v6ops J. Brzozowski
Internet-Draft Comcast Cable
Intended status: Best Current Practice D. Schinazi
Expires: January 1, 2018 S. Cheshire
Apple Inc.
L. Colitti
E. Kline
J. Linkova
Google
M. Keane
Microsoft
P. Saab
Facebook
June 30, 2017
Incremental Deployment of IPv6-only Wi-Fi for IETF Meetings
draft-jjmb-v6ops-ietf-ipv6-only-incremental-00
Abstract
The purpose of this document is to provide a blueprint and guidance
for deploying IPv6-only Wi-Fi at IETF meetings. This document
outlines infrastructure and operational guidance that operators
should consider when deploying IPv6-only networks using NAT64 and
DNS64 to support communication to legacy IPv4-only services.
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 January 1, 2018.
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Copyright Notice
Copyright (c) 2017 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
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 . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Design Principles . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Network Infrastructure . . . . . . . . . . . . . . . . . 4
3. Network Services . . . . . . . . . . . . . . . . . . . . . . 5
3.1. DNS64 . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. NAT64 . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.3. DHCPv6 . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. User Equipment . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Host Address Assignment and Configuration . . . . . . . . 7
4.2. IPv4 support . . . . . . . . . . . . . . . . . . . . . . 7
5. Network Management . . . . . . . . . . . . . . . . . . . . . 8
6. Telemetry and Monitoring . . . . . . . . . . . . . . . . . . 9
7. Support for User Applications and Services . . . . . . . . . 10
8. Support and Operations . . . . . . . . . . . . . . . . . . . 10
8.1. Reporting Issues (Ticketing) . . . . . . . . . . . . . . 10
8.2. Interactive Support . . . . . . . . . . . . . . . . . . . 11
9. Known Client-side Issues . . . . . . . . . . . . . . . . . . 11
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
10.1. Security Considerations . . . . . . . . . . . . . . . . 12
11. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 12
12. Related Industry Efforts . . . . . . . . . . . . . . . . . . 12
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
13.1. Normative References . . . . . . . . . . . . . . . . . . 13
13.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
The purpose of this document is to provide a blueprint and guidance
for deploying IPv6-only Wi-Fi at IETF meetings. This document
outlines infrastructure and operational guidance that operators
should consider when deploying IPv6-only networks using NAT64 and
DNS64 to support communication to legacy IPv4-only services.
One of the main strengths of the IETF has always been an insistence
on running code. As such, IETF meetings were one of the first
deployments of a dual-stack network to help test the first
implementations of IPv6. Many years later, as several networks are
shifting towards IPv6-only, it is the responsibility of the IETF to
lead the trend and make their main network IPv6-only.
This document outlines the requirements and design principles for an
IPv6-only network infrastructure that includes support for IPv4-only
content. It also discusses techniques and requirements for network
management, telemetry, and the operations and support for the
IPv6-only network. Recommendations and best practices for operations
and support will be provided, however, alternate approaches may be
utilized. Disabling or removal of IPv4 stacks is out of scope for
this document. This document focuses on the explicit provisioning of
IPv6-only using NAT64 [RFC6146] and DNS64 [RFC6147] to access
IPv4-only content and services.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
"Key words for use in RFCs to Indicate Requirement Levels" [RFC2119].
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2. Design Principles
2.1. Network Infrastructure
The following are specific network design details that are minimally
required to support an IPv6-only network that utilize NAT64 and
DNS64. The following have been drawn from real deployment scenarios
for large scale uses of IPv6-only with NAT64 and DNS64. The
parameters specified here are specific to providing IPv6-only
connectivity. It is assumed that IPv6-only is provisioned and that
IPv4 stacks remain active on network and host interfaces. The
disabling or removal of IPv4 stacks from hosts or routers is out of
scope for this document. As such, it is important to note that link
local IPv4 [RFC3927] will likely remain active and will appear on
hosts and network infrastructure.
