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Versions: 00 draft-ietf-rtcweb-qos

Network Working Group                                        S. Dhesikan
Internet-Draft                                                     Cisco
Intended status: Standards Track                                D. Druta
Expires: January 10, 2013                                            ATT
                                                             C. Jennings
                                                                P. Jones
                                                                 J. Polk
                                                                   Cisco
                                                            July 9, 2012


             DSCP and other packet markings for RTCWeb QoS
                      draft-jennings-rtcweb-qos-00

Abstract

   Many networks, such as Service Provider and Enterprise networks, can
   provide per packet treatments based on Differentiated Services Code
   Points (DSCP) on a per hop basis.  This document defines the
   recommended DSCP values for browsers to use for various classes of
   traffic.

   This draft is a very early and far from done.  It is meant to provide
   the structure for the idea of how to do this but much discussion is
   needed about the details.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.  This document may not be modified,
   and derivative works of it may not be created, and it may not be
   published except as an Internet-Draft.

   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 http://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 10, 2013.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the



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   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://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.


1.  Introduction

   DiffServ style packet marking can help provide QoS in some
   environments.  There are many use cases where such marking does not
   help, but it seldom make things worse, if packets are marked
   appropriately.  In other words, when attempting to avoid congestion
   by marking certain traffic flows, say all audio or all audio and
   video, marking too many audio and/or video flows for a given
   network's capacity can prevent desirable results.  Either too much
   other traffic will be starved, or there is not enough capacity for
   the preferentially marked packets (i.e., audio and/or video).

   This draft proposes how browser and other VoIP applications can mark
   packets.  This draft does not contradict or redefine any advice from
   previous IETF RFCs but simply provides a simple set of
   recommendations for implementors based on the previous RFCs.

   There are some environments where priority markings frequently help.
   These include:

   1.  If the congested link is the broadband uplink in a Cable or DSL
   scenario, often residential routers/NAT support preferential
   treatment based on DSCP.

   2.  If the congested link is a local WiFi network, marking may help.

   3.  In some some cellular style deployments, markings may help in
   cases where the network does not remove them.

   Traditionally DSCP values have been thought of as being site
   specific, with each site selecting its own code points for each QoS
   level.  However in the RTCWeb use cases, the browsers need to set
   them to something when there is no site specific information.  This
   document describes a reasonable default set of DSCP code point values
   drawn from existing RFCs and common usage.  These code points are



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   solely defaults.  Future drafts may define mechanisms for site
   specific mappings to override the values provided in this draft.

   This draft defines some inputs that the browser can look at to
   determine how to set the various packet markings and defines the a
   mapping from abstract QoS policies (media type, priority level) to
   those packet markings.


2.  Terminology

   TODO - add the boiler plate


3.  Inputs

   The first input is the type of the media.  The browser provides this
   input as it knows if the media is audio, video, or data.  In this
   specification, both interactive and streaming media is included.
   They are treated in different categories as their QoS requirements
   are slightly different.  The second input is the relative treatment
   of the stream within that session.  Many applications have multiple
   video streams and often some are more important than others.
   Javascript applications can tell the browser whether a particular
   media stream is high, medium, or low importance to the application.


4.  DSCP Mappings

       +-----------------------+-----------+-----------+-----------+
       |                       |    Low    |   Medium  |    High   |
       +-----------------------+-----------+-----------+-----------+
       | Audio                 |  46 (EF)  |  46 (EF)  |  46 (EF)  |
       | Interactive Video     | 38 (AF43) | 36 (AF42) | 34 (AF41) |
       | Non-Interactive Video | 26 (AF33) | 28 (AF32) | 30 (AF31) |
       | Data                  |  8 (CS1)  |   0 (BE)  | 10 (AF11) |
       +-----------------------+-----------+-----------+-----------+

                                  Table 1












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5.  QCI Mapping

              +-----------------------+-----+--------+------+
              |                       | Low | Medium | High |
              +-----------------------+-----+--------+------+
              | Audio                 |  1  |    1   |   1  |
              | Interactive Video     |  2  |    2   |   2  |
              | Non-Interactive Video |  8  |    6   |   4  |
              | Data                  |  9  |    9   |   3  |
              +-----------------------+-----+--------+------+

                                  Table 2

   This corresponds to the mapping provided in TODO REF which are: QCI
   values (LTE)

   +-------+--------+-----+--------------------------------------------+
   | Value |        |     |                     Use                    |
   +-------+--------+-----+--------------------------------------------+
   | 1     |   GBR  |  2  |              Interactive Voice             |
   | 2     |   GBR  |  4  |              Interactive Video             |
   | 3     |   GBR  |  5  |            Non-Interactive Video           |
   | 4     |   GBR  |  3  |              Real Time Gaming              |
   | 5     | Non-BG | R 1 |               IMS Signalling               |
   | 6     | Non-BG | R 7 |       interactive Voice, video, games      |
   | 7-9   | Non-BG | R 6 |  non interactive video / TCP web, email, / |
   |       |        |     |            Platinum vs gold user           |
   +-------+--------+-----+--------------------------------------------+

                                  Table 3


6.  WiFI Mapping

              +-----------------------+-----+--------+------+
              |                       | Low | Medium | High |
              +-----------------------+-----+--------+------+
              | Audio                 |  6  |    6   |   6  |
              | Interactive Video     |  5  |    5   |   5  |
              | Non-Interactive Video |  4  |    4   |   4  |
              | Data                  |  1  |    0   |   3  |
              +-----------------------+-----+--------+------+

