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Versions: (draft-wang-lsr-ospf-ifit-node-capability) 00

Link State Routing Working Group                                 Y. Wang
Internet-Draft                                                   T. Zhou
Intended status: Standards Track                                  M. Liu
Expires: September 24, 2020                                       Huawei
                                                                 R. Pang
                                                            China Unicom
                                                          March 23, 2020


In-situ Flow Information Telemetry (IFIT) Node Capability Advertisement
          draft-wang-lsr-ifit-node-capability-advertisement-00

Abstract

   For advertising In-situ Flow Information Telemetry (IFIT) node
   capabilities within the entire routing domain, this document extends
   a new optional TLV to the OSPF RI Opaque LSA, a new optional sub-TLV
   to the IS-IS Router CAPABILITY TLV, and a new Node Attribute TLV that
   is encoded in the BGP-LS attribute with Node NLRIs to carry IFIT node
   capabilities information.  Such advertisement allows entities (e.g. a
   centralized controller) to determine whether a particular IFIT
   functionality can be supported in a given network.

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 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 September 24, 2020.






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Copyright Notice

   Copyright (c) 2020 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
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   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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  IFIT Node Capability Advertisement  . . . . . . . . . . . . .   3
     3.1.  IFIT Node Capability Information  . . . . . . . . . . . .   3
     3.2.  OSPF Extension IFIT Node Capability TLV . . . . . . . . .   5
     3.3.  IS-IS Extension IFIT Node Capability Sub-TLV  . . . . . .   6
     3.4.  BGP-LS Extension IFIT Node Capability TLV . . . . . . . .   6
   4.  Application . . . . . . . . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   IFIT provides a complete framework architecture and a reflection-loop
   working solution for on-path flow telemetry
   [I-D.song-opsawg-ifit-framework].  At present, there are a family of
   emerging on-path flow telemetry techniques, including In-situ OAM
   (IOAM) [I-D.ietf-ippm-ioam-data], Postcard-Based Telemetry (PBT)
   [I-D.song-ippm-postcard-based-telemetry], IOAM Direct Export (DEX)
   [I-D.ioamteam-ippm-ioam-direct-export], Enhanced Alternate Marking
   (EAM) [I-D.zhou-ippm-enhanced-alternate-marking], etc.  IFIT is a
   solution focusing on network domains.  The "network domain" consists
   of a set of network devices or entities within a single Atonomous
   System (AS).  The part of the network which employs IFIT is referred
   to as the IFIT domain.  One network domain may consist of multiple
   IFIT domains.  An IFIT domain may cross multiple network domains.



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   The family of emerging on-path flow telemetry techniques may be
   selectively or partially enabled in different vendors' devices as an
   emerging feature for various use cases of application-aware network
   operations.  So that in order to dynamically enable IFIT
   functionality in a network domain, it is necessary to advertise the
   information of IFIT option types supported in each device.

   BGP-LS defines a way to advertise topology and associated attributes
   and capabilities of the nodes in that topology to a centralized
   controller [RFC7752].  Typically, BGP-LS is configured on a small
   number of nodes that do not necessarily act as head-ends.  In order
   for BGP-LS to signal IFIT node capabilities for all the devices in
   the network, IFIT node capabilities SHOULD be advertised by every IGP
   router in the network.  Therefore, this document defines extensions
   to OSPF, IS-IS, and BGP-LS to advertise the IFIT node capabilities.
   Entities (e.g. centralized controllers) that can use this information
   to determine whether a particular IFIT functionality can be enabled
   in a given IFIT domain.  An application to this information
   advertisement is described in detail in Section 4.

