Inter-Domain Routing G. Dawra, Ed. Internet-Draft LinkedIn Intended status: Standards Track C. Filsfils Expires: January 9, 2020 Cisco Systems D. Bernier Bell Canada J. Uttaro AT&T B. Decraene Orange H. Elmalky Ericsson X. Xu Alibaba F. Clad K. Talaulikar Cisco Systems July 8, 2019 BGP-LS Advertisement of Segment Routing Service Segments draft-dawra-idr-bgp-ls-sr-service-segments-02 Abstract BGP Link-State (BGP-LS) enables distribution of topology information from the network to a Path Computation Engine (PCE) or any controller/application in general so it can learn the network topology. Service functions are deployed as virtualized elements along with network elements or on servers in data centers. The advertisement of such attached service capabilities along with the network nodes that they are attached to or associated with enable their discovery and for programming of service paths that use these service functions. Segment Routing (SR) bring in the concept of segments which can be topological or service instructions. SR Policies enable setup of paths which are a mix of topological and service segments. This document specifies the extensions to BGP-LS for discovery and advertisement of service segments so as to enable setup of service programming paths using Segment Routing. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP Dawra, et al. Expires January 9, 2020 [Page 1] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 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 https://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 9, 2020. Copyright Notice Copyright (c) 2019 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 (https://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 . . . . . . . . . . . . . . . . . . . . . . . . 3 2. BGP-LS Extensions for Service Chaining . . . . . . . . . . . 4 3. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 7 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 4.1. Service Type Table . . . . . . . . . . . . . . . . . . . 7 4.2. Segment routing function Identifier(SFI) . . . . . . . . 8 5. Manageability Considerations . . . . . . . . . . . . . . . . 8 6. Operational Considerations . . . . . . . . . . . . . . . . . 8 6.1. Operations . . . . . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 8. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 9 Dawra, et al. Expires January 9, 2020 [Page 2] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction Segments are introduced in the SR architecture [I-D.ietf-spring-segment-routing]. Segment Routing based Service chaining is well described in Section 6 of [I-D.xuclad-spring-sr-service-programming] document with an example network and services. This document extend the example to add a Segment Routing Controller (SR-C) to the network, for the purpose of service discovery and SR policy [I-D.ietf-spring-segment-routing-policy] instantiation. Consider the network represented in Figure 1 below where: o A and B are two end hosts using IPv4. o S1 is an SR-aware firewall Service. o S2 is an SR-unaware DPI Service. SR-C --3-- | / \ | / \ A----1----2----4----5----6----B | | | | S1 S2 Figure 1: Network with Services SR Controller (SR-C) is connected to Node 1, but may be attached to any node 1-6 in the network. SR-C is capable of receiving BGP-LS updates to discover topology, and calculating constrained paths between 1 and 6. However, if SR-C is configured to computation a constrained path from 1 and 6, including a DPI service (i.e., S2) it is not yet possible due to the lack of service distribution. SR-C does not know where a DPI Service is nor the SID for it. It does not know that S2 is a service it needs. Dawra, et al. Expires January 9, 2020 [Page 3] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 This document proposes an extension to BGP-LS for Service Chaining to distribute the service information to SR-C. There may be other alternate mechanisms to distribute service information to SR-C and are outside of scope of this document. There are no extensions required in SR-TE Policy SAFI. 2. BGP-LS Extensions for Service Chaining For an attached service, following data needs to be shared with SR-C: o Service SID value (e.g. MPLS label or IPv6 address). Service SID MAY only be encoded as LOC:FUNCT, where LOC is the L most significant bits and FUNCT is the 128-L least significant bits[I-D.ietf-spring-srv6-network-programming]. ARGs bits, if any, MAY be set to 0 in the advertised service SID. o Function Identifier (Static Proxy, Dynamic Proxy, Shared Memory Proxy, Masquerading Proxy, SR Aware Service etc). o Service Type (DPI, Firewall, Classifier, LB etc). o Traffic Type (IPv4 OR IPv6 OR Ethernet) o Opaque Data (Such as brand and version, other extra information) [I-D.xuclad-spring-sr-service-programming] defines SR-aware and SR- unaware services. This document will reuse these definitions. Per [RFC7752] Node Attributes are ONLY associated with the Node NLRI. All non-VPN information SHALL be encoded using AFI 16388 / SAFI 71. VPN information SHALL be encoded using AFI 16388 / SAFI 72 with associated RTs. This document introduces new TLVs for the SRv6 SID NLRI [I-D.ietf-idr-bgpls-srv6-ext] and