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In: Waiting_for_Writeup
DetNet                                                     B. Varga, Ed.
Internet-Draft                                                 J. Farkas
Intended status: Standards Track                                Ericsson
Expires: August 6, 2020                                        L. Berger
                                                                D. Fedyk
                                                 LabN Consulting, L.L.C.
                                                                A. Malis
                                                             Independent
                                                               S. Bryant
                                                  Futurewei Technologies
                                                        February 3, 2020


                         DetNet Data Plane: IP
                        draft-ietf-detnet-ip-05

Abstract

   This document specifies the Deterministic Networking data plane when
   operating in an IP packet switched network.

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 August 6, 2020.

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
   carefully, as they describe your rights and restrictions with respect



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Terms Used In This Document . . . . . . . . . . . . . . .   3
     2.2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   3
     2.3.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   3.  DetNet IP Data Plane Overview . . . . . . . . . . . . . . . .   4
   4.  DetNet IP Data Plane Considerations . . . . . . . . . . . . .   6
     4.1.  End-system-specific Considerations  . . . . . . . . . . .   7
     4.2.  DetNet Domain-Specific Considerations . . . . . . . . . .   7
     4.3.  Forwarding Sub-Layer Considerations . . . . . . . . . . .   9
       4.3.1.  Class of Service  . . . . . . . . . . . . . . . . . .   9
       4.3.2.  Quality of Service  . . . . . . . . . . . . . . . . .  10
       4.3.3.  Path Selection  . . . . . . . . . . . . . . . . . . .  10
     4.4.  DetNet Flow Aggregation . . . . . . . . . . . . . . . . .  11
     4.5.  Bidirectional Traffic . . . . . . . . . . . . . . . . . .  12
   5.  DetNet IP Data Plane Procedures . . . . . . . . . . . . . . .  12
     5.1.  DetNet IP Flow Identification Procedures  . . . . . . . .  12
       5.1.1.  IP Header Information . . . . . . . . . . . . . . . .  13
       5.1.2.  Other Protocol Header Information . . . . . . . . . .  14
     5.2.  Forwarding Procedures . . . . . . . . . . . . . . . . . .  15
     5.3.  DetNet IP Traffic Treatment Procedures  . . . . . . . . .  15
   6.  Management and Control Information Summary  . . . . . . . . .  16
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  18
   10. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  18
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  18
     11.1.  Normative references . . . . . . . . . . . . . . . . . .  18
     11.2.  Informative references . . . . . . . . . . . . . . . . .  20
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  22

1.  Introduction

   Deterministic Networking (DetNet) is a service that can be offered by
   a network to DetNet flows.  DetNet provides these flows extremely low
   packet loss rates and assured maximum end-to-end delivery latency.
   General background and concepts of DetNet can be found in the DetNet
   Architecture [RFC8655].

   This document specifies the DetNet data plane operation for IP hosts
   and routers that provide DetNet service to IP encapsulated data.  No



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   DetNet-specific encapsulation is defined to support IP flows, instead
   the existing IP and higher layer protocol header information is used
   to support flow identification and DetNet service delivery.  Common
   data plane procedures and control information for all DetNet data
   planes can be found in the [I-D.ietf-detnet-data-plane-framework].

   The DetNet Architecture models the DetNet related data plane
   functions as two sub-layers: functions into two sub-layers: a service
   sub-layer and a forwarding sub-layer.  The service sub-layer is used
   to provide DetNet service protection (e.g., by packet replication and
   packet elimination functions) and reordering.  The forwarding sub-
   layer is used to provide congestion protection (low loss, assured
   latency, and limited out-of-order delivery).  The service sub-layer
   generally requires additional fields to provide its service; for
   example see [I-D.ietf-detnet-mpls].  Since no DetNet-specific fields
   are added to support DetNet IP flows, only the forwarding sub-layer
   functions are supported using the DetNet IP defined by this document.
   Service protection can be provided on a per sub-net basis using
   technologies such as MPLS [I-D.ietf-detnet-dp-sol-mpls] and Ethernet
   as specified in the IEEE 802.1 TSN task group(referred to in this
   document simply as IEEE802.1 TSN).

   This document provides an overview of the DetNet IP data plane in
   Section 3, considerations that apply to providing DetNet services via
   the DetNet IP data plane in Section 4.  Section 5 provides the
   procedures for hosts and routers that support IP-based DetNet
   services.  Section 6 summarizes the set of information that is needed
   to identify an individual DetNet flow.

2.  Terminology

2.1.  Terms Used In This Document

   This document uses the terminology and concepts established in the
   DetNet architecture [RFC8655], and the reader is assumed to be
   familiar with that document and its terminology.

2.2.  Abbreviations

   The following abbreviations used in this document:

   CoS           Class of Service

   DetNet        Deterministic Networking

   DN            DetNet

   DiffServ      Differentiated Services



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   DSCP          Differentiated Services Code Point

   L2            Layer-2

   L3            Layer-3

   LSP           Label-switched path

   MPLS          Multiprotocol Label Switching

   PREOF         Packet Replication, Elimination and Ordering Function

   QoS           Quality of Service

   TSN           Time-Sensitive Networking, TSN is a Task Group of the
                 IEEE 802.1 Working Group.

