draft-ietf-v6ops-happy-eyeballs-06.txt   draft-ietf-v6ops-happy-eyeballs-07.txt 
v6ops D. Wing v6ops D. Wing
Internet-Draft A. Yourtchenko Internet-Draft A. Yourtchenko
Intended status: Standards Track Cisco Intended status: Standards Track Cisco
Expires: June 10, 2012 December 8, 2011 Expires: June 22, 2012 December 20, 2011
Happy Eyeballs: Success with Dual-Stack Hosts Happy Eyeballs: Success with Dual-Stack Hosts
draft-ietf-v6ops-happy-eyeballs-06 draft-ietf-v6ops-happy-eyeballs-07
Abstract Abstract
When a server's IPv4 path and protocol is working but the server's When a server's IPv4 path and protocol is working but the server's
IPv6 path and protocol are not working, a dual-stack client IPv6 path and protocol are not working, a dual-stack client
application experiences significant connection delay compared to an application experiences significant connection delay compared to an
IPv4-only client. This is undesirable because it causes the dual- IPv4-only client. This is undesirable because it causes the dual-
stack client to have a worse user experience. This document stack client to have a worse user experience. This document
specifies requirements for algorithms that reduce this user-visible specifies requirements for algorithms that reduce this user-visible
delay, and provides an example algorithm. delay, and provides an algorithm.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 10, 2012. This Internet-Draft will expire on June 22, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 13 skipping to change at page 2, line 13
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Additional Network and Host Traffic . . . . . . . . . . . 3 1.1. Additional Network and Host Traffic . . . . . . . . . . . 3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3 3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3.1. URIs and hostnames . . . . . . . . . . . . . . . . . . . . 4 3.1. Hostnames . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Delay When IPv6 is not Accessible . . . . . . . . . . . . 4 3.2. Delay When IPv6 is not Accessible . . . . . . . . . . . . 4
4. Algorithm Requirements . . . . . . . . . . . . . . . . . . . . 5 4. Algorithm Requirements . . . . . . . . . . . . . . . . . . . . 5
4.1. Delay IPv4 . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. Delay IPv4 . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Stateful Behavior when IPv6 Fails . . . . . . . . . . . . 8 4.2. Stateful Behavior when IPv6 Fails . . . . . . . . . . . . 8
4.3. Reset on Network (re-)Initialization . . . . . . . . . . . 9 4.3. Reset on Network (re-)Initialization . . . . . . . . . . . 9
4.4. Abandon Non-Winning Connections . . . . . . . . . . . . . 9 4.4. Abandon Non-Winning Connections . . . . . . . . . . . . . 9
5. Additional Considerations . . . . . . . . . . . . . . . . . . 10 5. Additional Considerations . . . . . . . . . . . . . . . . . . 10
5.1. Determining Address Type . . . . . . . . . . . . . . . . . 10 5.1. Determining Address Type . . . . . . . . . . . . . . . . . 10
5.2. Debugging and Troubleshooting . . . . . . . . . . . . . . 10 5.2. Debugging and Troubleshooting . . . . . . . . . . . . . . 10
5.3. Three or More Interfaces . . . . . . . . . . . . . . . . . 10 5.3. Three or More Interfaces . . . . . . . . . . . . . . . . . 10
5.4. A and AAAA Resource Records . . . . . . . . . . . . . . . 10 5.4. A and AAAA Resource Records . . . . . . . . . . . . . . . 10
5.5. Connection time out . . . . . . . . . . . . . . . . . . . 11 5.5. Connection time out . . . . . . . . . . . . . . . . . . . 11
5.6. Interaction with Same Origin Policy . . . . . . . . . . . 11 5.6. Interaction with Same Origin Policy . . . . . . . . . . . 11
5.7. Happy Eyeballs in an Operating System . . . . . . . . . . 11 5.7. Implementation Strategies . . . . . . . . . . . . . . . . 11
6. Example Algorithm . . . . . . . . . . . . . . . . . . . . . . 12 6. Example Algorithm . . . . . . . . . . . . . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
10.1. Normative References . . . . . . . . . . . . . . . . . . . 13 10.1. Normative References . . . . . . . . . . . . . . . . . . . 13
10.2. Informational References . . . . . . . . . . . . . . . . . 13 10.2. Informational References . . . . . . . . . . . . . . . . . 13