2.  Terminology

   OSPF: Open Shortest Path First

   IS-IS: Intermediate System to Intermediate System

   RI: Router Information

   LSA: Link State Advertisement

   BGP-LS: Advertisement of Link-State and TE Information using Border
   Gateway Protocol

3.  IFIT Node Capability Advertisement

3.1.  IFIT Node Capability Information

   Each IFIT node is configured with a node-id which uniquely identifies
   a node within the associated IFIT domain.  To accommodate the
   different use cases or requirements of in-situ flow information
   telemetry, IFIT data fields updated by network nodes fall into
   different categories which are referred as different IFIT option
   types, including IOAM Trace Option-Types [I-D.ietf-ippm-ioam-data],
   IOAM Edge-to-Edge (E2E) Option-Type [I-D.ietf-ippm-ioam-data], IOAM
   DEX Option-Type [I-D.ioamteam-ippm-ioam-direct-export] and Enhanced
   Alternate Marking (EAM) Option-Type
   [I-D.zhou-ippm-enhanced-alternate-marking].  And a subset or all the
   IFIT-Option-Types and their corresponding IFIT-Data-Fields can be



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   associated to an IFIT-Namespce.  The Namespace identifiers allow
   devices which are IFIT capable to determine whether IFIT-Option-Types
   need to be processed.  So that IFIT-Option-Types and Namespace-ID
   SHOULD be carried in IFIT node capability information for
   advertisement.

   In this document, the IFIT-Node-Capability information consists of
   one or more pairs of a 2-octet Namespace-ID and 16-bit Option-Type
   enabled Flag.

    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
   +---------------------------------------------------------------+
   |          Namespace-ID_1       |  Option-Type enabled Flag_1   |
   +---------------------------------------------------------------+
   |          Namespace-ID_2       |  Option-Type enabled Flag_2   |
   +---------------------------------------------------------------+
   |              ...              |              ...              |
   +---------------------------------------------------------------+

                    Fig. 4 IFIT-Node-Capability Format

   Where:

   Namespace-ID: A 16-bit identifier, which MUST be present and
   populated in all IFIT-Option-Types.  The definition is the same as
   described in [I-D.ietf-ippm-ioam-data].

   Option-Type enabled Flag: A 16-bit field, which is defined as:

         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
        +-------------------------------+
        |p|i|d|e|m|       Reserved      |
        +-------------------------------+

   Where:

   p-Flag: IOAM Pre-allocated Trace Option Type-enabled flag.  If bit p
   is set (1), the router is capable of IOAM Pre-allocated Trace
   [I-D.ietf-ippm-ioam-data].

   i-Flag: IOAM Incremental Trace Option Type-enabled flag.  If bit i is
   set (1), the router is capable of IOAM Incremental Tracing
   [I-D.ietf-ippm-ioam-data].

   d-Flag: IOAM DEX Option Type-enabled flag.  If bit d is set (1), the
   router is capable of IOAM DEX [I-D.ioamteam-ippm-ioam-direct-export].





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   e-Flag: IOAM E2E Option Type-enabled flag.  If bit e is set (1), the
   router is capable of IOAM E2E processing [I-D.ietf-ippm-ioam-data].

   m-Flag: Enhanced Alternative Marking enabled flag.  If bit m is set
   (1), then the router is capable of processing Enhanced Alternative
   Marking packets [I-D.zhou-ippm-enhanced-alternate-marking].

   Reserved: Must be set to zero upon transmission and ignored upon
   receipt.

   An IFIT node SHALL be capable of more than one IFIT option types.  So
   in this case, Option-Type enabled Flag can has more than one bit
   being set.

3.2.  OSPF Extension IFIT Node Capability TLV

   Given that OSPF uses the options field in LSAs and hello packets to
   advertise optional router capabilities [RFC7770], this document
   defnes a new IFIT Node Capability TLV within the body of the OSPF RI
   Opaque LSA [RFC7770] to carry the IFIT node capabilities of the
   router originating the RI LSA.  The IFIT Node Capability TLV is
   composed of three fields, a 2-octet Type field, a 2-octet Length
   field, and 4-octet Value field.  The Type field indicates the type of
   items in the Value field.  The Length field indicates the length of
   the Value field in octets.  The Value field carries the IFIT Node
   Capability information, which is a multiple of 4 octets field.

   The IFIT node capability TLV has the following format:

    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             |
   +---------------------------------------------------------------+
   |                      IFIT-Node-Capability                     |
   ~                                                               ~
   +---------------------------------------------------------------+


                Fig. 1 OSPF IFIT Node Capability TLV Format

   Type: To be assigned by IANA

   Length: A 2-octet field that indicates the length of the value field.

   IFIT-Node-Capability: A multiple of 4 octets field, which is as
   defined in Section 3.1.




