Internet DRAFT - draft-xiong-detnet-flow-aggregation

draft-xiong-detnet-flow-aggregation







DetNet                                                          Q. Xiong
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                                T. Jiang
Expires: 2 September 2024                                   China Mobile
                                                                J. Joung
                                                    Sangmyung University
                                                            1 March 2024


                  Flow Aggregation for Enhanced DetNet
                 draft-xiong-detnet-flow-aggregation-00

Abstract

   This document describes the flow aggregation scenarios and proposes a
   method by aggregating DetNet flows based on DetNet flow-specific
   classification in enhanced DetNet and the flow identification of
   aggregated-class can be used to indicate the required treatment and
   forwarding behaviors in scaling networks.

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
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   This Internet-Draft will expire on 2 September 2024.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.










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   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
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Flow Aggregation Scenarios in Enhanced DetNet . . . . . . . .   4
     3.1.  Aggregating DetNet Flows across Different Network
           Domains . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Aggregating DetNet Flows to Provide Fine-grained QoS
           Behaviors . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  Aggregating DetNet Flows without Maintaining States at
           Transit Nodes . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Aggregating DetNet Flows on Aggregated-class Level  . . . . .   6
     4.1.  Flow Classification . . . . . . . . . . . . . . . . . . .   6
     4.2.  Flow Identification . . . . . . . . . . . . . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   According to [RFC8655], Deterministic Networking (DetNet) operates at
   the IP layer and delivers service which provides extremely low data
   loss rates and bounded latency within a network domain.  The DetNet
   Quality of Service (QoS) includes the bounded latency indicating the
   minimum and maximum end-to-end latency from source to destination and
   bounded jitter (packet delay variation).












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   As per [RFC8655], the DetNet data plane must support the aggregation
   of DetNet flows in order to support larger numbers of DetNet flows
   and improve scalability by reducing the per-hop states.  As per
   [RFC8938], flow aggregation is the ability to aggregate individual
   flows with and their associated resource control into a larger
   aggregate.  DetNet flow aggregation may be enabled for the flows with
   the same or very similar QoS and CoS characteristics via the use of
   wildcards, masks, prefixes, and ranges.  As per [RFC8964], two
   methods of flow aggregation have been proposed such as aggregation
   via LSP hierarchy and aggregating DetNet flows as a new DetNet flow.

   In scaling networks, as per [I-D.ietf-detnet-scaling-requirements],
   the enhanced DetNet should support that different levels of
   applications co-existed with different SLAs requirements.  From the
   use cases in [RFC8578] and [I-D.zhao-detnet-enhanced-use-cases],
   DetNet applications differ in their network topologies and specific
   desired behavior.  DetNet flows should be transmitted and forwarded
   with different DetNet QoS behaviors.  It should provide fine-grained
   service provisioning to achieve differentiated DetNet QoS.  The
   DetNet flows with the same level of services requirements can be
   aggregated to receive corresponding treatment and forwarding
   behaviour.  The DetNet flows can be classified and aggregated based
   on flow-specific characteristics.  Moreover, the existing aggregation
   of individual flows may be still challenging for network operations.
   The aggregated flows still requires a large amount of control
   signaling to establish and maintain the states of DetNet flows when
   it will be large-scale dynamic deterministic flows and network
   topology in enhanced DetNet.  It is required to improve the
   scalability and forward packets at class-aggregate level instead of
   the per-flow or flow-aggregate level and the flow identification of
   aggregated-class can be used to indicate the per-hop behavior without
   the maintain of the states in scaling networks.

   This document describes the flow aggregation scenarios and proposes a
   method by aggregating DetNet flows based on DetNet flow-specific
   classification in enhanced DetNet and the flow identification of
   aggregated-class can be used to indicate the required treatment and
   forwarding behaviors in scaling networks.

1.1.  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].







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2.  Terminology

   The terminology is defined as [RFC8655].

   DC: DetNet Traffic Class

3.  Flow Aggregation Scenarios in Enhanced DetNet

3.1.  Aggregating DetNet Flows across Different Network Domains

   The flow aggregation may be required in multi-domain scenario to
   achieve the end-to-end QoS guarantees and the aggregated flows may
   across multiple domains.  As per
   [I-D.ietf-detnet-scaling-requirements], different network
   implementations may be intended for different application domains,
   where there is no additional requirements for the coordination.  As
   defined in [ITU-T Y.2122], the network operating parameters of a flow
   aggregate should be exchanged among different network domains.  As
   shown in Figure 1, the DetNet domain B receiving aggregated flow
   should identify the flow and get the service requirements such as the
   QoS parameters of the flow aggregate.