SR-MPLS SID/Label TLV [I-D.ietf-idr-bgp-ls-segment-routing-ext] to associate the Service SID Value with Service-related Information using Service Chaining(SC) Sub-TLV. SRv6 SID Information TLV [I-D.ietf-idr-bgpls-srv6-ext] encodes behavior along with associated SID Flags. A Service Chaining (SC) TLV in Figure 2 is defined as: Dawra, et al. Expires January 9, 2020 [Page 4] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 +---------------------------------------+ | Type (2 octet) | +---------------------------------------+ | Length (2 octet) | +---------------------------------------+ | Service Type(ST) (2 octet | +---------------------------------------+ | Flags (1 octet) | +---------------------------------------+ | Traffic Type(1 octet) | +---------------------------------------+ | RESERVED (2 octet) | +---------------------------------------+ Figure 2: Service Chaining (SC) TLV Where: Type: 16 bit field. TBD Length: 16 bit field. The total length of the value portion of the TLV. Service Type(ST): 16bit field. Service Type: categorizes the Service: (such as "Firewall", "Classifier" etc). Flags: 8 bit field. Bits SHOULD be 0 on transmission and MUST be ignored on reception. Traffic Type: 8 Bit field. A bit to identify if Service is IPv4 OR IPv6 OR L2 Ethernet Capable. Where: Bit 0(LSB): Set to 1 if Service is IPv4 Capable Bit 1: Set to 1 if Service is IPv6 Capable Bit 2: Set to 1 if Service is Ethernet Capable RESERVED: 16bit field. SHOULD be 0 on transmission and MUST be ignored on reception. Service Type(ST) MUST be encoded as part of SC TLV. There may be multiple instances of similar Services that needs to be distinguished. For example, firewalls made by different vendors A and B may need to be identified differently because, while they have similar functionality, their behavior is not identical. Dawra, et al. Expires January 9, 2020 [Page 5] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 In order for SDN Controller to identify the categories of Services and their associated SIDs, this section defines the BGP-LS extensions required to encode these characteristics and other relevant information about these Services. Another Optional Opaque Metadata(OM) TLV of SRv6 SID NLRI may encode vendor specific information. Multiple of OM TLVs may be encoded. +---------------------------------------+ | Type (2 octet) | +---------------------------------------+ | Length (2 octet) | +---------------------------------------+ | Opaque Type (2 octet) | +---------------------------------------+ | Flags (1 octet) | +---------------------------------------+ | Value (variable) | +---------------------------------------+ Figure 3: Opaque Metadata(OM) TLV o Type: 16 bit field. TBD. o Length: 16 bit field. The total length of the value portion of the TLV. o Opaque Type: 8-bit field. Only publishers and consumers of the opaque data are supposed to understand the data. o Flags: 8 bit field. Bits SHOULD be 0 on transmission and MUST be ignored on reception. o Value: Variable Length. Based on the data being encoded and length is recorded in length field. Opaque Metadata(OM) TLV defined in Figure 3 may encode propriety or Service Opaque information such as: o Vendor specific Service Information. o Traffic Limiting Information to particular Service Type. o Opaque Information unique to the Service o Propriety Enterprise Service specific Information. Dawra, et al. Expires January 9, 2020 [Page 6] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 3. Illustration In our SRv6 example above Figure 1 , Node 5 is configured with an SRv6 dynamic proxy segments (End.AD) C5::AD:F2 for S2. The BGP-LS advertisement MUST include SRv6 SID NLRI with SRv6 SID Information TLV in the BGP-LS Attribute: o Service SID: C5::AD:F2 SID o Endpoint Behavior: END.AD The BGP-LS Attribute MUST contain a SC TLV with: o Service Type: Deep Packet Inspection(DPI) o Traffic Type: IPv4 Capable. The BGP-LS Attribute MAY contain a OM TLV with: o Opaque Type: Cisco DPI Version o Value: 3.5 In our example in Figure 1, using BGP SR-TE SAFI Update [I-D.ietf-idr-segment-routing-te-policy], SR Controller computes the candidate path and pushes the Policy. SRv6 encapsulation policy < CF1::, C3::, C5::AD:F2, C6::D4:B > is signaled to Node 1 which has mix of service and topological segments. 4. IANA Considerations This document requests assigning code-points from the registry "BGP- LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs". 