Internet DRAFT - draft-xiong-detnet-spring-srh-extensions
draft-xiong-detnet-spring-srh-extensions
DETNET Q. Xiong
Internet-Draft H. Wu
Intended status: Standards Track ZTE Corporation
Expires: 15 April 2024 D. Yang
Beijing Jiaotong University
13 October 2023
Segment Routing Header Extensions for DetNet Data Fields
draft-xiong-detnet-spring-srh-extensions-01
Abstract
The DetNet data fields defined in Deterministic Latency Action (DLA)
can be used in enhanced Deterministic Networking (DetNet) to provide
QoS treatment to achieve deterministic latency.
This document defines how DetNet data fields are encapsulated as part
of the Segment Routing with IPv6 data plane (SRv6) header.
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 15 April 2024.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 2
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. DetNet Data Fields Encapsulation in SRH . . . . . . . . . . . 3
3.1. SRH Segment List Extensions . . . . . . . . . . . . . . . 3
3.2. SRH TLV Extensions . . . . . . . . . . . . . . . . . . . 5
3.3. SRH DetNet Segment Extensions . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
7. Normative References . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
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. DetNet data
planes has been specified in [RFC8938].
[I-D.ietf-detnet-scaling-requirements]has described the enhancement
requirements for DetNet enhanced data plane in large-scale networks.
[I-D.xiong-detnet-large-scale-enhancements] has proposed the overall
framework of DetNet enhancements for large-scale deterministic
networks. The packet treatment should schedule the resources and
indicate the behaviour to ensure the deterministic latency.
Moreover, new functions and related metadata should be supported in
DetNet enhanced data plane. [I-D.xiong-detnet-data-fields-edp] has
proposed a common DetNet data fields and option types for enhanced
DetNet data plane and defined a Deterministic Latency Action (DLA)
option to carry queuing-based metadata.
This document defines how DetNet data fields are encapsulated as part
of the Segment Routing with IPv6 data plane (SRv6) header [RFC8754].
2. Conventions used in this document
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2.1. Terminology
The terminology is defined as [RFC8655] ,[RFC8938] and [RFC8754].
2.2. 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.
Abbreviations and definitions used in this document:
EDP: Enhanced Data plane
SRH: Segment Routing Header
SRv6: Segment Routing for IPv6 forwarding plane
DLA: Deterministic Latency Action
3. DetNet Data Fields Encapsulation in SRH
The DetNet data fields such as DLA option are defined in
[I-D.xiong-detnet-data-fields-edp], and can be used for ensuring
deterministic latency in enhanced DetNet data plane. The SRv6
encapsulation header (SRH) is defined in [RFC8754] and DetNet data
fields can be encapsulated in the SRH.
The DetNet data fields can be divided into option header and data.
And it can be carried in SRH extensions including the options such as
SRH header field, segment List, TLV and the last segment. This
enables the DetNet enhanced functions to build on the network
programmability capability of SRv6.
The following sections discuss the optional SRH extensions for
enhanced DetNet data plane in encapsulating the Deterministic Latency
Action Option.
3.1. SRH Segment List Extensions
The DetNet data field can be carried in SRH segment list. This
enables the ability of SRv6 networks to forward a DetNet flow per
segment list. This document defines a new SRv6 Endpoint behavior
which can be used to indicate the Deterministic Forwarding (DF)
function, called End.DF. The End.DF is a variant of the End.X
behavior defined in [RFC8986]. The End.DF SID SHOULD support the SRH
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processing of Penultimate S egment Pop (PSP),Ultimate Segment Pop
(USP), and Ultimate Segment Decapsulation (USD) flavors as defined in
[RFC8986]. The End.DF SIDs can be allocated by a centralized network
controller and advertized by IGP or BGP-LS.
The SRH segment list extensions for DetNet DLA Option is as follows.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Entry | Flags | TAG | DLA Q-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[0] (128-bit IPv6 address) |
| DLA Option Data List[0] |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
...
