Home Networking Architecture for IPv6
draft-ietf-homenet-arch-02
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 7368.
|
|
|---|---|---|---|
| Authors | Tim Chown , Jari Arkko , Anders Brandt , Ole Trøan , Jason Weil | ||
| Last updated | 2012-03-12 | ||
| Replaces | draft-chown-homenet-arch | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
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draft-ietf-homenet-arch-02
Network Working Group T. Chown, Ed.
Internet-Draft University of Southampton
Intended status: Informational J. Arkko
Expires: September 13, 2012 Ericsson
A. Brandt
Sigma Designs
O. Troan
Cisco Systems, Inc.
J. Weil
Time Warner Cable
March 12, 2012
Home Networking Architecture for IPv6
draft-ietf-homenet-arch-02
Abstract
This text describes evolving networking technology within small
residential home networks. The goal of this memo is to define the
architecture for IPv6-based home networking and the associated
principles, considerations and requirements. The text briefly
highlights the implications of the introduction of IPv6 for home
networking, discusses topology scenarios, and suggests how standard
IPv6 mechanisms and addressing can be employed in home networking.
The architecture describes the need for specific protocol extensions
for certain additional functionality. It is assumed that the IPv6
home network is not actively managed, and runs as an IPv6-only or
dual-stack network. There are no recommendations in this text for
the IPv4 part of the network.
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 September 13, 2012.
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Copyright Notice
Copyright (c) 2012 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.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Terminology and Abbreviations . . . . . . . . . . . . . . 5
2. Effects of IPv6 on Home Networking . . . . . . . . . . . . . . 5
2.1. Multiple subnets and routers . . . . . . . . . . . . . . . 5
2.2. Global addressability and elimination of NAT . . . . . . . 6
2.3. Multi-Addressing of devices . . . . . . . . . . . . . . . 7
2.4. Unique Local Addresses (ULAs) . . . . . . . . . . . . . . 7
2.5. Security and borders . . . . . . . . . . . . . . . . . . . 8
2.6. Naming, and manual configuration of IP addresses . . . . . 8
3. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1. Network Models . . . . . . . . . . . . . . . . . . . . . . 9
3.1.1. A: Single ISP, Single CER, Internal routers . . . . . 10
3.1.2. B: Two ISPs, Two CERs, Shared subnet . . . . . . . . . 12
3.1.3. C: Two ISPs, One CER, Shared subnet . . . . . . . . . 13
3.2. Determining the Requirements . . . . . . . . . . . . . . . 13
3.3. Considerations . . . . . . . . . . . . . . . . . . . . . . 14
3.3.1. Multihoming . . . . . . . . . . . . . . . . . . . . . 14
3.3.2. Quality of Service . . . . . . . . . . . . . . . . . . 16
3.3.3. Operations and Management . . . . . . . . . . . . . . 16
3.3.4. Privacy considerations . . . . . . . . . . . . . . . . 16
3.4. Design Principles and Requirements . . . . . . . . . . . . 17
3.4.1. Reuse existing protocols . . . . . . . . . . . . . . . 17
3.4.2. Dual-stack Operation . . . . . . . . . . . . . . . . . 18
3.4.3. Largest Possible Subnets . . . . . . . . . . . . . . . 19
3.4.4. Security vs Transparent, End-to-End Communications . . 19
3.4.5. IP Connectivity between All Nodes . . . . . . . . . . 20
3.4.6. Routing functionality . . . . . . . . . . . . . . . . 21
3.4.7. Self-Organising . . . . . . . . . . . . . . . . . . . 23
3.4.8. Fewest Topology Assumptions . . . . . . . . . . . . . 26
3.4.9. Naming and Service Discovery . . . . . . . . . . . . . 26
3.4.10. Proxy or Extend? . . . . . . . . . . . . . . . . . . . 27
3.4.11. Adapt to ISP constraints . . . . . . . . . . . . . . . 27
3.5. Implementing the Architecture on IPv6 . . . . . . . . . . 29
4. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 29
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.1. Normative References . . . . . . . . . . . . . . . . . . . 29
5.2. Informative References . . . . . . . . . . . . . . . . . . 31
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 34
Appendix B. Changes . . . . . . . . . . . . . . . . . . . . . . . 34
B.1. Version 02 . . . . . . . . . . . . . . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 35
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1. Introduction
This document focuses on evolving networking technology within small
residential home networks and the associated challenges. There is a
growing trend in home networking for the proliferation of networking
technology in an increasingly broad range of devices and media. This
evolution in scale and diversity sets requirements on IETF protocols.
Some of these requirements relate to the introduction of IPv6, others
to the introduction of specialised networks for home automation and
sensors. There are also likely to be scenarios where internal
routing is required, for example to support private and guest
networks, in which case home networks will use multiple subnets.
While some advanced home networks exist, most operate based on IPv4,
employ solutions that we would like to avoid such as (cascaded)
network address translation (NAT), or require expert assistance to
set up. The assumption of this document is that the homenet is as
far as possible self-organising and self-configuring, and is thus not
pro-actively managed by the residential user. The architectural
constructs in this document are focused on the problems to be solved
when introducing IPv6 with an eye towards a better result than what
we have today with IPv4, as well as a better result than if the IETF
had not given this specific guidance.
This architecture document aims to provide the basis and guiding
principles for how standard IPv6 mechanisms and addressing [RFC2460]
[RFC4291] can be employed in home networking, while coexisting with
existing IPv4 mechanisms. In emerging dual-stack home networks it is
vital that introducing IPv6 does not adversely affect IPv4 operation.
