Internet DRAFT - draft-yao-cats-awareness-architecture
draft-yao-cats-awareness-architecture
CATS H. Yao
Internet Draft China Mobile
Intended status: Informational X. Wang
Expires: April 23, 2024 Ruijie Networks
Z. Li
China Mobile
D.H. Daniel
ZTE Corporation
C. Lin
New H3C Technologies
October 23, 2023
Computing and Network Information Awareness (CNIA) system
architecture for CATS
draft-yao-cats-awareness-architecture-02
Abstract
This document describes a Computing and Network Information
Awareness (CNIA)system architecture for Computing-Aware Traffic
Steering (CATS). Based on the CATS framework, this document further
describes a proposal detailed awareness architecture about the
network information and computing information. It includes a new
component and the corresponding interfaces and workflows in the CATS
control plane.
Status of this Memo
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This Internet-Draft will expire on April 23, 2024.
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Table of Contents
1. Introduction...................................................3
2. Architecture Components and Interfaces.........................3
3. Architecture Workflow..........................................5
3.1. Awareness Information Classification......................5
3.2. Workflow..................................................6
3.2.1. A centralized model..................................6
3.2.2. A hybrid model.......................................8
3.2.3. A distributed model..................................9
4. IANA Considerations...........................................10
5. Security Considerations.......................................10
6. References....................................................10
6.1. Normative References.....................................10
6.2. Informative References...................................10
Authors' Addresses...............................................12
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1. Introduction
Computing-Aware Traffic Steering (CATS)[I-D.ldbc-cats-framework]aims
to solve the problem of how the network edge can steer traffic
between clients of a service and sites offering the service. To
enable the computing- and network-aware traffic steering decisions,
awareness of computing information and network information is the
foundation.
Currently there are some work being done on the classification and
awareness of computing and network information. As described in[I-
D.du-cats-computing-modeling-description], there could be two models
of computing information: one is some detailed computing parameters,
and another is a comprehensive computing level parameter.
Further, the former includes some static information such as service
ability, and some dynamic information such as service status. This
modeling document could be a solid foundation of CATS. For the
awareness solution of computing and network information, the current
recommended methods are generally BGP[I-D.ietf-idr-5g-edge-service-
metadata], BGP-LS[I-D.ls-idr-bgp-ls-service-metadata], and BGP-FS[I-
D.yi-idr-bgp-fs-edge-service-metadata]. CATS Service Metric
Agent(C-SMA) and CATS Path Selector (C-PS) components defined in [I-
D.ldbc-cats-framework] could be deployed in different locations.
Overall, the current awareness technology is some sporadic
solutions. This document hopes to comprehensively sort out the
computing and network awareness method and defines a comprehensive
awareness architecture to support the different types of computing
and network information, to facilitate the deployment of CATS. This
awareness architecture acts as the control plane of CATS.
2. Architecture Components and Interfaces
To consider various kinds of computing and network information, a
control center component is additionally introduced on the basis of
CATS framework. That is, CATS framework includes a control center and
CAT routers. A control center performs computing management and control
functions, including computing information awareness function, service
scheduling function, etc., A control center collects computing and
network information, and schedules service based on computing and
network information. CATS Router collects omputing and network
information, and schedules service based on computing and network
information, then forwarding data packets based on service scheduling.
As a comprehensive awareness architecture CNIA supports both
distributed,centralized,hybrid awareness models.
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For some coarse-grained and relatively static information with low
update frequency, it is recommended to be aware in a distributed way.
The distributed way has better robustness and high scalability.
For some fine-grained dynamic information with a high update frequency,
it is recommended to aware it in a centralized way. Frequent
information updates will greatly increase the burden on network devices
and are not conducive to information convergence. The centralized way
is more suitable for the management of fine- grained dynamic
information. This comprehensive-aware model is consistent with the
design philosophy of segment routing architecture[RFC8402]. The
services that require planning for dynamic resources, such as
TE(Traffic Engineering), are implemented by a centralized controller.
The BE(best-effort) service is still preserved on the devices and
implemented in a distributed manner, which could take advantage of
distributed robustness and reduce the burden of interfacing between the
controller and devices, facilitating deployment.
CATS-control center |
+----------------------------------+ | +----------+
| Management Plane | | API |cloud |
+----------------------------------+ |<=========>|management|
| Control Plane | | |platform |
+----------------------------------+ | +---+------+
/\ CATS-SBI | |
|| | |
CATS-Forwarder \/ | |
+----------------------------------+ | +--------+
| Data Plane | | API | +--------+
+----------------------------------+ |<=========>| |service |
| +-|instance|
| +--------+
Figure 1: CNIA System Arhicteture
To realize the scheduling of fine-grained computing information, the
control center introduces several components and interface:
CATS Computing information Base(C-CIB): Maintain fine-grained
computing information, such as service connections,CPU
performance,which may be obtained from the CATS-Forwarders or from
the cloud management platform.
CATS Network Metric information Base(C-NIB): Maintain fine-grained
network information, such as remaining bandwidth,delay, which
could be obtained from the routers.
