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(The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document date (July 14, 2013) is 3938 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) ** Downref: Normative reference to an Informational RFC: RFC 4594 Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group S. Dhesikan 3 Internet-Draft Cisco 4 Intended status: Standards Track D. Druta, Ed. 5 Expires: January 15, 2014 ATT 6 P. Jones 7 J. Polk 8 Cisco 9 July 14, 2013 11 DSCP and other packet markings for RTCWeb QoS 12 draft-dhesikan-tsvwg-rtcweb-qos-02 14 Abstract 16 Many networks, such as service provider and enterprise networks, can 17 provide per packet treatments based on Differentiated Services Code 18 Points (DSCP) on a per hop basis. This document provides the 19 recommended DSCP values for browsers to use for various classes of 20 traffic. 22 Status of This Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at http://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on January 15, 2014. 39 Copyright Notice 41 Copyright (c) 2013 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 57 2. Relation to Other Standards . . . . . . . . . . . . . . . . . 3 58 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 59 4. Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 60 5. DSCP Mappings . . . . . . . . . . . . . . . . . . . . . . . . 4 61 6. QCI Mapping . . . . . . . . . . . . . . . . . . . . . . . . . 4 62 7. WiFI Mapping . . . . . . . . . . . . . . . . . . . . . . . . 5 63 8. W3C API Implications . . . . . . . . . . . . . . . . . . . . 6 64 9. Security Considerations . . . . . . . . . . . . . . . . . . . 6 65 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 66 11. Downward References . . . . . . . . . . . . . . . . . . . . . 6 67 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 68 13. Document History . . . . . . . . . . . . . . . . . . . . . . 6 69 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 70 14.1. Normative References . . . . . . . . . . . . . . . . . . 7 71 14.2. Informative References . . . . . . . . . . . . . . . . . 7 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 74 1. Introduction 76 Differentiated Services Code Points (DSCP)[RFC2474] style packet 77 marking can help provide QoS in some environments. There are many 78 use cases where such marking does not help, but it seldom makes 79 things worse if packets are marked appropriately. In other words, 80 when attempting to avoid congestion by marking certain traffic flows, 81 say all audio or all audio and video, causes the marking of too many 82 audio and/or video flows for a given network's capacity, then it can 83 prevent desirable results. Either too much other traffic will be 84 starved, or there is not enough capacity for the preferentially 85 marked packets (i.e., audio and/or video). 87 This draft proposes how a browser and other VoIP applications can 88 mark packets. This draft does not contradict or redefine any advice 89 from previous IETF RFCs but simply provides a simple set of 90 recommendations for implementors based on the previous RFCs. 92 There are some environments where priority markings frequently help. 93 These include: 95 1. Private networks (Wide Area). 97 2. If the congested link is the broadband uplink in a Cable or DSL 98 scenario, often residential routers/NAT support preferential 99 treatment based on DSCP. 101 3. If the congested link is a local WiFi network, marking may help. 103 4. In some cellular style deployments, markings may help in cases 104 where the network does not remove them. 106 Traditionally DSCP values have been thought of as being site 107 specific, with each site selecting its own code points for each QoS 108 level. However in the RTCWeb use cases, the browsers need to set 109 them to something when there is no site specific information. This 110 document describes a reasonable default set of DSCP code point values 111 drawn from existing RFCs and common usage. These code points are 112 solely defaults. Future drafts may define mechanisms for site 113 specific mappings to override the values provided in this draft. 115 This draft defines some inputs that the browser can look at to 116 determine how to set the various packet markings and defines the 117 mapping from abstract QoS policies (media type, priority level) to 118 those packet markings. 