Flow Aggregation for Enhanced DetNet
draft-xiong-detnet-flow-aggregation-00
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Quan Xiong , Tianji Jiang , Jinoo Joung | ||
| Last updated | 2024-03-01 | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
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draft-xiong-detnet-flow-aggregation-00
DetNet Q. Xiong
Internet-Draft ZTE Corporation
Intended status: Standards Track T. Jiang
Expires: 2 September 2024 China Mobile
J. Joung
Sangmyung University
1 March 2024
Flow Aggregation for Enhanced DetNet
draft-xiong-detnet-flow-aggregation-00
Abstract
This document describes the flow aggregation scenarios and proposes a
method by aggregating DetNet flows based on DetNet flow-specific
classification in enhanced DetNet and the flow identification of
aggregated-class can be used to indicate the required treatment and
forwarding behaviors in scaling networks.
Status of This Memo
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This Internet-Draft will expire on 2 September 2024.
Copyright Notice
Copyright (c) 2024 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
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Flow Aggregation Scenarios in Enhanced DetNet . . . . . . . . 4
3.1. Aggregating DetNet Flows across Different Network
Domains . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Aggregating DetNet Flows to Provide Fine-grained QoS
Behaviors . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3. Aggregating DetNet Flows without Maintaining States at
Transit Nodes . . . . . . . . . . . . . . . . . . . . . . 5
4. Aggregating DetNet Flows on Aggregated-class Level . . . . . 6
4.1. Flow Classification . . . . . . . . . . . . . . . . . . . 6
4.2. Flow Identification . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
According to [RFC8655], Deterministic Networking (DetNet) operates at
the IP layer and delivers service which provides extremely low data
loss rates and bounded latency within a network domain. The DetNet
Quality of Service (QoS) includes the bounded latency indicating the
minimum and maximum end-to-end latency from source to destination and
bounded jitter (packet delay variation).
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As per [RFC8655], the DetNet data plane must support the aggregation
of DetNet flows in order to support larger numbers of DetNet flows
and improve scalability by reducing the per-hop states. As per
[RFC8938], flow aggregation is the ability to aggregate individual
flows with and their associated resource control into a larger
aggregate. DetNet flow aggregation may be enabled for the flows with
the same or very similar QoS and CoS characteristics via the use of
wildcards, masks, prefixes, and ranges. As per [RFC8964], two
methods of flow aggregation have been proposed such as aggregation
via LSP hierarchy and aggregating DetNet flows as a new DetNet flow.
In scaling networks, as per [I-D.ietf-detnet-scaling-requirements],
the enhanced DetNet should support that different levels of
applications co-existed with different SLAs requirements. From the
use cases in [RFC8578] and [I-D.zhao-detnet-enhanced-use-cases],
DetNet applications differ in their network topologies and specific
desired behavior. DetNet flows should be transmitted and forwarded
with different DetNet QoS behaviors. It should provide fine-grained
service provisioning to achieve differentiated DetNet QoS. The
DetNet flows with the same level of services requirements can be
aggregated to receive corresponding treatment and forwarding
behaviour. The DetNet flows can be classified and aggregated based
on flow-specific characteristics. Moreover, the existing aggregation
of individual flows may be still challenging for network operations.
The aggregated flows still requires a large amount of control
signaling to establish and maintain the states of DetNet flows when
it will be large-scale dynamic deterministic flows and network
topology in enhanced DetNet. It is required to improve the
scalability and forward packets at class-aggregate level instead of
the per-flow or flow-aggregate level and the flow identification of
aggregated-class can be used to indicate the per-hop behavior without
the maintain of the states in scaling networks.
This document describes the flow aggregation scenarios and proposes a
method by aggregating DetNet flows based on DetNet flow-specific
classification in enhanced DetNet and the flow identification of
aggregated-class can be used to indicate the required treatment and
forwarding behaviors in scaling networks.
1.1. 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].
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2. Terminology
The terminology is defined as [RFC8655].
DC: DetNet Traffic Class
3. Flow Aggregation Scenarios in Enhanced DetNet
3.1. Aggregating DetNet Flows across Different Network Domains
The flow aggregation may be required in multi-domain scenario to
achieve the end-to-end QoS guarantees and the aggregated flows may
across multiple domains. As per
[I-D.ietf-detnet-scaling-requirements], different network
implementations may be intended for different application domains,
where there is no additional requirements for the coordination. As
defined in [ITU-T Y.2122], the network operating parameters of a flow
aggregate should be exchanged among different network domains. As
shown in Figure 1, the DetNet domain B receiving aggregated flow
should identify the flow and get the service requirements such as the
QoS parameters of the flow aggregate.
