Internet DRAFT - draft-fu-panrg-path-selection-req
draft-fu-panrg-path-selection-req
PANRG Y. Fu
Internet-Draft P. Liu
Intended status: Informational China Mobile
Expires: January 13, 2022 July 12, 2021
Requirements of applying path-aware networking for dynamic path
selection
draft-fu-panrg-path-selection-req-00
Abstract
Emerging new services have new business characteristics, different
from traditional C/S business model, whose most traffic is downstream
traffic, more and more new business with gradually increasing
upstream traffic have appeared, such as short videos, live sales etc,
. Due to the new traffic characteristics of these services, more
requirements have been put forward for the choice of network paths.
In addition, emerging services also put forward new requirements for
computing. Only selecting the network path or the service node
cannot meet the stringent requirements. The perception of network
paths and path selection also need to consider the characteristics of
the service, and further need to coordinate the state of the network
side and the service node side. The application of path-aware
networking can assist the terminal to better perceive the network
status, and also combine the status of the service node to achieve
on-demand, more fine-grained path selection.
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].
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 13, 2022.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. On-demand awareness on paths and path properties . . . . . . 3
3. Definition and application of path property weight . . . . . 4
4. Service endpoint consideration in path-aware networking . . . 5
5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
9. Normative References . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
In path-aware networking architecture, endpoints have the ability to
select or influence the path through the network used by any given
packet or flow. The network and transport layers explicitly expose
information about the path or paths available from one endpoint to
another, and to those endpoints and the applications running on them,
so that they can make this selection [draft-irtf-panrg-questions-09].
This draft targets at the third question in [draft-irtf-panrg-
questions-09]: how can endpoints select paths to use for traffic in a
way that can be trusted by the network, the endpoints, and the
applications using them?
And this draft targets at the path selection use case of path-aware
networking, and we both consider the scenario that a set of paths to
the same destination and also the scenario that several destinations
with several paths. According to [draft-irtf-panrg-path-properties-
02], entities may select their paths to fulfill a specific goal,
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e.g., related to security or performance, as an example of
performance related path selection, an entity may prefer paths with
performance properties that best match its traffic requirements. In
this draft, we target at the services with various traffic
requirements for upstream and downstream traffic and also with
requirements to service endpoint Different types of services have
different requirements to network：
1. For transmission-intensive services, the amount of data
transmitted is large, so the choice of network path affects the
entire service larger.
2. For computing-intensive services, the computing tasks of service
endpoint are complex and the choice of endpoint affect the entire
service is large
3. And traditional transmission-intensive services tend to have a
lot of downstream traffic, so they usually specify the downstream
path.
4. For transmission-intensive services with large upstream traffic,
such as short video and live broadcast, the upstream path matters a
lot so the perception and specification of upstream path is necessary
to meet service requirements.
So the terminal needs to be aware of both the status of the uplink
path and the downlink path, and specify the uplink path and the
downlink path based on service characteristics. What's more, for
computing-intensive services, the terminal still needs to be aware of
the status of service endpoint, and the path-aware networking also
need to consider the status of endpoint when select network path.
2. On-demand awareness on paths and path properties
For services with different requirements, when path-aware networking
is applied to realize path perception, it is necessary to dynamically
determine the perceived target paths and target path attributes, such
as perceiving the given upstream path or the given downstream path,
and perceiving path latency or path bandwidth [draft-irtf-panrg-path-
properties-02]. When user initiates a service request, path-aware
networking needs to analyses service requirements related to path-
awareness, including time sensitivity, traffic amount, and traffic
characteristics etc, and decide to be aware of which set of paths and
which path properties of them. So path-aware networking needs to
specify the following information:
1. Service requirements towards path-awareness
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2. Target paths to be perceived
3. Target path properties to be perceived
For example, when a service with large amount of uplink traffic and
strict requirements on service latency is requested, path-aware
networking assign a set of uplink paths which are to be perceived,
and determine the target path property is path latency, and then
specify the above mentioned upstream paths to user, and then user
initiate uplink path detection packet towards given paths carrying
target path properties , and then the network nodes along the path
writes the required path properties information. With path-aware
networking, the given paths and corresponding properties are
obtained, and user can select optimal uplink path which meet service
requirements.
