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draft-martinsen-mmusic-ice-dualstack-fairness
MMUSIC T. Reddy
Internet-Draft P. Patil
Intended status: Standards Track P. Martinsen
Expires: June 12, 2014 Cisco
December 09, 2013
Happy Eyeballs Extension for ICE
draft-reddy-mmusic-ice-happy-eyeballs-04
Abstract
This document provides guidelines on how to make ICE [RFC5245]
conclude faster in IPv4/IPv6 dual-stack scenarios where broken paths
exists.
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
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 June 12, 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 2
2. Improving ICE Dual-stack Fairness . . . . . . . . . . . . . . 2
3. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 3
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3
7. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
There is a need to introduce more fairness in the handling of
connectivity checks in dual-stack IPv4/IPv6 ICE scenarios.
Section 4.1.2.1 of ICE [RFC5245] points to [RFC3484] for prioritizing
among the different IP families. [RFC3484] is obsoleted by [RFC6724]
but following the recommendations from the updated RFC will still
lead to prioritization of IPv6 over IPv4 with the same candidate
type. There can be a lot of ICE candidates belonging to one address
family which results in user-noticable setup delays if the path for
that address family is broken.
To avoid such user-noticable delays when the IPv6 path or IPv4 path
is broken, this specification encourages earlier checking of the
other address family. Greater IP address family fairness into ICE
connectivity checks will lead to more sustained IPv6 deployment (so
users will no longer have an incentive to disable IPv6), which incurs
only a small penalty for the IPv4 connectivity checks.
1.1. 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 document uses terminology defined in [RFC5245].
2. Improving ICE Dual-stack Fairness
Candidates SHOULD be prioritized such that a long sequence of
candidates belonging to the same address family be interleaved with
candidates from the alternate IP family. For example, promoting IPv4
candidates in the presence of many IPv6 addresses such that an IPv4
address candidate is always present after a small sequence of IPv6
addresses. This makes ICE connectivity checks more responsive to
failures of an address family by reordering the candidates such that
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IPv6 and IPv4 candidates get a fair chance during connectivity
checks.
An ICE agent can choose an algorithm or a technique of its choice to
promote IPv4 candidates.
3. Compatibility
ICE [RFC5245] section 4.1.2 states that the formula in section
4.1.2.1 SHOULD be used. Failing to do so may lead to ICE taking
longer to converge as the checklist no longer will be coordinated.
Therefore responsiveness of ICE candidate checks are improved when
both sides support Happy-Eyeballs, both sides have the same number of
candidate pairs, and both sides use the same Happy Eyeballs promotion
algorithm.
If each ICE agent uses a different algorithm to promote IPv4
candidates, ICE connectivity checks will be as responsive as the
least aggressive algorithm. This is because the MAX/MIN candiate-
pair logic ensures that for a particular agent, a lower-priority
candidate is never used (for media) until all higher-priority
candidates have been tried.
If only one ICE agent supports Happy-Eyeballs, there is potentially
no change in pacing of ICE connectivity checks and the situation is
no worse than what exists today
4. IANA Considerations
None.
5. 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.
6. Acknowledgements
Authors would like to thank Dan Wing, Ari Keranen, Bernard Aboba,
Martin Thomson and Jonathan Lennox for their comments and review.
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7. 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.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245, April
2010.
[RFC6724] Thaler, D., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, September 2012.
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.
Cessna Business Park, Varthur Hobli
Sarjapur Marathalli Outer Ring Road
Bangalore
India
Email: praspati@cisco.com
Paal-Erik Martinsen
Cisco Systems, Inc.
Philip Pedersens vei 22
Lysaker, Akershus 1325
Norway
Email: palmarti@cisco.com
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