Appendix A. Changes . . . . . . . . . . . . . . . . . . . . . . . 14 Appendix A. Changes . . . . . . . . . . . . . . . . . . . . . . . 15
A.1. changes from -05 to -06 . . . . . . . . . . . . . . . . . 14 A.1. changes from -06 to -07 . . . . . . . . . . . . . . . . . 15
A.2. changes from -04 to -05 . . . . . . . . . . . . . . . . . 15 A.2. changes from -05 to -06 . . . . . . . . . . . . . . . . . 15
A.3. changes from -03 to -04 . . . . . . . . . . . . . . . . . 15 A.3. changes from -04 to -05 . . . . . . . . . . . . . . . . . 15
A.4. changes from -03 to -04 . . . . . . . . . . . . . . . . . 15 A.4. changes from -03 to -04 . . . . . . . . . . . . . . . . . 16
A.5. changes from -02 to -03 . . . . . . . . . . . . . . . . . 15 A.5. changes from -03 to -04 . . . . . . . . . . . . . . . . . 16
A.6. changes from -01 to -02 . . . . . . . . . . . . . . . . . 15 A.6. changes from -02 to -03 . . . . . . . . . . . . . . . . . 16
A.7. changes from -00 to -01 . . . . . . . . . . . . . . . . . 16 A.7. changes from -01 to -02 . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 A.8. changes from -00 to -01 . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
In order to use applications over IPv6, it is necessary that users In order to use applications over IPv6, it is necessary that users
enjoy nearly identical performance as compared to IPv4. A enjoy nearly identical performance as compared to IPv4. A
combination of today's applications, IPv6 tunneling, IPv6 service combination of today's applications, IPv6 tunneling, IPv6 service
providers, and some of today's content providers all cause the user providers, and some of today's content providers all cause the user
experience to suffer (Section 3). For IPv6, a content provider may experience to suffer (Section 3). For IPv6, a content provider may
ensure a positive user experience by using a DNS white list of IPv6 ensure a positive user experience by using a DNS white list of IPv6
service providers who peer directly with them (e.g., [whitelist]). service providers who peer directly with them (e.g., [whitelist]).
skipping to change at page 4, line 20 skipping to change at page 4, line 20
which DNS claims to know an IPng address may in fact not be which DNS claims to know an IPng address may in fact not be
running IPng at a particular moment; thus an IPng packet to that running IPng at a particular moment; thus an IPng packet to that
host will be discarded on delivery. Knowing that a host has both host will be discarded on delivery. Knowing that a host has both
IPv4 and IPng addresses gives no information about black holes. A IPv4 and IPng addresses gives no information about black holes. A
solution to this must be proposed and it must not depend on solution to this must be proposed and it must not depend on
manually maintained information. (If this is not solved, the dual manually maintained information. (If this is not solved, the dual
stack approach is no better than the packet translation stack approach is no better than the packet translation
approach.)" approach.)"
As discussed in more detail in Section 3.1, it is important that the As discussed in more detail in Section 3.1, it is important that the
same URI and hostname be used for IPv4 and IPv6. same hostname be used for IPv4 and IPv6.
As discussed in more detail in Section 3.2, IPv6 connectivity is As discussed in more detail in Section 3.2, IPv6 connectivity is
broken to specific prefixes or specific hosts, or slower than native broken to specific prefixes or specific hosts, or slower than native
IPv4 connectivity. IPv4 connectivity.
The mechanism described in this document is directly applicable to The mechanism described in this document is directly applicable to
connection-oriented transports (e.g., TCP, SCTP), which is the scope connection-oriented transports (e.g., TCP, SCTP), which is the scope
of this document. For connectionless transport protocols (e.g., of this document. For connectionless transport protocols (e.g.,
UDP), a similar mechanism can be used if the application has request/ UDP), a similar mechanism can be used if the application has request/
response semantics (e.g., as done by ICE to select a working IPv6 or response semantics (e.g., as done by ICE to select a working IPv6 or
IPv4 media path [RFC6157]). IPv4 media path [RFC6157]).
