One document matched: draft-reddy-mmusic-ice-happy-eyeballs-03.xml
<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
<?rfc toc="yes"?>
<?rfc tocompact="yes"?>
<?rfc tocdepth="3"?>
<?rfc tocindent="yes"?>
<?rfc symrefs="yes"?>
<?rfc sortrefs="yes"?>
<?rfc comments="yes"?>
<?rfc inline="yes"?>
<?rfc compact="yes"?>
<?rfc subcompact="no"?>
<rfc category="std" docName="draft-reddy-mmusic-ice-happy-eyeballs-03"
ipr="trust200902">
<front>
<title abbrev="Happy Eyeballs for ICE ">Happy Eyeballs Extension for
ICE</title>
<author fullname="Tirumaleswar Reddy" initials="T." surname="Reddy">
<organization abbrev="Cisco">Cisco Systems, Inc.</organization>
<address>
<postal>
<street>Cessna Business Park, Varthur Hobli</street>
<street>Sarjapur Marathalli Outer Ring Road</street>
<city>Bangalore</city>
<region>Karnataka</region>
<code>560103</code>
<country>India</country>
</postal>
<email>tireddy@cisco.com</email>
</address>
</author>
<author fullname="Prashanth Patil" initials="P." surname="Patil">
<organization abbrev="Cisco">Cisco Systems, Inc.</organization>
<address>
<postal>
<street></street>
<city>Bangalore</city>
<country>India</country>
</postal>
<email>praspati@cisco.com</email>
</address>
</author>
<author fullname="Dan Wing" initials="D." surname="Wing">
<organization abbrev="Cisco">Cisco Systems, Inc.</organization>
<address>
<postal>
<street>170 West Tasman Drive</street>
<city>San Jose</city>
<region>California</region>
<code>95134</code>
<country>USA</country>
</postal>
<email>dwing@cisco.com</email>
</address>
</author>
<date />
<workgroup>MMUSIC</workgroup>
<abstract>
<t>This document describes an algorithm that makes Interactive
Connectivity Establishment (ICE) connectivity checks more responsive by
reducing delays in dual-stack host ICE connectivity checks when there is
a path failure for an address family preferred by the application or by
the operating system. As IPv6 is usually preferred over IPv4, the
procedures in this document helps avoid user-noticeable delays when the
IPv6 path is broken or excessively slow.</t>
</abstract>
</front>
<middle>
<section anchor="introduction" title="Introduction">
<t>In situations where there are many IPv6 addresses, <xref
target="RFC5245">ICE</xref> will prefer IPv6 candidates <xref
target="RFC6724"></xref> and will attempt connectivity checks on all the
IPv6 candidates before trying an IPv4 candidate. If the IPv6 path is
broken, this fallback to IPv4 can consume a lot of time, harming user
satisfaction of dual-stack devices. This causes ICE to perform terribly
in cases where IPv6 doesn't work, which is still very commonplace. This
document recommends an alternative prioritization for candidates that
improves this situation with a goal that the ICE agent not be
inordinately harmed by a simple reordering of the candidates.</t>
<t>This document describes an algorithm that makes ICE connectivity
checks more responsive to failures of an address family by reordering
the candidates such that IPv6 and IPv4 candidates get a fair chance
during connectivity checks. This algorithm change is backward compatible
with existing implementations, and does not require any changes other
than to the selection of candidate priority.</t>
</section>
<section anchor="notation" title="Notational Conventions">
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref
target="RFC2119"></xref>.</t>
<t>This note uses terminology defined in <xref
target="RFC5245"></xref>.</t>
</section>
<section anchor="problem_stmt" title="Candidate Priority">
<t>By using the technique described in <xref
target="alg_overview"></xref>, if there are both IPv6 and IPv4 addresses
candidates gathered, and the first 'N' candidates are of the same IP
address family, then the highest-priority candidate of the other address
family is promoted to position 'N+1' in the check list thus making ICE
connectivity checks more responsive to failures of an address family.