                                  Table 4

   This corresponds to the mappings from TODO REF of





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   +-------+----+------------------+---------------------+-------------+
   | Value |    |   Traffic Type   |   Access Category   | Designation |
   |       |    |                  |         (AC)        |             |
   +-------+----+------------------+---------------------+-------------+
   | 1     | BK |    Background    |        AC_BK        |  Background |
   | 2     |  - |      (spare)     |        AC_BK        |  Background |
   | 0     | BE |    Best Effort   |        AC_BE        | Best Effort |
   | 3     | EE | Excellent Effort |        AC_BE        | Best Effort |
   | 4     | CL |  Controlled Loat |        AC_VI        |    Video    |
   | 5     | VI |       Video      |        AC_VI        |    Video    |
   | 6     | VO |       Voice      |        AC_VO        |    Voice    |
   | 7     | NC |  Network Control |        AC_VO        |    Voice    |
   +-------+----+------------------+---------------------+-------------+

                                  Table 5


7.  W3C API Implications

   To work with this proposal, the W3C specification would need to
   provide a way to specify the importance of media and data streams.

   The W3C API should also provide a way for the application to find out
   the source and destination IP and ports of any flow as well as the
   DSCP value or other markings in use for that flow.  The JS
   application can then communicate this to a web service that may
   install a particular policy for that flow.


8.  Security Considerations

   TODO - discuss implications of what browser can set and what JS can
   set


9.  IANA Considerations

   This specification does not require any actions from IANA.


10.  Acknowledgements

   Thanks for hints on code to do this from Paolo Severini, Jim
   Hasselbrook, Joe Marcus, and Erik Nordmark.







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11.  Appendix: Code Hints

   On windows setting the source interface works but BSD, OSX, Linux use
   weak end-system model and will route out different interface if that
   looks like a better route.  (TODO - Can someone verify this with
   specific versions?)

   In windows you might be able to tell something about priority of an
   interface for ICE purposes with WlanQueryInterface or GetIfTable.

   The specific mechanisms required to set DSCP code points depend on
   the application platform.

   In windows, setting the DSCP is not easy.  See Knowledge Base Article
   KB248611.  TODO - add more information about what can be done for
   windows.

   For most unix variants, the following program can set DSCP.

   TODO - make this work in V6.  For v6 have a look at IPv6_TCLASS or
   better the tclass part of sin6_flowid for IPv6

   TODO - Can someone test and report back results of program in iOS,
   Android, Linux, OSX, BSD.

   Example test program:

 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 #include <errno.h>
 #include <unistd.h>


 #define MSG "Hello, World!"


 int
 main(void) {
    int sock = -1;
    struct sockaddr *local_addr = NULL;
    struct sockaddr_in sockin, host;
    int tos = 0x60; /* CS3 */



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    socklen_t socksiz = 0;
    char *buffer = NULL;

    sock = socket(AF_INET, SOCK_DGRAM, 0);
    if (sock < 0) {
       fprintf(stderr,"Error: %s\n", strerror(errno));
       exit(-1);
    }

    memset(&sockin, 0, sizeof(sockin));
    sockin.sin_family = PF_INET;
    sockin.sin_addr.s_addr = inet_addr("11.1.1.1");
    socksiz = sizeof(sockin);

    local_addr = (struct sockaddr *) &sockin;

    /* Set ToS/DSCP */
    if (setsockopt(sock, IPPROTO_IP, IP_TOS,  &tos,
                   sizeof(tos)) < 0) {
       fprintf(stderr,"Error setting TOS: %s\n", strerror(errno));
    }

    /* Bind to a specific local address */
    if (bind(sock, local_addr, socksiz) < 0) {
       fprintf(stderr,"Error binding to socket: %s\n", strerror(errno));
       close(sock); sock=-1;
       exit(-1);
    }

    buffer = (char *) malloc(strlen(MSG) + 1);
    if ( buffer == NULL ) {
       fprintf(stderr,"Error allocating memory: %s\n", strerror(errno));
       close( sock ); sock=-1;
       exit(-1);
    }
    strlcpy(buffer, MSG, strlen(MSG) + 1);
    memset(&host, 0, sizeof(host));
    host.sin_family = PF_INET;
    host.sin_addr.s_addr = inet_addr("10.1.1.1");
    host.sin_port = htons(12345);

    if (sendto(sock, buffer, strlen(buffer), 0,
               (struct sockaddr *) &host, sizeof(host)) < 0) {
       fprintf(stderr,"Error sending message: %s\n", strerror(errno));
       close(sock); sock=-1;
       free(buffer); buffer=NULL;
       exit(-1);
    }



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    free(buffer); buffer=NULL;
    close(sock); sock=-1;

    return 0;
 }



12.  Normative References

   [1]  Babiarz, J., Chan, K., and F. Baker, "Configuration Guidelines
        for DiffServ Service Classes", RFC 4594, August 2006.

   [2]  Davie, B., Charny, A., Bennet, J., Benson, K., Le Boudec, J.,
        Courtney, W., Davari, S., Firoiu, V., and D. Stiliadis, "An
        Expedited Forwarding PHB (Per-Hop Behavior)", RFC 3246,
        March 2002.

   [3]  Nichols, K., Blake, S., Baker, F., and D. Black, "Definition of
        the Differentiated Services Field (DS Field) in the IPv4 and
        IPv6 Headers", RFC 2474, December 1998.

   [4]  Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski, "Assured
        Forwarding PHB Group", RFC 2597, June 1999.

   [5]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
        Levels", BCP 14, RFC 2119, March 1997.


Authors' Addresses

   Subha Dhesikan
   Cisco

   Email: sdhesika@cisco.com


   Dan Druta
   ATT

   Email: dd5826@att.com


   Cullen Jennings
   Cisco

   Email: fluffy@cisco.com




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   Paul Jones
   Cisco

   Email: paulej@packetizer.com


   James Polk
   Cisco

   Email: jmpolk@cisco.com









































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