3.1. URIs and hostnames 3.1. Hostnames
URIs are often used between users to exchange pointers to content -- Hostnames are often used between users to exchange pointers to
such as on social networks, email, instant messaging, or other content -- such as on social networks, email, instant messaging, or
systems. Using separate namespaces (e.g., "ipv6.example.com") only other systems. Using separate namespaces (e.g., "ipv6.example.com")
accessible with certain technology (e.g., with an IPv6 client and a which are only accessible with certain client technology (e.g., an
working IPv6 path) causes namespace fragmentation and reduces the IPv6 client) and dependencies (e.g., a working IPv6 path) causes
ability for users to share URIs and hostnames, and complicates namespace fragmentation and reduces the ability for users to share
printed material that includes the URI or hostname. hostnames. It also complicates printed material that includes the
hostname.
The algorithm described in this document allows production URIs to The algorithm described in this document allows production hostnames
avoid these problematic references to IPv4 or IPv6. to avoid these problematic references to IPv4 or IPv6.
3.2. Delay When IPv6 is not Accessible 3.2. Delay When IPv6 is not Accessible
When IPv6 connectivity is impaired, today's IPv6-capable applications When IPv6 connectivity is impaired, today's IPv6-capable applications
(e.g., web browsers, email clients, xmpp clients) incur many seconds (e.g., web browsers, email clients, instant messaging clients) incur
of delay before falling back to IPv4. This delays overall many seconds of delay before falling back to IPv4. This delays
application operation, including harming the user's experience with overall application operation, including harming the user's
IPv6, which will slow the acceptance of IPv6, because IPv6 is experience with IPv6, which will slow the acceptance of IPv6, because
frequently disabled in its entirety on the end systems to improve the IPv6 is frequently disabled in its entirety on the end systems to
user experience. improve the user experience.
Reasons for such failure include no connection to the IPv6 Internet, Reasons for such failure include no connection to the IPv6 Internet,
broken 6to4 or Teredo tunnels, and broken IPv6 peering. The broken 6to4 or Teredo tunnels, and broken IPv6 peering. The
following diagram shows this behavior. following diagram shows this behavior.
The algorithm described in this document allows clients to connect to The algorithm described in this document allows clients to connect to
servers without significant delay, even if a path or the server is servers without significant delay, even if a path or the server is
slow or down. slow or down.
DNS Server Client Server DNS Server Client Server
skipping to change at page 6, line 31 skipping to change at page 6, line 31
10. | |==TCP SYN, IPv6===>X | 10. | |==TCP SYN, IPv6===>X |
Figure 2: Happy Eyeballs flow 1, IPv6 broken Figure 2: Happy Eyeballs flow 1, IPv6 broken
In the diagram above, the client sends two TCP SYNs at the same time In the diagram above, the client sends two TCP SYNs at the same time
over IPv6 (6) and IPv4 (7). In the diagram, the IPv6 path is broken over IPv6 (6) and IPv4 (7). In the diagram, the IPv6 path is broken
but has little impact to the user because there is no long delay but has little impact to the user because there is no long delay
before using IPv4. The IPv6 path is retried until the application before using IPv4. The IPv6 path is retried until the application
gives up (10). gives up (10).
After performing the above procedure, the client learns if After performing the above procedure, the client learns whether
connections to the host's IPv6 or IPv4 address was successful. The connections to the host's IPv6 or IPv4 address were successful. The
client MUST cache that information to avoid thrashing the network client MUST cache information regarding the outcome of each
with excessive subsequent connection attempts. For example, in the connection attempt and uses that information to avoid thrashing the
diagram above, the client has noticed that IPv6 to that address network with subsequent attempts. For example, in the example above,
failed, and it should provide a greater preference to using IPv4 the cache indicates that the IPv6 connection attempt failed, and
instead. therefore the system will prefer IPv4 instead. Cache entries should
be flushed when their age exceeds a system defined maximum on the
order of ten minutes.
