires January 5, 2015 [Page 8] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. 7.2. Informative References [I-D.ietf-pce-stateful-pce] Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP Extensions for Stateful PCE", draft-ietf-pce-stateful- pce-09 (work in progress), June 2014. [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of BGP, LDP, PCEP, and MSDP Issues According to the Keying and Authentication for Routing Protocols (KARP) Design Guide", RFC 6952, May 2013. Authors' Addresses Jie Dong Huawei Technologies Huawei Campus, No. 156 Beiqing Rd. Beijing 100095 China Email: jie.dong@huawei.com Mach(Guoyi) Chen Huawei Technologies Huawei Campus, No. 156 Beiqing Rd. Beijing 100095 China Email: mach.chen@huawei.com Hannes Gredler Juniper Networks, Inc. 1194 N. Mathilda Ave. Sunnyvale, CA 94089 US Email: hannes@juniper.net Dong, et al. Expires January 5, 2015 [Page 9] Internet-Draft MPLS TE LSP State Distribution using BGP July 2014 Stefano Previdi Cisco Systems, Inc. Via Del Serafico, 200 Rome 00142 Italy Email: sprevidi@cisco.com Jeff Tantsura Ericsson 300 Holger Way San Jose, CA 95134 US Email: jeff.tantsura@ericsson.com Dong, et al. Expires January 5, 2015 [Page 10]