Future deployments, or specific subnets within an otherwise dual-
stack home network, may be IPv6-only, in which case considerations
for IPv4 impact would not apply.
[RFC6204] defines basic requirements for customer edge routers
(CERs). The scope of this text is the homenet, and thus the relevant
part of RFC 6204 is the internal facing interface as well as any
other components within the home network. While the network may be
dual-stack or IPv6-only, the definition of specific transition tools
on the CER are out of scope of this text, as is any advice regarding
architecture of the IPv4 part of the network. We assume that IPv4
network architecture in home networks is what it is, and can not be
affected by new recommendations.
This architecture document proposes a baseline homenet architecture,
based on protocols and implementations that are as far as possible
proven and robust, and as such is a "version 1" architecture. A
future architecture may incorporate more advanced elements at a later
date.
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1.1. Terminology and Abbreviations
In this section we define terminology and abbreviations used
throughout the text.
o CER: Customer Edge Router. The border router at the edge of the
homenet.
o LLN: Low-power and lossy network.
o NAT: Network Address Translation. Typically referring to Network
Address and Port Translation (NAPT) [RFC3022].
o NPTv6: Network Prefix Translation for IPv6 [RFC6296].
o PCP: Port Control Protocol [I-D.ietf-pcp-base].
o ULA: Unique Local Addresses [RFC4193].
o UPnP: Universal Plug and Play. Includes Internet Gateway Device
(IGD) function, which for IPv6 is UPnP IGD Version 2 [IGD-2].
o VM: Virtual machine.
o WPA: Wi-Fi Protected Access, as defined by the Wi-Fi Alliance.
2. Effects of IPv6 on Home Networking
Service providers are deploying IPv6, content is becoming available
on IPv6, and support for IPv6 is increasingly available in devices
and software used in the home. While IPv6 resembles IPv4 in many
ways, it changes address allocation principles, makes multi-
addressing the norm, and allows direct IP addressability and routing
to devices in the home from the Internet. This section presents an
overview of some of the key implications of the introduction of IPv6
for home networking, that are both promising and problematic.
2.1. Multiple subnets and routers
While simple layer 3 topologies involving as few subnets as possible
are preferred in home networks, the incorporation of dedicated
(routed) subnets remains necessary for a variety of reasons.
For instance, a common feature in modern home routers is the ability
to support both guest and private network subnets. Also, link layer
networking technology is poised to become more heterogeneous, as
networks begin to employ both traditional Ethernet technology and
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link layers designed for low-power and lossy networks (LLNs) such as
those used for certain types of sensor devices. There may also be a
need to separate building control or corporate extensions from the
main Internet access network. Also, different subnets may be
associated with parts of the homenet that have different routing and
security policies.
Documents that provide some more specific background and depth on
this topic include: [I-D.herbst-v6ops-cpeenhancements],
[I-D.baker-fun-multi-router], and [I-D.baker-fun-routing-class].
The addition of routing between subnets raises the issue of how to
extend mechanisms such as service discovery which currently rely on
link-local addressing to limit scope. There will also be the need to
discover which are the border router(s) by an appropriate mechanism.
2.2. Global addressability and elimination of NAT
Current IPv4 home networks typically receive a single global IPv4
address from their ISP and use NAT with private [RFC1918] addresses
for devices within the network. An IPv6 home network removes the
need to use NAT given the ISP offers a sufficiently large globally
unique IPv6 prefix to the homenet, allowing every device on every
link to be assigned a globally unique IPv6 address.
The end-to-end communication that is potentially enabled with IPv6 is
on the one hand an incredible opportunity for innovation and simpler
network operation, but it is also a concern as it exposes nodes in
the internal networks to receipt of otherwise unwanted traffic from
the Internet.
In IPv4 NAT networks, the NAT provides an implicit firewall function.
[RFC4864] suggests that IPv6 networks with global addresses utilise
"Simple Security" in border firewalls to restrict incoming
connections through a default deny policy. Applications or hosts
wanting to accept inbound connections in networks that are compliant
with the architecture presented in this document would then need to
signal that desire through a protocol such as UPnP or PCP
[I-D.ietf-pcp-base]. In networks with multiple CERs, the signalling
would need to handle the cases of flows that may use one or both exit
routers.
The "Simple Security" default deny approach effectively replaces the
need for IPv4 NAT traversal by a need to use a signalling protocol to
request a firewall hole be opened. [RFC6092] states that while the
default should be default deny, CERs should also have an option to be
put into a "transparent" mode of operation which enables a default
allow model.
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It is important to distinguish between addressability and
reachability. While IPv6 offers global addressability through use of
globally unique addresses in the home, whether they are globally
reachable or not would depend on the firewall or filtering
configuration, and not presence or use of NAT.
2.3. Multi-Addressing of devices
In an IPv6 network, devices may acquire multiple addresses, typically
at least a link-local address and a globally unique address. They
may also have an IPv4 address if the network is dual-stack, a Unique
Local Address (ULA) [RFC4193] (see below), and one or more IPv6
Privacy Addresses [RFC4941].
Thus it should be considered the norm for devices on IPv6 home
networks to be multi-addressed, and to need to make appropriate
address selection decisions for the candidate source and destination
address pairs. Default Address Selection for IPv6
[I-D.ietf-6man-rfc3484bis] provides a solution for this, but may face
problems in the event of multihoming, where nodes will be configured
with one address from each upstream ISP prefix. In such cases the
presence of upstream ingress filtering requires multi-addressed nodes
to select the right source address to be used for the corresponding
uplink, but the node may not have the information it needs to make
that decision based on addresses alone.