CATS Path Calculation Unit(C-PCE): Calculate optimal computing
resource and network path based on C-CIB and C-NIB, and generate
path policy and deliver to the CATS-Forwarders.
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CATS-SBI interface: An extended interface based on the traditional
controller southbound interface between the CATS-Forwarders and
the CATS-control center, could be used to report network and
computing information from CATS routers to the CATS-control
center, and also could be used to send path and service policy
information or compute information to CATS-Forwarders.
C-SMA API: An extended interface based on the traditional controller
southbound interface between the CATS-Forwarders and the cloud
management or between CATS-Forwarders and service-instance, used
to report network and computing information to the CATS-control
center or to CATS-Forwarders.
Given the comprehensive architecture described above, this document
proposes a comprehensive awareness system of the deployment
location, real-time resource and service status, load information
and requirements of computing resources and services. On the one
hand, the network aggregates the computing and network metrics
reported by multiple nodes to build a globally unified computing and
network status view. On the other hand, the network completes the
unified analysis of service, computing and network requirements,
realizes the comprehensive perception and provides guarantee for
computing-aware scheduling based on service requirement.
3. Architecture Workflow
3.1. Awareness Information Classification
Currently the detailed network and computing parameters used by CATS
have not yet reached a consensus in the industry, in order to avoid
introducing too much signaling overhead into the whole network
advertisement, this document proposes to classify the content of the
computing advertisement according to the characteristics of the
content and frequency of information announcement, and adopt
different information awareness methods and information announcement
protocols. As shown in Table 1, the computing and network
information could be classified into capability information and
status information. Capability information contains the deployment
location and identifier information, and so on. Status information
tends to be some real-time status parameters of the network and
computing, such as remaining bandwidth,delay,service connections,CPU
performance. This type of information is mainly used for some
services that are sensitive to network and computing status, such as
AR/VR services.
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+=============+=========================+=========================+
| Awareness | Network information | Computing information |
| information | | |
+=============+=========================+=========================+
| Capability | Device location; Device | Service ID; Service- |
| parameters | type; Topology | domain name; Computing |
| | information | energy consumption; |
| | | Computing cost; Peak |
| | | value of available |
| | | computing |
+-------------+-------------------------+-------------------------+
| Status | Service policy | Number of available |
| parameters | information; Traffic | service connections; |
| | information | Available resources; |
| | (bandwidth,delay,packet | CPU/GPU/NPU |
| | loss rate,delay jitter) | performance; Storage |
| | | capacity; Service delay |
+-------------+-------------------------+-------------------------+
Table 1: Awareness information content examples
Table 1 provides some detailed parameters examples about the two
kinds of awareness information.
3.2. Workflow
3.2.1. A centralized model
In centralized mode, the collection of computing information and the
selection of paths are implemented by the controller, which is then
sent to the CATS-Forwarder via the CATS-SBI interface.
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CATS-control center
+----------------------------------+ +----------+
| Management | API |cloud |
| Plane +------+----------+ |<=========>|management|
| | | | | |platform |
| | +--v---+ +--v---+ | +---+------+
| | |C-CIB | |C-NIB | | |
| | +---^--+ +--^---+ | |
| | | | | |
+---------|-------|---------|------+ |
| Control | +---v--+ +--v---+ | |
| Plane | |C-SMA | |C-NMA | | |
| | +------+ +------+ | |
| | | |
| | +-------+ | |
| +-->| C-PCE | | |
| +-------+ | |
+----------------------------------+ |
/\ CATS-SBI |
|| |
CATS-Forwarder \/ |
+----------------------------------+ |
| Data +------+ | +--------+
| Plane |C-TC | | ...........| +--------+
| +------+ | ...........| |service |
+----------------------------------+ +-|instance|
+--------+
Figure 2: centralized model
For some services that are sensitive to computing and network
status, especially latency, such as AV/VR services, the network
needs to be able to perceive detailed computing information and
network information to meet the strict requirements of the service.
This kind of computing information could be aware by the CATS-
control center by restful interface from cloud management platform.
The network information could be aware by the BGP-LS or telemetry
interface to get the status parameters such as remaining bandwidth
and the delay. Further, CATS-control center performs service
scheduling according to the computing information and network
information, then generates routing policy and sends to CATS ingress
router . When CATS ingress router receives the service demand from
the client, it selects the optimal service instance and network
policy, and maintains the instance affinity subsequently.
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3.2.2. A hybrid model
In hybrid mode, both the controller and the CATS-Forwarder with
routing capabilities can perform the collection of computing
information and the selection of paths. The CATS-Forwarder with
routing capabilities can perform more precise path selection
operations based on instructions from the controller. CATS-
Forwarders without routing capabilities, on the other hand, directly
forward data based on the results provided by the controller.