DNS Server Client Server DNS Server Client Server
| | | | | |
1. |<--www.example.com A?-----| | 1. |<--www.example.com A?-----| |
2. |<--www.example.com AAAA?--| | 2. |<--www.example.com AAAA?--| |
3. |---192.0.2.1------------->| | 3. |---192.0.2.1------------->| |
4. |---2001:db8::1----------->| | 4. |---2001:db8::1----------->| |
5. | | | 5. | | |
6. | |==TCP SYN, IPv6=======>| 6. | |==TCP SYN, IPv6=======>|
7. | |--TCP SYN, IPv4------->| 7. | |--TCP SYN, IPv4------->|
skipping to change at page 9, line 30 skipping to change at page 9, line 30
address family SHOULD be used for subsequent connections. Because address family SHOULD be used for subsequent connections. Because
this implementation is stateful, it MAY track connection success (or this implementation is stateful, it MAY track connection success (or
failure) based on IPv6 or IPv4 prefix (e.g., connections to the same failure) based on IPv6 or IPv4 prefix (e.g., connections to the same
prefix assigned to the interface are successful whereas connections prefix assigned to the interface are successful whereas connections
to other prefixes are failing). to other prefixes are failing).
4.3. Reset on Network (re-)Initialization 4.3. Reset on Network (re-)Initialization
Because every network has different characteristics (e.g., working or Because every network has different characteristics (e.g., working or
broken IPv6 or IPv4 connectivity), a Happy Eyeballs algorithm SHOULD broken IPv6 or IPv4 connectivity), a Happy Eyeballs algorithm SHOULD
re-initialize when the host is connected to a new network. Hosts can re-initialize when the interface is connected to a new network.
determine network (re-)initialization by a variety of mechanisms Interfaces can determine network (re-)initialization by a variety of
(e.g., DNAv4 [RFC4436], DNAv6 [RFC6059]). mechanisms (e.g., DNAv4 [RFC4436], DNAv6 [RFC6059]).
If the client application is a web browser, see also Section 5.6. If the client application is a web browser, see also Section 5.6.
4.4. Abandon Non-Winning Connections 4.4. Abandon Non-Winning Connections
It is RECOMMENDED that the non-winning connections be abandoned, even It is RECOMMENDED that the non-winning connections be abandoned, even
though they could -- in some cases -- be put to reasonable use. though they could -- in some cases -- be put to reasonable use.
Justification: This reduces the load on the server (file Justification: This reduces the load on the server (file
descriptors, TCP control blocks), stateful middleboxes (NAT and descriptors, TCP control blocks), stateful middleboxes (NAT and
skipping to change at page 10, line 29 skipping to change at page 10, line 29
address family. address family.
5.2. Debugging and Troubleshooting 5.2. Debugging and Troubleshooting
This mechanism is aimed at ensuring a reliable user experience This mechanism is aimed at ensuring a reliable user experience
regardless of connectivity problems affecting any single transport. regardless of connectivity problems affecting any single transport.
However, this naturally means that applications employing these However, this naturally means that applications employing these
techniques are by default less useful for diagnosing issues with a techniques are by default less useful for diagnosing issues with a
particular address family. To assist in that regard, the particular address family. To assist in that regard, the
implementations MAY also provide a mechanism to disable their Happy implementations MAY also provide a mechanism to disable their Happy
Eyeballs behavior via a user setting. Eyeballs behavior via a user setting, and to provide data useful for
debugging (e.g., a log or way to review current preferences).
