Internet-Draft | DetNet Deterministic Latency Option for | January 2023 |
Xiong & Zhao | Expires 9 July 2023 | [Page] |
- Workgroup:
- DETNET
- Internet-Draft:
- draft-xiong-detnet-6man-queuing-option-03
- Published:
- Intended Status:
- Standards Track
- Expires:
DetNet Deterministic Latency Option for IPv6
Abstract
This document introduces new IPv6 options to identify the Deterministic Latency related information for DetNet flows in IPv6 and SRv6 networks.¶
Status of This Memo
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.¶
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.¶
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."¶
This Internet-Draft will expire on 9 July 2023.¶
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the document authors. All rights reserved.¶
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 and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
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]. The existing deterministic technologies are facing large-scale number of nodes and long-distance transmission, traffic scheduling, dynamic flows, and other controversial issues in large-scale networks. The enhanced DetNet Data plane is required to support a data plane method of flow identification and packet treatment. [I-D.liu-detnet-large-scale-requirements] has described the enhancement requirements for DetNet data plane, it is required to support information used by functions ensuring Deterministic Latency. [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. Moverover, new functions and related metadata shouled be supported in enhanced DetNet.¶
The queuing-based mechanisms is an important type of resource to ensure the deterministic latency. As described in [I-D.ietf-detnet-bounded-latency], the end-to-end bounded latency depends on the value of queuing delay bound along with the queuing mechanisms. Multiple queuing mechanisms can be used to guarantee the bounded latency in DetNet. And many types of queuing mechanisms have been proposed to provide diversified deterministic service for various applications. For example, time-scheduling queuing mechanisms includes the TAS (Time Aware Shaping) [IIEEE802.1Qbv] and priority-scheduling includes the CBS (Credit-Based Shaper)[IEEE802.1Q-2014] with ATS (Asynchronous Traffic Shaping)[IEEE802.1Qcr]. The cyclic-scheduling queuing mechanism has been proposed such as CQF (Cyclic Queuing and Forwarding) in [IEEE802.1Qch] and improved in [I-D.dang-queuing-with-multiple-cyclic-buffers]. The deadline-scheduling queuing mechanism has been proposed in [I-D.stein-srtsn] and improved in [I-D.peng-detnet-deadline-based-forwarding]. The per-flow queuing mechanism includes Guaranteed-Service Integrated service (IntServ) [RFC2212]. The asynchronous queuing mechanism includes the Asynchronous Deterministic Networking (ADN) as per [I-D.joung-detnet-asynch-detnet-framework]. The functions such as the queuing mechanisms should be provided for enhanced DetNet to ensure the deterministic latency.¶
And when queuing mechanisms uesed in large-scale networks, some queuing parameters should be carried for coordination between nodes so as to make appropriate packet forwarding and scheduling decisions to meet the time bounds. The DetNet forwarding nodes along the path can apply the function and the deterministic latency related information should be carried as metadata in the packet to achieve the end-to-end bounded latency.¶
This document introduces new IPv6 options to identify the Deterministic Latency related information for DetNet flows in IPv6 and SRv6 networks.¶
2. Conventions used in this document
2.1. Terminology
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.¶
3. The DetNet Options
This document defines new IPv6 options for DetNet to signal Deterministic Latency related information to the DetNet layers. The format of the options follow the generic definition in section 4.2 of [RFC8200]. The option may be placed either in an HbH or a DoH EH.¶
3.1. The Deterministic Latency Option
The DetNet Deterministic Latency Option helps to discriminate the types of mechanisms and specify the related parameters.¶
Option Type: 8-bit identifier of the type of option. Value TBD1 by IANA; the highest-order 3 bits of the field is 001 to skip over this option and continue processing the header if the processing IPv6 node does not recognize the Option Type and to permit the Option Data to be changed en route to the packet's final destination.¶
Opt Data Len: 8-bit unsigned integer. Length of the Option Data field of this option, in octets. It is set to 12.¶
DLA(Deterministic Latency Action) Type(16 bits): indicates the type of deterministic latency actions for IPv6/SRv6 metadata. The DLA Type is defined in section 3.1.1.¶
TU(3 bits): indicates the time units for the Deterministic Delay.¶
DLL(3 bits): Length of the Deterministic Latency Information field as an unsigned 3-bit integer.¶
Deterministic Latency Information(variable): it is optional and provides additional information for a node to forward a DetNet flow. The Sub-TLVs has been defined in section 3.1.2.¶
3.1.1. DLA Type
The DLA Type can be divided into two parts including behaviour action type and function/queuing type. The format is 16 bits such as 0xFFFF.¶
The DLA Type field is designed as follow:¶
Type(8 bits): indicates the behaviour action type of packet treatment ensuring the deterministic latency as following shown.¶
