Happy Eyeballs Extension for ICE
draft-reddy-mmusic-ice-happy-eyeballs-03
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Tirumaleswar Reddy.K , Prashanth Patil , Dan Wing | ||
| Last updated | 2013-10-08 | ||
| Replaced by | draft-martinsen-mmusic-ice-dualstack-fairness | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-reddy-mmusic-ice-happy-eyeballs-03
MMUSIC T. Reddy
Internet-Draft P. Patil
Intended status: Standards Track D. Wing
Expires: April 11, 2014 Cisco
October 08, 2013
Happy Eyeballs Extension for ICE
draft-reddy-mmusic-ice-happy-eyeballs-03
Abstract
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.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 11, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
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
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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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 2
3. Candidate Priority . . . . . . . . . . . . . . . . . . . . . 3
4. Algorithm overview . . . . . . . . . . . . . . . . . . . . . 3
4.1. Processing the Results . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
In situations where there are many IPv6 addresses, ICE [RFC5245] will
prefer IPv6 candidates [RFC6724] 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.
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.
2. Notational Conventions
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 [RFC2119].
This note uses terminology defined in [RFC5245].
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3. Candidate Priority
By using the technique described in Section 4, 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.
Even if an administrator changes the policy table to prefer IPv4
addresses over IPv6 addresses as explained in [RFC6724], 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
[RFC5245]) 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.
4. Algorithm overview
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 [RFC5245]:
a. 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.
b. Step (a) is repeated for subsequent candidates in the list until
all candidates of the preferred address family are exhausted.
The algorithm ensures that a long sequence of candidates belonging to
the same address family is interleaved with candidates from an
alternative IP version.
The following figure illustrates the result of the algorithm on
candidates:
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
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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
4.1. Processing the Results
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.
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.
Alice Bob
| |
| |
| Bind Req USE-CAND Bind Req |
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| 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 |
|<===========================================================>|
Figure 1: Happy Eyeballs Extension for ICE
5. IANA Considerations
None.
6. Security Considerations
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 [RFC5245] apply to this
use.
7. Acknowledgements
Authors would like to thank Bernard Aboba, Martin Thomson, Jonathan
Lennox, Pal Martinsen for their comments and review.
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8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3484] Draves, R., "Default Address Selection for Internet
Protocol version 6 (IPv6)", RFC 3484, February 2003.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245, April
2010.
[RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
"Session Traversal Utilities for NAT (STUN)", RFC 5389,
October 2008.
[RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using
Relays around NAT (TURN): Relay Extensions to Session
Traversal Utilities for NAT (STUN)", RFC 5766, April 2010.
[RFC6336] Westerlund, M. and C. Perkins, "IANA Registry for
Interactive Connectivity Establishment (ICE) Options", RFC
6336, July 2011.
[RFC6724] Thaler, D., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, September 2012.
8.2. Informative References
[I-D.keranen-mmusic-ice-address-selection]
Keraenen, A. and J. Arkko, "Update on Candidate Address
Selection for Interactive Connectivity Establishment
(ICE)", draft-keranen-mmusic-ice-address-selection-01
(work in progress), July 2012.
[RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address
Translator (NAT) Terminology and Considerations", RFC
2663, August 1999.
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Authors' Addresses
Tirumaleswar Reddy
Cisco Systems, Inc.
Cessna Business Park, Varthur Hobli
Sarjapur Marathalli Outer Ring Road
Bangalore, Karnataka 560103
India
Email: tireddy@cisco.com
Prashanth Patil
Cisco Systems, Inc.
Bangalore
India
Email: praspati@cisco.com
Dan Wing
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134
USA
Email: dwing@cisco.com
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