3. Definition and application of path property weight
In path-aware network, instead of using single MED value, other
properties such as Link Capacity or Link Usage could additionally be
used to improve load balancing or performance [I-D.ietf-idr-
performance-routing]. And more properties are required to be
considered for new emerging services [draft-irtf-panrg-path-
properties-02].
The transmission of upstream traffic and downstream traffic, and also
data processing by the service endpoint form a complete service
process (face recognition, CLOUD A/VR, etc.). So the completion of
the service needs to consider multi-dimensional factors.
For path-aware networking, facing diverse service requirements and
multi-dimensional path properties, to solve the problem of how to
comprehensive select path considering service requirements, a new
parameter needs to be introduced: path property weight values, which
represent the weight of each path properties and are used to
comprehensively define the perceived multi-dimensional path
properties. And then the path-aware networking needs to specify the
following information:
1. Service requirements towards path-awareness
2. Target paths to be perceived
3. Target path properties to be perceived
4. Path property weight values of target path properties
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For example, for requested services that require large uplink
bandwidth, path-aware networking need to define larger uplink path
bandwidth weight, and calculates the target "uplink path + downlink
path" pair based on the given weight value.
4. Service endpoint consideration in path-aware networking
Many emerging services not only put forward new requirements for the
network, but also put forward requirements for computing. For
services such as AR/VR, the budgets for computing delay and network
delay are almost equivalent [draft-liu-dyncast-ps-usecases-01] ,
therefore, when path-aware network perceives paths, designates path
and selects paths, it also needs to consider the status of the
service endpoint. And then the path-aware networking needs to
specify the following information:
1. Service requirements towards path-awareness, including service
endpoint
2. Target service endpoints and properties
3. Target paths to be perceived corresponding to target service
endpoints
4. Target path properties to be perceived
5. Path property weight values of target path properties including
service endpoint
And when the requested service is a computationally intensive
service, the status of the service endpoint will have a greater
impact in the entire process. Therefore, it is also necessary to
select an optimal service endpoint to provide services. Path-aware
networking needs to generate multiple target paths for multiple
candidate service endpoints, and specify new path parameter weight
values towards target path properties and target service endpoint
status.
5. Summary
The dynamic path selection considering service requirements and
service characteristics has become one of the current technical
development directions. This draft analyzes the application of path-
aware networking to achieve the on-demand path awareness and service
endpoint awareness, and provides optimal path selection.
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6. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
7. Security Considerations
TBD
8. Acknowledgements
TBD
9. Normative References
[I-D.ietf-idr-performance-routing]
Xu, X., Hegde, S., Talaulikar, K., Boucadair, M., and C.
Jacquenet, "Performance-based BGP Routing Mechanism",
draft-ietf-idr-performance-routing-03 (work in progress),
December 2020.
[I-D.irtf-panrg-path-properties]
Enghardt, T. and C. Kraehenbuehl, "A Vocabulary of Path
Properties", draft-irtf-panrg-path-properties-02 (work in
progress), February 2021.
[I-D.irtf-panrg-questions]
Trammell, B., "Current Open Questions in Path Aware
Networking", draft-irtf-panrg-questions-09 (work in
progress), April 2021.
[I-D.liu-dyncast-ps-usecases]
Liu, P., Willis, P., and D. Trossen, "Dynamic-Anycast
(Dyncast) Use Cases & Problem Statement", draft-liu-
dyncast-ps-usecases-01 (work in progress), February 2021.
[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>.
Authors' Addresses
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Yuexia Fu
China Mobile
Beijing
100053
China
Email: fuyuexia@chinamobile.com
Peng Liu
China Mobile
Beijing
100053
China
Email: liupengyjy@chinamobile.com
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