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Tan 4 Intended status: Standards Track ZTE Corporation 5 Expires: July 15, 2022 January 11, 2022 7 Deadline Option 8 draft-peng-6man-deadline-option-00 10 Abstract 12 This document introduces new IPv6 options for Hop-by-Hop Options 13 header, to carry deadline related information for deterministic 14 flows. 16 Status of This Memo 18 This Internet-Draft is submitted in full conformance with the 19 provisions of BCP 78 and BCP 79. 21 Internet-Drafts are working documents of the Internet Engineering 22 Task Force (IETF). Note that other groups may also distribute 23 working documents as Internet-Drafts. The list of current Internet- 24 Drafts is at https://datatracker.ietf.org/drafts/current/. 26 Internet-Drafts are draft documents valid for a maximum of six months 27 and may be updated, replaced, or obsoleted by other documents at any 28 time. It is inappropriate to use Internet-Drafts as reference 29 material or to cite them other than as "work in progress." 31 This Internet-Draft will expire on July 15, 2022. 33 Copyright Notice 35 Copyright (c) 2022 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents 40 (https://trustee.ietf.org/license-info) in effect on the date of 41 publication of this document. Please review these documents 42 carefully, as they describe your rights and restrictions with respect 43 to this document. Code Components extracted from this document must 44 include Simplified BSD License text as described in Section 4.e of 45 the Trust Legal Provisions and are provided without warranty as 46 described in the Simplified BSD License. 48 Table of Contents 50 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 51 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 52 2. Deadline Option . . . . . . . . . . . . . . . . . . . . . . . 3 53 3. Encapsulation of Deadline Options On Ingress Node . . . . . . 4 54 4. Operations of Deadline Options On Transit Node . . . . . . . 5 55 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 56 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 57 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 58 8. Normative References . . . . . . . . . . . . . . . . . . . . 6 59 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 61 1. Introduction 63 [RFC8655] describes the architecture of deterministic network and 64 defines the QoS goals of deterministic forwarding: Minimum and 65 maximum end-to-end latency from source to destination, timely 66 delivery, and bounded jitter (packet delay variation); packet loss 67 ratio under various assumptions as to the operational states of the 68 nodes and links; an upper bound on out-of-order packet delivery. In 69 order to achieve these goals, deterministic networks use resource 70 reservation, explicit routing, service protection and other means. 71 In general, a deterministic path is a strictly explicit path 72 calculated by a centralized controller, and resources are reserved on 73 the nodes along the path to meet the SLA requirements of 74 deterministic services. 76 [I-D.peng-detnet-deadline-based-forwarding] describes a deadline 77 based forwarding mechanism to get bounded latency and jitter. A 78 single or multiple planned deadline offset time, as well as dynamic 79 delay budget adjustment, are used to control the packets scheduling 80 of all nodes along the path. The offset time is based on the time 81 when the packet enters the node and represents the maximum time 82 allowed for the packet to stay inside the node. 84 This document introduces new IPv6 options for Hop-by-Hop Options 85 header, to carry deadline related information for deterministic 86 flows. 88 1.1. Requirements Language 90 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 91 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 92 "OPTIONAL" in this document are to be interpreted as described in BCP 93 14 [RFC2119] [RFC8174] when, and only when, they appear in all 94 capitals, as shown here. 96 2. Deadline Option 98 [I-D.peng-detnet-deadline-based-forwarding] describes the following 99 deadline related informatin that can be carried in packets. 101 Planned deadline. 103 Existing accumulated planned deadline 105 Existing accumulated actual dwell time 107 Existing accumulated deadline deviation 109 The planned deadline of the packet is an offset time, i.e., a delay 110 budget allowed for the packet to stay inside the local node. 112 The existing accumulated planned deadline of the packet refers to the 113 sum of the planned deadline of all upstream nodes before the packet 114 is transmitted to this node. 116 The existing accumulated actual dwell time of the packet, refers to 117 the sum of the actual dwell time of all upstream nodes before the 118 packet is transmitted to this node. 120 The existing accumulated deadline deviation equals existing 121 accumulated planned deadline minus existing accumulated actual dwell 122 time. This value can be positive or negative. 124 The deadline option has the following format: 126 0 1 2 3 127 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 1 128 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 | Option Type | Opt Data Len | 130 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 131 | Flags |D| Planned Deadline | 132 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 133 | Accumulated Planned Deadline / Accumulated Deadline Deviation | 134 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 135 | Accumulated Actual Dwell Time / Reserved | 136 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 138 Figure 1: Deadline Option Format 140 Option Type: 8-bit identifier of the type of option. Value TBD by 141 IANA; the highest-order 3 bits of thie field is 001 to skip over this 142 option and continue processing the header if the processing IPv6 node 143 does not recognize the Option Type and to permit the Option Data to 144 be changed en route to the packet's final destination. 146 Opt Data Len: 8-bit unsigned integer. Length of the Option Data 147 field of this option, in octets. It is set to 12. 