+-----------------+ +-----------------+
| | | |
Individual Flows | DetNet Domain A | Aggregated Flow | DetNet Domain B |
---------------->| | --------------> | |
+-----------------+ +-----------------+
Figure 1: Aggregating DetNet Flows across Multiple Domains
3.2. Aggregating DetNet Flows to Provide Fine-grained QoS Behaviors
As per [I-D.ietf-detnet-scaling-requirements], different levels of
applications differ in the SLAs requirements such as tight jitter,
strict latency, loose latency and so on. The individual flows demand
differentiated DetNet treatment and QoS forwarding behaviors. And
the DetNet node or domain providing multiple forwarding technologies
needs to transmit the individual flows by aggregating the flows to a
selecting treatment solution with corresponding per-hop QoS behavior
as shown in Figure 2. For example, as per [I-D.jlg-detnet-5gs], the
5GS as a logical DetNet node or nodes needs to get the service
requirements and service level of the aggregated flows to provide
fine-grained per-hop behaviors.
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DetNet-aware Node/Network
+--------------------------+
Aggregated-flow 1 ----->| Per-hop QoS Behavior 1 |
+--------------------------+
Aggregated-flow 2 ----->| Per-hop QoS Behavior 2 |
+--------------------------+
... | ... |
+--------------------------+
Aggregated-flow n ----->| Per-hop QoS Behavior N |
+--------------------------+
Figure 2: Aggregating DetNet flows to the corresponding QoS behavior
3.3. Aggregating DetNet Flows without Maintaining States at Transit
Nodes
As per [I-D.joung-detnet-taxonomy-dataplane], the treatment solutions
in data plane can be categorized based on performance and functional
characteristics. For example, the solution can be categorized based
on traffic granularity such as flow aggregate and class level. The
class level is provided to simplify the control and accommodate
traffic fluctuations by aggregating flows with the same level of
service requirements. The flow aggregation based on the class level
could further improve the scalability. As per
[I-D.ietf-detnet-scaling-requirements], it may have the large number
of traffic flows in scaling network and it is impossible for per-flow
state identification. As shown in Figure 3, the flow identification
of aggregated-class can be used to indicate the required treatment
and forwarding behaviors without the maintain of the states at
transit nodes.
+-------------+ +-------------+ +-------------+
Aggregated| | Aggregated| | | |
Flows|DetNet Node A| Flows|DetNet Node B| |DetNet Node N|
--------->| |---------->| |----->...| |
+-------------+ +-------------+ +-------------+
Figure 3: Aggregating DetNet Flows to Improve Scalability
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4. Aggregating DetNet Flows on Aggregated-class Level
When DetNet flows are aggregated on aggregated-class level, transit
nodes provide deterministic services to the aggregate and on a per-
class scheduling without the states maintaining. The nodes
performing aggregation should ensure all per-flow service
requirements within the class are achieved. For example, the latency
or jitter bounds of a class aggregate should not exceed bounds of the
individual flows. The aggregation based on the class level has data
plane and controller plane aspects.
For the data plane, when DetNet flows are aggregated to a class,
transit nodes provide service to the aggregate and not on a per-
DetNet-flow basis. And the transit nodes supporting this type of
aggregation should identify the class of the aggregated flows and
ensure that individual flows receive the corresponding traffic
treatment and forwarding behaviour.
For the controller plane, the service should be provisioned on an
aggregated-class level. The resources should be controlled and
scheduled on a per-class basis and the routes should be established
to meet the service requirements with the allocated resources. The
edge nodes must be able to handle admission control for DetNet flows
to an aggregated class based on the available resources.
4.1. Flow Classification
The DetNet QoS can be achieved by aggregating flows based on DetNet
flow-specific traffic classification and providing the traffic-
forwarding treatment. The flow classification should consider the
flow-specific characteristics such as traffic specification and
service requirements. For example, the DetNet flows MAY be
classified based on the service SLAs requirements of applications in
scaling networks as per [I-D.xiong-detnet-differentiated-detnet-qos].
And the services can also be classified into tight/loose latency,
large/small burst, periodic/non-periodic and large/small scale
services as per [I-D.joung-detnet-taxonomy-dataplane]. Several
classes can be predefined to indicate the different levels of
applications with SLAs requirements and each class demands
differentiated QoS behaviors and treatment as well as different
DetNet capabilities in scaling networks.
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4.2. Flow Identification
The flow identification is required to be dynamic and simplified to
ensure the aggregated flows have compatible DetNet flow-specific QoS
characteristics. For the data plane, individual flows may be
aggregated for treatment based on shared service specification on
aggregated-class level which identified by an aggregation class
(A-Class). The nodes should provide the class level traffic
treatment based on A-Class. The aggregation class information may be
used alone or together with other metadata to indicate the required
queuing and forwarding behaviors. The encoding of the A-Class may
reuse the DSCP/TC or existing field such as the TC field in A-Label
as per [RFC8964]. And it also can be encapsulated with the
deterministic latency information as per
[I-D.xiong-detnet-data-fields-edp].
5. Security Considerations
TBA
6. IANA Considerations
TBA
7. Acknowledgements
TBA
8. References
8.1. Normative References
[I-D.ietf-detnet-scaling-requirements]
Liu, P., Li, Y., Eckert, T. T., Xiong, Q., Ryoo, J.,
zhushiyin, and X. Geng, "Requirements for Scaling
Deterministic Networks", Work in Progress, Internet-Draft,
draft-ietf-detnet-scaling-requirements-05, 20 November
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
detnet-scaling-requirements-05>.