4.1. Service Type Table IANA is request to create a new top-level registry called "Service Type Table (STT)". Valid values are in the range 0 to 65535. Values 0 and 65535 are to be marked "Reserved, not to be allocated". Dawra, et al. Expires January 9, 2020 [Page 7] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 +------------+-----------------------+------------+-------------+ | Service | Service | Reference | Date | | Value(TBD) | | | | +------------+-----------------------+------------+-------------+ | 32 | Classifier | ref-to-set | date-to-set | +------------+-----------------------+------------+-------------+ | 33 | Firewall | ref-to-set | date-to-set | +------------+-----------------------+------------+-------------+ | 34 | Load Balancer | ref-to-set | date-to-set | +------------+-----------------------+------------+-------------+ | 35 | DPI | ref-to-set | date-to-set | +------------+-----------------------+------------+-------------+ Figure 4 4.2. Segment routing function Identifier(SFI) IANA is request to extend a top-level registry called "Segment Routing Function Identifier(SFI)" with new code points. This document extends the SFI values defined in [I-D.ietf-idr-bgpls-srv6-ext]. Details about the Service functions are defined in[I-D.xuclad-spring-sr-service-programming]. +--------------------------+---------------------------+ | Function | Function Identifier | | | | +--------------------------+---------------------------+ | Static Proxy | 8 | +--------------------------+---------------------------+ | Dynamic Proxy | 9 | +--------------------------+---------------------------+ | Shared Memory Proxy | 10 | +--------------------------+---------------------------+ | Masquerading Proxy | 11 | +--------------------------+---------------------------+ | SRv6 Aware Service | 12 | +--------------------------+---------------------------+ 5. Manageability Considerations This section is structured as recommended in[RFC5706] 6. Operational Considerations Dawra, et al. Expires January 9, 2020 [Page 8] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 6.1. Operations Existing BGP and BGP-LS operational procedures apply. No additional operation procedures are defined in this document. 7. Security Considerations Procedures and protocol extensions defined in this document do not affect the BGP security model. See the 'Security Considerations' section of [RFC4271] for a discussion of BGP security. Also refer to[RFC4272] and[RFC6952] for analysis of security issues for BGP. 8. Conclusions This document proposes extensions to the BGP-LS to allow discovery of Services using Segment Routing. 9. Acknowledgements The authors would like to thank Krishnaswamy Ananthamurthy for his review of this document. 10. References 10.1. Normative References [I-D.ietf-idr-bgp-ls-segment-routing-ext] Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H., and M. Chen, "BGP Link-State extensions for Segment Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16 (work in progress), June 2019. [I-D.ietf-idr-bgpls-srv6-ext] Dawra, G., Filsfils, C., Talaulikar, K., Chen, M., daniel.bernier@bell.ca, d., and B. Decraene, "BGP Link State Extensions for SRv6", draft-ietf-idr-bgpls- srv6-ext-01 (work in progress), July 2019. [I-D.ietf-spring-segment-routing] Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", draft-ietf-spring-segment-routing-15 (work in progress), January 2018. Dawra, et al. Expires January 9, 2020 [Page 9] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 [I-D.ietf-spring-srv6-network-programming] Filsfils, C., Camarillo, P., Leddy, J., daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6 Network Programming", draft-ietf-spring-srv6-network- programming-01 (work in progress), July 2019. [I-D.xuclad-spring-sr-service-programming] Clad, F., Xu, X., Filsfils, C., daniel.bernier@bell.ca, d., Li, C., Decraene, B., Ma, S., Yadlapalli, C., Henderickx, W., and S. Salsano, "Service Programming with Segment Routing", draft-xuclad-spring-sr-service- programming-02 (work in progress), April 2019. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", RFC 7752, DOI 10.17487/RFC7752, March 2016, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 10.2. Informative References [I-D.ietf-idr-segment-routing-te-policy] Previdi, S., Filsfils, C., Mattes, P., Rosen, E., Jain, D., and S. Lin, "Advertising Segment Routing Policies in BGP", draft-ietf-idr-segment-routing-te-policy-07 (work in progress), July 2019. [I-D.ietf-spring-segment-routing-policy] Filsfils, C., Sivabalan, S., daniel.voyer@bell.ca, d., bogdanov@google.com, b., and P. Mattes, "Segment Routing Policy Architecture", draft-ietf-spring-segment-routing- policy-03 (work in progress), May 2019. [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, . Dawra, et al. Expires January 9, 2020 [Page 10] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC 4272, DOI 10.17487/RFC4272, January 2006, . [RFC5706] Harrington, D., "Guidelines for Considering Operations and Management of New Protocols and Protocol Extensions", RFC 5706, DOI 10.17487/RFC5706, November 2009, . [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, DOI 10.17487/RFC6952, May 2013, . Authors' Addresses Gaurav Dawra (editor) LinkedIn USA Email: gdawra.ietf@gmail.com Clarence Filsfils Cisco Systems Belgium Email: cfilsfil@cisco.com Daniel Bernier Bell Canada Canada Email: daniel.bernier@bell.ca Jim Uttaro AT&T USA Email: ju1738@att.com Dawra, et al. Expires January 9, 2020 [Page 11] Internet-Draft BGP-LS Extensions for SR Service Segments July 2019 Bruno Decraene Orange France Email: bruno.decraene@orange.com Hani Elmalky Ericsson USA Email: hani.elmalky@gmail.com Xiaohu Xu Alibaba Email: xiaohu.xxh@alibaba-inc.com Francois Clad Cisco Systems France Email: fclad@cisco.com Ketan Talaulikar Cisco Systems India Email: ketant@cisco.com Dawra, et al. Expires January 9, 2020 [Page 12]