Computing-Aware Traffic Steering                              X. Yi, Ed.
Internet-Draft                                              R. Pang, Ed.
Intended status: Standards Track                            China Unicom
Expires: 25 January 2025                                            H. Shi
                                                                  Huawei
                                                         24 July 2024


  Hybrid Computing and Network Awareness and Routing Solution for CATS
                    draft-yi-cats-hybrid-solution-03

Abstract

   Computing-Aware Traffic Steering (CATS) is a traffic engineering
   architecture that takes the dynamic changes of computing and network
   resources into account when forwarding traffic to appropriate service
   instances for processing.  For the development of the current
   network, it is important to have a solution that meets different
   types of service requirements and can be deployed reasonably.
   Therefore, this document proposes a hybrid solution to provide
   differentiated and flexible traffic streering capabilities for
   different service while saving the cost of retrofitting existing
   network equipment.

Discussion Venues

   This note is to be removed before publishing as an RFC.

   Discussion of this document takes place on the Computing-Aware
   Traffic Steering Working Group mailing list (cats@ietf.org), which is
   archived at https://mailarchive.ietf.org/arch/browse/cats/.

   Source for this draft and an issue tracker can be found at
   https://github.com/VMatrix1900/draft-yi-cats-hybrid-solution.

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/.







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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Background and Motivation . . . . . . . . . . . . . . . . . .   3
   3.  Service Flow  . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Service Overview  . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Workflow Overview . . . . . . . . . . . . . . . . . . . .   5
   4.  Application in High-speed IoV . . . . . . . . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . .   6
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   CATS enables large-scale interconnected collaboration at the edge,
   providing optimal service access and load balancing to adapt to
   dynamic service.  The computing power and network based on the actual
   processing delay condition can dynamically process the service
   request to switch to the appropriate service node, thereby improving
   the quality of service resource utilization and user
   experience[I-D.ldbc-cats-framework].  CATS needs to provide
   diversified and differentiated service capabilities so that different
   service traffic can be forwarded to appropriate service instance.
   This document proposes a hybrid solution, on the one hand, it uses
   centralized computing information awareness and distributed routing
   decision.  On the other hand, it can provide the service capability



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   of distributed routing or centralized routing for different services
   to achieve service differentiation.

1.1.  Terminology

1.2.  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.

2.  Background and Motivation

   There are three main aspects of CATS 'work: - Computing information
   awareness: The network of the resource utilization status and service
   status of service instanct needs to be notified, so that the network
   can perceive the status of service contact instance. - Select the
   optimal service contact instance : The optimal service instance needs
   to be calculated based on the status of computing and network. -
   Calculate the optimal forwarding path: After determining the optimal
   service instance, the optimal forwarding path to the service needs to
   be calculated.  The optimal forwarding path can be determined based
   on network factors such as delay, packet loss rate, and bandwidth.

   In the implementation of the above work, CATS still has some
   problems: - A number of devices will be upgraded and the cost will be
   high, if the computing information needs to be notified between
   service instance and engress router. - As business scenarios become
   more and more diverse, CATS needs to provide differentiated network
   and computing capabilities for different requirements of different
   businesses.

   This document designs a hybrid solution from two aspects: - Collect
   the computing information through the cloud management platform, and
   then process and send it to the network device on demand.  This kind
   of centralized computing information awareness is more easier to
   achieve and less costly to deploy compared to collect the computing
   information distributedly. - Distributed or centralized routing
   decision-making methods for different services.  For intelligence
   transportation:The location of vehicles is constantly changing when
   vehicles are driving normally on the road.  CATS needs to re-select
   the optimal service instance and the optimal forwarding path
   according to the latest vehicle location.  In addition, the scenario
   of intelligence transportation has very high requirements on delay,
   and the delay value will directly affect the driving safety of
   vehicles.  Therefore, it is recommended that the ingress router of



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   CATS makes routing decision, rather than the centralized controller
   recalculating and sending to the ingress router.  In this way, the
   signaling transmission time between the centralized controller and
   the ingress router is reduced.  Thus, the service quality is
   improved.  For other scenario such as VR/AR, SDWAN, which generally
   prioritize global utilization, it is suitable to use the centralized
   routing decision method since the centralized controlller has a
   global perspective.

