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Versions: 00                                                            
DetNet                                                      J. Dang, Ed.
Internet-Draft                                                    Huawei
Intended status: Informational                                     Z. Du
Expires: January 13, 2022                                   China Mobile
                                                           July 12, 2021


            Services Deployment Guideline in DetNet Network
                    draft-dang-detnet-deployment-00

Abstract

   Deterministic Networking (DetNet) defined in [RFC8655] provides a
   capability for the delivery of data flows with extremely low packet
   loss rates and bounded end-to-end delivery latency.  DetNet network
   administrators worldwide can deploy DetNet services into their
   networks.  This document aims to provide a guideline for DetNet
   network administrators.

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-
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   Internet-Drafts are draft documents valid for a maximum of six months
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   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 13, 2022.

Copyright Notice

   Copyright (c) 2021 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



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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   2
   3.  Terminology & Abbreviations . . . . . . . . . . . . . . . . .   3
   4.  Preparation of DetNet networks  . . . . . . . . . . . . . . .   3
   5.  How to Introduce Deterministic Flow into DetNet network . . .   4
     5.1.  Parameter Specification . . . . . . . . . . . . . . . . .   4
       5.1.1.  Definition of Deterministic Flow  . . . . . . . . . .   5
       5.1.2.  Establishing Explicit Path  . . . . . . . . . . . . .   6
     5.2.  DetNet Network Element Configuration and Functions  . . .   9
   6.  How to Maintain Deterministic Flow in DetNet network  . . . .   9
   7.  How to Withdraw Deterministic Flow in DetNet network  . . . .  10
   8.  Deployment Trial Experience . . . . . . . . . . . . . . . . .  10
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   11. Normative References  . . . . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Deterministic Networking (DetNet) defined in [RFC8655] provides a
   capability for the delivery of data flows with extremely low packet
   loss rates and bounded end-to-end delivery latency.  The diverse
   industries in [RFC8578] have in common a need for "deterministic
   flows".  How to introduce deterministic flows to the DetNet network
   is required.

   While the DetNet technologies are becoming mature, the DetNet
   deployment is about to enter the live network experiment and even to
   large-scale commercial deployment.  The DetNet network is actively
   managed by a network operations entity (the "administrator", whether
   a single person or a department of administrators).  A network
   administrator is responsible for the deployment of DetNet services,
   who can must master the skills of how to introduce deterministic
   flows into DetNet networks and the related maintenance.

   This document is intended as guidance for DetNet network
   administrators.

2.  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.



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3.  Terminology & Abbreviations

   DetNet UPE

   A DetNet edge node, which connects DetNet flows into DetNet network.

   DetNet P

   A DetNet relay node or DetNet transit node.

   DetNet PE

   A DetNet edge node, where DetNet flows leave DetNet network.

   DetNet source

   An end system is capable of originating a DetNet flow.

   DetNet Destination

   An end system is capable of terminating a DetNet flow.

4.  Preparation of DetNet networks

   The premise of this section is that the network has not yet enabled
   DetNet capability.  First of all, a network administrator must enable
   the DetNet capability of the network on demand.

   The DetNet network administrator must plan the scope of DetNet
   network, DetNet network topology and DetNet network element roles.
   As usual, the network controller has collected the topology of the
   entire network.  So the DetNet network administrators only need to
   specify the scope of DetNet networks, DetNet network topology and
   DetNet network element roles on the controller interface.  When the
   scope of the DetNet network is determined, the DetNet network
   administrators can naturally get the DetNet network topology.  At
   that time, the DetNet network administrators must figure out whether
   the DetNet network is in a single domain or in multiple domains.

   o  If in a single domain, it contains DetNet Ingress UPE nodes,
      DetNet P nodes, DetNet PE nodes.  In fact, a P node may be
      connected to multiple different UPE devices or PE nodes or P node.

   o  If in multiple domains, it also contains ASBR nodes in addition to
      Ingress UPE nodes, DetNet P nodes and DetNet PE nodes, for the
      purpose of cross-domain interconnection.





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   The example is shown in Figure 1, which contain DetNet Ingress UPE
   node, DetNet P nodes, DetNet PE node.  In fact, a P node may be
   connected to multiple different UPE devices or PE nodes or P node.