2.3.  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
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  DetNet IP Data Plane Overview

   This document describes how IP is used by DetNet nodes, i.e., hosts
   and routers, to identify DetNet flows and provide a DetNet service
   using an IP data plane.  From a data plane perspective, an end-to-end
   IP model is followed.  As mentioned above, existing IP and higher
   layer protocol header information is used to support flow
   identification and DetNet service delivery.  Common data plane
   procedures and control information for all DetNet data planes can be
   found in the [I-D.ietf-detnet-data-plane-framework].

   The DetNet IP data plane primarily uses "6-tuple" based flow
   identification, where 6-tuple refers to information carried in IP and
   higher layer protocol headers.  The 6-tuple referred to in this
   document is the same as that defined in [RFC3290].  Specifically
   6-tuple is (destination address, source address, IP protocol, source
   port, destination port, and differentiated services (DiffServ) code
   point (DSCP).  General background on the use of IP headers, and
   5-tuples, to identify flows and support Quality of Service (QoS) can
   be found in [RFC3670].  [RFC7657] also provides useful background on
   the delivery of DiffServ and "tuple" based flow identification.  Note
   that a 6-tuple is composed of a 5-tuple plus the addition of a DSCP
   component.



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   The DetNet IP data plane also allows for optional matching on the
   IPv6 flow label field, as defined in [RFC8200].

   Non-DetNet and DetNet IP packets are identical on the wire.
   Generally the fields used in flow identification are forwarded
   unmodified, however modification of these fields is allowed, for
   example to a DSCP value, when required by the DetNet service.

   DetNet flow aggregation may be enabled via the use of wildcards,
   masks, lists, prefixes and ranges.  IP tunnels may also be used to
   support flow aggregation.  In these cases, it is expected that
   DetNet-aware intermediate nodes will provide DetNet service on the
   aggregate through resource allocation and congestion control
   mechanisms.

    DetNet IP       Relay                        Relay       DetNet IP
    End System      Node                         Node        End System

   +----------+                                             +----------+
   |   Appl.  |<------------ End to End Service ----------->|   Appl.  |
   +----------+  ............                 ...........   +----------+
   | Service  |<-: Service  :-- DetNet flow --: Service  :->| Service  |
   +----------+  +----------+                 +----------+  +----------+
   |Forwarding|  |Forwarding|                 |Forwarding|  |Forwarding|
   +--------.-+  +-.------.-+                 +-.---.----+  +-------.--+
            : Link :       \      ,-----.      /     \   ,-----.   /
            +......+        +----[  Sub  ]----+       +-[  Sub  ]-+
                                 [Network]              [Network]
                                  `-----'                `-----'

            |<--------------------- DetNet IP --------------------->|

             Figure 1: A Simple DetNet (DN) Enabled IP Network

   Figure 1 illustrates a DetNet enabled IP network.  The DetNet enabled
   end systems originate IP encapsulated traffic those are identified
   within the DetNet domain as DetNet flows, relay nodes understand the
   forwarding requirements of the DetNet flow and ensure that node,
   interface and sub-network resources are allocated to ensure DetNet
   service requirements.  The dotted line around the Service component
   of the Relay Nodes indicates that the transit routers are DetNet
   service aware but do not perform any DetNet service sub-layer
   function, e.g., PREOF.

   Note: The sub-network can represent a TSN, MPLS network or other
   network technology that can carry DetNet IP traffic.





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    IP              Edge                        Edge         IP
    End System      Node                        Node         End System

   +----------+   +.........+                 +.........+   +----------+
   |   Appl.  |<--:Svc Proxy:-- E2E Service---:Svc Proxy:-->|   Appl.  |
   +----------+   +.........+                 +.........+   +----------+
   |    IP    |<--:IP : :Svc:---- IP flow ----:Svc: :IP :-->|    IP    |
   +----------+   +---+ +---+                 +---+ +---+   +----------+
   |Forwarding|   |Fwd| |Fwd|                 |Fwd| |Fwd|   |Forwarding|
   +--------.-+   +-.-+ +-.-+                 +-.-+ +-.-+   +---.------+
            :  Link :      \      ,-----.      /     /  ,-----.  \
            +.......+       +----[  Sub  ]----+     +--[  Sub  ]--+
                                 [Network]             [Network]
                                  `-----'               `-----'

         |<--- IP --->| |<------ DetNet IP ------>| |<--- IP --->|

      Figure 2: Non-DetNet-aware IP end systems with DetNet IP Domain

   Figure 2 illustrates a variant of Figure 1 where the end systems are
   not DetNet aware.  In this case, edge nodes sit at the boundary of
   the DetNet domain and provide DetNet service proxies for the end
   applications by initiating and terminating DetNet service for the
   application's IP flows.  The existing header information or an
   approach such as described in Section 4.4 can be used to support
   DetNet flow identification.

   Note, that Figure 1 and Figure 2 can be collapsed, so IP DetNet End
   Systems can communicate over DetNet IP network with IP End System.

   As non-DetNet and DetNet IP packets are identical on the wire, from
   data plane perspective, the only difference is that there is flow-
   associated DetNet information on each DetNet node that defines the
   flow related characteristics and required forwarding behavior.  As
   shown above, edge nodes provide a Service Proxy function that
   "associates" one or more IP flows with the appropriate DetNet flow-
   specific information and ensures that the receives the proper traffic
   treatment within the domain.