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3.3.  IS-IS Extension IFIT Node Capability Sub-TLV

   The IS-IS Extensions for Advertising Router Information TLV named IS-
   IS Router CAPABILITY TLV [RFC7981], which allows a router to announce
   its capabilities within an IS-IS level or the entire routing domain,
   has been chosen for IFIT node capabilities advertisement.  IS-IS
   Router CAPABILITY TLV is formed of multiple sub-TLVs [RFC5305].

   According to the format of IS-IS Router CAPABILITY TLV [RFC7981], the
   IFIT Node Capability sub-TLV is composed of three fields, a one-octet
   Type field, a one-octet Length field, and zero or more octets of
   Value.  The Type field indicates the type of items in the Value
   field.  The Length field indicates the length of the Value field in
   octets.  The Value field indicates the IFIT Node Capability, which is
   a multiple of 4 octets field.

   The IS-IS IFIT Node-capability Sub-TLV has the following format:

    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     |
   +---------------+---------------+-------------------------------+
   |                      IFIT-Node-Capability                     |
   ~                                                               ~
   +---------------------------------------------------------------+

             Fig. 2 IS-IS IFIT Node Capability Sub-TLV Format

   Type: To be assigned by IANA

   Length: A 8-bit field that indicates the length of the value portion
   in octets.

   IFIT-Node-Capability: A multiple of 4 octets field, which is as
   defined in Section 3.1.

3.4.  BGP-LS Extension IFIT Node Capability TLV

   This document describes extensions enabling BGP-LS speakers to
   announce the IFIT node capabilities of routers in a network to a BGP-
   LS consumer (e.g. a centralized controller).  The centralized
   controller can leverage this information in enabling IFIT
   applications in network domains based on IFIT node capabilities and
   OAM use cases.

   IFIT Node-Capability TLV is defined as a new Node Attribute TLV that
   is encoded in the BGP-LS attribute with Node NLRIs [RFC7752].  The



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   IFIT Node Capability TLV is defined as a TLV triplet, i.e. a 2-octet
   Type field, a 2-octet Length field, and 4-octet Value field.  The
   Type field indicates the type of items in the Value field.  The
   Length field indicates the length of the Value field in octets.  The
   Value field indicates the IFIT Node Capability, which is a multiple
   of 4 octets field.

   The BGP-LS IFIT Node Capability TLV has the following format:

    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             |
   +---------------------------------------------------------------+
   |                      IFIT-Node-Capability                     |
   ~                                                               ~
   +---------------------------------------------------------------+


               Fig. 3 BGP-LS IFIT Node Capability TLV Format

   Type: To be assigned by IANA

   Length: A 2-octet field that indicates the length of the value.

   IFIT-Node-Capability: A multiple of 4 octets field, which is as
   defined in Section 3.1.

4.  Application

   Within an IFIT domain, one or more IFIT-Option-Types are added into
   packets at the IFIT-capable head node that is referred to as the IFIT
   encapsulating node.  Then IFIT-Data-Fields may be updated by IFIT
   transit nodes that the packet traverses.  Finally, IFIT-Option-Types
   are removed at the IFIT-capable end node that is referred to as the
   IFIT decapsulating node.  The role of an IFIT-encapsulating, IFIT-
   transit or IFIT-decapsulating node is always performed within a
   specific Namespce.

   As any packet with IFIT-specific header and metadata MUST not leak
   out from the IFIT domain, the IFIT decapsulating node MUST be able to
   capture packets with IFIT-specific header and metadata and recover
   their format before forwarding them out of the IFIT domain.  So that
   entities (e.g., centralized controllers) can use IFIT node
   capabilities information to avoid the leak of IFIT-specific header
   and metadata.





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   Besides, in order to adapt to different network conditions and
   different application requirements, a centralized controller needs to
   switch between different underlying techniques.  As different IFIT
   option types have different encapsulation format in packets and have
   different processing procedure when packets travers to encapsulating,
   transit, and decapsulating nodes.  For example, for IOAM Trace
   Option-Types, IOAM tracing data is expected to be collected at every
   IOAM transit node that a packet traverses to ensure visibility into
   the entire path a packet takes within an IOAM-domain.  If not all
   nodes within a domain are IOAM Trace Option-Type capable, IOAM-Data-
   Fields will only be changed on those nodes which are IOAM Trace
   Option-Type capable and IOAM tracing information will only be
   collected by those IOAM-capable nodes.  For IOAM DEX Option-Type, the
   requred IOAM data is expected to be exported at every transit node
   that process a packet with the DEX option.

