Network Shaofu. Peng Internet-Draft Bin. Tan Intended status: Standards Track ZTE Corporation Expires: January 12, 2023 Peng. Liu China Mobile July 11, 2022 Deadline Option draft-peng-6man-deadline-option-01 Abstract This document introduces new IPv6 options for Hop-by-Hop Options header, to carry deadline related information for deterministic flows. 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 January 12, 2023. Copyright Notice Copyright (c) 2022 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 Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Peng, et al. Expires January 12, 2023 [Page 1] Internet-Draft Deadline Options July 2022 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. Deadline Option . . . . . . . . . . . . . . . . . . . . . . . 3 3. Encapsulation of Deadline Options On Ingress Node . . . . . . 4 4. Operations of Deadline Options On Transit Node . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 8. Normative References . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction [RFC8655] describes the architecture of deterministic network and defines the QoS goals of deterministic forwarding: Minimum and maximum end-to-end latency from source to destination, timely delivery, and bounded jitter (packet delay variation); packet loss ratio under various assumptions as to the operational states of the nodes and links; an upper bound on out-of-order packet delivery. In order to achieve these goals, deterministic networks use resource reservation, explicit routing, service protection and other means. In general, a deterministic path is a strictly explicit path calculated by a centralized controller, and resources are reserved on the nodes along the path to meet the SLA requirements of deterministic services. [I-D.peng-detnet-deadline-based-forwarding] describes a deadline based forwarding mechanism to get bounded latency and jitter. A single or multiple planned deadline offset time, as well as dynamic delay budget adjustment, are used to control the packets scheduling of all nodes along the path. The offset time is based on the time when the packet enters the node and represents the maximum time allowed for the packet to stay inside the node. This document introduces new IPv6 options for Hop-by-Hop Options header, to carry deadline related information for deterministic flows. 1.1. 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. Peng, et al. Expires January 12, 2023 [Page 2] Internet-Draft Deadline Options July 2022 2. Deadline Option [I-D.peng-detnet-deadline-based-forwarding] describes the following deadline related informatin that can be carried in packets. Planned deadline. Existing accumulated planned deadline Existing accumulated actual residence time Existing accumulated deadline deviation The planned deadline of the packet is an offset time, i.e., a delay budget allowed for the packet to stay inside the local node. The existing accumulated planned deadline of the packet refers to the sum of the planned deadline of all upstream nodes before the packet is transmitted to this node. The existing accumulated actual residence time of the packet, refers to the sum of the actual residence time of all upstream nodes before the packet is transmitted to this node. The existing accumulated deadline deviation equals existing accumulated planned deadline minus existing accumulated actual residence time. This value can be positive or negative. The deadline option has the following format: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Opt Data Len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags |M|D| Planned Deadline | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Accumulated Planned Deadline / Accumulated Deadline Deviation | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Accumulated Actual Residence Time / Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Deadline Option Format Option Type: 8-bit identifier of the type of option. Value TBD by IANA; the highest-order 3 bits of thie field is 001 to skip over this option and continue processing the header if the processing IPv6 node Peng, et al. Expires January 12, 2023 [Page 3] Internet-Draft Deadline Options July 2022 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. Flags: 8-bit flags. Currently two flags are defined. D-Flag: if D-flag is 0, the "Accumulated Planned Deadline / Accumulated Deadline Deviation" field contains Accumulated Planned Deadline information, and "Accumulated Actual Residence Time / Reserved" contains Accumulated Actual Residence Time information, otherwise these fields contain Accumulated Deadline Deviation and Reserved, respectively. M-Flag: if M-flag is 0, the packet will apply in-time mode, otherwise apply on-time mode. For more description of the forwarding mode, please refer to [I-D.peng-detnet-deadline-based-forwarding]. Planned Deadline: 24-bit unsigned integer, represents the delay budget allowed for the packet to stay inside the received node. A single planned deadline is used for each node along the path. For multiple planned deadlines case, it is defined in future. Accumulated Planned Deadline: 32-bit unsigned integer, represents the sum of the planned deadline of all upstream nodes before the packet is transmitted to the received node. Accumulated Deadline Deviation: 32-bit signed integer, represents the sum of the deviation between delay budget and actual residence time of all upstream nodes before the packet is transmitted to the received node. Accumulated Actual Residence Time: 32-bit unsigned integer, represents the sum of the actual residence time of all upstream nodes before the packet is transmitted to the received node. Reserved: 32-bit unused. 