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[n] (128-bit IPv6 address) |
| DLA Option Data List[n] |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
// Optional Type Length Value objects (variable) //
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: SRH Segment List Extensions for DLA Option
DLA Q-Type (8bits): as defined by the DLA Option Header field, and is
defined in Section 4.2.1.2 of [I-D.xiong-detnet-data-fields-edp].
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DLA Option Data List (variable): as defined by the DLA Option Data
field, and is defined in Section 4.2.2 of
[I-D.xiong-detnet-data-fields-edp].
3.2. SRH TLV Extensions
The DetNet data field can be carried in SRH TLV. This enables the
ability for an SRv6 node to determine whether to process or ignore
some specific SRH TLVs is based on the SID function. The nodes which
support the enhanced DetNet functionality can process the SRH TLV and
the others can ignore the SRH DetNet TLV. The SRH TLV for DetNet DLA
Option is as follows.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRH-TLV-Type |SRH-TLV-Length | DetNet-Type | DetNet-Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DLA Type | Data Len | Ancillary Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DLA Data List[0](variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DLA Data List[n](variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: SRH TLV Extensions for DLA Option
SRH-TLV-Type/SRH-TLV-Length (8 bits): DetNet TLV Type for SRH is
defined as TBA1. Length of the SRH TLV in 4-octet units. The fields
related to the encapsulation of DetNet data fields in the SRH are
defined as follows:
DetNet-Length (8 bits): indicates the DetNet option length.
DetNet-Type (8 bits): indicates the DetNet option type.
DLA Type (16 bits): as defined by the Option Type field, and is
defined in Section 4.1 of [I-D.xiong-detnet-data-fields-edp].
Data Len (8 bits): unsigned integer. This field specifies the length
of DLA option data added by each node.
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Ancillary Len (8 bits): unsigned integer. This field specifies the
length of DLA ancillary data added by each node.
DLA Data List(variable): as defined by the Data field including
option data and ancillary data, and is defined in Section 4.2 of
[I-D.xiong-detnet-data-fields-edp]. The DLA Option Data can be
carried one time or in list.
3.3. SRH DetNet Segment Extensions
The DetNet data field can be carried in SRH segment called DetNet
Segment when a particular option data is processed within each node.
The mapping from DLA data of current node to DLA data of next node
SHOULD be provided in the control plane. It SHOULD swap and
encapsulate the DetNet Segment at each forwarding node. The SRH
segment extensions for DetNet DLA Option is as follows.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segments Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Entry | Flags |D| Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[0] (128-bit IPv6 address) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
...
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[n] (128-bit IPv6 address) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| SRv6 DetNet Segment (Segment List[n+1] (128-bit IPv6 value) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
// Optional Type Length Value objects (variable) //
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: SRH DetNet Segment Extensions for DLA Option
D (Deterministic Flag) : when it is set, indicates the SRH extension
for DLA Option Data.
The SRv6 DetNet Segment format is as follows.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DLA Type | Data len | Ancillary Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DLA Option data field determined by DLA Q-Type (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DLA Ancillary data field determined by DLA Type (variable)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: DetNet Segment Format for DLA Option
The definition of the value can be referred as
[I-D.xiong-detnet-data-fields-edp].
4. Security Considerations
TBA
5. IANA Considerations
TBA
6. Acknowledgements
TBA
7. 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-03, 7 July 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
scaling-requirements-03>.
[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>.
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[I-D.xiong-detnet-large-scale-enhancements]
Xiong, Q., Du, Z., Zhao, J., and D. Yang, "Enhanced DetNet
Data Plane (EDP) Framework for Scaling Deterministic
Networks", Work in Progress, Internet-Draft, draft-xiong-
detnet-large-scale-enhancements-03, 10 July 2023,
<https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
large-scale-enhancements-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>.
[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>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>.
[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>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>.
[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>.
Authors' Addresses
Quan Xiong
ZTE Corporation
No.6 Huashi Park Rd
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Wuhan
Hubei, 430223
China
Email: xiong.quan@zte.com.cn
Haisheng Wu
ZTE Corporation
Nanjing
Jiangsu,
China
Email: wu.haisheng@zte.com.cn
Dong Yang
Beijing Jiaotong University
Beijing
China
Email: dyang@bjtu.edu.cn
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