                     DetNet                                  DetNet
                     Source                                  Destination
                                DetNet-UNI (U)
                     +--+--+   |                            +--+--+
                     |     |   |                            |     |
                     +--+--+   v                            +--+--+
                        |                                      |
                        |    +----+   +---+   +---+   +---+    |
                        +----U PE +---+ P +---+...+---+ PE+----+
                             +----+   +---+   +---+   +---+
                        |                                      |
                        |            End-to-End Service        |
                        |------------------------------------->|
                        |    Explicit Routes (DetNet Network)  |
                        |    |--------------------------->|    |

   Figure-1: DetNet Network

5.  How to Introduce Deterministic Flow into DetNet network

   For the next work, the DetNet network administrator must specify the
   following information on the controller.

   1.  Definition of Deterministic Flow

   2.  Establishing Explicit Path for Deterministic Flow

       *  Definition of Deterministic Flow

       *  Specifying Encapsulation Type of Networking Technology

       *  Specifying Type of Queuing Mechanism

       *  Definition of Service Protection

       *  Network Resource Evaluation and Reservation

   The section 5.1 focus on how to use these parameters.

5.1.  Parameter Specification







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5.1.1.  Definition of Deterministic Flow

   A DetNet network administrator must figure out

   o  how to identify a deterministic flow,

   o  the related DetNet SLA requirements,

   o  which node the DetNet flow is accessed from and which node the
      DetNet flow leaves from.

   This above information must be given the DetNet network administrator
   by DetNet service providers who initiate or terminate DetNet flows.

   The flow identification in [RFC9016] let the DetNet UPE node identify
   the flow.  Flow identification for MPLS and IP Data Planes are
   described in [RFC8939] , [RFC8964], and Ethernet information (such as
   MAC address, VLAN) respectively.

   o  IP Data plane: five tuple

   o  Ethernet data plane: MAC address or VLAN

   o  MPLS or SR data plane: label

   The SLA information of DetNet flow in section 5.9 of [RFC9016] are
   listed as follows.

   o  MinBandwidth

   o  MaxLatency

   o  MaxLoss

   o  MaxConsecutiveLossTolerance

   o  MaxMisordering

   If the deterministic flow has requirement for Jitter, a new parameter
   named jitter needs to be added.

   In the follow-up work, the DetNet network administrator creates
   explicit route defined in section 3.2.3 of [RFC8655] according to the
   information which node the DetNet flow is accessed from and which
   node the DetNet flow leaves from.






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5.1.2.  Establishing Explicit Path

   The DetNet network administrator must pay attention to the
   encapsulation type of the explicit route, which is added to the
   DetNet flows when DetNet flow enters the UPE node.  The DetNet
   network administrator may freely choose encapsulation type of the
   networking technology according to his/her preferences.  The way of
   IP over SR or [IP-Over-MPLS] or IP over SR) is recommended.

5.1.2.1.  Encapsulation Type of Networking Technology

   The DetNet network administrator must pay attention to the
   encapsulation type of the explicit route, which is added to the
   DetNet flows when DetNet flow enters the UPE node.  The DetNet
   network administrator may freely choose encapsulation type of the
   networking technology according to his/her preferences.  The way of
   IP over SR or [IP-Over-MPLS] or IP over SR) is recommended.

5.1.2.2.  Type of Queuing Mechanism

   The DetNet network administrator obtains or sets the queuing type
   used by the network.  If the cyclic queuing mechanism is used in the
   network, the parameters of the queuing need to be set as follows.
   This mechanism must allow multiple deterministic flows to share a
   periodic buffer.

   o  CyclicBufferSize: the length of the cyclic buffer

   o  CyclicInterval: duration of periodic scheduling

   o  BufferNumber: the number of the cyclic buffer

   o  MinBurstSize: the minimum burst size that can be tolerated by
      cyclic queue mechanism, which is specified in octets per second
      and excludes additional DetNet header (if any).Bandwidth used
      above the Committed Information rate is called Burst traffic.  It
      is used when the bandwidth available is more than CIR.
      MinBurstSize is the minimum burst size that has to be guaranteed
      for the DetNet traffic.  The queuing mechanism needs to pay
      attention to how to shape burst size traffic into buffers.

5.1.2.3.  Definition of Service Protection

   The DetNet network administrator can consider how to do with service
   protection to meet MaxLoss, MaxConsecutiveLossTolerance and
   MaxMisordering of a deterministic flow.  The premise of service
   protection is that there are multiple available explicit paths for a
   DetNet flow.  These types of packet loss can be greatly reduced by



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   spreading the data over multiple disjointed forwarding paths.  The
   PREOF embeded in the PE node ensures that packets are not out of
   order.

