Inter-Domain Routing G. Dawra, Ed.Internet-Draft LinkedInIntended status: Standards Track C. FilsfilsExpires: August 19, 2021 K. Talaulikar, Ed. F. Clad Cisco Systems D. Bernier Bell Canada J. Uttaro AT&T B. Decraene Orange H. Elmalky Ericsson X. Xu Alibaba J. Guichard Futurewei Technologies C. Li Huawei Technologies February 15, 2021BGP-LS Advertisement of Segment Routing Service Segmentsdraft-dawra-idr-bgp-ls-sr-service-segments-05Abstract Service functions are deployed as, physical or virtualized elements along with network nodes or on servers in data centers. Segment Routing (SR) brings in the concept of segments which can be topological or service instructions. Service segments are SR segments that are associated with service functions. SR Policies are used for the setup of paths for steering of traffic through service functions using their service segments. BGP Link-State (BGP-LS) enables distribution of topology information from the network to a controller or an application in general so it can learn the network topology. This document specifies the extensions to BGP-LS for the advertisement of service functions along their associated service segments. The BGP-LS advertisement of service function information along with the network nodes that they are attached to, or associated with, enables controllers compute and setup service paths in the network.Dawra, et al. Expires August 19, 2021 [Page 1]
Internet-Draft BGP-LS Extensions for SR Service Segments February 2021Status of This Memo This Internet-Draft is submitted in full conformance with the provisions ofBCP 78 andBCP 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 athttps://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 19, 2021.Copyright Notice Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject toBCP 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 Contents1. Introduction . . . . . . . . . . . . . . . . . . . . . . . .31.1. Requirements Language . . . . . . . . . . . . . . . . . .42. BGP-LS Extensions for Service Chaining . . . . . . . . . . .43. Illustration . . . . . . . . . . . . . . . . . . . . . . . .74. IANA Considerations . . . . . . . . . . . . . . . . . . . . .74.1. Service Type Table . . . . . . . . . . . . . . . . . . .74.2. Segment routing function Identifier(SFI) . . . . . . . .85. Manageability Considerations . . . . . . . . . . . . . . . .86. Operational Considerations . . . . . . . . . . . . . . . . .86.1. Operations . . . . . . . . . . . . . . . . . . . . . . .97. Security Considerations . . . . . . . . . . . . . . . . . . .98. Acknowledgements . . . . . . . . . . . . . . . . . . . . . .99. References . . . . . . . . . . . . . . . . . . . . . . . . .99.1. Normative References . . . . . . . . . . . . . . . . . .9Dawra, et al. Expires August 19, 2021 [Page 2]
Internet-Draft BGP-LS Extensions for SR Service Segments February 20219.2. Informative References . . . . . . . . . . . . . . . . .10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . .111. Introduction Segments are introduced in the SR architecture [RFC8402]. Segment Routing based Service chaining is well described in [I-D.ietf-spring-sr-service-programming] with an example of 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 can receive BGP-LS updates to discover topology, and calculate constrained paths between nodes 1 and 6. However, if SR-C is configured to compute 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. 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 andDawra, et al. Expires August 19, 2021 [Page 3]
Internet-Draft BGP-LS Extensions for SR Service Segments February 2021 are outside the scope of this document. There are no extensions required in SR-TE Policy SAFI.1.1. 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 inBCP14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.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.ietf-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 August 19, 2021 [Page 4]
Internet-Draft BGP-LS Extensions for SR Service Segments February 2021 +---------------------------------------+ | 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 need 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 August 19, 2021 [Page 5]
Internet-Draft BGP-LS Extensions for SR Service Segments February 2021 In order for the 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 August 19, 2021 [Page 6]
Internet-Draft BGP-LS Extensions for SR Service Segments February 20213. 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 August 19, 2021 [Page 7]
