idnits 2.17.1 draft-song-ippm-inband-e2e-rtt-measurement-02.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document doesn't use any RFC 2119 keywords, yet seems to have RFC 2119 boilerplate text. -- The document date (29 November 2021) is 878 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-17) exists of draft-ietf-ippm-ioam-data-16 -- Obsolete informational reference (is this intentional?): RFC 8321 (Obsoleted by RFC 9341) Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IPPM H. Song 3 Internet-Draft D. Linda 4 Intended status: Standards Track Futurewei Technologies 5 Expires: 2 June 2022 29 November 2021 7 In-band Edge-to-Edge Round Trip Time Measurement 8 draft-song-ippm-inband-e2e-rtt-measurement-02 10 Abstract 12 This draft describes a lightweight in-band edge-to-edge flow-based 13 network round trip time measurement architecture and proposes the 14 implementation over IOAM E2E option. By augmenting the IOAM E2E 15 option header, the process can be fully done in data plane without 16 needing to involve the control plane to maintain any states. 18 Requirements Language 20 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 21 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 22 "OPTIONAL" in this document are to be interpreted as described in BCP 23 14 [RFC2119][RFC8174] when, and only when, they appear in all 24 capitals, as shown here. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at https://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on 2 June 2022. 43 Copyright Notice 45 Copyright (c) 2021 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 50 license-info) in effect on the date of publication of this document. 51 Please review these documents carefully, as they describe your rights 52 and restrictions with respect to this document. Code Components 53 extracted from this document must include Revised BSD License text as 54 described in Section 4.e of the Trust Legal Provisions and are 55 provided without warranty as described in the Revised BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 2. In-band E2E RTT Measurement Architecture . . . . . . . . . . 3 61 3. Implementation Considerations . . . . . . . . . . . . . . . . 4 62 4. Security Considerations . . . . . . . . . . . . . . . . . . . 5 63 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 64 6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6 65 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 66 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 67 8.1. Normative References . . . . . . . . . . . . . . . . . . 6 68 8.2. Informative References . . . . . . . . . . . . . . . . . 6 69 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 71 1. Introduction 73 In-network service-based traffic engineering or load balancing needs 74 to monitor particular flows' edge-to-edge performance, such as round 75 trip time (RTT), in the operator's network domain. The host-based 76 ping using ICMPv6 [RFC4443] is of no use because it is usually beyond 77 the access of network operators. The router-based ping, as an active 78 measurement approach, cannot reflect the real performance of the 79 specific flows under scrutiny. This is also true for the other 80 active measurement approaches such as TWAMP [RFC5357]. 82 In-situ OAM (IOAM) [I-D.ietf-ippm-ioam-data] supports in-band flow- 83 based performance measurement. However, on the one hand, the IOAM 84 trace option can be too heavy for applications which do not care 85 about the per-hop performance; on the other hand, the IOAM E2E option 86 only supports the one-way measurement. 88 Alternate Marking(AM) [RFC8321], mainly designed for one-way 89 measurement, can be used to measure the two-way edge-to-edge delay if 90 both edges initiate a one-way measurement session. However, AM's 91 measurement interval needs to be large enough to avoid the 92 measurement ambiguity, and it requires both edges to conduct the 93 measurements and export results to a controller. 95 We need a lightweight in-band flow RTT measurement method. 96 "Lightweight" means the extra header overhead is low, and the extra 97 network processing overhead is also low. A network operator should 98 be able to pick a flow to monitor and get find-grained per-packet RTT 99 measurement for edge to edge. Moreover, the method should be 100 stateless and does not need a control plane to maintain sessions. 101 Depending on the application scenario and the network domain scope, 102 the edge can extend to the host, the network interface card (NIC), or 103 the network switch or router. To this end, we propose an in-band 104 edge-to-edge flow RTT measurement method and the implementation 105 approaches. 107 Such measurement only reflects the network delay for a flow but 108 excludes the application layer delay incurred by server or client. 110 2. In-band E2E RTT Measurement Architecture 112 The measurement architecture is shown in Figure 1. The controller, 113 either on a remote machine or on the edge node's control plane, 114 configures the ingress edge node to measure some flow's RTT between 115 the ingress edge and the egress edge. The ingress edge node uses ACL 116 to filter the flow packets and, at given interval or probability, add 117 the timestamp and the other metadata to the selected packets. The 118 egress edge, after capturing the data, either piggyback the data on a 119 reverse flow packet, or generate a feedback packet carrying the data 120 back to the ingress edge node. Once the ingress edge node receives 121 the feedback data, it sends the data along with the current timestamp 122 to the controller. The controller can then calculate the flow RTT 123 and react with followup actions. 