5.1.2.4.  Network Resource Evaluation and Reservation

   The DetNet network administrator can enable network resource
   evaluation and reservation of the controller.  In fact, the network
   may support a distributed protocol similar to RSVP defined in
   [draft-trossen-detnet-rsvp-tsn], so this function can rely on the
   distributed protocol.

   The DetNet SLA requirements to the DetNet flow generally have
   deterministic bandwidth, bounded latency and bounded jitter.  But in
   fact these three parameters are interrelated.  For example, the
   insufficient bandwidth reservation might introduce the additional
   delay or the additional jitter.  Therefore, the bandwidth reservation
   should consider the latency and jitter requirements.

   There are three methods here to do with, one is to get it through
   centralized calculation provided by controller or other centralized
   systems, the other is to get it through negotiation between DetNet
   Nodes along the explicit routes, and the third is to rely on the
   human brain.  When the scale of the network becomes larger or the
   types of services become more, the third method is difficult to
   handle.  Therefore, the first and the second methods are recommended.
   These centralized and distributed solutions can cooperate with each
   other, for example, if the centralized system is offline, the
   distributed system functions will be enabled.  Or in order to support
   rapid network decision-making, the priority is given to using
   distributed systems for deployment, and the centralized systems are
   responsible for global optimization.

   The algorithm on the network resource reservation is not discussed
   now in this document.

5.1.2.4.1.  DetNet Bandwidth Evaluation and Reservation

   The DetNet network administrator must know the bandwidth resource
   evaluation and reservation can be divided into service access
   interface part on the DetNet UPE node and explicit route part.

   o  Service access interface part on the DetNet UPE node: The
      bandwidth of service access interface part on the DetNet UPE is
      reserved according to the MinBandwidth of the DetNet flow.






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   o  Explicit route part: This mechanism ensures that the available
      bandwidth along the explicit path can meet MinBandwidth of DetNet
      flow.

   The P node should take into account that there are multiple explicit
   routes passing in the same direction.  For example, if one interface
   of P node accesses 3 explicit paths, the reserved bandwidth of the
   interface is the total required bandwidth of the 3 explicit paths.

   It is emphasized that the remaining bandwidth of the interface on the
   DetNet nodes can also be used for non-DetNet flows.

5.1.2.4.2.  DetNet Latency Evaluation

   The DetNet network administrator can let the controller collect the
   network-wide delay information for calculation and evaluation, and
   obtain the queuing type.

   Given that DetNet nodes have a finite amount of buffer space, the
   resource allocation necessarily results in a maximum end-to-end
   latency.  The overall latency of the explicit route can be calculated
   based on the queue scheduling mechanism on the data plane of the
   DetNet nodes.  The queue scheduling mechanisms have various types,
   such as DiffServ,Qch[IEEE802.1QCH] and so on.
   [DetNet-Bounded-Latency] provides end-to-end delay bound and backlog
   bound computations for such mechanisms that can be used by the
   control plane to provide DetNet QoS.  If the CQF is used,
   CyclicBufferSize, CyclicInterval and BufferNumber of queuing
   mechanism can be included in the calculation factors that affect the
   E2E delay.

   The controller evaluates the path delay based on the resources of the
   entire network, and judges whether it meets the MaxLatency of the
   deterministic flow.

5.1.2.4.3.  DetNet Jitter Evaluation

   The DetNet network administrator can figure out that there are two
   aspects to reduce network jitter.  The first is through resource
   reservation in section 4.4.1 to 4.4.2 , and the second is through
   effective queuing control methods.  The former is not easy to
   evaluate jitter, but the latter is very convenient.  The DetNet
   network administrator also can know the queuing type, because not all
   queuing mechanisms have a jitter control mechanism.  The CQF is
   recommend to effectively solve the uncertainty of jitter.  Under this
   mechanism, the end to end jitter can be controlled within 2 *
   CyclicInterval.




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5.2.  DetNet Network Element Configuration and Functions

   After the information is input by the DetNet network administrator,
   the controller will convert the information into the network
   configuration and send it to the DetNet network element node, using a
   protocol such as NETCONF [RFC6241]/YANG[RFC6020].  Deterministic
   Networking (DetNet) YANG Model defined in [DetNet-YANG] contains the
   specification for the Deterministic Networking YANG Model for
   configuration and operational data for DetNet Flows.

   After DetNet network equipment receives the configuration, it starts
   to execute.  As Figure 2 is shown, the functions of each DetNet
   network element is clearly visible.