The following section outlines the requirement to provisioning
IPv6-only. We minimally assume that SLAAC will be utilized, however,
for completeness the parameters required for DHCPv6 [RFC3315] and
[RFC3736] are also provided:
o IPv6-only hosts are expected to be provisioned with IPv6-only
connectivity, however, link local IPv4 is likely to be present.
o RA interval is RECOMMENDED to be minimally set to 600 seconds per
the guidance outlined in [RFC7772].
o Support for solicited unicast router advertisements are also
recommended per [RFC7772]
o At least one prefix information option (PIO) MUST be included in
router advertisements, the transmitted PIO MUST correspond to the
IPv6 prefix that is valid for a given IPv6 link.
o The use of SLAAC [RFC4862] MUST be signalled by the network,
specifically for each transmitted PIO the A bit MUST be set to
one.
o DHCPv6 support SHOULD be included to support legacy operating
systems that do not support DNS RA options but is not required.
Whether stateless or stateful DHCPv6 is used, both the DNS Server
IPv6 address and DNS Search List options [RFC8106] MUST minimally
be included. The DNS server IPv6 address(es) MUST be those used
for DNS64. It is RECOMMENDED that these values be identical to
those used in the IPv6 router advertisements that include the DNS
options [RFC8106]. If DHCPv6 support is deployed, stateless
DHCPv6 MUST minimally be available.
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o IPv6 router advertisements MUST include the DNS options [RFC8106].
Both the DNS Server IPv6 address(es) and DNS Search List are
REQUIRED. If DHCPv6 support is deployed the values sent here for
DNS RA options are RECOMMENDED to match those sent via DHCPv6.
To ensure seamless and to support an incremental deployment of
IPv6-only access to legacy dual stack infrastructure should remain
available. The following are recommended approaches that may be
considered to achieve the same.
The deployment of IPv6-only with NAT64 and DNS64 may very well help
to identify applications, services, or use cases that are not
entirely compatible with the same. It is therefore important to
ensure that users of IP networks, whether wired or wireless, have
access to legacy dual stack infrastructure as a fallback. For
wireless network it is recommend to have a secondary SSID labelled
accordingly, e.g. example-ssid-dual-stack or example-ssid-legacy.
For wired network connectivity having secondary ports that are dual
stack enabled is also recommended. Note that while it is recommended
to ensure the presence of a fallback network, the goal remains to
make the IPv6-only network the primary network.
This document assumes that dual stack connectivity is available by
default and that IPv4-only connectivity is no longer supported. As
such, it is out of scope for this document to outline fallback or
access to legacy connectivity that is IPv4-only.
3. Network Services
The following network services are required for an IPv6-only where
support for and access to IPv4 content, services, and applications
are required.
3.1. DNS64
The following recommendations apply to the use and deployment of
DNS64:
o Use of the well known DNS64 prefix per [RFC6052]
o It is also recommended that query logging be enabled for DNS64,
performance impacts of query logging must be noted but are largely
out of scope for this document. Query logging is essential to
determine the volume and make up of DNS queries and replies that
are are specific to DNS64 and IPv4-only content, services, and
applications.
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3.2. NAT64
The following recommendations apply to the use and deployment of
NAT64:
o DNS64 is a critical aspect to direct requests from IPv6-only hosts
to a NAT64 service.
o NAT64 configurations vary widely, port allocation techniques are
largely out of scope for this document. One-to-one (1:1) mappings
can be used to allocate an IPv4 address per connected device or
alternatively blocks of IPv4 ports can also be assigned per
device, each has different properties. It is generally
recommended to allocate IPv4 ports per device in an effort to
maximize IPv4 utilization for NAT64.