2.4. Unique Local Addresses (ULAs)
[RFC4193] defines Unique Local Addresses (ULAs) for IPv6 that may be
used to address devices within the scope of a single site. Support
for ULAs for IPv6 CERs is described in [RFC6204]. A home network
running IPv6 may deploy ULAs for stable communication between devices
(on different subnets) within the network where externally allocated
global prefix changes over time (either due to renumbering within the
subscriber's ISP or a change of ISP) or where external connectivity
is temporarily unavailable.
A counter-argument to using ULAs is that it is undesirable to
aggressively deprecate global prefixes for temporary loss of
connectivity, so for a host to lose its global address there would
have to be a connection breakage longer than the lease period, and
even then, deprecating prefixes when there is no connectivity may not
be advisable. It should also be noted that there are timers on the
prefix lease to the homenet, on the internal prefix delegations, and
on the Router Advertisements to the hosts. Despite this counter-
argument, while setting a network up there may be a period with no
connectivity, in which case ULAs would be required for inter-subnet
communication.
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It has been suggested that using ULAs would provide an indication to
applications that received traffic is locally sourced. This could
then be used with security settings to designate where a particular
application is allowed to connect to or receive traffic from.
ULA addresses will allow constrained LLN devices to create permanent
relations between IPv6 addresses, e.g. from a wall controller to a
lamp. Symbolic host names would require additional non-volatile
memory. Updating global prefixes in sleeping LLN devices might also
be problematic.
Default address selection mechanisms should ensure a ULA source
address is used to communicate with ULA destination addresses when
appropriate. Unlike the IPv4 RFC1918 space, the use of ULAs does not
imply use of host-based IPv6 NAT, or NPTv6 prefix-based NAT
[RFC6296], rather that external communications should use a node's
globally unique IPv6 source address.
2.5. Security and borders
Advanced Security for IPv6 CPEs [I-D.vyncke-advanced-ipv6-security]
takes the approach that in order to provide the greatest end-to-end
transparency as well as security, security policies must be updated
by a trusted party which can provide intrusion signatures and other
"active" information on security threats. Such methods should be
able to be automatically updating.
In addition to establishing the security mechanisms themselves, it is
important to know where the borders are at which they need to be
enabled. Any required policies must be able to be applied by typical
home users, e.g. to give a visitor in a "guest" network access to
media services in the home. Thus simple "association" mechanisms
will be required.
It may be useful to classify the external border of the home network
as a unique logical interface separating the home network from
service provider network/s. This border interface may be a single
physical interface to a single service provider, multiple layer 2
sub-interfaces to a single service provider, or multiple connections
to a single or multiple providers. This border is useful for
describing edge operations and interface requirements across multiple
functional areas including security, routing, service discovery, and
router discovery.
2.6. Naming, and manual configuration of IP addresses
Some IPv4 home networking devices expose IPv4 addresses to users,
e.g. the IPv4 address of a home IPv4 CER that may be configured via a
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web interface. Users should not be expected to enter IPv6 literal
addresses in homenet devices or applications, given their much
greater length and apparent randomness to a typical home user. While
shorter addresses, perhaps ones registered with IANA from ULA-C
space, could be used for specific devices/services, in general it is
better to not expose users to real IPv6 addresses. Thus, even for
the simplest of functions, simple naming and the associated discovery
of services is imperative for easy use of homenet devices and
applications.
In a multi-subnet homenet, naming and service discovery should be
expected to operate across the scope of the entire home network, and
thus be able to cross subnet boundaries. It should be noted that in
IPv4, such services do not generally function across home router NAT
boundaries, so this is one area where there is scope for an
improvement in IPv6.
3. Architecture
An architecture outlines how to construct home networks involving
multiple routers and subnets. In this section, we present a set of
typical home network topology models/scenarios, followed by a list of
topics that may influence the architecture discussions, and a set of
architectural principles that govern how the various nodes should
work together. Finally, some guidelines are given for realising the
architecture with the IPv6 addressing, prefix delegation, global and
ULA addresses, source address selection rules and other existing
components of the IPv6 architecture. The architecture also drives
what protocol extensions are necessary, as will be discussed in
Section 3.5.
3.1. Network Models
Most IPv4 home network models tend to be relatively simple, typically
a single NAT router to the ISP and a single internal subnet, but as
discussed earlier, evolution in network architectures is driving more
complex architectures, such as separation of visitors and private
networks. These considerations apply to IPv6 networks as well.
In general, the models described in [RFC6204] and
[I-D.ietf-v6ops-ipv6-cpe-router-bis] should be supported by an IPv6
home networking architecture.
The following properties apply to any IPv6 home network:
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o Presence of internal routers. The homenet may have one or more
internal routers, or may only provide subnetting from interfaces
on the CER.
o Presence of isolated internal subnets. There may be isolated
internal subnets, with no direct connectivity between them within
the homenet. Isolation may be physical, or implemented via IEEE
802.1q VLANs.
o Demarcation of the CER. The CER(s) may or may not be managed by
the ISP. If the demarcation point is such that the customer can
provide or manage the CER, its configuration must be simple. Both
models must be supported.