The algorithm ensures that there are no more than a fixed number of
candidates of a given IP version in a single sequence.</t>
<t>Even if an administrator changes the policy table to prefer IPv4
addresses over IPv6 addresses as explained in <xref
target="RFC6724"></xref>, the IPv4 server-reflexive candidates will
still have lower priority than IPv6 host candidates as per the
"Recommended Formula" (section 4.1.2.1 of <xref
target="RFC5245"></xref>) which is not desired. The Happy Eyeballs
extension for ICE algorithm resolves the problem in this scenario as
well by ensuring that IPv4 server-reflexive candidates are placed before
IPv6 host candidates and thus ordering based on candidate types is no
longer in effect.</t>
</section>
<section anchor="alg_overview" title="Algorithm overview">
<t>The Happy Eyeballs Extension for ICE algorithm proposes the following
steps after candidates are prioritized using the formula in section
4.1.2.1 of <xref target="RFC5245"></xref>:</t>
<t><list style="letters">
<t>If the first 'N' candidates are of the same IP address family,
then the highest-priority candidate of the other address family is
promoted to position 'N+1' in the list.</t>
<t>Step (a) is repeated for subsequent candidates in the list until
all candidates of the preferred address family are exhausted.</t>
</list></t>
<t>The algorithm ensures that a long sequence of candidates belonging to
the same address family is interleaved with candidates from an
alternative IP version.</t>
<t>The following figure illustrates the result of the algorithm on
candidates:</t>
<t><figure>
<artwork><![CDATA[Before Happy Eyeballs Extension for ICE algorithm :
----------------------------------------------------
(highest) IPv6 Host Candidate-1
IPv6 Host Candidate-2
IPv6 Host Candidate-3
IPv6 Host Candidate-4
IPv6 Host Candidate-5
IPv6 Host Candidate-6
IPv6 Host Candidate-7
IPv4 Host Candidate
IPv6 Server Reflexive Candidate
IPv4 Server Reflexive Candidate
IPv6 Relayed Transport Candidate
(lowest) IPv4 Relayed Transport Candidate
After Happy Eyeballs Extension for ICE algorithm :
--------------------------------------------------
(highest) IPv6 Host Candidate-1
IPv6 Host Candidate-2
IPv6 Host Candidate-3
IPv4 Host Candidate ---> Promoted candidate
IPv6 Host Candidate-4
IPv6 Host Candidate-5
IPv6 Host Candidate-6
IPv4 Server Reflexive Candidate ---> Promoted candidate
IPv6 Host Candidate-7
IPv6 Server Reflexive Candidate
IPv6 Relayed Transport Candidate
(lowest) IPv4 Relayed Transport Candidate]]></artwork>
</figure></t>
<section anchor="result" title="Processing the Results">
<t>If ICE connectivity checks using an IPv4 candidate is successful
for each component of the media stream and connectivity checks using
IPv6 candidates is not yet successful, the ICE endpoint will declare
victory, conclude ICE for the media stream and start sending media
using IPv4. However, it is also possible that ICE endpoint continues
to perform ICE connectivity checks with IPv6 candidate pairs and if
checks using higher-priority IPv6 candidate pair is successful then
media stream can be moved to the IPv6 candidate pair. Continuing to
perform connectivity checks can be useful for subsequent connections,
to optimize which connectivity checks are tried first. Such
optimizations are out of scope of this document.</t>
<t>The following diagram shows the behaviour during the connectivity
check when Alice calls Bob and Agent Alice is the controlling agent
and uses the aggressive nomination algorithm. "USE-CAND" implies the
presence of the USE-CANDIDATE attribute.</t>
<figure anchor="Figure2" title="Happy Eyeballs Extension for ICE">
<artwork align="left"><![CDATA[ Alice Bob
| |
| |
| Bind Req USE-CAND Bind Req |
| using IPv6 using IPv6 |
|------------------>X X<-----------------------|
| Bind Req USE-CAND Bind Req |
| using IPv6 after Ta using IPv6 |
|------------------>X X<-----------------------|
| |
[after connectivity checks for 2 IPv6 addresses, try IPv4] |
| |
| Bind Req USE-CAND |
| using IPv4 |
|------------------------------------------------------------>|
| Bind Resp |
| using IPv4 |
|<----------------------------------------------------------- |
| RTP |
|============================================================>|
| Bind Req |
| using IPv4 |
|<------------------------------------------------------------|
| Bind Response |
| using IPv4 |
|------------------------------------------------------------>|
| RTP |
|<===========================================================>|
]]></artwork>
</figure>
</section>
</section>
<section title="IANA Considerations">
<t>None.</t>
</section>
<section anchor="security" title="Security Considerations">
<t>STUN connectivity check using MAC computed during key exchanged in
the signaling channel provides message integrity and data origin
authentication as described in section 2.5 of <xref
target="RFC5245"></xref> apply to this use.</t>
</section>
<section anchor="ack" title="Acknowledgements">
<t>Authors would like to thank Bernard Aboba, Martin Thomson, Jonathan
Lennox, Pal Martinsen for their comments and review.</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include="reference.RFC.2119"?>
<?rfc include="reference.RFC.3484"?>
<?rfc include="reference.RFC.5766"?>
<?rfc include="reference.RFC.5245"?>
<?rfc include="reference.RFC.5389"?>
<?rfc include="reference.RFC.4566"?>
<?rfc include="reference.RFC.6724"?>
<?rfc include="reference.RFC.4566"
?>
<?rfc include="reference.RFC.6336"?>
</references>
<references title="Informative References">
<?rfc include='reference.RFC.2663'
?>
<?rfc include='reference.I-D.keranen-mmusic-ice-address-selection'?>
<!---->
</references>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-24 01:42:19 |