   Note: The operation of IEEE802.1 TSN end systems over DetNet enabled
   IP networks is not described in this document.  TSN over MPLS is
   discribed in [I-D.ietf-detnet-tsn-vpn-over-mpls].

4.  DetNet IP Data Plane Considerations

   This section provides informative considerations related to providing
   DetNet service to flows which are identified based on their header
   information.



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4.1.  End-system-specific Considerations

   Data-flows requiring DetNet service are generated and terminated on
   end systems.  This document deals only with IP end systems.  The
   protocols used by an IP end system are specific to an application,
   and end systems peer with other end systems.  DetNet's use of 6-tuple
   IP flow identification means that DetNet must be aware of not only
   the format of the IP header, but also of the next protocol carried
   within an IP packet (see Section 5.1.1.3).

   When IP end systems are DetNet-aware, no application-level or
   service-level proxy functions are needed inside the DetNet domain.
   For DetNet unaware IP end systems service-level proxy functions are
   needed inside the DetNet domain.

   End systems need to ensure that DetNet service requirements are met
   when processing packets associated to a DetNet flow.  When forwarding
   packets, this means that packets are appropriately shaped on
   transmission and receive appropriate traffic treatment on the
   connected sub-network, see Section 4.3.2 and Section 4.2 for more
   details.  When receiving packets, this means that there are
   appropriate local node resources, e.g., buffers, to receive and
   process the packets of that DetNet flow.

   In order to maximize reuse of existing mechanisms, DetNet-aware
   applications and end systems SHOULD NOT mix DetNet and non-DetNet
   traffic within a single 5-tuple.

4.2.  DetNet Domain-Specific Considerations

   As a general rule, DetNet IP domains need to be able to forward any
   DetNet flow identified by the IP 6-tuple.  Doing otherwise would
   limit the number of 6-tuple flow ID combinations that could be used
   by the end systems.  From a practical standpoint this means that all
   nodes along the end-to-end path of DetNet flows need to agree on what
   fields are used for flow identification.

   From a connection type perspective two scenarios are identified:

   1.  DN attached: the end system is directly connected to an edge
       node, or the end system is behind a sub-network (See ES1 and ES2
       in figure below)

   2.  DN integrated: the end system is part of the DetNet domain.  (See
       ES3 in figure below)

   L3 (IP) end systems may use any of these connection types.  A DetNet
   domain allows communication between any end-systems using the same



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   encapsulation format, independent of their connection type and DetNet
   capability.  DN attached end systems have no knowledge about the
   DetNet domain and its encapsulation format.  See Figure 3 for L3 end
   system connection examples.

                                               ____+----+
                       +----+        _____    /    | ES3|
                       | ES1|____   /     \__/     +----+___
                       +----+    \ /                        \
                                  +                          |
                          ____     \                        _/
            +----+     __/    \     +__  DetNet IP domain  /
            | ES2|____/  L2/L3 |___/   \         __     __/
            +----+    \_______/         \_______/  \___/



               Figure 3: Connection types of L3 end systems

   Within a DetNet domain, the DetNet-enabled IP Routers are
   interconnected by links and sub-networks to support end-to-end
   delivery of DetNet flows.  From a DetNet architecture perspective,
   these routers are DetNet relays, as they must be DetNet service
   aware.  Such routers identify DetNet flows based on the IP 6-tuple,
   and ensure that the DetNet service required traffic treatment is
   provided both on the node and on any attached sub-network.

   This solution provides DetNet functions end to end, but does so on a
   per link and sub-network basis.  Congestion protection and latency
   control and the resource allocation (queuing, policing, shaping) are
   supported using the underlying link / sub net specific mechanisms.
   However, service protection (packet replication and packet
   elimination functions) is not provided at the DetNet layer end to
   end.  Instead service protection can be provided on a per underlying
   L2 link and sub-network basis.

   The DetNet Service Flow is mapped to the link / sub-network specific
   resources using an underlying system-specific means.  This implies
   each DetNet-aware node on path looks into the forwarded DetNet
   Service Flow packet and utilize e.g., a 6-tuple to find out the
   required mapping within a node.

   As noted earlier, service protection must be implemented within each
   link / sub-network independently, using the domain specific
   mechanisms.  This is due to the lack of unified end-to-end sequencing
   information that could be used by the intermediate nodes.  Therefore,
   service protection (if enabled) cannot be provided end-to-end, only
   within sub-networks.  This is shown for a three sub-network scenario



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   in Figure 4, where each sub-network can provide service protection
   between its borders.  "R" and "E" denotes replication and elimination
   points within the sub-network.



        <-------------------- DenNet IP ------------------------>
                                         ______
                          ____     /      \__
               ____      /     \__/          \___   ______
   +----+   __/    +====+                       +==+      \     +----+
   |src |__/ SubN1  )   |                       |  \ SubN3 \____| dst|
   +----+  \_______/    \       Sub-Network2    |   \______/    +----+
                         \_                    _/
                           \         __     __/
                            \_______/  \___/


             +---+        +---------E--------+      +-----+
   +----+    |   |        |         |        |      |     |      +----+
   |src |----R   E--------R     +---+        E------R     E------+ dst|
   +----+    |   |        |     |            |      |     |      +----+
             +---+        +-----R------------+      +-----+


    Figure 4: Replication and elimination in sub-networks for DetNet IP
                                 networks

   If end to end service protection is desired, it can be implemented,
   for example, by the DetNet end systems using Layer-4 (L4) transport
   protocols or application protocols.  However, these protocols are out
   of scope of this document.

