Internet DRAFT - draft-quinn-sfc-nsh-tlv

draft-quinn-sfc-nsh-tlv







Network Working Group                                           P. Quinn
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                                U. Elzur
Expires: April 21, 2018                                            Intel
                                                                S. Majee
                                                                      F5
                                                        October 18, 2017


                      Network Service Header TLVs
                     draft-quinn-sfc-nsh-tlv-04.txt

Abstract

   This draft describes Network Service Header (NSH) MD-Type 2 metadata
   TLVs that can be used within a service function path.

Status of This Memo

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  NSH Type 2 Format . . . . . . . . . . . . . . . . . . . . . .   2
   3.  NSH Type 2 TLVs . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Network Service Header [NSH] is the SFC encapsulation protocol used
   to create Service Function Chains.  As such, NSH provides two key
   elements:

   1.  Service Function Path identification

   2.  Metadata

   NSH further defines two metadata formats (MD Types): 1 and 2.  MD
   Type 1 defines fixed length, 16 byte metadata, whereas MD Type 2
   defines a variable-length TLV format for metadata.  This draft
   defines some common TLVs for use with NSH MD Type 2.

   This draft does not address metadata usage, updating/chaining of
   metadata or other SFP functions.  Those topics are described in NSH.

2.  NSH Type 2 Format

   A NSH is composed of a 4-byte Base Header, a 4-byte Service Path
   Header and Context Headers.  The Base Header identifies the MD-Type
   in use:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |Ver|O|C|R|R|R|R|R|R|   Length  |    MD Type    | Next Protocol |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                         Figure 1: NSH Base Header

   Please refer to NSH [NSH] for a detailed header description.





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   When the base header specifies MD Type= 0x2, zero or more Variable
   Length Context Headers MAY be added, immediately following the
   Service Path Header.  Therefore, Length = 0x2, indicates that only
   the Base Header followed by the Service Path Header are present.  The
   number, indicated in the length field, of optional Variable Length
   Context Headers MUST be of an integer indicating length in 4-bytes
   words Figure 3 below depicts the format the context header.

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          TLV Class            |C|    Type     |R|R|R|   Len   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Variable Metadata                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                         Figure 2: NSH TLV Format

3.  NSH Type 2 TLVs

   As per NSH, TLV Class 0-7 are reserved for standards use.  In this
   draft we use TLV Class 0 for the following Types:

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type     |R|R|R|   Len   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Variable Metadata                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                        Figure 3: NSH TLV Class=0x0

   1.  Forwarding Context

       This TLV carries network-centric forwarding context, used for
       segregation and forwarding scope.  Forwarding context can take
       several forms depending on the network environment.  Commonly
       used data includes VXLAN/VXLAN- GPE VNID, VRF identification or
       VLAN.












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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type=0x1 |R|R|R|  L=0x2  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |CT  (4)|             Reserved                                  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     Tentant ID                                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Context Type (CT), 4 bits:
      0x0: 24 bit VXLAN/LISP virtual network identifier (VNI)
      0x1: 32 bit MPLS VPN label
      0x2: VLAN


                       Figure 4: Forwarding Context

   2.  Tenant

       Tenant identification is often used for segregation within a
       multi-tenant environment.  Orchestration system generated tenant
       IDs are an example of such data.

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type=0x4 |R|R|R|  L=0x3  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |TT  (4)|             Reserved                                  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Tenant ID                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Tenant ID                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Tenant Type (TT), 4 bits:
      0x0: 32 bit
      0x1: 64 bit

                        Figure 5: Tenant Identifier

   3.  Content Type

       Provides explicit information about the content being carried,
       for example, type of video or content value for billing purposes









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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type=0x6 |R|R|R|   L=0x1 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     Content Type                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                          Figure 6: Content Type

   4.  Ingress Network Information

       This data identifies ingress network node, and, if required,
       ingress interface.

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type=0x7 |R|R|R|   L=0x2 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Node ID                                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     Source Interface/Port                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 7: Ingress Network Info

   5.  Flow ID

       Flow ID provides a representation of flow.  Akin, but not
       identical to the usage described in [RFC6437]

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type=0x8 |R|R|R|   L=0x1 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     Flow ID                                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                             Figure 8: Flow ID

   6.  Source and/or Destination Groups

       Intent-based systems can use this data to express the logical
       grouping of source and/or destination objects.
       [GROUPBASEDPOLICY] and [GROUPPOLICY] provide examples of such a
       system.








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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type=0x9 |R|R|R|   L=0x3 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |GT(4)  |                Reserved                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Source Group                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Dest Group                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Group type (4):
      0x1: Group Based Policy (GBP) end point group (EPG)


                         Figure 9: End Point Group

   7.  Universal Resource Identifier (URI)

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type=0xA |R|R|R|   L=var |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |UT(4)  |                URI                                    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                        URI                                    ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


      URI type (4):
      0x1: URI in standard string format as defined in RFC 3986
      0x2: URI represented in a compacted hash format


                              Figure 10: URI

   8.  Policy Identifier (POLICY_ID)

       Policy is often referred by a system generated identifier which
       is then used by the devices to lookup the content of the policy
       locally.  For example this identifier could be an index to an
       array, a lookup key, a database Id.  The identifier allows
       enforcement agents or services to lookup up the content of their
       part of the policy quite efficiently.









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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         TLV Class = 0x0       |C|    Type=0xB |R|R|R|   L=0x2 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     POLICY_ID                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                     POLICY_ID                                  ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                           Figure 11: POLICY_ID

4.  Security Considerations

   NSH describes the requisite security considerations for protecting
   NSH metadata.

5.  Acknowledgments

   The authors would like to thank Behcet Sarikaya, Dirk von Hugo and
   Mohamed Boucadair for their work regarding usage of subscriber and
   host information TLVs.

6.  IANA Considerations

   IANA is requested to create a new "Network Service Header (NSH) TLV
   Type" registry.  TLV types 0-127 are specified in this document.  New
   values are assigned via Standards Action [RFC5226].

7.  References

7.1.  Normative References

   [NSH]      Quinn, P., Ed. and U. Elzur, Ed., "Network Service
              Header", 2016, <https://datatracker.ietf.org/doc/draft-
              ietf-sfc-nsh/>.

7.2.  Informative References

   [GROUPBASEDPOLICY]
              OpenStack, "Group Based Policy", 2014,
              <https://wiki.openstack.org/wiki/GroupBasedPolicy>.

   [GROUPPOLICY]
              OpenDaylight, "Group Policy", 2014,
              <https://wiki.opendaylight.org/view/Group_Policy:Main>.







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   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", RFC 5226,
              DOI 10.17487/RFC5226, May 2008, <https://www.rfc-
              editor.org/info/rfc5226>.

   [RFC6437]  Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
              "IPv6 Flow Label Specification", RFC 6437,
              DOI 10.17487/RFC6437, November 2011, <https://www.rfc-
              editor.org/info/rfc6437>.

Authors' Addresses

   Paul Quinn
   Cisco Systems, Inc.

   Email: paulq@cisco.com


   Uri Elzur
   Intel

   Email: uri.elzur@intel.com


   Sumandra Majee
   F5

   Email: S.Majee@F5.com























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