It has also been suggested that various forms of multihoming are more
prevalent with IPv6 home networks. Thus the following properties may
also apply to such networks:
o Number of upstream providers. A typical homenet might just have a
single upstream ISP, but it may become more common for there to be
multiple ISPs, whether for resilience or provision of additional
services. Each would offer its own prefix. Some may or may not
be walled gardens.
o Number of CERs. The homenet may have a single CER, which might be
used for one or more providers, or multiple CERs. Multiple CERs
adds additional complexity for multihoming scenarios, and
protocols like PCP that need to manage connection-oriented state
mappings.
Some separate discussion of physical infrastructures for homenets is
included in and [I-D.arkko-homenet-physical-standard].
In the following sections we show some example homenet models.
3.1.1. A: Single ISP, Single CER, Internal routers
Figure 1 shows a network with multiple local area networks. These
may be needed for reasons relating to different link layer
technologies in use or for policy reasons, e.g. classic Ethernet in
one subnet and a LLN link layer technology in another. In this
example there is no single router that a priori understands the
entire topology. The topology itself may also be complex, and it may
not be possible to assume a pure tree form, for instance. This is a
valid consideration as home users may plug routers together to form
arbitrary topologies including loops (we discuss support for
arbitrary topologies in layer sections).
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+-------+-------+ \
| Service | \
| Provider | | Service
| Router | | Provider
+-------+-------+ | network
| /
| Customer /
| Internet connection
|
+------+--------+ \
| IPv6 | \
| Customer Edge | \
| Router | |
+----+-+---+----+ |
Network A | | | Network B/E |
----+-------------+----+ | +---+-------------+------+ |
| | | | | | | |
+----+-----+ +-----+----+ | +----+-----+ +-----+----+ | |
|IPv6 Host | |IPv6 Host | | | IPv6 Host| |IPv6 Host | | |
| | | | | | | | | | |
+----------+ +----------+ | +----------+ +----------+ | |
| | | | |
| ---+------+------+-----+ |
| | Network B/E |
+------+--------+ | | End-User
| IPv6 | | | networks
| Interior +------+ |
| Router | |
+---+-------+-+-+ |
Network C | | Network D |
----+-------------+---+- --+---+-------------+--- |
| | | | |
+----+-----+ +-----+----+ +----+-----+ +-----+----+ |
|IPv6 Host | |IPv6 Host | | IPv6 Host| |IPv6 Host | |
| | | | | | | | /
+----------+ +----------+ +----------+ +----------+ /
Figure 1
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3.1.2. B: Two ISPs, Two CERs, Shared subnet
+-------+-------+ +-------+-------+ \
| Service | | Service | \
| Provider A | | Provider B | | Service
| Router | | Router | | Provider
+------+--------+ +-------+-------+ | network
| | /
| Customer | /
| Internet connections | /
| |
+------+--------+ +-------+-------+ \
| IPv6 | | IPv6 | \
| Customer Edge | | Customer Edge | \
| Router 1 | | Router 2 | /
+------+--------+ +-------+-------+ /
| | /
| | | End-User
---+---------+---+---------------+--+----------+--- | network(s)
| | | | \
+----+-----+ +-----+----+ +----+-----+ +-----+----+ \
|IPv6 Host | |IPv6 Host | | IPv6 Host| |IPv6 Host | /
| | | | | | | | /
+----------+ +----------+ +----------+ +----------+
Figure 2
Figure 2 illustrates a multihomed home network model, where the
customer has connectivity via CER1 to ISP A and via CER2 to ISP B.
This example shows one shared subnet where IPv6 nodes would
potentially be multihomed and receive multiple IPv6 global addresses,
one per ISP. This model may also be combined with that shown in
Figure 1 to create a more complex scenario with multiple internal
routers. Or the above shared subnet may be split in two, such that
each CER serves a separate isolated subnet, which is a scenario seen
with some IPv4 networks today.
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3.1.3. C: Two ISPs, One CER, Shared subnet
+-------+-------+ +-------+-------+ \
| Service | | Service | \
| Provider A | | Provider B | | Service
| Router | | Router | | Provider
+-------+-------+ +-------+-------+ | network
| | /
| Customer | /
| Internet | /
| connections | |
+---------+---------+ \
| IPv6 | \
| Customer Edge | \
| Router | /
+---------+---------+ /
| /
| | End-User
---+------------+-------+--------+-------------+--- | network(s)
| | | | \
+----+-----+ +----+-----+ +----+-----+ +-----+----+ \
|IPv6 Host | |IPv6 Host | | IPv6 Host| |IPv6 Host | /
| | | | | | | | /
+----------+ +----------+ +----------+ +----------+
Figure 3
Figure 3 illustrates a model where a home network may have multiple
connections to multiple providers or multiple logical connections to
the same provider, with shared internal subnets.
3.2. Determining the Requirements
[RFC6204] defines "basic" requirements for IPv6 Customer Edge
Routers, while [I-D.ietf-v6ops-ipv6-cpe-router-bis] describes
"advanced" features. In general, home network equipment needs to
cope with the different types of network properties and topologies
discussed above. Manual configuration is rarely, if at all,
possible, given the knowledge level of typical home users. The
equipment needs to be prepared to handle at least
o Routing
o Prefix configuration for routers
o Name resolution
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o Service discovery
o Network security
The remainder of the architecture document is presented as
considerations and principles that lead to more specific requirements
for the five general areas listed above.
3.3. Considerations
This section lists some considerations for home networking that may
affect the architecture and associated requirements.