   Note that not mixing DetNet and non-DetNet traffic within a single
   5-tuple, as described above, enables simpler 5-tuple filters to be
   used (or re-used) at the edges of a DetNet network to prevent non-
   congestion-responsive DetNet traffic from escaping the DetNet domain.

4.3.  Forwarding Sub-Layer Considerations

4.3.1.  Class of Service

   Class of Service (CoS) for DetNet flows carried in IPv6 is provided
   using the standard differentiated services code point (DSCP) field
   [RFC2474] and related mechanisms.

   One additional consideration for DetNet nodes which support CoS
   services is that they MUST ensure that the CoS service classes do not



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   impact the congestion protection and latency control mechanisms used
   to provide DetNet QoS.  This requirement is similar to the
   requirement for MPLS LSRs that CoS LSPs cannot impact the resources
   allocated to TE LSPs [RFC3473].

4.3.2.  Quality of Service

   Quality of Service (QoS) for DetNet service flows carried in IP MUST
   be provided locally by the DetNet-aware hosts and routers supporting
   DetNet flows.  Such support leverages the underlying network layer
   such as 802.1 TSN.  The traffic control mechanisms used to deliver
   QoS for IP encapsulated DetNet flows are expected to be defined in a
   future document.  From an encapsulation perspective, the combination
   of the 6-tuple i.e., the typical 5-tuple enhanced with the DSCP and
   previously mentioned optional field, uniquely identifies a DetNet IP
   flow.

   Packets that are identified as part of a DetNet IP flow but that have
   not been the subject of a completed reservation, can disrupt the QoS
   offered to properly reserved DetNet flows by using resources
   allocated to the reserved flows.  Therefore, the network nodes of a
   DetNet network MUST ensure that no DetNet allocated resources, e.g.,
   queue or shaper, is used by such flows.  There are multiple methods
   that MAY be used by an implementation to defend service delivery to
   reserved DetNet flows, including but not limited to:

   o  Treating packets associated with an incomplete reservation as non-
      DetNet traffic.

   o  Discarding packets associated with an incomplete reservation.

   o  Remarking packets associated with an incomplete reservation.
      Remarking can be accomplished by changing the value of the DSCP,
      or optional, field to a value that results in the packet no longer
      matching any other reserved DetNet IP flow.

4.3.3.  Path Selection

   While path selection algorithms and mechanisms are out of scope of
   the DetNet data plane definition, it is important to highlight the
   implications of DetNet IP flow identification on path selection and
   next hops.  As mentioned above, the DetNet IP data plane identifies
   flows using "6-tuple" header information as well as the additional
   optional header field.  DetNet generally allows for both flow-
   specific traffic treatment and flow-specific next-hops.

   In non-DetNet IP forwarding, it is generally assumed that the same
   series of next hops, i.e., the same path, will be used for a



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   particular 5-tuple or, in some cases, e.g., [RFC5120], for a
   particular 6-tuple.  Using different next hops for different 5-tuples
   does not take any special consideration for DetNet-aware
   applications.

   Care should be taken when using different next hops for the same
   5-tuple.  As discussed in [RFC7657], unexpected behavior can occur
   when a single 5-tuple application flow experience reordering due to
   being split across multiple next hops.  Understanding of the
   application and transport protocol impact of using different next
   hops for the same 6-tuple is required.  Again, this impacts path
   selection for DetNet flows and this document only indirectly.

4.4.  DetNet Flow Aggregation

   As described in [I-D.ietf-detnet-data-plane-framework], the ability
   to aggregate individual flows, and their associated resource control,
   into a larger aggregate is an important technique for improving
   scaling by reducing the state per hop.  DetNet IP data plane
   aggregation can take place within a single node, when that node
   maintains state about both the aggregated and individual flows.  It
   can also take place between nodes, where one node maintains state
   about only flow aggregates while the other node maintains state on
   all or a portion of the component flows.  In either case, the
   management or control function that provisions the aggregate flows
   must ensure that adequate resources are allocated and configured to
   provide combined service requirements of the individual flows.  As
   DetNet is concerned about latency and jitter, more than just
   bandwidth needs to be considered.

   From a single node perspective, the aggregation of IP flows impacts
   DetNet IP data plane flow identification and resource allocation.  As
   discussed above, IP flow identification uses the IP "6-tuple" for
   flow identification.  DetNet IP flows can be aggregated using any of
   the 6-tuple, and an additional optional field defined in Section 5.1.
   The use of prefixes, wildcards, lists, and value ranges allows a
   DetNet node to identify aggregate DetNet flows.  From a resource
   allocation perspective, DetNet nodes must provide service to an
   aggregate and not on a component flow basis.