Sub-type(8 bits): indicates the type of functions ensuring the deterministic latency and related metadata. For example, the functions such as a pirticular queuing mechanism may be indicated and related parameters should be provided as section 3.1.2 shown.¶
The types of Deterministic Latency functions should cover all the mechanisms ensuring the Deterministic Latency such as the existing queuing and scheduling mechanisms and other mechanisms which may be proposed in the future.¶
3.1.2. Deterministic Latency Information
It provides deterministic latency information for a node to forward a DetNet flow. The format is based on the sub-type.¶
When the Sub-type is set to 0x0001, indicates the Multiple Cyclic Queuing mechasims as defined in [I-D.dang-queuing-with-multiple-cyclic-buffers]. The Cycle information may be carried and designed as following shown:¶
Cycle Profile ID (32bits): indicates the profile ID which the cyclic queue applied at a node.¶
Cycle ID (32bits): indicates the Cycle ID for a node to forward a DetNet flow.¶
When the Sub-type is set to 0x0002, the Deadline Information may be carried and designed as follow:¶
Planned and deadline Deviation has been provided as defined in [I-D.peng-6man-deadline-option].¶
When the Sub-type is set to 0x0003, the Local Deadline Information may be carried and designed as follow:¶
Local Deadline: indicates the local deadline as defined in [I-D.stein-srtsn].¶
4. Encapsulation of DetNet Options
4.1. IPv6 Networks
The DetNet Deterministic Latency Option is intended to be placed in an IPv6 HbH EH since it must be processed by every DetNet forwarding node along the path. All DetNet forwarding nodes can use the queuing information to achieve the packet forwarding and queue scheduling.¶
4.2. SRv6 Networks
The DetNet Deterministic Latency Option is intended to be placed in an DOH EH before an SRH since it must be processed by the DetNet forwarding nodes of the SRv6 segment list. The DetNet forwarding nodes among SRv6 segment list can use the Deterministic Latency to achieve the packet forwarding and queue scheduling.¶
5. Security Considerations
TBA¶
6. Acknowledgements
The authors would like to thank Peng Liu, Bin Tan, Shaofu Peng for their review, suggestions and comments to this document.¶
7. IANA Considerations
7.1. New Option for IPv6
This specification updates the "Destination Options and Hop-by-Hop Options" under the "Internet Protocol Version 6 (IPv6) Parameters" registry with the values below:¶
Type | Description | Reference |
---|---|---|
TBD1 | Deterministic Latency Option | [this document] |
8. Normative References
- [I-D.dang-queuing-with-multiple-cyclic-buffers]
- Liu, B. and J. Dang, "A Queuing Mechanism with Multiple Cyclic Buffers", Work in Progress, Internet-Draft, draft-dang-queuing-with-multiple-cyclic-buffers-00, , <https://www.ietf.org/archive/id/draft-dang-queuing-with-multiple-cyclic-buffers-00.txt>.
- [I-D.ietf-detnet-bounded-latency]
- Finn, N., Boudec, J. L., Mohammadpour, E., Zhang, J., and B. Varga, "DetNet Bounded Latency", Work in Progress, Internet-Draft, draft-ietf-detnet-bounded-latency-10, , <https://www.ietf.org/archive/id/draft-ietf-detnet-bounded-latency-10.txt>.
- [I-D.joung-detnet-asynch-detnet-framework]
- Joung, J., Ryoo, J., Cheung, T., Li, Y., and P. Liu, "Asynchronous Deterministic Networking Framework for Large-Scale Networks", Work in Progress, Internet-Draft, draft-joung-detnet-asynch-detnet-framework-00, , <https://www.ietf.org/archive/id/draft-joung-detnet-asynch-detnet-framework-00.txt>.
- [I-D.liu-detnet-large-scale-requirements]
- Liu, P., Li, Y., Eckert, T., Xiong, Q., and J. Ryoo, "Requirements for Large-Scale Deterministic Networks", Work in Progress, Internet-Draft, draft-liu-detnet-large-scale-requirements-02, , <https://www.ietf.org/archive/id/draft-liu-detnet-large-scale-requirements-02.txt>.
- [I-D.peng-6man-deadline-option]
- Peng, S. and B. Tan, "Deadline Option", Work in Progress, Internet-Draft, draft-peng-6man-deadline-option-00, , <https://www.ietf.org/archive/id/draft-peng-6man-deadline-option-00.txt>.
- [I-D.peng-detnet-deadline-based-forwarding]
- Peng, S., Tan, B., and P. Liu, "Deadline Based Deterministic Forwarding", Work in Progress, Internet-Draft, draft-peng-detnet-deadline-based-forwarding-01, , <https://www.ietf.org/archive/id/draft-peng-detnet-deadline-based-forwarding-01.txt>.
- [I-D.stein-srtsn]
- Stein, Y. (., "Segment Routed Time Sensitive Networking", Work in Progress, Internet-Draft, draft-stein-srtsn-01, , <https://www.ietf.org/archive/id/draft-stein-srtsn-01.txt>.
- [I-D.xiong-detnet-large-scale-enhancements]
- Xiong, Q. and Z. Du, "DetNet Enhancements for Large-Scale Deterministic Networks", Work in Progress, Internet-Draft, draft-xiong-detnet-large-scale-enhancements-00, , <https://www.ietf.org/archive/id/draft-xiong-detnet-large-scale-enhancements-00.txt>.
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
- [RFC2212]
- Shenker, S., Partridge, C., and R. Guerin, "Specification of Guaranteed Quality of Service", RFC 2212, DOI 10.17487/RFC2212, , <https://www.rfc-editor.org/info/rfc2212>.
- [RFC8174]
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
- [RFC8200]
- Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, , <https://www.rfc-editor.org/info/rfc8200>.
- [RFC8655]
- Finn, N., Thubert, P., Varga, B., and J. Farkas, "Deterministic Networking Architecture", RFC 8655, DOI 10.17487/RFC8655, , <https://www.rfc-editor.org/info/rfc8655>.
- [RFC8938]
- Varga, B., "Deterministic Networking (DetNet) Data Plane Framework", RFC 8938, DOI 10.17487/RFC8938, , <https://www.rfc-editor.org/info/rfc8938>.