5.3. Three or More Interfaces 5.3. Three or More Interfaces
A dual-stack host normally has two logical interfaces: an IPv6 A dual-stack host normally has two logical interfaces: an IPv6
interface and an IPv4 interface. However, a dual-stack host might interface and an IPv4 interface. However, a dual-stack host might
have more than two logical interfaces because of a VPN (where a third have more than two logical interfaces because of a VPN (where a third
interface is the tunnel address, often assigned by the remote interface is the tunnel address, often assigned by the remote
corporate network) or because of multiple physical interfaces such as corporate network) or because of multiple physical interfaces such as
wired and wireless Ethernet, because the host belongs to multiple wired and wireless Ethernet, because the host belongs to multiple
VLANs, or other reasons. The interaction of Happy Eyeballs with more VLANs, or other reasons. The interaction of Happy Eyeballs with more
skipping to change at page 11, line 29 skipping to change at page 11, line 29
The primary purpose of Happy Eyeballs is to reduce the wait time for The primary purpose of Happy Eyeballs is to reduce the wait time for
a dual stack connection to complete, especially when the IPv6 path is a dual stack connection to complete, especially when the IPv6 path is
broken and IPv6 is preferred. Aggressive time outs (on the order of broken and IPv6 is preferred. Aggressive time outs (on the order of
tens of milliseconds) achieve this goal, but at the cost of network tens of milliseconds) achieve this goal, but at the cost of network
traffic. This network traffic may be billable on certain networks, traffic. This network traffic may be billable on certain networks,
will create state on some middleboxes (e.g., firewalls, IDS, NAT), will create state on some middleboxes (e.g., firewalls, IDS, NAT),
and will consume ports if IPv4 addresses are shared. For these and will consume ports if IPv4 addresses are shared. For these
reasons, it is RECOMMENDED that connection attempts be paced to give reasons, it is RECOMMENDED that connection attempts be paced to give
connections a chance to complete. It is RECOMMENDED that connections connections a chance to complete. It is RECOMMENDED that connections
attempts be paced 150-250ms apart. Stateful algorithms are expected attempts be paced 150-250ms apart, to balance human factors against
to be more aggressive (that is, make connection attempts closer network load. Stateful algorithms are expected to be more aggressive
together), as stateful algorithms maintain an estimate of the (that is, make connection attempts closer together), as stateful
expected connection completion time. algorithms maintain an estimate of the expected connection completion
time.
5.6. Interaction with Same Origin Policy 5.6. Interaction with Same Origin Policy
Web browsers implement a Same Origin Policy [I-D.ietf-websec-origin] Web browsers implement a Same Origin Policy [RFC6454] which causes
which causes subsequent connections to the same hostname to go to the subsequent connections to the same hostname to go to the same IPv4
same IPv4 (or IPv6) address as the previous successful connection. (or IPv6) address as the previous successful connection. This is
This is done to prevent certain types of attacks. done to prevent certain types of attacks.
The same-origin policy harms user-visible responsiveness if a new The same-origin policy harms user-visible responsiveness if a new
connection fails (e.g., due to a transient event such as router connection fails (e.g., due to a transient event such as router
failure or load balancer failure). While it is tempting to use Happy failure or load balancer failure). While it is tempting to use Happy
Eyeballs to maintain responsiveness, web browsers MUST NOT change Eyeballs to maintain responsiveness, web browsers MUST NOT change
their Same Origin Policy because of Happy Eyeballs, as that would their Same Origin Policy because of Happy Eyeballs, as that would
create an additional security exposure. create an additional security exposure.
5.7. Happy Eyeballs in an Operating System 5.7. Implementation Strategies
Applications would have to change in order to use the mechanism The simplest venue for implementation of Happy Eyeballs is within the
described in this document, by either implementing the mechanism application itself. The algorithm specified in this document is
directly, or by calling APIs made available to them. To improve IPv6 relatively simple to implement, and would require no specific support
connectivity experience for legacy applications (e.g., applications from the operating system beyond the commonly-available APIs that
which simply rely on the operating system's address preference provide transport service. It could also be added to applications by
order), operating systems may consider more sophisticated approaches. way of a specific Happy Eyeballs API, replacing or augmenting the
These can include changing default address selection sorting transport service APIs.
([RFC3484]) based on configuration received from the network, or
observing connection failures to IPv6 and IPV4 destinations. To improve IPv6 connectivity experience for legacy applications
(e.g., applications which simply rely on the operating system's
address preference order), operating systems may consider more
sophisticated approaches. These can include changing default address
selection sorting ([RFC3484]) based on configuration received from
the network, or observing connection failures to IPv6 and IPV4
destinations.
6. Example Algorithm 6. Example Algorithm
What follows is the algorithm implemented in Google Chrome and What follows is the algorithm implemented in Google Chrome and
Mozilla Firefox. Mozilla Firefox.
1. Call getaddinfo(), which returns a list of IP addresses sorted by 1. Call getaddinfo(), which returns a list of IP addresses sorted by
the host's address preference policy. the host's address preference policy.