120 2. Relation to Other Standards 122 This specification does not change or override the advice in any 123 other standards about setting packet markings. It simply provides a 124 non-normative summary of them and provides the context of how they 125 relate into the RTCWeb context. This document also specifies the 126 requirements for the W3C WebRTC API to understand what it needs to 127 control, and how the control splits between things the JavaScript 128 application running in the browser can control and things the browser 129 needs to control. In some cases, such as DSCP where the normative 130 RFC leaves open multiple options to choose from, this clarifies which 131 choice should be used in the RTCWeb context. 133 3. Terminology 135 The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" 136 in this document are to be interpreted as described in [RFC2119]. 138 4. Inputs 140 The following are the inputs that the browser provides to the media 141 engine: 143 o Type of flow: The browser provides this input as it knows if the 144 flow is audio, video, or data. In this specification, both 145 interactive and streaming media are included. They are treated in 146 different categories as their QoS requirements are slightly 147 different. If the type of flow is multiplexed content, then the 148 input is a list of the type of flows that are multiplexed within 149 the single stream. 150 o Session Context: This input provides the session context for the 151 type of flow. For example, the type of flow may be audio. The 152 flow may be part of a VoIP session or an audio/video session. 153 Such session context information helps the media engine and the 154 underlying network to make decisions on how to treat the audio 155 flow which may differ based on the entire session to which the 156 flow belongs. The browser should know this information. 157 o Relative priority: Another input is the relative treatment of the 158 stream within that session. Many applications have multiple video 159 flows and often some are more important than others. JavaScript 160 applications can tell the browser whether a particular media flow 161 is high, medium, or low importance to the application. 163 5. DSCP Mappings 165 Below is a table of DSCP markings for each media type RTCWeb is 166 interested in. These DSCPs for each media type listed are a 167 reasonable default set of code point values taken from [RFC4594]. A 168 web browser SHOULD use these values to mark the appropriate media 169 packets. More information on EF can be found in [RFC3246]. More 170 information on AF can be found in [RFC2597]. 172 +-----------------------+-----------+-----------+-----------+ 173 | Media Type | Low | Medium | High | 174 +-----------------------+-----------+-----------+-----------+ 175 | Audio | 46 (EF) | 46 (EF) | 46 (EF) | 176 | Interactive Video | 38 (AF43) | 36 (AF42) | 34 (AF41) | 177 | Non-Interactive Video | 26 (AF33) | 28 (AF32) | 30 (AF31) | 178 | Data | 8 (CS1) | 0 (BE) | 10 (AF11) | 179 +-----------------------+-----------+-----------+-----------+ 181 Table 1 183 6. QCI Mapping 185 +-----------------------+-----+--------+------+ 186 | Media Type | Low | Medium | High | 187 +-----------------------+-----+--------+------+ 188 | Audio | 1 | 1 | 1 | 189 | Interactive Video | 2 | 2 | 2 | 190 | Non-Interactive Video | 8 | 6 | 4 | 191 | Data | 9 | 9 | 3 | 192 +-----------------------+-----+--------+------+ 193 Table 2 195 This corresponds to the mapping provided in TODO REF which are: QCI 196 values (LTE) 198 +---------+----------+-----+----------------------------------------+ 199 | Value | | | Use | 200 +---------+----------+-----+----------------------------------------+ 201 | 1 | GBR | 2 | Interactive Voice | 202 | 2 | GBR | 4 | Interactive Video | 203 | 3 | GBR | 5 | Non-Interactive Video | 204 | 4 | GBR | 3 | Real Time Gaming | 205 | 5 | Non-BG | R 1 | IMS Signaling | 206 | 6 | Non-BG | R 7 | interactive Voice, video, games | 207 | 7-9 | Non-BG | R 6 | non interactive video / TCP web, | 208 | | | | email, / Platinum vs gold user | 209 +---------+----------+-----+----------------------------------------+ 211 Table 3 213 7. WiFI Mapping 215 +-----------------------+-----+--------+------+ 216 | Media Type | Low | Medium | High | 217 +-----------------------+-----+--------+------+ 218 | Audio | 6 | 6 | 6 | 219 | Interactive Video | 5 | 5 | 5 | 220 | Non-Interactive Video | 4 | 4 | 4 | 221 | Data | 1 | 0 | 3 | 222 +-----------------------+-----+--------+------+ 224 Table 4 226 This corresponds to the mappings from TODO REF of 228 +---------+----+------------------+----------------+----------------+ 229 | Value | | Traffic Type | Access | Designation | 230 | | | | Category (AC) | | 231 +---------+----+------------------+----------------+----------------+ 232 | 1 | BK | Background | AC_BK | Background | 233 | 2 | - | (spare) | AC_BK | Background | 234 | 0 | BE | Best Effort | AC_BE | Best Effort | 235 | 3 | EE | Excellent Effort | AC_BE | Best Effort | 236 | 4 | CL | Controlled Load | AC_VI | Video | 237 | 5 | VI | Video | AC_VI | Video | 238 | 6 | VO | Voice | AC_VO | Voice | 239 | 7 | NC | Network Control | AC_VO | Voice | 240 +---------+----+------------------+----------------+----------------+ 241 Table 5 243 8. W3C API Implications 245 To work with this proposal, the W3C specification SHOULD provide a 246 way to specify the importance of media and data streams. 248 The W3C API SHOULD also provide a way for the application to find out 249 the source and destination IP and ports of any flow as well as the 250 DSCP value or other markings in use for that flow. The JavaScript 251 application can then communicate this to a web service that may 252 install a particular policy for that flow. 254 The W3C API SHOULD NOT provide a way for the JavaScript to 255 arbitrarily set the marking to any value of the JavaScript choosing 256 as this reduces the security provided by the browser knowing the 257 media type. 259 9. Security Considerations 261 This draft does not add any additional security implication other 262 than the normal application use of DSCP. For security implications 263 on use of DSCP, please refer to Section 6 of RFC 4594 . Please also 264 see work-in-progress draft draft-ietf-rtcweb-security-04 as an 265 additional reference. 267 10. IANA Considerations 269 This specification does not require any actions from IANA. 271 11. Downward References 273 This specification contains a downwards reference to [RFC4594] 274 however the parts of that RFC used by this specificaiton are 275 sufficiently stable for this donward reference. 277 12. Acknowledgements 279 Cullen Jennings was one of the authors of this text in the original 280 individual submission but was unceremoniously kicked off by the 281 chairs when it became a WG version. Thanks for hints on code to do 282 this from Paolo Severini, Jim Hasselbrook, Joe Marcus, and Erik 283 Nordmark. 285 13. Document History 287 Note to RFC Editor: Please remove this section. 289 This document was originally an individual submission in RTCWeb WG. 290 The RTCWeb working group selected it to be become a WG document. 291 Later the transport ADs requested that this be moved to the TSVWG WG 292 as that seemed to be a better match. This document is now being 293 submitted as individual submission to the TSVWG with the hope that WG 294 will select it as a WG draft and move it forward to an RFC. 296 14. References 298 14.1. Normative References 300 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 301 Requirement Levels", BCP 14, RFC 2119, March 1997. 303 [RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration 304 Guidelines for DiffServ Service Classes", RFC 4594, August 305 2006. 307 14.2. Informative References 309 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 310 "Definition of the Differentiated Services Field (DS 311 Field) in the IPv4 and IPv6 Headers", RFC 2474, December 312 1998. 314 [RFC2597] Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski, 315 "Assured Forwarding PHB Group", RFC 2597, June 1999. 317 [RFC3246] Davie, B., Charny, A., Bennet, J., Benson, K., Le Boudec, 318 J., Courtney, W., Davari, S., Firoiu, V., and D. 319 Stiliadis, "An Expedited Forwarding PHB (Per-Hop 320 Behavior)", RFC 3246, March 2002. 322 Authors' Addresses 324 Subha Dhesikan 325 Cisco 327 Email: sdhesika@cisco.com 329 Dan Druta (editor) 330 ATT 332 Email: dd5826@att.com 333 Paul Jones 334 Cisco 336 Email: paulej@packetizer.com 338 James Polk 339 Cisco 341 Email: jmpolk@cisco.com