3.  Service Flow

                  +--------------+       +------------------+
                  |  network     |       | cloud management |
                  |  controller  |<------| platform         |
                  +--------------+       +------------------+
                            /                         \
               +------------------+      +---------------+
               |     R2     R3    |------|service instance|
               |                  |      +----------------+
      Client---|R1(ingress router)|
               |                  |      +---------------+
               |     R4     R5    |------|service instance|
               +------------------+      +---------------+

                   Figure 1: Hybrid-Solution-Arhicteture

3.1.  Service Overview

   During the deployment of the service, the cloud management platform
   or other upper-layer systems collect computing information, process
   it, and then send it to the required network devices, which are
   generally network ingress router.  Then, CATS determines whether to
   use the centralized routing decision-making mode or the distributed
   routing decision-making mode based on the service type.  Generally,
   it is recommended that services with strict requirements on time
   delay adopt the distributed routing decision making mode, and the
   other services adopt the centralized routing decision making mode.

   When the distributed routing decision-making mode is adopted, the
   CATS ingress router selects the optimal service instance and
   calculates the optimal forwarding path according to the status of
   computing and network, and then directs the user traffic to the path
   towards the service instance.








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   When the centralized routing decision-making mode is adopted, the
   network controller selects the optimal service instance and
   calculates the optimal forwarding path according to the status of
   computing and network, and sends the results to the ingress router.
   The ingress router directs user traffic to the path towards the
   service instance.

3.2.  Workflow Overview

   1.  The service instance reports the computing information to the
       cloud management platform.

   2.  The cloud management platform processes computing information and
       send it to the network controller.

   3.  The network controller collect the network information and
       process it along with computing information.

       1.  Distributed routing decision mode: The network controller
           sends computing information to the network ingress router.
           The ingress router selects the optimal service instance and
           calculates the optimal forwarding path.

       2.  Centralized routing decision mode: The network controller
           selects the optimal service instance, calculates the optimal
           forwarding path and sends the result to the ingress router.

   4.  The ingress router performs traffic steering.

4.  Application in High-speed IoV

     The hybrid CATS scheme based high-speed IoV solution has been
     deployed and validated for the first time in Hebei, China.

     Due to the significant advantages of the hybrid CATS scheme, it provided
     high quality and more flexible solution for high-speed IoV. The computing
     and network status were comprehensively used for service selection and
     path computation, which provided high quality computing service with
     the optimal service site and optimal forwarding path for vehicle terminal
     applications.

     Distributed and centralized routing decisions collaborated to provide
     differentiated services based on client demands.
     Distributed routing decision provided real-time optimization and fast
     switching capabilities for delay-sensitive applications, such as the
     autonomous driving.
     The hybrid CATS scheme also retained the centralized routing decision mode.
     Some non-delay sensitive applications, such as online media and entertainment,
     used centralized routing decision mode to achieve global resource scheduling.
     Besides, due to the use of a centralized computing status advertisement method,
     the hybrid CATS scheme reduced the deployment difficulty of large-scale
     computing-aware network.

     The hybrid CATS scheme has great potential to promote the implementation
     of high- speed IoV application, both in terms of economic benefits and
     technological advantages.

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5.  Security Considerations

   TBD

6.  Normative References

   [I-D.ldbc-cats-framework]
              Li, C., Du, Z., Boucadair, M., Contreras, L. M., Drake,
              J., Huang, D., and G. S. Mishra, "A Framework for
              Computing-Aware Traffic Steering (CATS)", Work in
              Progress, Internet-Draft, draft-ldbc-cats-framework-03, 4
              August 2023, <https://datatracker.ietf.org/doc/html/draft-
              ldbc-cats-framework-03>.

   [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>.

   [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>.

Authors' Addresses

   Xinxin Yi (editor)
   China Unicom
   Beijing
   China
   Email: yixx3@chinaunicom.cn


   Pang Ran (editor)
   China Unicom
   Beijing
   China
   Email: pangran@chinaunicom.cn


   Hang Shi
   Huawei
   Beijing
   China
   Email: shihang9@huawei.com




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