2. Initiate a connection attempt with the first address in that list 2. Initiate a connection attempt with the first address in that list
(e.g., IPv6). (e.g., IPv6).
3. If that connection does not complete within a short period of 3. If that connection does not complete within a short period of
time (e.g., 200-300ms), initiate a connection attempt with the time (Firefox and Chrome use 300ms), initiate a connection
first address belonging to the other address family (e.g., IPv4) attempt with the first address belonging to the other address
family (e.g., IPv4)
4. The first connection that is established is used. The other 4. The first connection that is established is used. The other
connection is discarded. connection is discarded.
If an algorithm were to cache connection success/failure, the caching
would occur after step 4 determined which connection was successful.
Other example algorithms include [Perreault] and [Andrews]. Other example algorithms include [Perreault] and [Andrews].
7. Security Considerations 7. Security Considerations
See Section 4.4 and Section 5.6. See Section 4.4 and Section 5.6.
8. Acknowledgements 8. Acknowledgements
The mechanism described in this paper was inspired by Stuart The mechanism described in this paper was inspired by Stuart
Cheshire's discussion at the IAB Plenary at IETF72, the author's Cheshire's discussion at the IAB Plenary at IETF72, the author's
skipping to change at page 14, line 5 skipping to change at page 14, line 15
T., and J. Morse, "Experiences of host behavior in broken T., and J. Morse, "Experiences of host behavior in broken
IPv6 networks", March 2011, IPv6 networks", March 2011,
<http://www.ietf.org/proceedings/80/slides/v6ops-12.pdf>. <http://www.ietf.org/proceedings/80/slides/v6ops-12.pdf>.
[I-D.ietf-6man-addr-select-opt] [I-D.ietf-6man-addr-select-opt]
Matsumoto, A., Fujisaki, T., Kato, J., and T. Chown, Matsumoto, A., Fujisaki, T., Kato, J., and T. Chown,
"Distributing Address Selection Policy using DHCPv6", "Distributing Address Selection Policy using DHCPv6",
draft-ietf-6man-addr-select-opt-01 (work in progress), draft-ietf-6man-addr-select-opt-01 (work in progress),
June 2011. June 2011.
[I-D.ietf-websec-origin]
Barth, A., "The Web Origin Concept",
draft-ietf-websec-origin-06 (work in progress),
October 2011.
[Perreault] [Perreault]
Perreault, S., "Happy Eyeballs in Erlang", February 2011, Perreault, S., "Happy Eyeballs in Erlang", February 2011,
<http://www.viagenie.ca/news/ <http://www.viagenie.ca/news/
index.html#happy_eyeballs_erlang>. index.html#happy_eyeballs_erlang>.
[RFC1671] Carpenter, B., "IPng White Paper on Transition and Other [RFC1671] Carpenter, B., "IPng White Paper on Transition and Other
Considerations", RFC 1671, August 1994. Considerations", RFC 1671, August 1994.
[RFC4436] Aboba, B., Carlson, J., and S. Cheshire, "Detecting [RFC4436] Aboba, B., Carlson, J., and S. Cheshire, "Detecting
Network Attachment in IPv4 (DNAv4)", RFC 4436, March 2006. Network Attachment in IPv4 (DNAv4)", RFC 4436, March 2006.
skipping to change at page 14, line 38 skipping to change at page 14, line 43
November 2010. November 2010.
[RFC6157] Camarillo, G., El Malki, K., and V. Gurbani, "IPv6 [RFC6157] Camarillo, G., El Malki, K., and V. Gurbani, "IPv6
Transition in the Session Initiation Protocol (SIP)", Transition in the Session Initiation Protocol (SIP)",
RFC 6157, April 2011. RFC 6157, April 2011.
[RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P. [RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P.
Roberts, "Issues with IP Address Sharing", RFC 6269, Roberts, "Issues with IP Address Sharing", RFC 6269,
June 2011. June 2011.
[RFC6454] Barth, A., "The Web Origin Concept", RFC 6454,
December 2011.
[whitelist] [whitelist]
Google, "Google IPv6 DNS Whitelist", January 2009, Google, "Google IPv6 DNS Whitelist", January 2009,
<http://www.google.com/intl/en/ipv6>. <http://www.google.com/intl/en/ipv6>.