   It is the responsibility of the DetNet controller plane to properly
   provision the use of these aggregation mechanisms.  This includes
   ensuring that aggregated flows have compatible e.g., the same or very
   similar QoS and/or CoS characteristics, see Section 4.3.2.  It also
   includes ensuring that per component-flow service requirements are
   satisfied by the aggregate, see Section 5.3.





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4.5.  Bidirectional Traffic

   While the DetNet IP data plane must support bidirectional DetNet
   flows, there are no special bidirectional features with respect to
   the data plane other than the need for the two directions of a co-
   routed bidirectional flow to take the same path.  That is to say that
   bidirectional DetNet flows are solely represented at the management
   and control plane levels, without specific support or knowledge
   within the DetNet data plane.  Fate sharing and associated or co-
   routed bidirectional flows can be managed at the control level.

   Control and management mechanisms need to support bidirectional
   flows, but the specification of such mechanisms are out of scope of
   this document.  An example control plane solution for MPLS can be
   found in [RFC7551].

5.  DetNet IP Data Plane Procedures

   This section provides DetNet IP data plane procedures.  These
   procedures have been divided into the following areas: flow
   identification, forwarding and traffic treatment.  Flow
   identification includes those procedures related to matching IP and
   higher layer protocol header information to DetNet flow (state)
   information and service requirements.  Flow identification is also
   sometimes called Traffic classification, for example see [RFC5777].
   Forwarding includes those procedures related to next hop selection
   and delivery.  Traffic treatment includes those procedures related to
   providing an identified flow with the required DetNet service.

   DetNet IP data plane establishment and operational procedures also
   have requirements on the control and management systems for DetNet
   flows and these are referred in this section.  Specifically this
   section identifies a number of information elements that require
   support via the management and control interfaces supported by a
   DetNet node.  The specific mechanism used for such support is out of
   the scope of this document.  A summary of the requirements for
   management and control related information is included.  Conformance
   language is not used in the summary since applies to future
   mechanisms such as those that may be provided in YANG models
   [I-D.ietf-detnet-yang].

5.1.  DetNet IP Flow Identification Procedures

   IP and higher layer protocol header information is used to identify
   DetNet flows.  All DetNet implementations that support this document
   MUST identify individual DetNet flows based on the set of information
   identified in this section.  Note, that additional flow




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   identification requirements, e.g., to support other higher layer
   protocols, may be defined in the future.

   The configuration and control information used to identify an
   individual DetNet flow MUST be ordered by an implementation.
   Implementations MUST support a fixed order when identifying flows,
   and MUST identify a DetNet flow by the first set of matching flow
   information.

   Implementations of this document MUST support DetNet flow
   identification when the implementation is acting as a DetNet end
   systems, a relay node, or as an edge node.

5.1.1.  IP Header Information

   Implementations of this document MUST support DetNet flow
   identification based on IP header information.  The IPv4 header is
   defined in [RFC0791] and the IPv6 is defined in [RFC8200].

5.1.1.1.  Source Address Field

   Implementations of this document MUST support DetNet flow
   identification based on the Source Address field of an IP packet.
   Implementations SHOULD support longest prefix matching for this
   field, see [RFC1812] and [RFC7608].  Note that a prefix length of
   zero (0) effectively means that the field is ignored.

5.1.1.2.  Destination Address Field

   Implementations of this document MUST support DetNet flow
   identification based on the Destination Address field of an IP
   packet.  Implementations SHOULD support longest prefix matching for
   this field, see [RFC1812] and [RFC7608].  Note that a prefix length
   of zero (0) effectively means that the field is ignored.

   Note: any IP address value is allowed, including an IP multicast
   destination address.

5.1.1.3.  IPv4 Protocol and IPv6 Next Header Fields

   Implementations of this document MUST support DetNet flow
   identification based on the IPv4 Protocol field when processing IPv4
   packets, and the IPv6 Next Header Field when processing IPv6 packets.
   An implementation MUST support flow identification based on the next
   protocol values defined in Section 5.1.2.  Other, non-zero values,
   MUST be used for flow identification.  Implementations SHOULD allow
   for these fields to be ignored for a specific DetNet flow.




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5.1.1.4.  IPv4 Type of Service and IPv6 Traffic Class Fields

   These fields are used to support Differentiated Services [RFC2474]
   [RFC2475].  Implementations of this document MUST support DetNet flow
   identification based on the DSCP field in the IPv4 Type of Service
   field when processing IPv4 packets, and the DSCP field in the IPv6
   Traffic Class Field when processing IPv6 packets.  Implementations
   MUST support list based matching of DSCP values, where the list is
   composed of possible field values that are to be considered when
   identifying a specific DetNet flow.  Implementations SHOULD allow for
   this field to be ignored for a specific DetNet flow.

5.1.1.5.  IPv6 Flow Label Field

   Implementations of this document SHOULD support identification of
   DetNet flows based on the IPv6 Flow Label field.  Implementations
   that support matching based on this field MUST allow for this field
   to be ignored for a specific DetNet flow.  When this field is used to
   identify a specific DetNet flow, implementations MAY exclude the IPv6
   Next Header field and next header information as part of DetNet flow
   identification.

5.1.2.  Other Protocol Header Information

   Implementations of this document MUST support DetNet flow
   identification based on header information identified in this
   section.  Support for TCP, UDP and IPsec flows is defined.  Future
   documents are expected to define support for other protocols.