   Therefore, this advertisement allows entities (e.g., centralized
   controllers) to determine whether a specific IFIT functionality can
   be supported by all devices in a network domain, then enable the
   IFIT-Data-Fields encapsulation at the head node.

5.  IANA Considerations

   This document makes the following registrations for a TLV type of the
   new IFIT Node Capability TLV within the body of the OSPF RI Opaque
   LSA, a Sub-TLV type of the new Sub-TLV proposed from the "Sub-TLVs
   for TLV 242 (IS-IS Router CAPABILITY TLV)" registry, and a BGP-LS
   Node Attribute TLV code point for the IFIT Node Capability TLV.

            +------+-----------------------------------------+
            | Type | Description                             |
            +------+-----------------------------------------+
            | TBD  | OSPF Extension IFIT Node Capability TLV |
            +------+-----------------------------------------+

          +------+----------------------------------------------+
          | Type | Description                                  |
          +------+----------------------------------------------+
          | TBD  | IS-IS Extension IFIT Node Capability Sub-TLV |
          +------+----------------------------------------------+

        +------------+-------------------------------------------+
        | Code Point | Description                               |
        +------------+-------------------------------------------+
        | TBD        | BGP-LS Extension IFIT Node Capability TLV |
        +------------+-------------------------------------------+





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6.  Security Considerations

   This document introduces a new TLV within the existing OSPF RI Opaque
   LSA, a new sub-TLV for the existing IS-IS Router capability TLV, and
   a new Node Attribute TLV for the existing Node NLRIs.  It does not
   introduce any new security risks to OSPF, IS-IS and BGP-LS.

7.  Acknowledgements

   TBD.

8.  References

8.1.  Normative References

   [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>.

   [RFC5305]  "IS-IS Extensions for Traffic Engineering",
              <https://www.rfc-editor.org/info/rfc5305>.

   [RFC7752]  "North-Bound Distribution of Link-State and Traffic
              Engineering (TE) Information Using BGP",
              <https://datatracker.ietf.org/doc/rfc7752/>.

   [RFC7770]  "Extensions to OSPF for Advertising Optional Router
              Capabilities", <https://www.rfc-editor.org/info/rfc7770>.

   [RFC7981]  "IS-IS Extensions for Advertising Router Information",
              <https://www.rfc-editor.org/info/rfc7981>.

8.2.  Informative References

   [I-D.ietf-ippm-ioam-data]
              "Data Fields for In-situ OAM".

   [I-D.ioamteam-ippm-ioam-direct-export]
              "In-situ OAM Direct Exporting",
              <https://datatracker.ietf.org/doc/draft-ioamteam-ippm-
              ioam-direct-export/>.

   [I-D.song-ippm-postcard-based-telemetry]
              "Postcard-based On-Path Flow Data Telemetry",
              <https://datatracker.ietf.org/doc/draft-song-ippm-
              postcard-based-telemetry/>.




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   [I-D.song-opsawg-ifit-framework]
              "In-situ Flow Information Telemetry Framework",
              <https://datatracker.ietf.org/doc/draft-song-opsawg-ifit-
              framework/>.

   [I-D.zhou-ippm-enhanced-alternate-marking]
              "Enhanced Alternate Marking Method",
              <https://datatracker.ietf.org/doc/draft-zhou-ippm-
              enhanced-alternate-marking/>.

Authors' Addresses

   Yali Wang
   Huawei
   156 Beiqing Rd., Haidian District
   Beijing
   China

   Email: wangyali11@huawei.com


   Tianran Zhou
   Huawei
   156 Beiqing Rd., Haidian District
   Beijing
   China

   Email: zhoutianran@huawei.com


   Min Liu
   Huawei
   156 Beiqing Rd., Haidian District
   Beijing
   China

   Email: lucy.liumin@huawei.com


   Ran Pang
   China Unicom
   9 Shouti South Rd., Haidian District
   Beijing
   China

   Email: pangran@chinaunicom.cn





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