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Bhandari 4 Intended status: Standards Track V. Govindan 5 Expires: December 29, 2018 C. Pignataro 6 Cisco 7 H. Gredler 8 RtBrick Inc. 9 J. Leddy 10 Comcast 11 S. Youell 12 JMPC 13 T. Mizrahi 14 Marvell 15 P. Lapukhov 16 Facebook 17 B. Gafni 18 A. Kfir 19 Mellanox Technologies, Inc. 20 M. Spiegel 21 Barefoot Networks 22 June 27, 2018 24 Geneve encapsulation for In-situ OAM Data 25 draft-brockners-ippm-ioam-geneve-01 27 Abstract 29 In-situ Operations, Administration, and Maintenance (IOAM) records 30 operational and telemetry information in the packet while the packet 31 traverses a path between two points in the network. This document 32 outlines how IOAM data fields are encapsulated in Geneve. 34 Status of This Memo 36 This Internet-Draft is submitted in full conformance with the 37 provisions of BCP 78 and BCP 79. 39 Internet-Drafts are working documents of the Internet Engineering 40 Task Force (IETF). Note that other groups may also distribute 41 working documents as Internet-Drafts. The list of current Internet- 42 Drafts is at http://datatracker.ietf.org/drafts/current/. 44 Internet-Drafts are draft documents valid for a maximum of six months 45 and may be updated, replaced, or obsoleted by other documents at any 46 time. It is inappropriate to use Internet-Drafts as reference 47 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on December 29, 2018. 50 Copyright Notice 52 Copyright (c) 2018 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (http://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 68 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 69 2.1. Requirement Language . . . . . . . . . . . . . . . . . . 3 70 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3 71 3. IOAM Data Field Encapsulation in Geneve . . . . . . . . . . . 3 72 4. Considerations . . . . . . . . . . . . . . . . . . . . . . . 5 73 4.1. Discussion of the encapsulation approach . . . . . . . . 5 74 4.2. IOAM and the use of the Geneve O-bit . . . . . . . . . . 6 75 4.3. Transit devices . . . . . . . . . . . . . . . . . . . . . 6 76 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 77 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 78 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 79 8. Normative References . . . . . . . . . . . . . . . . . . . . 7 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 82 1. Introduction 84 In-situ OAM (IOAM) records OAM information within the packet while 85 the packet traverses a particular network domain. The term "in-situ" 86 refers to the fact that the IOAM data fields are added to the data 87 packets rather than is being sent within packets specifically 88 dedicated to OAM. This document defines how IOAM data fields are 89 transported as part of the Geneve [I-D.ietf-nvo3-geneve] 90 encapsulation. The IOAM data fields are defined in 91 [I-D.ietf-ippm-ioam-data]. 93 2. Conventions 95 2.1. Requirement Language 97 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 98 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 99 document are to be interpreted as described in [RFC2119]. 101 2.2. Abbreviations 103 Abbreviations used in this document: 105 IOAM: In-situ Operations, Administration, and Maintenance 107 OAM: Operations, Administration, and Maintenance 109 Geneve: Generic Network Virtualization Encapsulation 111 3. IOAM Data Field Encapsulation in Geneve 113 Geneve is defined in [I-D.ietf-nvo3-geneve]. IOAM data fields are 114 carried in the Geneve header as a tunnel option, using a single 115 Geneve Option Class TBD_IOAM. The different IOAM data fields defined 116 in [I-D.ietf-ippm-ioam-data] are added as TLVs using that Geneve 117 Option Class. In an administrative domain where IOAM is used, 118 insertion of the IOAM header in Geneve is enabled at the Geneve 119 tunnel endpoints, which also serve as IOAM encapsulating/ 120 decapsulating nodes by means of configuration. 122 0 1 2 3 123 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 1 124 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+ 125 |Ver| Opt Len |O|C| Rsvd. | Protocol Type | | 126 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Hdr 127 | Virtual Network Identifier (VNI) | Reserved | | 128 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+ 129 | Option Class = TBD_IOAM | Type |R|R|R| Length | | 130 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ I 131 ! | O 132 ! | A 133 ~ IOAM Option and Data Space ~ M 134 | | | 135 | | | 136 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ 137 | | 138 | | 139 | Payload + Padding (L2/L3/ESP/...) | 140 | | 141 | | 142 | | 143 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 145 Figure 1: IOAM data encapsulation in Geneve 147 The Geneve header and fields are defined in [I-D.ietf-nvo3-geneve]. 