5.1.2.1.  TCP and UDP

   DetNet flow identification for TCP [RFC0793] and UDP [RFC0768] is
   achieved based on the Source and Destination Port fields carried in
   each protocol's header.  These fields share a common format and
   common DetNet flow identification procedures.

5.1.2.1.1.  Source Port Field

   Implementations of this document MUST support DetNet flow
   identification based on the Source Port field of a TCP or UDP packet.
   Implementations MUST support flow identification based on a
   particular value carried in the field, i.e., an exact value.
   Implementations SHOULD support range-based port matching.
   Implementation MUST also allow for the field to be ignored for a
   specific DetNet flow.






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5.1.2.1.2.  Destination Port Field

   Implementations of this document MUST support DetNet flow
   identification based on the Destination Port field of a TCP or UDP
   packet.  Implementations MUST support flow identification based on a
   particular value carried in the field, i.e., an exact value.
   Implementations SHOULD support range-based port matching.
   Implementation MUST also allow for the field to be ignored for a
   specific DetNet flow.

5.1.2.2.  IPsec AH and ESP

   IPsec Authentication Header (AH) [RFC4302] and Encapsulating Security
   Payload (ESP) [RFC4303] share a common format for the Security
   Parameters Index (SPI) field.  Implementations MUST support flow
   identification based on a particular value carried in the field,
   i.e., an exact value.  Implementation SHOULD also allow for the field
   to be ignored for a specific DetNet flow.

5.2.  Forwarding Procedures

   General requirements for IP nodes are defined in [RFC1122], [RFC1812]
   and [RFC8504], and are not modified by this document.  The typical
   next-hop selection process is impacted by DetNet.  Specifically,
   implementations of this document SHALL use management and control
   information to select the one or more outgoing interfaces and next
   hops to be used for a packet associated with a DetNet flow.

   The use of multiple paths or links, e.g., ECMP, to support a single
   DetNet flow is NOT RECOMMENDED.  ECMP MAY be used for non-DetNet
   flows within a DetNet domain.

   The above implies that management and control functions will be
   defined to support this requirement, e.g., see
   [I-D.ietf-detnet-yang].

5.3.  DetNet IP Traffic Treatment Procedures

   Implementations of this document MUST ensure that a DetNet flow
   receives the traffic treatment that is provisioned for it via
   configuration or the controller plane, e.g., via
   [I-D.ietf-detnet-yang].  General information on DetNet service can be
   found in [I-D.ietf-detnet-flow-information-model].  Typical
   mechanisms used to provide different treatment to different flows
   includes the allocation of system resources (such as queues and
   buffers) and provisioning or related parameters (such as shaping, and
   policing).  Support can also be provided via an underlying network
   technology such as MPLS [I-D.ietf-detnet-ip-over-mpls] or IEEE802.1



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   TSN [I-D.ietf-detnet-ip-over-tsn].  Other than in the TSN case, the
   specific mechanisms used by a DetNet node to ensure DetNet service
   delivery requirements are met for supported DetNet flows is outside
   the scope of this document.

6.  Management and Control Information Summary

   The following summarizes the set of information that is needed to
   identify individual and aggregated DetNet flows:

   o  IPv4 and IPv6 source address field.

   o  IPv4 and IPv6 source address prefix length, where a zero (0) value
      effectively means that the address field is ignored.

   o  IPv4 and IPv6 destination address field.

   o  IPv4 and IPv6 destination address prefix length, where a zero (0)
      effectively means that the address field is ignored.

   o  IPv4 protocol field.  A limited set of values is allowed, and the
      ability to ignore this field, e.g., via configuration of the value
      zero (0), is desirable.

   o  IPv6 next header field.  A limited set of values is allowed, and
      the ability to ignore this field, e.g., via configuration of the
      value zero (0), is desirable.

   o  For the IPv4 Type of Service and IPv6 Traffic Class Fields:

      *  If the DSCP field is to be used in flow identification.
         Ignoring the DSCP filed is optional.

      *  When the DSCP field is used in flow identification, a list of
         field values that may be used by a specific flow.

   o  IPv6 flow label field.  This field can be optionally used for
      matching.  When used, can be used instead of matching against the
      Next Header field.

   o  TCP and UDP Source Port.  Exact and wildcard matching is required.
      Port ranges can optionally be used.

   o  TCP and UDP Destination Port.  Exact and wildcard matching is
      required.  Port ranges can optionally be used.

   o  IPsec Header SPI field.  Exact matching is required.




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   This information MUST be provisioned per DetNet flow via
   configuration, e.g., via the controller or management plane.

   Information identifying a DetNet flow is ordered and implementations
   use the first match.  This can, for example, be used to provide a
   DetNet service for a specific UDP flow, with unique Source and
   Destination Port field values, while providing a different service
   for the aggregate of all other flows with that same UDP Destination
   Port value.

   It is the responsibility of the DetNet controller plane to properly
   provision both flow identification information and the flow specific
   resources needed to provided the traffic treatment needed to meet
   each flow's service requirements.  This applies for aggregated and
   individual flows.

