[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-dawra-idr-bgp-sr-service-chaining) 00 01 02

Inter-Domain Routing                                       G. Dawra, Ed.
Internet-Draft                                                  LinkedIn
Intended status: Standards Track                             C. Filsfils
Expires: January 17, 2019                                  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 16, 2018


        BGP-LS Advertisement of Segment Routing Service Segments
             draft-dawra-idr-bgp-ls-sr-service-segments-00

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", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].




Dawra, et al.           Expires January 17, 2019                [Page 1]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


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 17, 2019.

Copyright Notice

   Copyright (c) 2018 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
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   9



Dawra, et al.           Expires January 17, 2019                [Page 2]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


     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 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.

   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



Dawra, et al.           Expires January 17, 2019                [Page 3]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


   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.filsfils-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 extends SRv6 Node SID TLV
   [I-D.dawra-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.

   Function Sub-TLV [I-D.dawra-idr-bgpls-srv6-ext] of Node SID TLV
   encodes Identifier(Function ID) along with associated Function Flags.

   A Service Chaining (SC) Sub-TLV in Figure 2 is defined as:












Dawra, et al.           Expires January 17, 2019                [Page 4]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


           +---------------------------------------+
           |         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) Sub-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 Sub-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 17, 2019                [Page 5]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


   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) Sub-TLV of Node SID TLV may
   encode vendor specific information.  Multiple of OM Sub-TLVs may be
   encoded.

           +---------------------------------------+
           |         Type (2 octet)                |
           +---------------------------------------+
           |        Length (2 octet)               |
           +---------------------------------------+
           |        Opaque  Type (2 octet)         |
           +---------------------------------------+
           |        Flags (1 octet)                |
           +---------------------------------------+
           |        Value (variable)               |
           +---------------------------------------+

                   Figure 3: Opaque Metadata(OM) Sub-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) Sub-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 17, 2019                [Page 6]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


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 contain and Node SID TLV:

   o  Service SID: C5::AD:F2 SID

   o  Function ID: END.AD

   The BGP-LS advertisement MUST contain a SC Sub-TLV with:

   o  Service Type: Deep Packet Inspection(DPI)

   o  Traffic Type: IPv4 Capable.

   The BGP-LS advertisement MAY contain a OM Sub-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 17, 2019                [Page 7]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


   +------------+-----------------------+------------+-------------+
   |  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.dawra-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 17, 2019                [Page 8]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


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.dawra-idr-bgpls-srv6-ext]
              Dawra, G., Filsfils, C., Talaulikar, K., Chen, M.,
              daniel.bernier@bell.ca, d., Uttaro, J., Decraene, B., and
              H. Elmalky, "BGP Link State extensions for IPv6 Segment
              Routing(SRv6)", draft-dawra-idr-bgpls-srv6-ext-03 (work in
              progress), March 2018.

   [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.

   [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-00 (work in progress), July 2018.






Dawra, et al.           Expires January 17, 2019                [Page 9]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


   [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>.

10.2.  Informative References

   [I-D.filsfils-spring-srv6-network-programming]
              Filsfils, C., Camarillo, P., Leddy, J.,
              daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
              Network Programming", draft-filsfils-spring-srv6-network-
              programming-05 (work in progress), July 2018.

   [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-08
              (work in progress), May 2018.

   [I-D.ietf-idr-segment-routing-te-policy]
              Previdi, S., Filsfils, C., Jain, D., Mattes, P., Rosen,
              E., and S. Lin, "Advertising Segment Routing Policies in
              BGP", draft-ietf-idr-segment-routing-te-policy-04 (work in
              progress), July 2018.

   [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-01 (work in progress), June 2018.

   [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>.






Dawra, et al.           Expires January 17, 2019               [Page 10]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


   [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>.

   [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


   Daniel Bernier
   Bell Canada
   Canada

   Email: daniel.bernier@bell.ca


   Jim Uttaro
   AT&T
   USA

   Email: ju1738@att.com


   Bruno Decraene
   Orange
   France

   Email: bruno.decraene@orange.com





Dawra, et al.           Expires January 17, 2019               [Page 11]


Internet-Draft  BGP-LS Extensions for SR Service Segments      July 2018


   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 17, 2019               [Page 12]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/