149 Flags: 8-bit flags. Currently D-flag is defined. If D-flag is 0, 150 the "Accumulated Planned Deadline / Accumulated Deadline Deviation" 151 field contains Accumulated Planned Deadline information, and 152 "Accumulated Actual Dwell Time / Reserved" contains Accumulated 153 Actual Dwell Time information, otherwise these fields contain 154 Accumulated Deadline Deviation and Reserved, respectively. 156 Planned Deadline: 24-bit unsigned integer, represents the delay 157 budget allowed for the packet to stay inside the received node. A 158 single planned deadline is used for each node along the path. For 159 multiple planned deadlines case, it is defined in future. 161 Accumulated Planned Deadline: 32-bit unsigned integer, represents the 162 sum of the planned deadline of all upstream nodes before the packet 163 is transmitted to the received node. 165 Accumulated Deadline Deviation: 32-bit signed integer, represents the 166 sum of the deviation between delay budget and actual dwell time of 167 all upstream nodes before the packet is transmitted to the received 168 node. 170 Accumulated Actual Dwell Time: 32-bit unsigned integer, represents 171 the sum of the actual dwell time of all upstream nodes before the 172 packet is transmitted to the received node. 174 Reserved: 32-bit unused. 176 3. Encapsulation of Deadline Options On Ingress Node 178 The ingress PE node, when encapsulating the deterministic service 179 flow, can explicitly insert the deadline option into the packet 180 according to SLA. 182 For a deterministic delay path based on deadline queue scheduling, 183 the path it passes through has deterministic end-to-end delay 184 requirements. It includes two parts, one is the accumulated node 185 delay and the other is the accumulated link transmission delay. The 186 end-to-end delay requirement is subtracted from the accumulated link 187 transmission delay to obtain the accumulated node delay. A simple 188 method is that the accumulated node delay is shared equally by each 189 intermediate node along the path to obtain the planning deadline of 190 each node. 192 Suppose that the planned deadline is D, the actual dwell time is R, 193 then the packet sent by the ingress PE may have one of the following 194 deadline option information: 196 D-flag is set to 0; Planned Deadline is set to D; Accumulated 197 Planned Deadline is set to D; Accumulated Actual Dwell Time is set 198 to R. 200 D-flag is set to 1; Planned Deadline is set to D; Accumulated 201 Deadline Deviation is set to D minus R; 203 4. Operations of Deadline Options On Transit Node 205 The intermediate node, after receiving the packet, can obtain the 206 planned deadline from the packet as the delay budget of this node. 207 It need get the existing accumulated deadline deviation, and then add 208 it to the planned deadline of this node, to obtain the deadline 209 adjustment value, and then on the basis of the deadline adjustment 210 value, deducting the forwarding delay of the packet in the node, the 211 allowable queuing delay value is obtained, and then the packet will 212 be put to the deadline queue with TTL as the above allowable queuing 213 delay value for sending. See 214 [I-D.peng-detnet-deadline-based-forwarding] for more details. 216 If D-flag of the received packet is set to 0, the existing 217 accumulated deadline deviation is the value of the Accumulated 218 Planned Deadline field minus the value of the Accumulated Actual 219 Dwell Time field. 221 If D-flag of the received packet is set to 1, the existing 222 accumulated deadline deviation is directly get from the Accumulated 223 Deadline Deviation field. 225 When the intermediate node continues to send the packet to the 226 downstream node, it need update the Accumulated Planned Deadline 227 field and the Accumulated Actual Dwell Time field, or the Accumulated 228 Deadline Deviation field. Note that field Planned Deadline remains 229 unchanged. 231 For the update of field Accumulated Planned Deadline, it can add the 232 planned deadline of this node to this field. 234 For the update of field Accumulated Actual Dwell Time, it can add the 235 actual dwell time of this node to this field. A possible method to 236 get the actual dwell time in the node is that, the receiving and 237 sending time of the packet can be recorded in the auxiliary data 238 structure (note that is not packet itself) of the packet, then the 239 actual dwell time of the packet in the node can be calculated 240 according to these two times. 242 For the update of field Accumulated Deadline Deviation, it can add 243 the difference of the planned deadline and the actual dwell time to 244 this field. 246 5. IANA Considerations 248 This document updates the "Destination Options and Hop-by-Hop 249 Options" under the "Internet Protocol Version 6 (IPv6) Parameters" 250 registry: 252 +---------+-----+-----+------+-------------------+-------------+ 253 |Hex Value| act | chg | rest | Description | Reference | 254 +---------+-----+-----+------+-------------------+-------------+ 255 | TBD | 00 | 1 |00000 | Deadline Option |This document| 256 +---------+-----+-----+------+-------------------+-------------+ 258 6. Security Considerations 260 TBD 262 7. Acknowledgements 264 TBD 266 8. Normative References 268 [I-D.peng-detnet-deadline-based-forwarding] 269 Peng, S. and B. Tan, "Deadline Based Deterministic 270 Forwarding", draft-peng-detnet-deadline-based- 271 forwarding-00 (work in progress), January 2022. 273 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 274 Requirement Levels", BCP 14, RFC 2119, 275 DOI 10.17487/RFC2119, March 1997, 276 . 278 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 279 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 280 May 2017, . 282 [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, 283 "Deterministic Networking Architecture", RFC 8655, 284 DOI 10.17487/RFC8655, October 2019, 285 . 287 Authors' Addresses 289 Shaofu Peng 290 ZTE Corporation 291 China 293 Email: peng.shaofu@zte.com.cn 295 Bin Tan 296 ZTE Corporation 297 China 299 Email: tan.bin@zte.com.cn