3.3.1. Multihoming
A homenet may be multihomed to multiple providers. This may either
take a form where there are multiple isolated networks within the
home a more integrated network where the connectivity selection is
dynamic. Current practice is typically of the former kind, but the
latter is expected to become more commonplace.
In an integrated network, specific appliances or applications may use
their own external connectivity, or the entire network may change its
connectivity based on the status of the different upstream
connections. The complexity of the multihoming solution required
will depend on the Network Model deployed. For example, Network
Model C in the previous section has a single CER and thus could
perform source routing at the single network exit point.
The general approach for IPv6 multihoming is for a host to receive
multiple addresses from multiple providers, and to select the
appropriate source address to communicate via a given provider. An
alternative is to deploy ULAs with a site and then use NPTv6
[RFC6296], a prefix translation-based mechanism, at the edge. This
obviously comes at some architectural cost, which is why approaches
such as [I-D.v6ops-multihoming-without-ipv6nat] have been suggested.
There has been much work on multihoming in the IETF, without (yet)
widespread deployment of proposed solutions.
Host-based methods such as Shim6 [RFC5533] have been defined, but of
course require support in the hosts. There are also application-
oriented approaches such as Happy Eyeballs
[I-D.ietf-v6ops-happy-eyeballs] exist; simplified versions of this
are implemented in some commonly used web browsers for example.
There are some other multihoming considerations for homenet
scenarios. First, it may be the case that multihoming applies due to
an ISP migration from a transition method to a native deployment,
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e.g. a 6rd [RFC5969] sunset scenario. Second, one upstream may be a
"walled garden", and thus only appropriate to be used for
connectivity to the services of that provider.
If the homenet architecture supports multihoming, additional
requirements apply. The general multihoming problem is broad, and
solutions may include complex architectures for monitoring
connectivity, traffic engineering, identifier-locator separation,
connection survivability across multihoming events, and so on. This
implies that if there is any support for multihoming defined in the
homenet architecture it should be limited to a very small subset of
the overall problem.
The current set of assumptions and requirements proposed by the
homenet architecture team is:
MH1) The homenet WG should not try to make another attempt at
solving complex multihoming; we should prefer to support
scenarios for which solutions exist today.
MH2) Single CER Network Model C is in scope, and may be solved by
source routing at the CER.
MH3) The architecture does not support deployment of NPTv6 [RFC6296]
at the CER. Hosts should be multi-addressed with globally
unique prefixes from each ISP they may communicate with or
through.
MH4) Solutions that require host changes should be avoided, but
solutions which incrementally improve with host changes may be
acceptable.
MH5) Walled garden multihoming is in scope.
MH6) Transition method sunsetting is in scope. The topic of
multihoming with specific (6rd) transition coexistence is
discussed in [I-D.townsley-troan-ipv6-ce-transitioning].
MH7) "Just" picking the right source address to use to fall foul of
ingress filtering on upstream ISP connections (as per Network
Model B) is not a trivial task. A solution is highly
desirable, but not required in the baseline homenet
architecture.
MH8) A multihoming model for multiple CERs based on
[I-D.baker-fun-multi-router] requires source routing throughout
the homenet and thus relatively significant routing changes to
"guarantee" routing the packet to the correct exit given the
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source address. Thus this approach is currently out of scope
for homenet.
Thus the homenet multihoming support is focused on the single CER
model.
3.3.2. Quality of Service
Support for QoS in a multi-service homenet may be a requirement, e.g.
for a critical system (perhaps healthcare related), or for
differentiation between different types of traffic (file sharing,
cloud storage, live streaming, VoIP, etc). Different media types may
have different such properties or capabilities.
However, homenet scenarios should require no new QoS protocols. A
DiffServ [RFC2475] approach with a small number of predefined traffic
classes should generally be sufficient, though at present there is
little experience of QoS deployment in home networks.
There may also be complementary mechanisms that could be beneficial
to application performance and behaviour in the homenet domain, such
as ensuring proper buffering algorithms are used as described in
[Gettys11].
3.3.3. Operations and Management
The homenet should be self-organising and configuring as far as
possible, and thus not be pro-actively managed by the home user.
Thus protocols to manage the network are not discussed in detail in
the architecture text.
However, users may be interested in the status of their networks and
devices on the network, in which case simplified monitoring
mechanisms may be desirable. It may also be the case that an ISP, or
a third party, might offer management of the homenet on behalf of a
user, in which case management protocols would be required. The
SNMPv3 family of protocols described in [RFC3411] and friends may be
appropriate (previous versions are not deemed secure and have been
marked as Historic by the IETF).
3.3.4. Privacy considerations
There are no specific privacy concerns discussed in this text. It
should be noted that many ISPs are expected to offer relatively
stable IPv6 prefixes to customers, and thus the network prefix
associated with the host addresses they use would not generally
change over a reasonable period of time. This exposure is similar to
IPv4 networks that expose the same IPv4 global address via use of
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NAT, where the IPv4 address received from the ISP may change over
time.
3.4. Design Principles and Requirements
There is little that the Internet standards community can do about
the physical topologies or the need for some networks to be separated
at the network layer for policy or link layer compatibility reasons.
However, there is a lot of flexibility in using IP addressing and
inter-networking mechanisms. In this section we discuss how this
flexibility should be used to provide the best user experience and
ensure that the network can evolve with new applications in the
future.
The following principles should be followed when designing homenet
solutions. Where requirements are associated with those principles,
they are listed here. There is no implied priority by the order in
which the principles themselves are listed.