148 The Geneve Option Class value for use with IOAM is TBD_IOAM. 150 The fields related to the encapsulation of IOAM data fields in Geneve 151 are defined as follows: 153 Option Class: 16-bit unsigned integer that determines the IOAM 154 option class. The value is from the IANA registry setup for 155 Geneve option classes as defined in [I-D.ietf-nvo3-geneve]. 157 Type: 8-bit field defining the IOAM Option type, as defined in 158 Section 7.2 of [I-D.ietf-ippm-ioam-data]. 160 R (3 bits): Option control flags reserved for future use. MUST be 161 zero on transmission and ignored on receipt. 163 Length: 5-bit unsigned integer. Length of the IOAM HDR in 4-octet 164 units. 166 IOAM Option and Data Space: IOAM option header and data is present 167 as defined by the Type field, and is defined in Section 4 of 168 [I-D.ietf-ippm-ioam-data]. 170 Multiple IOAM options MAY be included within the Geneve 171 encapsulation. For example, if a Geneve encapsulation contains two 172 IOAM options before a data payload, there would be two fields with 173 TBD_IOAM Option Class each, differentiated by the Type field which 174 specifies the type of the IOAM data included. 176 4. Considerations 178 This section summarizes a set of considerations on the overall 179 approach taken for IOAM data encapsulation in Geneve, as well as 180 deployment considerations. 182 4.1. Discussion of the encapsulation approach 184 This section is to support the working group discussion in selecting 185 the most appropriate approach for encapsulating IOAM data fields in 186 Geneve. 188 An encapsulation of IOAM data fields in Geneve should be friendly to 189 an implementation in both hardware as well as software forwarders and 190 support a wide range of deployment cases, including large networks 191 that desire to leverage multiple IOAM data fields at the same time. 193 Hardware and software friendly implementation: Hardware forwarders 194 benefit from an encapsulation that minimizes iterative look-ups of 195 fields within the packet: Any operation which looks up the value 196 of a field within the packet, based on which another lookup is 197 performed, consumes additional gates and time in an implementation 198 - both of which are desired to be kept to a minimum. This means 199 that flat TLV structures are to be preferred over nested TLV 200 structures. IOAM data fields are grouped into three option 201 categories: Trace, proof-of-transit, and edge-to-edge. Each of 202 these three options defines a TLV structure. A hardware-friendly 203 encapsulation approach avoids grouping these three option 204 categories into yet another TLV structure, but would rather carry 205 the options as a serial sequence. 207 Total length of the IOAM data fields: The total length of IOAM 208 data can grow quite large in case multiple different IOAM data 209 fields are used and large path-lengths need to be considered. If 210 for example an operator would consider using the IOAM trace option 211 and capture node-id, app_data, egress/ingress interface-id, 212 timestamp seconds, timestamps nanoseconds at every hop, then a 213 total of 20 octets would be added to the packet at every hop. In 214 case this particular deployment would have a maximum path length 215 of 15 hops in the IOAM domain, then a maximum of 300 octets of 216 IOAM data were to be encapsulated in the packet. 218 Concerns with the current encapsulation approach: 220 Hardware support: Using Geneve tunnel options to encapsulate IOAM 221 data fields leads to a nested TLV structure. Each IOAM data field 222 option (trace, proof-of-transit, and edge-to-edge) represents a 223 type, with the different IOAM data fields being TLVs within this 224 the particular option type. Nested TLVs require iterative look- 225 ups, a fact that creates potential challenges for implementations 226 in hardware. It would be desirable to offer a way to encapsulate 227 IOAM in a way that keeps TLV nesting to a minimum. 229 Length: Geneve tunnel option length is a 5-bit field in the 230 current specification [I-D.ietf-nvo3-geneve] resulting in a 231 maximum option length of 128 (2^5 x 4) octets which constrains the 232 use of IOAM to either small domains or a few IOAM data fields 233 only. Support for large domains with a variety of IOAM data 234 fields would be desirable. 