    SDN         +----+  1.Entrance to the above information
   Controller   |    |  2.Network Resource Evaluation and Reservation(Optional)
                +----+  3.Converting the information into the network configuration
                  |
      +--------+-------+------+
      |        |       |      |
   +----+   +---+   +---+   +---+
   U PE +---+ P +---+...+---+ PE+
   +----+   +---+   +---+   +---+
     |        |              |
     |        |              +-->+-----------------------------+
     |        |                  |1. Enabling queuing mechanism|
     |        |                  |2. End Explicit Path         |
     |        |                  +-----------------------------+
     |        +-->+--------------------------+
     |            |Enabling queuing mechanism|
     |            +--------------------------+
     +--> +-------------------------------------------------------+
          |1.Identifying a deterministic flow                     |
          |2.Establishing explicit path for the deterministic flow|
          |3.Enabling queuing mechanism                           |
          +-------------------------------------------------------+

   Figure-2: DetNet Network Functions

6.  How to Maintain Deterministic Flow in DetNet network

   TBD

   If a new DetNet flow needs to be added into the existing DetNet
   network, the network administrators will operate according to section
   4.1~4.5.





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7.  How to Withdraw Deterministic Flow in DetNet network

   TBD

   If a DetNet flow deployed needs to be canceled, the network
   administrator will execute the corresponding undo operation through
   the controller, and the network will release the corresponding
   resources.

8.  Deployment Trial Experience

   TBD

9.  Security Considerations

   TBD

10.  Acknowledgements

   TBD

11.  Normative References

   [DetNet-Bounded-Latency]
              "DetNet Bounded Latency", <https://www.rfc-
              editor.org/info/draft-ietf-detnet-bounded-latency>.

   [DetNet-YANG]
              "Deterministic Networking (DetNet) YANG Model",
              <https://www.rfc-editor.org/info/draft-ietf-detnet-yang-
              12>.

   [draft-trossen-detnet-rsvp-tsn]
              "RSVP for TSN Networks", <https://www.rfc-editor.org/info/
              draft-trossen-detnet-rsvp-tsn>.

   [IEEE802.1QCH]
              "IEEE Standard for Local and metropolitan area networks--
              Bridges and Bridged Networks--Amendment 29: Cyclic Queuing
              and Forwarding",
              <https://ieeexplore.ieee.org/document/7961303>.

   [IP-Over-MPLS]
              "DetNet Data Plane: IP over MPLS", <https://www.rfc-
              editor.org/info/draft-ietf-detnet-ip-over-mpls>.






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   [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>.

   [RFC3209]  "RSVP-TE: Extensions to RSVP for LSP Tunnels",
              <https://www.rfc-editor.org/info/rfc3209>.

   [RFC6020]  "YANG - A Data Modeling Language for the Network
              Configuration Protocol (NETCONF)",
              <https://www.rfc-editor.org/info/RFC6020>.

   [RFC6241]  "Network Configuration Protocol (NETCONF)",
              <https://www.rfc-editor.org/info/RFC6241>.

   [RFC8402]  "Segment Routing Architecture",
              <https://www.rfc-editor.org/info/RFC8402>.

   [RFC8578]  "Deterministic Networking Use Cases",
              <https://www.rfc-editor.org/info/rfc8578>.

   [RFC8655]  "Deterministic Networking Architecture",
              <https://www.rfc-editor.org/info/rfc8655>.

   [RFC8934]  "Deterministic Networking (DetNet) Data Plane: MPLS",
              <https://www.rfc-editor.org/info/rfc8934>.

   [RFC8939]  "Deterministic Networking (DetNet) Data Plane: IP",
              <https://www.rfc-editor.org/info/rfc8939>.

   [RFC8964]  "Deterministic Networking (DetNet) Data Plane: MPLS",
              <https://www.rfc-editor.org/info/rfc8964>.

   [RFC9016]  "Flow and Service Information Model for Deterministic
              Networking (DetNet)",
              <https://www.rfc-editor.org/info/RFC9016>.

   [RFC9023]  "Deterministic Networking (DetNet) Data Plane: IP over
              IEEE 802.1 Time-Sensitive Networking (TSN)",
              <https://www.rfc-editor.org/info/rfc9023>.

Authors' Addresses









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   Joanna Dang (editor)
   Huawei
   No.156 Beiqing Road
   Beijing, P.R. China  100095
   China

   Email: dangjuanna@huawei.com


   Zongpeng Du
   China Mobile
   32 Xuanwumen West St
   Beijing, P.R. China  100053
   China

   Email: duzongpeng@chinamobile.com



































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