3.4.1. Reuse existing protocols
It is desirable to reuse existing protocols where possible, but at
the same time to avoid consciously precluding the introduction of new
or emerging protocols. A generally conservative approach, giving
weight to running code, is preferable. Where new protocols are
required, evidence of commitment to implementation by appropriate
vendors or development communities is highly desirable. Protocols
used should be backwardly compatible.
Where possible, changes to hosts should be minimised. Some changes
may be unavoidable however, e.g. signalling protocols to punch holes
in firewalls where "Simple Security" is deployed in a CER. Changes
to routers should also be minimised, e.g.
[I-D.baker-fun-routing-class] suggests introducing a routing protocol
that may route on both source and destination addresses, which would
be a significant change compared to current practices.
Liaisons with other appropriate standards groups and related
organisations is desirable, e.g. the IEEE and Wi-Fi Alliance.
RE1) Reuse existing protocols, giving weight to running code.
RE2) Minimise changes to hosts and routers.
RE3) Maintain backwards compatibility where possible.
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3.4.2. Dual-stack Operation
The homenet architecture targets both IPv6-only and dual-stack
networks. While the CER requirements in RFC 6204 are aimed at IPv6-
only networks, it is likely that dual-stack homenets will be the norm
for some period of time. IPv6-only networking may first be deployed
in home networks in "greenfield" scenarios, or perhaps as one element
of an otherwise dual-stack network. The homenet architecture must
operate in the absence of IPv4, and IPv6 must work in the same
scenarios as IPv4 today.
Running IPv6-only may require documentation of additional
considerations such as:
o Ensuring there is a way to access content in the IPv4 Internet.
This can be arranged through incorporating NAT64 [RFC6144] and
DNS64 [RFC6145] functionality in the home gateway router, for
instance.
o DNS discovery mechanisms are enabled for IPv6. Both stateless
DHCPv6 [RFC3736] [RFC3646] and Router Advertisement options
[RFC6106] may have to be supported and turned on by default to
ensure maximum compatibility with all types of hosts in the
network. This requires, however, that a working DNS server is
known and addressable via IPv6.
o All nodes in the home network support operations in IPv6-only
mode. Some current devices work well with dual-stack but fail to
recognise connectivity when IPv4 DHCP fails, for instance.
In dual-stack networks, solutions for IPv6 should not adversely
affect IPv4 operation. It is likely that topologies of IPv4 and IPv6
networks would be as congruent as possible.
Note that specific transition tools, particularly those running on
the border CER to support transition tools being used inside the
homenet, are out of scope. Use of tools, such as 6rd, on the border
CER to support ISP access network transition are to be expected, but
not within scope of homenet, which focuses on the internal
networking.
DS1) The homenet must support IPv6-only or dual-stack operation; it
must thus operate in the absence of IPv4 and IPv6 must work in
the same scenarios as IPv4 today.
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DS2) IPv6 solutions should not adversely affect IPv4 operation.
3.4.3. Largest Possible Subnets
Today's IPv4 home networks generally have a single subnet, and early
dual-stack deployments have a single congruent IPv6 subnet, possibly
with some bridging functionality.
Future home networks are highly likely to have one or more internal
routers and thus need multiple subnets, for the reasons described
earlier. As part of the self-organisation of the network, the
network should subdivide itself to the largest possible subnets that
can be constructed within the constraints of link layer mechanisms,
bridging, physical connectivity, and policy. For instance, separate
subnetworks are necessary where two different link layers cannot be
bridged, or when a policy requires the separation of private and
visitor parts of the network.
While it may be desirable to maximise the chance of link-local
protocols operating across a homenet by maximising the size of a
subnet across the homenet, multiple subnet home networks are
inevitable, so their support must be included. A general
recommendation is to follow the same topology for IPv6 as is used for
IPv4, but not to use NAT. Thus there should be routed IPv6 where an
IPv4 NAT is used, and where there is no NAT there should be bridging
if the link layer allows this.
In some cases IPv4 NAT home networks may feature cascaded NATs, e.g.
where NAT routers are included within VMs or Internet connection
services are used. IPv6 routed versions of such tools will be
required.
SN1) The network should subdivide itself to the largest possible
subnets that can be formed.
SN2) The IPv6 topology should follow the IPv4 topology, but not use
NAT, thus there should be routed IPv6 where IPv4 NAT is used.
3.4.4. Security vs Transparent, End-to-End Communications
An IPv6-based home network architecture should naturally offer a
transparent end-to-end communications model as described in
[RFC2775]. Each device should be addressable by a globally unique
address, and those addresses must not be altered in transit.
Security perimeters can of course restrict the end-to-end
communications, and thus while a host may be globally addressable it
may not be globally reachable. RFC 4864 sets a default deny "Simple
Security" model, in which filtering is to be expected (while host-
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based IPv6 NAT is not). However, RFC 6092 states that while the
default should be default deny, CERs should also have an option to be
put into a "transparent" mode of operation which enables a default
allow model (in which case home devices must be independently
secure). Such end-to-end communications are important for their
robustness against failure of intermediate systems, where in contrast
NAT is dependent on state machines which are not self-healing.
In the presence of "Simple Security" the use of signalling protocols
such as UPnP IGD (Version 2) or PCP may be expected to punch holes in
the firewall (and be able to handle cases where there are multiple
CERs/firewall(s). When configuring holes in filters, protocols for
securely associating devices are desirable.
EE1) The homenet should embrace transparent, end-to-end
communications to, from and within the homenet.
EE2) The default security model at the homenet border is "Simple
Security" (default deny).