[I-D.ietf-teas-rfc3272bis]
Farrel, A., "Overview and Principles of Internet Traffic
Engineering", Work in Progress, Internet-Draft, draft-
ietf-teas-rfc3272bis-27, 12 August 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
rfc3272bis-27>.
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[I-D.jlg-detnet-5gs]
Jiang, T., Liu, P., and X. Geng, "DetNet YANG Model
Extension for 5GS as a Logical DetNet Node", Work in
Progress, Internet-Draft, draft-jlg-detnet-5gs-01, 20
October 2023, <https://datatracker.ietf.org/doc/html/
draft-jlg-detnet-5gs-01>.
[I-D.joung-detnet-taxonomy-dataplane]
Joung, J., Geng, X., Peng, S., and T. T. Eckert,
"Dataplane Enhancement Taxonomy", Work in Progress,
Internet-Draft, draft-joung-detnet-taxonomy-dataplane-01,
25 February 2024, <https://datatracker.ietf.org/doc/html/
draft-joung-detnet-taxonomy-dataplane-01>.
[I-D.xiong-detnet-data-fields-edp]
Xiong, Q., Liu, A., Gandhi, R., and D. Yang, "Data Fields
for DetNet Enhanced Data Plane", Work in Progress,
Internet-Draft, draft-xiong-detnet-data-fields-edp-01, 10
July 2023, <https://datatracker.ietf.org/doc/html/draft-
xiong-detnet-data-fields-edp-01>.
[I-D.xiong-detnet-differentiated-detnet-qos]
Xiong, Q., Zhao, J., Du, Z., Zeng, Q., and C. Liu,
"Differentiated DetNet QoS for Deterministic Services",
Work in Progress, Internet-Draft, draft-xiong-detnet-
differentiated-detnet-qos-00, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
differentiated-detnet-qos-00>.
[I-D.xiong-detnet-enhanced-detnet-gap-analysis]
Xiong, Q. and A. Liu, "Gap Analysis for Enhanced DetNet",
Work in Progress, Internet-Draft, draft-xiong-detnet-
enhanced-detnet-gap-analysis-03, 25 February 2024,
<https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
enhanced-detnet-gap-analysis-03>.
[I-D.xiong-detnet-large-scale-enhancements]
Xiong, Q., Du, Z., Zhao, J., and D. Yang, "Enhanced DetNet
Data Plane Framework for Scaling Deterministic Networks",
Work in Progress, Internet-Draft, draft-xiong-detnet-
large-scale-enhancements-04, 26 February 2024,
<https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
large-scale-enhancements-04>.
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[I-D.zhao-detnet-enhanced-use-cases]
Zhao, J., Xiong, Q., and Z. Du, "Enhanced Use cases for
Scaling Deterministic Networks", Work in Progress,
Internet-Draft, draft-zhao-detnet-enhanced-use-cases-00,
23 October 2023, <https://datatracker.ietf.org/doc/html/
draft-zhao-detnet-enhanced-use-cases-00>.
[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>.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
RFC 4915, DOI 10.17487/RFC4915, June 2007,
<https://www.rfc-editor.org/info/rfc4915>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
[RFC6549] Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
Instance Extensions", RFC 6549, DOI 10.17487/RFC6549,
March 2012, <https://www.rfc-editor.org/info/rfc6549>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[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>.
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[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>.
[RFC8233] Dhody, D., Wu, Q., Manral, V., Ali, Z., and K. Kumaki,
"Extensions to the Path Computation Element Communication
Protocol (PCEP) to Compute Service-Aware Label Switched
Paths (LSPs)", RFC 8233, DOI 10.17487/RFC8233, September
2017, <https://www.rfc-editor.org/info/rfc8233>.
[RFC8578] Grossman, E., Ed., "Deterministic Networking Use Cases",
RFC 8578, DOI 10.17487/RFC8578, May 2019,
<https://www.rfc-editor.org/info/rfc8578>.
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>.
[RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "Path Computation Element Communication
Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
DOI 10.17487/RFC8664, December 2019,
<https://www.rfc-editor.org/info/rfc8664>.
[RFC8938] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane
Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020,
<https://www.rfc-editor.org/info/rfc8938>.
[RFC8964] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant,
S., and J. Korhonen, "Deterministic Networking (DetNet)
Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January
2021, <https://www.rfc-editor.org/info/rfc8964>.
[RFC9320] Finn, N., Le Boudec, J.-Y., Mohammadpour, E., Zhang, J.,
and B. Varga, "Deterministic Networking (DetNet) Bounded
Latency", RFC 9320, DOI 10.17487/RFC9320, November 2022,
<https://www.rfc-editor.org/info/rfc9320>.
[RFC9357] Xiong, Q., "Label Switched Path (LSP) Object Flag
Extension for Stateful PCE", RFC 9357,
DOI 10.17487/RFC9357, February 2023,
<https://www.rfc-editor.org/info/rfc9357>.
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Authors' Addresses
Quan Xiong
ZTE Corporation
China
Email: xiong.quan@zte.com.cn
Tianji Jiang
China Mobile
Email: tianjijiang@chinamobile.com
Jinoo Joung
Sangmyung University
Email: jjoung@smu.ac.kr
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