CATS-control center
+----------------------------------+ +----------+
| Management | API |cloud |
| Plane +------+----------+ |<============>|management|
| | | | | |platform |
| | +--v---+ +--v---+ | +---+------+
| | |C-CIB | |C-NIB | | |
| | +---^--+ +--^---+ | |
| | | | | |
+---------|-------|---------|------+ |
| Control | +---v--+ +--v---+ | |
| Plane | |C-SMA | |C-NMA | | |
| | +------+ +------+ | |
| | | |
| | +-------+ | |
| +-->| C-PCE | | |
| +-------+ | |
+----------------------------------+ |
/\ CATS-SBI /\ CATS-SBI |
|| || |
CATS-Forwarder1 \/ CATS-Forwarder2 \/ |
+-------------------+ +--------------------------------+ |
| Data +------+ | | Data +-----+-------+ | +--------+
| Plane |C-TC | | | Plane |C-TC |C-PS | |...... | +--------+
| +------+ | | +-----+---+---+ |...... | |service |
+-------------------+ | | | +-|instance|
| +------+---+ | +--------+
| | | |
| +--+---+ +-+----+ |
| |C-SMA | |C-NMA | |
| +------+ +------+ |
+--------------------------------+
Figure 4: hybrid model
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For some high-value customers, hybrid awareness can be deployed to
accurately match customer requirements. After the CATS-control
center obtains computing and network information through SBI or
restful interfaces, the details of this information are directly
transmitted to the CATS ingress routers. The device performs
accurate resource matching and continuous experience detection after
receiving service traffic.
3.2.3. A distributed model
In distributed mode, these operations are performed by the CATS-
Forwarder itself, while the controller is responsible for monitoring
the information.
CATS-control center
+----------------------------------+
| Management +------+ +------+ |
| Plane |C-CIB | |C-NIB | |
| +------+ +------+ | +----------+
| | |cloud |
+----------------------------------+ |management|
| Control | |platform |
| Plane | +---+------+
+----------------------------------+ |
/\ CATS-SBI |
|| |
CATS-Forwarder \/ |
+--------------------------------+ |
| Data +-----+-------+ | API +--------+
| Plane |C-TC |C-PS | |<========= | +--------+
| +-----+---+---+ | | |service |
| | | +-|instance|
| +------+---+ | +--------+
| | | |
| +--+---+ +-+----+ |
| |C-SMA | |C-NMA | |
| +------+ +------+ |
+--------------------------------+
Figure 3: distributed model
For distributed mode, the ingress CATS router responsibles for
collecting computing and network information and scheduling service.
When the ingress CATS router receives the service demand from the
client it makes decision of the service instance to access
independently according to the service instances status and network
status and maintains instance affinity. The detailed workflow can
be seen in[I-D.ldbc-cats-framework].
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4. IANA Considerations
TBD
5. Security Considerations
TBD
6. References
6.1. Normative References
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
6.2. Informative References
[I-D.ietf-idr-5g-edge-service-metadata] Dunbar, L., Majumdar, K.,
Wang, H., Mishra, G. S., and Z. Du, "BGP Extension for 5G
Edge Service Metadata", Work in Progress, Internet-Draft,
draft-ietf-idr-5g-edge-service- metadata-04, 6 July 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-5g-
edge-service-metadata-04>.
[I-D.ls-idr-bgp-ls-service-metadata] Li, C., Shi, H., He, T., Pang,
R., and G. Qian, "Distribution of Service Metadata in BGP-
LS", Work in Progress, Internet-Draft, draft-ls-idr-bgp-
ls-service-metadata-01, 24 February 2023,
<https://datatracker.ietf.org/doc/html/draft-ls-idr-bgp-
ls-service-metadata-01>.
[I-D.yi-idr-bgp-fs-edge-service-metadata] yixinxin, He, T., Shi, H.,
Ding, X., and H. Wang, "Distribution of Service Metadata
in BGP FlowSpec", Work in Progress, Internet-Draft, draft-
yi-idr-bgp-fs-edge-service-metadata-00, 23 February 2023,
<https://datatracker.ietf.org/doc/html/draft-yi-idr-bgp-
fs-edge-service-metadata-00>.
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[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-02, 22 June 2023,
<https://datatracker.ietf.org/doc/html/draft-ldbc-cats-
framework-02>.
[I-D.du-cats-computing-modeling-description] Du, Z., Fu, Y., Li, C.,
Huang, D., and Z. Fu, "Computing Information Description
in Computing-Aware Traffic Steering", Work in Progress,
Internet-Draft, draft-du- cats-computing-modeling-
description-01, 4 July 2023,
<https://datatracker.ietf.org/doc/html/draft-du-cats-
computing-modeling-description-01>.
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Authors' Addresses
Huijuan Yao
China Mobile
No.32 XuanWuMen West Street
Beijing
100053
China
Email: yaohuijuan@chinamobile.com
Xuewei Wang
Ruijie Networks
Beijing
China
Email: wangxuewei1@ruijie.com.cn
Zhiqiang Li
China Mobile
No.32 XuanWuMen West Street
Beijing
100053
China
Email: lizhiqiangyjy@chinamobile.com
Daniel Huang
ZTE Corporation
Nanjing
Phone: +86 13770311052
Email: huang.guangping@zte.com.cn
Changwang Lin
New H3C Technologies
Beijing
China
Email: linchangwang.04414@h3c.com
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