EE3) Where "Simple Security" is applied, there must be support for
an appropriate signalling protocol to open per-application
holes for communications.
EE4) The homenet should also support a "transparent" mode of
operation at its borders if configured to do so.
EE5) Users should have simple methods to associate devices to
services that are expected to operate through borders at which
"Simple Security" is applied.
3.4.5. IP Connectivity between All Nodes
A logical consequence of the end-to-end communications model is that
the network should by default attempt to provide IP-layer
connectivity between all internal parts as well as between the
internal parts and the Internet. This connectivity should be
established at the link layer, if possible, and using routing at the
IP layer otherwise.
Local addressing (ULAs) may be used within the scope of a home
network to provide a method to route between subnets. It would be
expected that ULAs may be used alongside one or more globally unique
ISP-provided addresses/prefixes in a homenet. ULAs may be used for
all devices, not just those intended to have internal connectivity
only. ULAs may then be used for stable internal communications
should the ISP-provided prefix (suddenly) change, or external
connectivity be temporarily lost. The use of ULAs should be
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restricted to the homenet scope through filtering at the border(s) of
the homenet; thus "end-to-end" for ULAs is limited to the homenet.
In some cases full internal connectivity may not be desirable, e.g.
in certain utility networking scenarios, or where filtering is
required for policy reasons against guest network subnet(s). Certain
scenarios may require co-existence of ISP connectivity providing a
general Internet service with provider connectivity to a private
"walled garden" network.
Some home networking scenarios/models may involve isolated subnet(s)
with their own CERs. In such cases connectivity would only be
expected within each isolated network (though traffic may potentially
pass between them via external providers).
LLNs provide an example of where there may be secure perimeters
inside the homenet. Constrained LLN nodes may implement WPA-style
network key security but may depend on access policies enforced by
the LLN border router.
CN1) The homenet should utilise ULAs to provide stable addressing in
the event of there being no global prefix available or changes
in the global prefix.
CN2) ULAs must be filtered at the homenet site border(s).
CN3) Walled garden connectivity must be supported.
CN4) Isolated networks within the homenet must be supported.
3.4.6. Routing functionality
Routing functionality is required when there are multiple routers
deployed within the internal home network. This functionality could
be as simple as the current "default route is up" model of IPv4 NAT,
or it could involve running an appropriate routing protocol.
The homenet routing environment may include traditional IP networking
where existing link-state or distance-vector protocols may be used,
but also new LLN or other "constrained" networks where other
protocols may be more appropriate. IPv6 VM solutions may also add
additional routing requirements. Current home deployments use
largely different mechanisms in sensor and basic Internet
connectivity networks.
In this section we list the assumptions and requirements for routing
functionality within the homenet environment.
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RT1) The protocol should preferably be an existing deployed
protocol that has been shown to be reliable and robust.
RT2) It is preferable that the protocol is "lightweight".
RT3) The protocol should be able to provide reachability between
all nodes in the homenet.
RT4) In general, LLN or other networks should be able to attach and
participate the same way as the main homenet, or alternatively
map/be gatewayed to the main homenet.
RT5) Multiple interface PHYs must be accounted for in the homenet
routed topology. Technologies such as Ethernet, WiFi, MoCA,
etc must be capable of coexisting in the same environment and
should be treated as part of any routed deployment. The
inclusion of the PHY layer characteristics including
bandwidth, loss, and latency in path computation should be
considered for optimising communication in the homenet.
RT6) Minimising convergence time should be a goal in any routed
environment, but as a guideline a maximum convergence time of
a couple of minutes should be the target.
RT7) It is desirable that the routing protocol has knowledge of the
homenet topology, which implies a link-state protocol may be
preferable. If so, it is also desirable that the
announcements and use of LSAs and RAs are appropriately
coordinated.
RT8) Any routed solution will require a means for determining the
boundaries of the homenet. Borders may include but are not
limited to the interface to the upstream ISP, a gateway device
to a separate home network such as a SmartGrid or similar LLN
network. In some cases there may be no border such as before
an upstream connection has been established. Devices in the
homenet must be able to find the path to the Internet as well
as other devices on the home intranet. The border discovery
functionality may be integrated into the routing protocol
itself, but may also be imported via a separate discovery
mechanism.
RT9) The routing environment should be self-configuring, as
discussed in the next subsection. An example of how OSPFv3
can be self-configuring in a homenet is described in
[I-D.acee-ospf-ospfv3-autoconfig]. An exception is
configuration of a "secret" for authentication methods.
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RT10) The protocol should not require upstream ISP connectivity to
be established to continue routing within the homenet.
RT11) Multiple upstreams should be supported, as described in the
multihoming section earlier. The primary target for
multihoming support is the single CER case (where source
routing may assist path selection).
RT12) To support multihoming within a homenet, a routing protocol
that can make routing decisions based on source and
destination addresses is desirable, to avoid upstream ISP
ingress filtering problems. In general the routing protocol
should support multiple ISP uplinks and delegated prefixes in
concurrent use.
RT13) Load-balancing to multiple providers is not a requirement, but
failover from a primary to a backup link when available must
be a requirement.
RT14) It is assumed that the typical router designed for residential
use does not contain the memory or CPU required to process a
full Internet routing table this should not be a requirement
for any homenet device.
A new I-D has been published on homenet routing requirements, see
[I-D.howard-homenet-routing-comparison] and evaluations of common
routing protocols made against those requirements, see
[I-D.howard-homenet-routing-requirements]. The requirements from the
former document have been worked into this architecture text.
