Application Aware Computing Network

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Table of Contents

1. Introduction

Many services deploy their service instances in multiple geographically distributed sites to get better response time. As described in [I-D.ietf-cats-usecases-requirements], traffic steering that takes into account both the computing resource metric and network metric would improve the QoE of several services, e.g., AR/VR and intelligent transportation.¶

A CATS framework is described in [I-D.draft-ldbc-cats-framework]. It defines following core concepts:¶

1. CATS service identifier represents a service which consists of multiple service contact instances.¶

2. Service contact instance affinity means that packet that belongs to a flow should always goes to the same service contact instance.¶

These concepts are similar to APN described in [I-D.draft-li-apn-header]. The Application-aware Networking (APN) framework[I-D.li-apn-framework] defines that application-aware information (i.e. APN attribute) including APN identification (ID) and/or APN parameters (e.g. network performance requirements) is encapsulated at network edge devices and carried in packets traversing an APN domain in order to facilitate service provisioning, perform fine-granularity traffic steering and network resource adjustment. [I-D.li-apn-app-side-framework] defines the extension of the APN framework for the application side. In this extension, the APN resources of an APN domain is allocated to applications which compose and encapsulate the APN attribute in packets. The APN ID includes application group ID and user group ID. Application group ID can be used as part of CATS service identifier. User group ID + application group ID can be used as CATS flow ID. This document describes a CATS framework using APN. The realization can use APN framework for application side.¶

2. Terminology

This document reuses terms defined in [I-D.draft-ldbc-cats-framework] and [I-D.draft-li-apn-header].¶

3. Locator and APN ID

In CATS, the packet needs to carry the locator information and the application identifier information. The application identifier information can be carried in APN ID. As described in [I-D.draft-li-apn-header], the length of the APN ID can be 32bit, 64 bit or 128bit. Depending on whether APN ID can fit into 128bit, the following two formats are defined. They carry the same information and can be used in different deployment scenarios.¶

4. Overview

For simplicity, this document use APN segment as an illustration example, see Figure 1.¶

APN Seg: APN segment = LOC:FUNCT(APN ID): ARG
                                                            APN Seg
                                     +-------------+       +----------+
                                     |CATS-Router 1|       | Service  |
                                     +-------------+-------| contact  |
           CATS Forwarding Table     |    C-SMA    |       | instance |
LOC+APP ID, metrics, To CATS-Router1 +-------------+       +----------+
LOC+APP ID, metrics, To CATS-Router3        |
             +-------------+        +----------------+
             |    C-TC     |        |                |
+------+     |-------------|        |    Underlay    |
|Client|-----|     | C-PS  |--------| Infrastructure |
+------+     |     +-------|        |                |
             |CATS-Router 2|        |                |
             +-------------+        +----------------+
              CATS Flow Table               |              APN Seg
      LOC+APN ID, To CATS-Router1    +-------------+       +----------+
                                     |CATS-Router 3|       | Service  |
                                     +-------------+-------| contact  |
                                     |    C-SMA    |       | instance |
                                     +-------------+       +----------+
                    <----------------------    <----------------
         (Overlay route of APN Seg, metrics)   (APN Seg, metrics)
            Service overlay route w/ metrics   Service route w/ metrics

5. APN for Real Locator

[I-D.draft-shi-cats-with-real-locator] defines real locator for CATS. When implementing solution of APN for CATS, the real locator can be carried in APN Para. Other procedure is the same as defined in [I-D.draft-shi-cats-with-real-locator].¶

6. Security Considerations

This document does not introduce any new security considerations.¶

7. IANA Considerations

TBD.¶

Authors' Addresses