3.3. DHCPv6
Support for DHCPv6 may be required in some deployments. If required,
parameters pertaining to IPv6 router discovery may require
adjustment. The following outlines the guidance specific to the use
of DHCPv6:
o Stateless DHCPv6 SHOULD be supported to facilitate the
transmission of DNS servers IPv6 address(es) and DNS search lists
to legacy hosts that do not support DNS RA options.
o Stateful DHCPv6 for address assignment MAY be supported, but is
not required. If stateful DHCPv6 is used the DNS parameters
mentioned above MUST be included.
o If, at some future date, support for IPv6 prefix delegation
becomes necessary, stateful DHCPv6 will likely be mandatory
(Future Work (Section 11)). The details of IPv6 prefix delegation
are out of scope for this document.
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4. User Equipment
4.1. Host Address Assignment and Configuration
o Hosts MUST support SLAAC.
o Hosts SHOULD support DNS RA options [RFC8106] for the acquisition
of DNS server IPv6 addresses and a DNS Search List.
o Hosts MAY support DHCPv6 for address acquisition, the use of
DHCPv6 for address acquisition is not prohibited.
o DHCPv6 option to configure DNS server option 23 and domain search
list option 24 [RFC3646] address MUST be implemented if DHCPv6 is
to be utilized.
4.2. IPv4 support
The IPv4 stacks of hosts MAY remain enabled, which means that Link
Local IPv4 [RFC3927] (169.254/16) addresses MAY continue to be
present and in use. Disabling of the IPv4 stack of hosts is out of
scope for this document.
Host operating systems SHOULD provide a means for applications to
easily connect to IPv4-only servers by using the NAT64/DNS64. While
modern applications simply need to make AAAA queries and connect to
the resulting IPv6 address, operating systems SHOULD provide simple
ways for applications to do so or even connect to IPv4 literals in
the absence of host names. Possible solutions include 464XLAT
[RFC6877], "Bump-in-the-Host" [RFC6535] and Happy Eyeballs v2 [HEv2].
Finally, it is RECOMMENDED that support for DHCPv4 be explicitly
suppressed in particular to prevent the inadvertent assignment of
IPv4 addresses on networks that do not have a valid IPv4 egress.
DHCPv4 servers, rogue or otherwise, could adversely impact the
experience of end users of the IPv6-only network.
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5. Network Management
The focus of this document is user equipment and hosts. The network
and network service requirements are oriented around providing
IPv6-only connectivity that allows for the use of NAT64 and DNS64 to
maintain reachability to IPv4-only content, applications, and
services. Operations and management of the underlying network is
technically out of scope for this document, however, given the
relevance of the same to the focus of this draft some guidance is
being provided.
Strictly speaking the primary requirement for the underlying network
is that IPv6 is supported along with the services required to enable
the use of NAT64 and DNS64. This suggests that the underlying
network could in fact be dual stack for management and operations.
It is required that the provisioning of IPv4 for user equipment and
host connectivity not be supported. User equipment or host facing
interfaces MUST NOT acquire non-link-local IPv4 addresses or IPv4 DNS
server addresses. Additionally, the network MUST NOT respond to
DHCPv4 requests or DNS queries sent over IPv4.
Given the above, within a given VLAN it is possible and likely that
IPv4 may be observed, present, and possibly used. It is out of scope
for this document to prevent the use of IPv4 entirely.
Depending on the level of readiness IPv6-only network management may
or may not be possible. Network management and operations includes
but is not limited to the following:
o Remote access to network infrastructure via SSH or telnet
o Remote SNMP communications
o Remote NETCONF communications
o Remote Syslog communications
While it is strongly recommended that all network management and
operations be performed over IPv6-only it is not strictly required.
However, it is important to note that the presence and use of IPv4
for network management and operations must not impede or impact the
use of IPv6-only with NAT64 and DNS64.
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6. Telemetry and Monitoring
At this point in time, IPv6-only networks with no IPv4 support at all
are still not widespread and may expose issues in host operating
systems or applications. It is therefore recommended that telemetry
summarizing how hosts are being provisioned and accessing the
Internet be collected and analyzed. In order to preserve the privacy
of users of the network, it is paramount that connectivity
information (e.g. DNS64 records) cannot be correlated with
individual client nodes.