236 4.2. IOAM and the use of the Geneve O-bit 238 [I-D.ietf-nvo3-geneve] defines an "O bit" for OAM packets. Per 239 [I-D.ietf-nvo3-geneve] the O bit indicates that the packet contains a 240 control message instead of data payload. Packets that carry IOAM 241 data fields in addition to regular data payload / customer traffic 242 must not set the O bit. Packets that carry only IOAM data fields 243 without any payload must set the O bit. 245 4.3. Transit devices 247 If IOAM is deployed in domains where UDP port numbers are not 248 controlled and do not have a domain-wide meaning, such as on the 249 global Internet, transit devices MUST NOT attempt to modify the IOAM 250 data contained in the IOAM option class. In case UDP port numbers 251 are not controlled there might be UDP packets, which leverage the UDP 252 port number that Geneve utilizes, i.e. 6081, but the payload of these 253 packets isn't Geneve. The scenario and associated reasoning is 254 discussed in [RFC7605] which states that "it is important to 255 recognize that any interpretation of port numbers -- except at the 256 endpoints -- may be incorrect, because port numbers are meaningful 257 only at the endpoints." 259 5. IANA Considerations 261 IANA is requested to allocate a Geneve "option class" numbers for 262 IOAM: 264 +---------------+-------------+---------------+ 265 | Option Class | Description | Reference | 266 +---------------+-------------+---------------+ 267 | x | TBD_IOAM | This document | 268 +---------------+-------------+---------------+ 270 6. Security Considerations 272 The security considerations of Geneve are discussed in 273 [I-D.ietf-nvo3-geneve], and the security considerations of IOAM in 274 general are discussed in [I-D.ietf-ippm-ioam-data]. 276 IOAM is considered a "per domain" feature, where one or several 277 operators decide on leveraging and configuring IOAM according to 278 their needs. Still, operators need to properly secure the IOAM 279 domain to avoid malicious configuration and use, which could include 280 injecting malicious IOAM packets into a domain. 282 7. Acknowledgements 284 The authors would like to thank Eric Vyncke, Nalini Elkins, Srihari 285 Raghavan, Ranganathan T S, Karthik Babu Harichandra Babu, Akshaya 286 Nadahalli, Stefano Previdi, Hemant Singh, Erik Nordmark, LJ Wobker, 287 and Andrew Yourtchenko for the comments and advice. 289 8. Normative References 291 [I-D.ietf-ippm-ioam-data] 292 Brockners, F., Bhandari, S., Pignataro, C., Gredler, H., 293 Leddy, J., Youell, S., Mizrahi, T., Mozes, D., Lapukhov, 294 P., Chang, R., daniel.bernier@bell.ca, d., and J. Lemon, 295 "Data Fields for In-situ OAM", draft-ietf-ippm-ioam- 296 data-02 (work in progress), March 2018. 298 [I-D.ietf-nvo3-geneve] 299 Gross, J., Ganga, I., and T. Sridhar, "Geneve: Generic 300 Network Virtualization Encapsulation", draft-ietf- 301 nvo3-geneve-06 (work in progress), March 2018. 303 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 304 Requirement Levels", BCP 14, RFC 2119, 305 DOI 10.17487/RFC2119, March 1997, . 308 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 309 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 310 DOI 10.17487/RFC2784, March 2000, . 313 [RFC3232] Reynolds, J., Ed., "Assigned Numbers: RFC 1700 is Replaced 314 by an On-line Database", RFC 3232, DOI 10.17487/RFC3232, 315 January 2002, . 317 [RFC7605] Touch, J., "Recommendations on Using Assigned Transport 318 Port Numbers", BCP 165, RFC 7605, DOI 10.17487/RFC7605, 319 August 2015, . 321 Authors' Addresses 323 Frank Brockners 324 Cisco Systems, Inc. 325 Hansaallee 249, 3rd Floor 326 DUESSELDORF, NORDRHEIN-WESTFALEN 40549 327 Germany 329 Email: fbrockne@cisco.com 331 Shwetha Bhandari 332 Cisco Systems, Inc. 333 Cessna Business Park, Sarjapura Marathalli Outer Ring Road 334 Bangalore, KARNATAKA 560 087 335 India 337 Email: shwethab@cisco.com 339 Vengada Prasad Govindan 340 Cisco Systems, Inc. 342 Email: venggovi@cisco.com 344 Carlos Pignataro 345 Cisco Systems, Inc. 346 7200-11 Kit Creek Road 347 Research Triangle Park, NC 27709 348 United States 350 Email: cpignata@cisco.com 351 Hannes Gredler 352 RtBrick Inc. 354 Email: hannes@rtbrick.com 356 John Leddy 357 Comcast 359 Email: John_Leddy@cable.comcast.com 361 Stephen Youell 362 JP Morgan Chase 363 25 Bank Street 364 London E14 5JP 365 United Kingdom 367 Email: stephen.youell@jpmorgan.com 369 Tal Mizrahi 370 Marvell 371 6 Hamada St. 372 Yokneam 20692 373 Israel 375 Email: talmi@marvell.com 377 Petr Lapukhov 378 Facebook 379 1 Hacker Way 380 Menlo Park, CA 94025 381 US 383 Email: petr@fb.com 385 Barak Gafni 386 Mellanox Technologies, Inc. 387 350 Oakmead Parkway, Suite 100 388 Sunnyvale, CA 94085 389 U.S.A. 391 Email: gbarak@mellanox.com 392 Aviv Kfir 393 Mellanox Technologies, Inc. 394 350 Oakmead Parkway, Suite 100 395 Sunnyvale, CA 94085 396 U.S.A. 398 Email: avivk@mellanox.com 400 Mickey Spiegel 401 Barefoot Networks 402 2185 Park Boulevard 403 Palo Alto, CA 94306 404 US 406 Email: mspiegel@barefootnetworks.com