3. Encapsulation of Deadline Options On Ingress Node The ingress PE node, when encapsulating the deterministic service flow, can explicitly insert the deadline option into the packet according to SLA. For a deterministic delay path based on deadline queue scheduling, the path it passes through has deterministic end-to-end delay Peng, et al. Expires January 12, 2023 [Page 4] Internet-Draft Deadline Options July 2022 requirements. It includes two parts, one is the accumulated node delay and the other is the accumulated link propagation delay. The end-to-end delay requirement is subtracted from the accumulated link propagation delay to obtain the accumulated node delay. A simple method is that the accumulated node delay is shared equally by each intermediate node along the path to obtain the planning deadline of each node. Suppose that the planned deadline is D, the actual residence time is R, then the packet sent by the ingress PE may have one of the following deadline option information: D-flag is set to 0; Planned Deadline is set to D; Accumulated Planned Deadline is set to D; Accumulated Actual Residence Time is set to R. D-flag is set to 1; Planned Deadline is set to D; Accumulated Deadline Deviation is set to D minus R; For in-time service, the M-flag is set to 0, and for on-time service, the M-flag is set to 1. 4. Operations of Deadline Options On Transit Node The intermediate node, after receiving the packet, can obtain the planned deadline from the packet as the delay budget of this node. It need get the existing accumulated deadline deviation, and then add it to the planned deadline of this node, to obtain the deadline adjustment value, and then on the basis of the deadline adjustment value, deducting the forwarding delay of the packet in the node, the allowable queuing delay value is obtained, and then the packet will be put to the deadline queue with TTL as the above allowable queuing delay value for sending. If M-flag is 0, the packet will be put to in-time queue, otherwise, it is put to on-time queue. See [I-D.peng-detnet-deadline-based-forwarding] for more details. If D-flag of the received packet is set to 0, the existing accumulated deadline deviation is the value of the Accumulated Planned Deadline field minus the value of the Accumulated Actual Residence Time field. If D-flag of the received packet is set to 1, the existing accumulated deadline deviation is directly get from the Accumulated Deadline Deviation field. When the intermediate node continues to send the packet to the downstream node, it need update the Accumulated Planned Deadline field and the Accumulated Actual Residence Time field, or the Peng, et al. Expires January 12, 2023 [Page 5] Internet-Draft Deadline Options July 2022 Accumulated Deadline Deviation field. Note that field Planned Deadline remains unchanged. For the update of field Accumulated Planned Deadline, it can add the planned deadline of this node to this field. For the update of field Accumulated Actual Residence Time, it can add the actual residence time of this node to this field. A possible method to get the actual residence time in the node is that, the receiving and sending time of the packet can be recorded in the auxiliary data structure (note that is not packet itself) of the packet, then the actual residence time of the packet in the node can be calculated according to these two times. For the update of field Accumulated Deadline Deviation, it can add the difference of the planned deadline and the actual residence time to this field. 5. IANA Considerations This document updates the "Destination Options and Hop-by-Hop Options" under the "Internet Protocol Version 6 (IPv6) Parameters" registry: +---------+-----+-----+------+-------------------+-------------+ |Hex Value| act | chg | rest | Description | Reference | +---------+-----+-----+------+-------------------+-------------+ | TBD | 00 | 1 |00000 | Deadline Option |This document| +---------+-----+-----+------+-------------------+-------------+ 6. Security Considerations TBD 7. Acknowledgements TBD 8. Normative References [I-D.peng-detnet-deadline-based-forwarding] Peng, S., Tan, B., and P. Liu, "Deadline Based Deterministic Forwarding", draft-peng-detnet-deadline- based-forwarding-02 (work in progress), July 2022. Peng, et al. Expires January 12, 2023 [Page 6] Internet-Draft Deadline Options July 2022 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, "Deterministic Networking Architecture", RFC 8655, DOI 10.17487/RFC8655, October 2019, . Authors' Addresses Shaofu Peng ZTE Corporation China Email: peng.shaofu@zte.com.cn Bin Tan ZTE Corporation China Email: tan.bin@zte.com.cn Peng Liu China Mobile China Email: liupengyjy@chinamobile.com Peng, et al. Expires January 12, 2023 [Page 7]