We can measure how hosts:
o Configure IPv6 addresses (SLAAC, DHCPv6) and which ones they use
o Configure DNS server addresses (DNS RA options vs DHCPv6)
We can measure what percentage of the traffic:
o Uses native IPv6
o Uses NAT64
Recording the most common hostnames that require the DNS64 would also
allow operators to establish a list of the most prominent IPv4-only
services.
Observing the TCP/UDP ports used by applications that still leverage
IPv4 link-local on an IPv6-only network will also help prepare for
the time when routers stop supporting IPv4 communications altogether.
Given that some users may have devices running legacy IPv4-only
software, the network should provide a different fallback network
that is dual-stack. It is worth measuring the number of users that
switch to this network, and possibly use an anonymous survey asking
users what software failure caused them to switch. Additionally, the
fallback network SHOULD use different authentication credentials per
meeting (such as SSID) to make sure a failure causing a user to
switch does not mean they will stay on the fallback network forever.
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7. Support for User Applications and Services
Following is a list of commonly used applications and services that
are expected to operate, without incident, when used in an IPv6-only
environment that utilizes NAT64 and DNS64. The list below is not
exhaustive.
o VPN
o Chat
o Email
o SSH/Telnet
o Git
o Voice
8. Support and Operations
Most every network has customers or end users of some sort, therefore
it essential to ensure that end users or consumers of the have means
to do the following while transitions are occurring in networks and
related infrastructure. One key item referenced earlier is the
availability of temporary fallback networks that support legacy
communications.
The following outline additional items that end users must have
available to communicate with network operators. All of the items
below must be available via dual stack connectivity.
8.1. Reporting Issues (Ticketing)
Tools and systems that can be used to report issues with
applications, services, or content must be available for end-users.
Network and systems operators are responsible for acknowledging and
classifying issues and ultimately ensuring that the same are properly
addressed. Specifically to this document "fixed" is meant to imply
that proper support for IPv6 is available. In some cases network and
system operators may need to implement temporary workarounds to
ensure that end users can access the desired content, application, or
service.
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In order for users experiencing IPv6-specific issues to be able to
report them, the ticketing system MUST also be reachable over the
dual-stack fallback network. The existence of the fallback network
SHOULD also be made clear to users ahead of time. In order to help
narrow down issues, the ticketing system SHOULD ask the user whether
the issue is specific to IPv6-only and whether they have experienced
the issue or a different outcome on the fallback network.
8.2. Interactive Support
Interactive support is often desired in lieu or in conjunction with
traditional support models like trouble ticket creation. It is
recommended that interactive support be available via real time and
near real time mechanisms like Slack or electronic mail (e-mail).
9. Known Client-side Issues
Following are known client side issues that are specific to the
deployment of IPv6-only networks and/or the use of NAT64/DNS64:
o Use of literal IPv4 addresses - the use of literal IPv4 addresses
is a known issue given the approach that is documented in this
I-D. Addressing the use of literal IPv4 addresses is out of scope
for this document.
o Applications that explicitly require IPv4 by only performing AAAA
queries or restricting the type of underlying socket they use.
o Unreachable but valid AAAA RR in the DNS - in some cases a valid
AAAA RR is returns by the DNS, however, if the same is unreachable
or is not configured the presence of the same will prevent a DNS64
query which in turn prevents the use of the NAT64 to reach the
target host references by the address in the AAAA DNS RR.
10. IANA Considerations
This memo includes no request to IANA.
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10.1. Security Considerations
The vastness of the IPv6 address space often makes it more difficult
to scan the same unlike legacy IPv4-only or dual stack IP networks.
It is conceivable that IPv6-only network represent a reduction in
attack surface area which in turn could be viewed a security
improvement compared to IPv4-only or dual stack IP networks.