7.  Security Considerations

   Security considerations for DetNet are described in detail in
   [I-D.ietf-detnet-security].  General security considerations are
   described in [RFC8655].  This section considers exclusively security
   considerations which are specific to the DetNet IP data plane.

   Security aspects which are unique to DetNet are those whose aim is to
   provide the specific quality of service aspects of DetNet, which are
   primarily to deliver data flows with extremely low packet loss rates
   and bounded end-to-end delivery latency.

   The primary considerations for the data plane is to maintain
   integrity of data and delivery of the associated DetNet service
   traversing the DetNet network.  Application flows can be protected
   through whatever means is provided by the underlying technology.  For
   example, encryption may be used, such as that provided by IPSec
   [RFC4301] for IP flows and/or by an underlying sub-net using MACSec
   [IEEE802.1AE-2018] for IP over Ethernet (Layer-2) flows.

   From a data plane perspective this document does not add or modify
   any header information.

   At the management and control level DetNet flows are identified on a
   per-flow basis, which may provide controller plane attackers with
   additional information about the data flows (when compared to
   controller planes that do not include per-flow identification).  This
   is an inherent property of DetNet which has security implications
   that should be considered when determining if DetNet is a suitable
   technology for any given use case.





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   To provide uninterrupted availability of the DetNet service,
   provisions can be made against DOS attacks and delay attacks.  To
   protect against DOS attacks, excess traffic due to malicious or
   malfunctioning devices can be prevented or mitigated, for example
   through the use of existing mechanism such as policing and shaping
   applied at the input of a DetNet domain.  To prevent DetNet packets
   from being delayed by an entity external to a DetNet domain, DetNet
   technology definition can allow for the mitigation of Man-In-The-
   Middle attacks, for example through use of authentication and
   authorization of devices within the DetNet domain.

8.  IANA Considerations

   This document does not require an action from IANA.

9.  Acknowledgements

   The authors wish to thank Pat Thaler, Norman Finn, Loa Anderson,
   David Black, Rodney Cummings, Ethan Grossman, Tal Mizrahi, David
   Mozes, Craig Gunther, George Swallow, Yuanlong Jiang and Carlos J.
   Bernardos for their various contributions to this work.  David Black
   served as technical advisor to the DetNet working group during the
   development of this document and provided many valuable comments.

10.  Contributors

   This document is derived from an earlier draft that was edited by
   Jouni Korhonen (jouni.nospam@gmail.com) and as such, he contributed
   to and authored text in this document.

11.  References

11.1.  Normative references

   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              DOI 10.17487/RFC0768, August 1980,
              <https://www.rfc-editor.org/info/rfc768>.

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              DOI 10.17487/RFC0791, September 1981,
              <https://www.rfc-editor.org/info/rfc791>.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, DOI 10.17487/RFC0793, September 1981,
              <https://www.rfc-editor.org/info/rfc793>.






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   [RFC1812]  Baker, F., Ed., "Requirements for IP Version 4 Routers",
              RFC 1812, DOI 10.17487/RFC1812, June 1995,
              <https://www.rfc-editor.org/info/rfc1812>.

   [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>.

   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              DOI 10.17487/RFC2474, December 1998,
              <https://www.rfc-editor.org/info/rfc2474>.

   [RFC3473]  Berger, L., Ed., "Generalized Multi-Protocol Label
              Switching (GMPLS) Signaling Resource ReserVation Protocol-
              Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
              DOI 10.17487/RFC3473, January 2003,
              <https://www.rfc-editor.org/info/rfc3473>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.

   [RFC4302]  Kent, S., "IP Authentication Header", RFC 4302,
              DOI 10.17487/RFC4302, December 2005,
              <https://www.rfc-editor.org/info/rfc4302>.

   [RFC4303]  Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, DOI 10.17487/RFC4303, December 2005,
              <https://www.rfc-editor.org/info/rfc4303>.

   [RFC7608]  Boucadair, M., Petrescu, A., and F. Baker, "IPv6 Prefix
              Length Recommendation for Forwarding", BCP 198, RFC 7608,
              DOI 10.17487/RFC7608, July 2015,
              <https://www.rfc-editor.org/info/rfc7608>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.





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11.2.  Informative references

   [I-D.ietf-detnet-data-plane-framework]
              Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A.,
              Bryant, S., and J. Korhonen, "DetNet Data Plane
              Framework", draft-ietf-detnet-data-plane-framework-03
              (work in progress), October 2019.

   [I-D.ietf-detnet-dp-sol-mpls]
              Korhonen, J. and B. Varga, "DetNet MPLS Data Plane
              Encapsulation", draft-ietf-detnet-dp-sol-mpls-02 (work in
              progress), March 2019.

   [I-D.ietf-detnet-flow-information-model]
              Farkas, J., Varga, B., Cummings, R., Jiang, Y., and D.
              Fedyk, "DetNet Flow Information Model", draft-ietf-detnet-
              flow-information-model-06 (work in progress), October
              2019.

   [I-D.ietf-detnet-ip-over-mpls]
              Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A.,
              Bryant, S., and J. Korhonen, "DetNet Data Plane: IP over
              MPLS", draft-ietf-detnet-ip-over-mpls-04 (work in
              progress), November 2019.