                   +-----------------+                 +-----------------+
                   |                 |                 |                 |
  Individual Flows | DetNet Domain A | Aggregated Flow | DetNet Domain B |
  ---------------->|                 | --------------> |                 |
                   +-----------------+                 +-----------------+



      Figure 1: Aggregating DetNet Flows across Multiple Domains

3.2.  Aggregating DetNet Flows to Provide Fine-grained QoS Behaviors

   As per [I-D.ietf-detnet-scaling-requirements], different levels of
   applications differ in the SLAs requirements such as tight jitter,
   strict latency, loose latency and so on.  The individual flows demand
   differentiated DetNet treatment and QoS forwarding behaviors.  And
   the DetNet node or domain providing multiple forwarding technologies
   needs to transmit the individual flows by aggregating the flows to a
   selecting treatment solution with corresponding per-hop QoS behavior
   as shown in Figure 2.  For example, as per [I-D.jlg-detnet-5gs], the
   5GS as a logical DetNet node or nodes needs to get the service
   requirements and service level of the aggregated flows to provide
   fine-grained per-hop behaviors.




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                                          DetNet-aware Node/Network
                                        +--------------------------+
                Aggregated-flow 1 ----->|  Per-hop QoS Behavior 1  |
                                        +--------------------------+
                Aggregated-flow 2 ----->|  Per-hop QoS Behavior 2  |
                                        +--------------------------+
                       ...              |           ...            |
                                        +--------------------------+
                Aggregated-flow n ----->|  Per-hop QoS Behavior N  |
                                        +--------------------------+


    Figure 2: Aggregating DetNet flows to the corresponding QoS behavior

3.3.  Aggregating DetNet Flows without Maintaining States at Transit
      Nodes

   As per [I-D.joung-detnet-taxonomy-dataplane], the treatment solutions
   in data plane can be categorized based on performance and functional
   characteristics.  For example, the solution can be categorized based
   on traffic granularity such as flow aggregate and class level.  The
   class level is provided to simplify the control and accommodate
   traffic fluctuations by aggregating flows with the same level of
   service requirements.  The flow aggregation based on the class level
   could further improve the scalability.  As per
   [I-D.ietf-detnet-scaling-requirements], it may have the large number
   of traffic flows in scaling network and it is impossible for per-flow
   state identification.  As shown in Figure 3, the flow identification
   of aggregated-class can be used to indicate the required treatment
   and forwarding behaviors without the maintain of the states at
   transit nodes.




          +-------------+           +-------------+         +-------------+
Aggregated|             | Aggregated|             |         |             |
     Flows|DetNet Node A|      Flows|DetNet Node B|         |DetNet Node N|
--------->|             |---------->|             |----->...|             |
          +-------------+           +-------------+         +-------------+



      Figure 3: Aggregating DetNet Flows to Improve Scalability







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4.  Aggregating DetNet Flows on Aggregated-class Level

   When DetNet flows are aggregated on aggregated-class level, transit
   nodes provide deterministic services to the aggregate and on a per-
   class scheduling without the states maintaining.  The nodes
   performing aggregation should ensure all per-flow service
   requirements within the class are achieved.  For example, the latency
   or jitter bounds of a class aggregate should not exceed bounds of the
   individual flows.  The aggregation based on the class level has data
   plane and controller plane aspects.

   For the data plane, when DetNet flows are aggregated to a class,
   transit nodes provide service to the aggregate and not on a per-
   DetNet-flow basis.  And the transit nodes supporting this type of
   aggregation should identify the class of the aggregated flows and
   ensure that individual flows receive the corresponding traffic
   treatment and forwarding behaviour.

   For the controller plane, the service should be provisioned on an
   aggregated-class level.  The resources should be controlled and
   scheduled on a per-class basis and the routes should be established
   to meet the service requirements with the allocated resources.  The
   edge nodes must be able to handle admission control for DetNet flows
   to an aggregated class based on the available resources.