Appendix A. Changes Appendix A. Changes
A.1. changes from -05 to -06 [RFC Editor: Please remove this section prior to publication as an
RFC.]
A.1. changes from -06 to -07
o Changed "xmpp clients" to "instant messaging clients".
o For debugging/troubleshooting, providing a log of activity or a
way to see current settings is useful.
o tweaked abstract
o "URIs and hostnames" -> "hostnames"
o tweaked text on caching
o interfaces (not hosts) notice when they are connected to a new
network.
o encourage implementations to provide log or other way to view
Happy Eyeballs settings.
o detailed that implementation can be in OS or in application.
o 150-250ms is for human factors
A.2. changes from -05 to -06
o Added paragraph describing current AAAA practice on the Internet o Added paragraph describing current AAAA practice on the Internet
(one AAAA record) due to non-Happy Eyeballs implementations, per (one AAAA record) due to non-Happy Eyeballs implementations, per
opsdir review. opsdir review.
o fixed "=" in Figure 1. o fixed "=" in Figure 1.
o Removed text discussing A6. A6 is being deprecated in another o Removed text discussing A6. A6 is being deprecated in another
document, and querying A6 is not a significant operational problem document, and querying A6 is not a significant operational problem
on the Internet. on the Internet.
A.2. changes from -04 to -05 A.3. changes from -04 to -05
o Updated citations. o Updated citations.
A.3. changes from -03 to -04 A.4. changes from -03 to -04
o Make RFC3363 a non-normative reference. o Make RFC3363 a non-normative reference.
A.4. changes from -03 to -04 A.5. changes from -03 to -04
o Better explained why IPv6 needs to be preferred o Better explained why IPv6 needs to be preferred
o Don't query A6. o Don't query A6.
A.5. changes from -02 to -03 A.6. changes from -02 to -03
o Re-casted this specification as a list of requirements for a o Re-casted this specification as a list of requirements for a
compliant algorithm, rather than trying to dictate a One True compliant algorithm, rather than trying to dictate a One True
algorithm. algorithm.
A.6. changes from -01 to -02 A.7. changes from -01 to -02
o Now honors host's address preference (RFC3484 and friends) o Now honors host's address preference (RFC3484 and friends)
o No longer requires thread-safe DNS library. It uses getaddrinfo() o No longer requires thread-safe DNS library. It uses getaddrinfo()
o No longer describes threading. o No longer describes threading.
o IPv6 is given a 200ms head start (Initial Headstart variable). o IPv6 is given a 200ms head start (Initial Headstart variable).
o If the IPv6 and IPv4 connection attempts were made at nearly the o If the IPv6 and IPv4 connection attempts were made at nearly the
skipping to change at page 16, line 10 skipping to change at page 17, line 4
serious affect to Smoothed P. serious affect to Smoothed P.
o encourages that every 10 minutes the exception cache and Smoothed o encourages that every 10 minutes the exception cache and Smoothed
P be reset. This allows IPv6 to be attempted again, so we don't P be reset. This allows IPv6 to be attempted again, so we don't
get 'stuck' on IPv4. get 'stuck' on IPv4.
o If we didn't get both A and AAAA, abandon all Happy Eyeballs o If we didn't get both A and AAAA, abandon all Happy Eyeballs
processing (thanks to Simon Perreault). processing (thanks to Simon Perreault).
o added discussion of Same Origin Policy o added discussion of Same Origin Policy
o Removed discussion of NAT-PT and address learning; those are only o Removed discussion of NAT-PT and address learning; those are only
used with IPv6-only hosts whereas this document is about dual- used with IPv6-only hosts whereas this document is about dual-
stack hosts contacting dual-stack servers. stack hosts contacting dual-stack servers.
A.7. changes from -00 to -01 A.8. changes from -00 to -01
o added SRV section (thanks to Matt Miller) o added SRV section (thanks to Matt Miller)
Authors' Addresses Authors' Addresses
Dan Wing Dan Wing
Cisco Systems, Inc. Cisco Systems, Inc.
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
 End of changes. 31 change blocks. 
76 lines changed or deleted 115 lines changed or added

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/