Given the criticality of the DNS64 for reachability to the NAT64,
poisoning of one or both could represent a vector for the attack of
the DNS64 and NAT64 which could in turn impact the end user
experience. Worse poisoning of the DNS64 and/or NAT64 could result
in redirection of end use devices to malicious hosts. It is likely
that this vulnerability is no greater in IPv6-only networks utilizing
DNS64 and NAT64 compared to traditional IPv4-only or dual stack
networks.
11. Future Work
The following items are out of scope for this document, however, the
following are listed as future work items specific to incremental
IPv6-only deployments:
o Support for IPv6 prefix delegation
o Disabling IPv4 stacks at some point in the future
o Fully deprecating the fallback legacy IPv4 network
12. Related Industry Efforts
o Comcast new building and IPv6-only (John Jason Brzozowski
<john_brzozowski@comcast.com>)
o Microsoft corporate IT IPv6-only (Marcus Keane
<marcus.keane@microsoft.com>)
o Google (Jen Linkova <furry@google.com>)
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13. References
13.1. Normative References
[HEv2] Schinazi, D. and T. Pauly, "Happy Eyeballs Version 2",
Work in Progress, draft-ietf-v6ops-rfc6555bis, June 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
2003, <http://www.rfc-editor.org/info/rfc3315>.
[RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic
Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
DOI 10.17487/RFC3646, December 2003,
<http://www.rfc-editor.org/info/rfc3646>.
[RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol
(DHCP) Service for IPv6", RFC 3736, DOI 10.17487/RFC3736,
April 2004, <http://www.rfc-editor.org/info/rfc3736>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<http://www.rfc-editor.org/info/rfc4862>.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
DOI 10.17487/RFC6052, October 2010,
<http://www.rfc-editor.org/info/rfc6052>.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146,
April 2011, <http://www.rfc-editor.org/info/rfc6146>.
[RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van
Beijnum, "DNS64: DNS Extensions for Network Address
Translation from IPv6 Clients to IPv4 Servers", RFC 6147,
DOI 10.17487/RFC6147, April 2011,
<http://www.rfc-editor.org/info/rfc6147>.
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[RFC7772] Yourtchenko, A. and L. Colitti, "Reducing Energy
Consumption of Router Advertisements", BCP 202, RFC 7772,
DOI 10.17487/RFC7772, February 2016,
<http://www.rfc-editor.org/info/rfc7772>.
[RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Options for DNS Configuration",
RFC 8106, DOI 10.17487/RFC8106, March 2017,
<http://www.rfc-editor.org/info/rfc8106>.
13.2. Informative References
[RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
Configuration of IPv4 Link-Local Addresses", RFC 3927,
DOI 10.17487/RFC3927, May 2005,
<http://www.rfc-editor.org/info/rfc3927>.
[RFC6535] Huang, B., Deng, H., and T. Savolainen, "Dual-Stack Hosts
Using "Bump-in-the-Host" (BIH)", RFC 6535,
DOI 10.17487/RFC6535, February 2012,
<http://www.rfc-editor.org/info/rfc6535>.
[RFC6877] Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT:
Combination of Stateful and Stateless Translation",
RFC 6877, DOI 10.17487/RFC6877, April 2013,
<http://www.rfc-editor.org/info/rfc6877>.
Authors' Addresses
John Jason Brzozowski
Comcast Cable
1701 John F. Kennedy Blvd.
Philadelphia, PA
USA
Email: john_brzozowski@cable.comcast.com
David Schinazi
Apple Inc.
1 Infinite Loop
Cupertino, California 95014
US
Email: dschinazi@apple.com
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Stuart Cheshire
Apple Inc.
1 Infinite Loop
Cupertino, California 95014
USA
Email: cheshire@apple.com
Lorenzo Colitti
Google
Email: lorenzo@google.com
Erik Kline
Google
Email: ek@google.com
Jen Linkova
Google
Email: furry@google.com
Marcus Keane
Microsoft
Email: marcus.keane@microsoft.com
Paul Saab
Facebook
Email: ps@fb.com
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