4.1.  Flow Classification

   The DetNet QoS can be achieved by aggregating flows based on DetNet
   flow-specific traffic classification and providing the traffic-
   forwarding treatment.  The flow classification should consider the
   flow-specific characteristics such as traffic specification and
   service requirements.  For example, the DetNet flows MAY be
   classified based on the service SLAs requirements of applications in
   scaling networks as per [I-D.xiong-detnet-differentiated-detnet-qos].
   And the services can also be classified into tight/loose latency,
   large/small burst, periodic/non-periodic and large/small scale
   services as per [I-D.joung-detnet-taxonomy-dataplane].  Several
   classes can be predefined to indicate the different levels of
   applications with SLAs requirements and each class demands
   differentiated QoS behaviors and treatment as well as different
   DetNet capabilities in scaling networks.










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4.2.  Flow Identification

   The flow identification is required to be dynamic and simplified to
   ensure the aggregated flows have compatible DetNet flow-specific QoS
   characteristics.  For the data plane, individual flows may be
   aggregated for treatment based on shared service specification on
   aggregated-class level which identified by an aggregation class
   (A-Class).  The nodes should provide the class level traffic
   treatment based on A-Class.  The aggregation class information may be
   used alone or together with other metadata to indicate the required
   queuing and forwarding behaviors.  The encoding of the A-Class may
   reuse the DSCP/TC or existing field such as the TC field in A-Label
   as per [RFC8964].  And it also can be encapsulated with the
   deterministic latency information as per
   [I-D.xiong-detnet-data-fields-edp].

5.  Security Considerations

   TBA

6.  IANA Considerations

   TBA

7.  Acknowledgements

   TBA

8.  References

8.1.  Normative References

   [I-D.ietf-detnet-scaling-requirements]
              Liu, P., Li, Y., Eckert, T. T., Xiong, Q., Ryoo, J.,
              zhushiyin, and X. Geng, "Requirements for Scaling
              Deterministic Networks", Work in Progress, Internet-Draft,
              draft-ietf-detnet-scaling-requirements-05, 20 November
              2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
              detnet-scaling-requirements-05>.

   [I-D.ietf-teas-rfc3272bis]
              Farrel, A., "Overview and Principles of Internet Traffic
              Engineering", Work in Progress, Internet-Draft, draft-
              ietf-teas-rfc3272bis-27, 12 August 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              rfc3272bis-27>.





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   [I-D.jlg-detnet-5gs]
              Jiang, T., Liu, P., and X. Geng, "DetNet YANG Model
              Extension for 5GS as a Logical DetNet Node", Work in
              Progress, Internet-Draft, draft-jlg-detnet-5gs-01, 20
              October 2023, <https://datatracker.ietf.org/doc/html/
              draft-jlg-detnet-5gs-01>.

   [I-D.joung-detnet-taxonomy-dataplane]
              Joung, J., Geng, X., Peng, S., and T. T. Eckert,
              "Dataplane Enhancement Taxonomy", Work in Progress,
              Internet-Draft, draft-joung-detnet-taxonomy-dataplane-01,
              25 February 2024, <https://datatracker.ietf.org/doc/html/
              draft-joung-detnet-taxonomy-dataplane-01>.

   [I-D.xiong-detnet-data-fields-edp]
              Xiong, Q., Liu, A., Gandhi, R., and D. Yang, "Data Fields
              for DetNet Enhanced Data Plane", Work in Progress,
              Internet-Draft, draft-xiong-detnet-data-fields-edp-01, 10
              July 2023, <https://datatracker.ietf.org/doc/html/draft-
              xiong-detnet-data-fields-edp-01>.

   [I-D.xiong-detnet-differentiated-detnet-qos]
              Xiong, Q., Zhao, J., Du, Z., Zeng, Q., and C. Liu,
              "Differentiated DetNet QoS for Deterministic Services",
              Work in Progress, Internet-Draft, draft-xiong-detnet-
              differentiated-detnet-qos-00, 23 October 2023,
              <https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
              differentiated-detnet-qos-00>.

   [I-D.xiong-detnet-enhanced-detnet-gap-analysis]
              Xiong, Q. and A. Liu, "Gap Analysis for Enhanced DetNet",
              Work in Progress, Internet-Draft, draft-xiong-detnet-
              enhanced-detnet-gap-analysis-03, 25 February 2024,
              <https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
              enhanced-detnet-gap-analysis-03>.

