DetNet Working Group X. Song Internet-Draft Q. Xiong Intended status: Standards Track ZTE Corp. Expires: 26 December 2022 24 June 2022 DetNet Queue Encapsulation with MPLS Data Plane draft-sx-detnet-mpls-queue-00 Abstract This document specifies format and principals for the MPLS header which contains the queuing delay information, designed for use over a DetNet network with MPLS data plane. The guaranteed delay support enables forwarding and scheduling decisions for time-sensitive service running on DetNet transit nodes that operate within a constrained network domain. This document also specifies a representation for the delay field values in such 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 26 December 2022. Copyright Notice Copyright (c) 2022 IETF Trust and the persons identified as the document authors. All rights reserved. Song & Xiong Expires 26 December 2022 [Page 1] Internet-Draft DetNet MPLS Queue June 2022 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 3. DetNet queue encapsulation with MPLS data plane . . . . . . . 3 3.1. Queuing delay . . . . . . . . . . . . . . . . . . . . . . 4 3.2. DetNet MPLS Queue Encapsulation . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References . . . . . . . . . . . . . . . . . . 7 7.2. Informative References . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction As specified in [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 data planes specification refers to [RFC8938]. Based on the updates for DetNet Charter at March, 2022. It is required to support a data plane method of packet treatment including forwarding, service protection, and queuing over Layer 3. As defined in [RFC8964], the DetNet MPLS data plane provides a foundation of building blocks to enable PREOF (Packet Replication, Elimination and Ordering Functions (PREOF)) functions to DetNet service and forwarding sub-layer. The DetNet service sub-layer includes a DetNet Control Word (d-CW) and an identifying service label (S-Label), an aggregation label (A-Label) is a special case of S-Label used for aggregation. The DetNet forwarding sub-layer supports one or more forwarding labels (F-Labels) for providing necessary resource allocation and explicit routes. Song & Xiong Expires 26 December 2022 [Page 2] Internet-Draft DetNet MPLS Queue June 2022 To support time-sensitive service with ultra-low packet loss rates and bounded end-to-end delivery latency, necessary and feasible queuing mechanisms applied to specific applicability on DetNet flows are required. 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. The queuing methodology, mentioned in [I-D.ietf-detnet-bounded-latency] and [RFC8655], describes queuing mechanisms that can be used in packets of control and data plane to achieve DetNet service with bounded latency guarantee. The queuing mechanisms include, time-scheduling queuing mechanisms that include the Time Aware Shaping IEEE802.1Qbv, priority-scheduling queuing mechanisms that include the Credit-Based Shaper IEEE802.1Q-2014 with Asynchronous Traffic Shaping IEEE802.1Qcr, the cyclic-scheduling queuing mechanism proposed in IEEE802.1Qch. This draft uses the queuing mechanisms described in [I-D.ietf-detnet-bounded-latency] as the proof for queuing selection, leverages the existing DetNet MPLS encapsulations and mechanisms [RFC8964], and defines the extensible DetNet MPLS options for queuing support over DetNet flows in the context of MPLS data plane so as to make appropriate packet forwarding and scheduling decisions to achieve the end-to-end bounded latency from customers' SLA requirements. 2. Conventions 2.1. 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. 2.2. Terminology Refer to [RFC8655], [RFC8964], and [I-D.ietf-detnet-bounded-latency] for the key terms used in this document. 3. DetNet queue encapsulation with MPLS data plane Song & Xiong Expires 26 December 2022 [Page 3] Internet-Draft DetNet MPLS Queue June 2022 3.1. Queuing delay [RFC8655] provides the architecture for deterministic networking (DetNet) enables the service delivery of DetNet flows with extremely low packet loss rates and bounded end-to-end latency. The reference for computation and selection for methodology of queuing is described at [I-D.ietf-detnet-bounded-latency]. The end-to-end latency bound for one DetNet flow is the sum of delay bound of non-queuing and queuing processing. The delay bound for non-queuing processing may include output delay, link delay, frame preemption delay, and processing delay, the delay bound for queuing processing may include regulator delay, queuing delay. It is assumed that the delay of non- queuing processing is fixed or be ignorable, the delay of queuing processing is variable. To realize the guarantee of bounded latency service it is important to select right queuing methodology applied to specific applications and carry necessary queuing delay information for computation of end-to-end latency. The DetNet data plane encapsulation in transport network with MPLS data plane is specified in [RFC8964]. This document provides additional encapsulation for the queuing delay of DetNet flows in MPLS data plane. 3.2. DetNet MPLS Queue Encapsulation DetNet MPLS Queue, uses DetNet-MPLS based encapsulation with queuing option extension, listed as the below, +---------------------------+ | DetNet App-Flow | | Payload Packet | +---------------------------+--\ | DetNet Control Word | | +---------------------------+ | | S-Label | | DetNet Data Plane +---------------------------+ | MPLS Encapsulation | F-Label(s) | | +---------------------------+ | | SPL (DetNet Queque) | | +---------------------------+--/ | Data-Link | +---------------------------+ | Physical | +---------------------------+ Figure 1: DetNet queue encapsulation in MPLS data plane Song & Xiong Expires 26 December 2022 [Page 4] Internet-Draft DetNet MPLS Queue June 2022 The SPL (Special Purpose Label) may be B-SPL [RFC9017], new-SPL, extended SPL [RFC9017]. Refer to [I-D.andersson-mpls-mna-fwk], the SPL carries the action indicator for queue support showed as the Figure 2. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label |x x x|S|H|x x x x x x x| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Label: Label value, 20 bits x: Bit available for other solutions definition S: Bottom of Stack, 1 bit H: Indicator of hop-by-hop processing, 1 bit Figure 2: SPL encapsulation for DetNet queuing indicator Generally speaking the queuing mechanisms are processed hop by hop, end-to-end processing for queuing support is FFS. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Flags | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sub-TLV(s) | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type : Type value, TBD, 1 Octet Flags : Identifier for quequing mechanisms, 1 Octet Length : Length value, 2 Octet sub-TLV(s): Specific ququing information carried, 8 Octet Figure 3: Uniform queuing options TLV The Flags field is designed as follow: 0 1 2 3 4 5 6 7 8 +-+-+-+-+-+-+-+-+ |T|P|C| | +-+-+-+-+-+-+-+-+ Figure 4: Flag field Song & Xiong Expires 26 December 2022 [Page 5] Internet-Draft DetNet MPLS Queue June 2022 T flag: 1 bit, time-scheduling queuing indicator, e.g., Time Aware Shaping [IIEEE802.1Qbv]. If the flag is set 1, the time-scheduling queuing mechanism is used for the DetNet flows, the can be correlated with the special label encapsulated in figure 2, or be mapped with F-Label (s) or S-Label showed in figure 1. P Flag: 1 bit, priority-scheduling queuing indicator, e.g., Credit- Based Shaper [IEEE802.1q-2014]. C Flag: 1 bit, cyclic-scheduling queueing indicator, e.g., CQF [IEEE802.1Qch]. Note: For one specific DetNet flow, there is one or more choices for queuing mechanisms selection, the queuing mechanisms can be used respectively or combined with each other. If the flag field is set 1 it will associate its sub-TLV to carry detailed or ancillary data for specific queuing delay information. The encapsulation for sub-TLV is showed below: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Special Queuing Ancillary Data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: Special Queuing options Sub-TLV The encapsulation for queuing delay information will follow the requirements and framework of MPLS MNA discussed in MPLS WG. The encapsulation for Special Queuing Ancillary Data field is specific for queuing mechanisms. E.g., the sub-TLV for queuing scheduling mechanism may carry deadline time data related, refer to [I-D.peng-6man-deadline-option].The sub-TLV for cyclic-scheduling queuing mechanism may carry cycle time related, refer to [I-D.dang-queuing-with-multiple-cyclic-buffers] 4. IANA Considerations This document describes a new IANA-managed registry to identify DetNet MPLS Queue Flags Bits. The registration procedure is "IETF Review" [RFC8126]. The registry name is "DetNet MPLS Queue Flags". There are 4 flags in the 8-bit Flags field, defined as in Table 1. Song & Xiong Expires 26 December 2022 [Page 6] Internet-Draft DetNet MPLS Queue June 2022 +=====+=============+===============+ | Bit | Description | Reference | +=====+=============+===============+ | 0-7 | unassigned | this document | +-----+-------------+---------------+ Table 1: DetNet MPLS Queue Flags 5. Security Considerations Security considerations for DetNet are covered in the DetNet Architecture RFC8655 and DetNet Security Considerations [RFC9055]. MPLS security considerations are covered in [RFC8964], [RFC3031], [RFC3032]. These security considerations also apply to this document. 6. Acknowledgements The authors would like to acknowledge Shaofu Peng for his thorough review and very helpful comments. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, DOI 10.17487/RFC3031, January 2001, . [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001, . [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Song & Xiong Expires 26 December 2022 [Page 7] Internet-Draft DetNet MPLS Queue June 2022 [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, "Deterministic Networking Architecture", RFC 8655, DOI 10.17487/RFC8655, October 2019, . [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, . [RFC9017] Andersson, L., Kompella, K., and A. Farrel, "Special- Purpose Label Terminology", RFC 9017, DOI 10.17487/RFC9017, April 2021, . 7.2. Informative References [I-D.andersson-mpls-mna-fwk] Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS Network Actions Framework", Work in Progress, Internet- Draft, draft-andersson-mpls-mna-fwk-03, 1 June 2022, . [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, 22 February 2021, . [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, 8 April 2022, . [I-D.peng-6man-deadline-option] Peng, S. and B. Tan, "Deadline Option", Work in Progress, Internet-Draft, draft-peng-6man-deadline-option-00, 11 January 2022, . [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, . Song & Xiong Expires 26 December 2022 [Page 8] Internet-Draft DetNet MPLS Queue June 2022 [RFC9055] Grossman, E., Ed., Mizrahi, T., and A. Hacker, "Deterministic Networking (DetNet) Security Considerations", RFC 9055, DOI 10.17487/RFC9055, June 2021, . Authors' Addresses Xueyan Song ZTE Corp. Nanjing China Email: song.xueyan2@zte.com.cn Quan Xiong ZTE Corp. Wuhan China Email: xiong.quan@zte.com.cn Song & Xiong Expires 26 December 2022 [Page 9]