   [I-D.ietf-detnet-ip-over-tsn]
              Varga, B., Farkas, J., Malis, A., and S. Bryant, "DetNet
              Data Plane: IP over IEEE 802.1 Time Sensitive Networking
              (TSN)", draft-ietf-detnet-ip-over-tsn-01 (work in
              progress), October 2019.

   [I-D.ietf-detnet-mpls]
              Varga, B., Farkas, J., Berger, L., Fedyk, D., Malis, A.,
              Bryant, S., and J. Korhonen, "DetNet Data Plane: MPLS",
              draft-ietf-detnet-mpls-04 (work in progress), November
              2019.

   [I-D.ietf-detnet-security]
              Mizrahi, T., Grossman, E., Hacker, A., Das, S., Dowdell,
              J., Austad, H., and N. Finn, "Deterministic Networking
              (DetNet) Security Considerations", draft-ietf-detnet-
              security-07 (work in progress), January 2020.

   [I-D.ietf-detnet-tsn-vpn-over-mpls]
              Varga, B., Farkas, J., Malis, A., Bryant, S., and D.
              Fedyk, "DetNet Data Plane: IEEE 802.1 Time Sensitive
              Networking over MPLS", draft-ietf-detnet-tsn-vpn-over-
              mpls-01 (work in progress), October 2019.



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   [I-D.ietf-detnet-yang]
              Geng, X., Chen, M., Ryoo, Y., Li, Z., and R. Rahman,
              "Deterministic Networking (DetNet) Configuration YANG
              Model", draft-ietf-detnet-yang-04 (work in progress),
              November 2019.

   [IEEE802.1AE-2018]
              IEEE Standards Association, "IEEE Std 802.1AE-2018 MAC
              Security (MACsec)", 2018,
              <https://ieeexplore.ieee.org/document/8585421>.

   [RFC1122]  Braden, R., Ed., "Requirements for Internet Hosts -
              Communication Layers", STD 3, RFC 1122,
              DOI 10.17487/RFC1122, October 1989,
              <https://www.rfc-editor.org/info/rfc1122>.

   [RFC2475]  Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
              and W. Weiss, "An Architecture for Differentiated
              Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
              <https://www.rfc-editor.org/info/rfc2475>.

   [RFC3290]  Bernet, Y., Blake, S., Grossman, D., and A. Smith, "An
              Informal Management Model for Diffserv Routers", RFC 3290,
              DOI 10.17487/RFC3290, May 2002,
              <https://www.rfc-editor.org/info/rfc3290>.

   [RFC3670]  Moore, B., Durham, D., Strassner, J., Westerinen, A., and
              W. Weiss, "Information Model for Describing Network Device
              QoS Datapath Mechanisms", RFC 3670, DOI 10.17487/RFC3670,
              January 2004, <https://www.rfc-editor.org/info/rfc3670>.

   [RFC5120]  Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
              Topology (MT) Routing in Intermediate System to
              Intermediate Systems (IS-ISs)", RFC 5120,
              DOI 10.17487/RFC5120, February 2008,
              <https://www.rfc-editor.org/info/rfc5120>.

   [RFC5777]  Korhonen, J., Tschofenig, H., Arumaithurai, M., Jones, M.,
              Ed., and A. Lior, "Traffic Classification and Quality of
              Service (QoS) Attributes for Diameter", RFC 5777,
              DOI 10.17487/RFC5777, February 2010,
              <https://www.rfc-editor.org/info/rfc5777>.

   [RFC7551]  Zhang, F., Ed., Jing, R., and R. Gandhi, Ed., "RSVP-TE
              Extensions for Associated Bidirectional Label Switched
              Paths (LSPs)", RFC 7551, DOI 10.17487/RFC7551, May 2015,
              <https://www.rfc-editor.org/info/rfc7551>.




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   [RFC7657]  Black, D., Ed. and P. Jones, "Differentiated Services
              (Diffserv) and Real-Time Communication", RFC 7657,
              DOI 10.17487/RFC7657, November 2015,
              <https://www.rfc-editor.org/info/rfc7657>.

   [RFC8504]  Chown, T., Loughney, J., and T. Winters, "IPv6 Node
              Requirements", BCP 220, RFC 8504, DOI 10.17487/RFC8504,
              January 2019, <https://www.rfc-editor.org/info/rfc8504>.

   [RFC8655]  Finn, N., Thubert, P., Varga, B., and J. Farkas,
              "Deterministic Networking Architecture", RFC 8655,
              DOI 10.17487/RFC8655, October 2019,
              <https://www.rfc-editor.org/info/rfc8655>.

Authors' Addresses

   Balazs Varga (editor)
   Ericsson
   Magyar Tudosok krt. 11.
   Budapest  1117
   Hungary

   Email: balazs.a.varga@ericsson.com


   Janos Farkas
   Ericsson
   Magyar Tudosok krt. 11.
   Budapest  1117
   Hungary

   Email: janos.farkas@ericsson.com


   Lou Berger
   LabN Consulting, L.L.C.

   Email: lberger@labn.net


   Don Fedyk
   LabN Consulting, L.L.C.

   Email: dfedyk@labn.net







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   Andrew G. Malis
   Independent

   Email: agmalis@gmail.com


   Stewart Bryant
   Futurewei Technologies

   Email: stewart.bryant@gmail.com









































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