   [I-D.xiong-detnet-large-scale-enhancements]
              Xiong, Q., Du, Z., Zhao, J., and D. Yang, "Enhanced DetNet
              Data Plane Framework for Scaling Deterministic Networks",
              Work in Progress, Internet-Draft, draft-xiong-detnet-
              large-scale-enhancements-04, 26 February 2024,
              <https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
              large-scale-enhancements-04>.








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   [I-D.zhao-detnet-enhanced-use-cases]
              Zhao, J., Xiong, Q., and Z. Du, "Enhanced Use cases for
              Scaling Deterministic Networks", Work in Progress,
              Internet-Draft, draft-zhao-detnet-enhanced-use-cases-00,
              23 October 2023, <https://datatracker.ietf.org/doc/html/
              draft-zhao-detnet-enhanced-use-cases-00>.

   [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>.

   [RFC4655]  Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
              Computation Element (PCE)-Based Architecture", RFC 4655,
              DOI 10.17487/RFC4655, August 2006,
              <https://www.rfc-editor.org/info/rfc4655>.

   [RFC4915]  Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
              Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
              RFC 4915, DOI 10.17487/RFC4915, June 2007,
              <https://www.rfc-editor.org/info/rfc4915>.

   [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>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.

   [RFC6549]  Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
              Instance Extensions", RFC 6549, DOI 10.17487/RFC6549,
              March 2012, <https://www.rfc-editor.org/info/rfc6549>.

   [RFC7752]  Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
              S. Ray, "North-Bound Distribution of Link-State and
              Traffic Engineering (TE) Information Using BGP", RFC 7752,
              DOI 10.17487/RFC7752, March 2016,
              <https://www.rfc-editor.org/info/rfc7752>.

   [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>.





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   [RFC8231]  Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
              Computation Element Communication Protocol (PCEP)
              Extensions for Stateful PCE", RFC 8231,
              DOI 10.17487/RFC8231, September 2017,
              <https://www.rfc-editor.org/info/rfc8231>.

   [RFC8233]  Dhody, D., Wu, Q., Manral, V., Ali, Z., and K. Kumaki,
              "Extensions to the Path Computation Element Communication
              Protocol (PCEP) to Compute Service-Aware Label Switched
              Paths (LSPs)", RFC 8233, DOI 10.17487/RFC8233, September
              2017, <https://www.rfc-editor.org/info/rfc8233>.

   [RFC8578]  Grossman, E., Ed., "Deterministic Networking Use Cases",
              RFC 8578, DOI 10.17487/RFC8578, May 2019,
              <https://www.rfc-editor.org/info/rfc8578>.

   [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>.

   [RFC8664]  Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
              and J. Hardwick, "Path Computation Element Communication
              Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
              DOI 10.17487/RFC8664, December 2019,
              <https://www.rfc-editor.org/info/rfc8664>.

   [RFC8938]  Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
              Bryant, "Deterministic Networking (DetNet) Data Plane
              Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020,
              <https://www.rfc-editor.org/info/rfc8938>.

   [RFC8964]  Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant,
              S., and J. Korhonen, "Deterministic Networking (DetNet)
              Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January
              2021, <https://www.rfc-editor.org/info/rfc8964>.

   [RFC9320]  Finn, N., Le Boudec, J.-Y., Mohammadpour, E., Zhang, J.,
              and B. Varga, "Deterministic Networking (DetNet) Bounded
              Latency", RFC 9320, DOI 10.17487/RFC9320, November 2022,
              <https://www.rfc-editor.org/info/rfc9320>.

   [RFC9357]  Xiong, Q., "Label Switched Path (LSP) Object Flag
              Extension for Stateful PCE", RFC 9357,
              DOI 10.17487/RFC9357, February 2023,
              <https://www.rfc-editor.org/info/rfc9357>.





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Authors' Addresses

   Quan Xiong
   ZTE Corporation
   China
   Email: xiong.quan@zte.com.cn


   Tianji Jiang
   China Mobile
   Email: tianjijiang@chinamobile.com


   Jinoo Joung
   Sangmyung University
   Email: jjoung@smu.ac.kr



































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