Internet-Draft BGP-LS Extensions for SR Service Segments February 2021 +------------+-----------------------+------------+-------------+ | 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 44.2. 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.ietf-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 ConsiderationsDawra, et al. Expires August 19, 2021 [Page 8]
Internet-Draft BGP-LS Extensions for SR Service Segments February 20216.1. 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. Acknowledgements The authors would like to thank Krishnaswamy Ananthamurthy for his review of this document.9. References9.1. 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-05 (work in progress), November 2020. [I-D.ietf-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-ietf-spring-sr-service-programming-03 (work in progress), September 2020. [I-D.ietf-spring-srv6-network-programming] Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., Matsushima, S., and Z. Li, "SRv6 Network Programming",draft-ietf-spring-srv6-network-programming-28 (work in progress), December 2020.Dawra, et al. Expires August 19, 2021 [Page 9]
Internet-Draft BGP-LS Extensions for SR Service Segments February 2021 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels",BCP 14,RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>. [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, <https://www.rfc-editor.org/info/rfc7752>. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase inRFC2119 Key Words",BCP 14,RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>. [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture",RFC 8402, DOI 10.17487/RFC8402, July 2018, <https://www.rfc-editor.org/info/rfc8402>.9.2. Informative References [I-D.ietf-idr-segment-routing-te-policy] Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., Rosen, E., Jain, D., and S. Lin, "Advertising Segment Routing Policies in BGP",draft-ietf-idr-segment-routing-te-policy-11 (work in progress), November 2020. [I-D.ietf-spring-segment-routing-policy] Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture",draft-ietf-spring-segment-routing-policy-09 (work in progress), November 2020. [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, <https://www.rfc-editor.org/info/rfc4271>. [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",RFC 4272, DOI 10.17487/RFC4272, January 2006, <https://www.rfc-editor.org/info/rfc4272>. [RFC5706] Harrington, D., "Guidelines for Considering Operations and Management of New Protocols and Protocol Extensions",RFC 5706, DOI 10.17487/RFC5706, November 2009, <https://www.rfc-editor.org/info/rfc5706>.Dawra, et al. Expires August 19, 2021 [Page 10]
Internet-Draft BGP-LS Extensions for SR Service Segments February 2021 [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, <https://www.rfc-editor.org/info/rfc6952>.Authors' Addresses Gaurav Dawra (editor) LinkedIn USA Email: gdawra.ietf@gmail.com Clarence Filsfils Cisco Systems Belgium Email: cfilsfil@cisco.com Ketan Talaulikar (editor) Cisco Systems India Email: ketant@cisco.com Francois Clad Cisco Systems France Email: fclad@cisco.com Daniel Bernier Bell Canada Canada Email: daniel.bernier@bell.ca Jim Uttaro AT&T USA Email: ju1738@att.comDawra, et al. Expires August 19, 2021 [Page 11]
Internet-Draft BGP-LS Extensions for SR Service Segments February 2021 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 Jim Guichard Futurewei Technologies USA Email: james.n.guichard@futurewei.com Cheng Li Huawei Technologies China Email: chengli13@huawei.comDawra, et al. Expires August 19, 2021 [Page 12]Datatracker
draft-dawra-idr-bgp-ls-sr-service-segments-05
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
| Document | Document type | This is an older version of an Internet-Draft whose latest revision state is "Replaced". This document is an Internet-Draft (I-D). Anyone may submit an I-D to the IETF. This I-D isnot endorsed by the IETF and hasno formal standing in theIETF standards process. | |
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| Authors | Gaurav Dawra,Clarence Filsfils,Ketan Talaulikar,Francois Clad,Daniel Bernier,Jim Uttaro,Bruno Decraene,Hani Elmalky,Xiaohu Xu,Jim Guichard,Cheng Li | ||
| Replaces | draft-dawra-idr-bgp-sr-service-chaining | ||
| Replaced by | draft-ietf-idr-bgp-ls-sr-service-segments | ||
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| Additional resources | Mailing list discussion |