CATS                                                          X. Yi, Ed.
Internet-Draft                                              R. Pang, Ed.
Intended status: Standards Track                            China Unicom
Expires: 24 April 2024                                            H. Shi
                                                                  Huawei
                                                         22 October 2023


  Hybrid Computing and Network Awareness and Routing Solution for CATS
                    draft-yi-cats-hybrid-solution-01

Abstract

   Computation 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.

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   This Internet-Draft will expire on 24 April 2024.

Copyright Notice

   Copyright (c) 2023 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
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   Please review these documents carefully, as they describe your rights
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  Background and Motivation . . . . . . . . . . . . . . . . . .   3
   3.  Service Flow  . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Service Overview  . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Work Flow Overview  . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

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] . In service scenarios, 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 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.



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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
   CATS makes routing decision, rather than the network controller or
   other upper layer system recalculating and sending to the ingress
   router.  In this way, the signaling transmission time between the
   upper-layer system 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 centralized way
   has a global perspective.

3.  Service Flow






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                  +--------------+       +------------------+
                  |  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 the services that have 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 traffic to the service
   instance.  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 until the service
   instance.

3.2.  Work Flow Overview

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

   2.  The cloud management platform processes computing information and
       send is to the network controller. 3.1 Distributed routing
       decision mode: The network controller sends computing information
       to the network ingress router. 3.2 Centralized routing decision
       mode: The network controller selects the optimal service instance
       and calculates the optimal forwarding path. 4.1 Distributed



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       routing decision mode: The ingress router selects the optimal
       service instance and calculates the optimal forwarding path. 4.2
       Centralized routing decision mode: The network controller sends
       the result of routing desicion to the ingress router.

   3.  The ingress router performs traffic guidance and forwarding.

4.  Security Considerations

   TBD

5.  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







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














































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