125 The RTT calculation can be done in the slow path (e.g., in the 126 controller), the metadata incurs only small and fix header overhead, 127 and the nodes in the domain does not do any processing. All these 128 make the measurement lightweight, accurate, and have little impact to 129 the network forwarding performance. 131 +------+ 132 | | 133 |Ctrl. | 134 | | 135 +-+----+ 136 | ^ 137 Config. | | Export 138 V | 139 +------+ +----+-+ Forwarding +------+ +------+ 140 | | pkt. | +-----......------>| | pkt. | | 141 |Client+----->| Edge | | Edge +----->|Server| 142 | | | |<----......-------+ | | | 143 +------+ +------+ Feedback +------+ +------+ 145 |<-- Operator Network Domain -->| 147 Figure 1: In-band E2E RTT Measurement 149 To differentiate a feedback packet from an original packet, a flag 150 needs to be raised in the feedback. Optionally, to correlate a 151 feedback with its original packet, the original packet can also 152 include an identifier (e.g., a sequence number) which the feedback 153 packet will carry back as well. The ingress edge node can use the 154 reverse flow ID plus the identifier to pair an original packet with 155 its feedback. 157 The feedback can also include some other local data at the egress 158 edge (e.g., the egress edge node ID or the egress flow statistics) 159 other than simply reflecting the original data back. 161 3. Implementation Considerations 163 One approach to implement the in-band E2E RTT measurement is to use 164 the IOAM E2E option augmented with the feedback mechanism. Current 165 IOAM E2E option only sends one-way data from one edge to the other 166 edge. The data fields can include the ingress edge timestamp which 167 is exactly what is needed. Moreover, the data fields can also 168 include a packet sequence number used for correlating the feedback 169 packet with the original packet. However, current IOAM E2E option 170 lacks a feedback mechanism. It has no flag field reserved in its 171 current option header specification, so it is not easy to indicate 172 the feedback packets. 174 To enable the two-way measurement behavior, we need to add some 175 indicator to the IOAM E2E option header to indicate the request for a 176 feedback. We also need another indicator to tell if the current 177 packet is a feedback. 179 To support this, we can either introduce another IOAM two-way E2E 180 option while keeping the current IOAM E2E option unchanged, or simply 181 modify the current IOAM E2E option header specification to extend its 182 usage. The simplest modification is to reserve a few flag bits and 183 among them, two bits are used for the two-way measurement. One 184 possible layout is shown in Figure 2. Alternatively, the flags can 185 take several bits from the Namespace-ID field. 187 0 1 2 3 188 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 1 189 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 190 | Namespace-ID | Flags | IOAM-E2E-Type | 191 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 192 | | 193 | E2E Option data field determined by IOAM-E2E-Type | 194 | | 195 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 197 Figure 2: Modified IOAM E2E Option Header 199 The data field can carry the timestamp, the sequence number, of a 200 unique packet identifier number. Other data types can also be 201 carried to enrich the feedback information. 203 A packet can serve as both a forward packet and a feedback packet 204 when both flags are set. In this case, there are two records for 205 each data type in the data field. The forward packet's data are 206 located in front of the feedback packet's data. 208 4. Security Considerations 210 To prevent the timestamp to be maliciously altered during the packet 211 forwarding, the ingress edge can instead keep the timestamp locally 212 and only send a packet identifier (e.g., a random data). When a 213 reverse flow packet carrying the same identifier is received, the 214 current timestamp along with the saved timestamp are forwarded to the 215 controller. 217 The ingress edge node can limit the frequency of measurement to the 218 flow packets. The egress edge node can also rate limit the feedback. 219 So the potential DoS attack can be mitigated. 221 5. IANA Considerations 223 Depending on the discussion output, either a registry for a new IOAM 224 option is required or a modification to the current IOAM E2E option 225 specification is needed. 227 6. Contributors 229 TBD. 231 7. Acknowledgments 233 TBD. 235 8. References 237 8.1. Normative References 239 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 240 Requirement Levels", BCP 14, RFC 2119, 241 DOI 10.17487/RFC2119, March 1997, 242 . 244 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 245 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 246 May 2017, . 248 8.2. Informative References 250 [I-D.ietf-ippm-ioam-data] 251 Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields 252 for In-situ OAM", Work in Progress, Internet-Draft, draft- 253 ietf-ippm-ioam-data-16, 8 November 2021, 254 . 257 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 258 Control Message Protocol (ICMPv6) for the Internet 259 Protocol Version 6 (IPv6) Specification", STD 89, 260 RFC 4443, DOI 10.17487/RFC4443, March 2006, 261 . 263 [RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. 264 Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", 265 RFC 5357, DOI 10.17487/RFC5357, October 2008, 266 . 268 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 269 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 270 "Alternate-Marking Method for Passive and Hybrid 271 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 272 January 2018, . 274 Authors' Addresses 276 Haoyu Song 277 Futurewei Technologies 278 Santa Clara, 279 United States of America 281 Email: haoyu.song@futurewei.com 283 Linda Dunbar 284 Futurewei Technologies 285 Plano, 286 United States of America 288 Email: linda.dunbar@futurewei.com