3.4.7. Self-Organising
A home network architecture should be naturally self-organising and
self-configuring under different circumstances relating to the
connectivity status to the Internet, number of devices, and physical
topology. While the homenet should be self-organising, it should be
possible to manually adjust (override) the current configuration.
The homenet will need to be aware of the extent of its own "site".
The homenet will have one or more borders, with external connectivity
providers and potentially parts of the internal network (e.g. for
policy-based reasons). It should be possible to automatically
perform border discovery at least for the ISP borders. Such borders
determine for example the scope of ULAs, service discovery
boundaries, site scope multicast boundaries and where firewall
policies may be applied.
The most important function in this respect is prefix delegation and
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management. The assumptions and requirements for the prefix
delegation function are summarised as follows:
PD1) From the homenet perspective, a single prefix from each ISP
should be received on the border CER [RFC3633]. The ISP
should only see that aggregate, and not single /64 prefixes
allocated within the homenet.
PD2) Each link in the homenet should receive a prefix from within
the ISP-provided prefix(es).
PD3) Delegation should be autonomous, and not assume a flat or
hierarchical model.
PD4) The assignment mechanism should provide reasonable efficiency,
so that typical home network prefix allocation sizes can
accommodate all the necessary /64 allocations in most cases.
A currently typical /60 allocation gives 16 /64 subnets.
PD5) Duplicate assignment of multiple /64s to the same network
should be avoided.
PD6) The network should behave as gracefully as possible in the
event of prefix exhaustion. The options in such cases may
however be limited.
PD7) Where multiple CERs exist with multiple ISP prefix pools, it
is expected that routers within the homenet would assign
themselves prefixes from each ISP they communicate with/
through.
PD8) Where ULAs are used, most likely but not necessarily in
parallel with global prefixes, one router will need to be
elected to offer ULA prefixes for the homenet. The router
should generate a /48 ULA for the site, and then delegate
/64's from that ULA prefix to subnets.
PD9) Delegation within the homenet should give each link a prefix
that is persistent across reboots, power outages and similar
short-term outages.
PD10) Addition of a new routing device should not affect existing
persistent prefixes, but persistence may not be expected in
the face of significant "replumbing" of the homenet.
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PD11) Persistent prefixes should not depend on router boot order.
PD12) Persistent prefixes may imply the need for stable storage on
routing devices, and also a method for a home user to "reset"
the stored prefix should a significant reconfiguration be
required (though ideally the home user should not be involved
at all).
PD13) The delegation method should support "flash" renumbering. As
a minimum, delegated ULA prefixes within the homenet should
remain persistent through an ISP-driven renumbering event.
Several proposals have been made for prefix delegation within a
homenet. One group of proposals is based on DHCPv6 PD, as described
in [I-D.baker-homenet-prefix-assignment],
[I-D.chakrabarti-homenet-prefix-alloc], [RFC3315] and [RFC3633]. The
other uses OSPFv3, as described in
[I-D.arkko-homenet-prefix-assignment]. More detailed analysis of
these approaches needs to be made against the requirements/
assumptions listed above.
Other parameters of the network will need to be self-organising. The
network elements will need to be integrated in a way that takes
account of the various lifetimes on timers that are used on those
different elements, e.g. DHCPv6 PD, router, valid prefix and
preferred prefix timers.
The network cannot be expected to be completely self-organising, e.g.
some security parameters are likely to need manual configuration,
e.g. WPA2 configuration for wireless access control. Some existing
mechanisms exist to assist home users to associate devices as simply
as possible, e.g. "connect" button support.
ZC1) The homenet must as far as possible be self-organising and
self-configuring.
ZC2) Manual override of the configuration should be possible.
ZC3) The homenet must be able to determine where its own borders
lie.
ZC4) The homenet "site" defines the borders for ULAs, site scope
multicast, service discovery and security policies.
ZC5) It is important that self-configuration with "unintended"
devices is avoided. Methods are needed for devices to know
whether they are intended to be part of the same homenet site
or not.
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3.4.8. Fewest Topology Assumptions
There should ideally be no built-in assumptions about the topology in
home networks, as users are capable of connecting their devices in
ingenious ways. Thus arbitrary topologies will need to be supported.
It is important not to introduce new IPv6 scenarios that would break
with IPv4+NAT, given that dual-stack homenets will be commonplace for
some time. There may be IPv6-only topologies that work where IPv4 is
not used or required.
ZC1) Arbitrary topologies should be supported.
3.4.9. Naming and Service Discovery
The most natural way to think about naming and service discovery
within a homenet is to enable it to work across the entire residence
(site), disregarding technical borders such as subnets but respecting
policy borders such as those between visitor and internal networks.
Homenet naming systems will be required that work internally or
externally, be the user within the homenet or outside it, though the
domains used may be different from those different perspectives. It
is possible that not all internal devices should be reflected by name
in an external-facing domain.
A desirable target may be a fully functional self-configuring secure
local DNS service so that all devices can be referred to by name, and
these FQDNs are resolved locally. This would make clean use of ULAs
and multiple ISP-provided prefixes much easier. Such a local DNS
service should be (by default) authoritative for the local name space
in both IPv4 and IPv6. A dual-stack residential gateway should
include a dual-stack DNS server.
Consideration will also need to be given for existing protocols that
may be used within a network, e.g. mDNS, and how these interact with
unicast-based DNS services.
With the introduction of new "dotless" top level domains, there is
potential for ambiguity between for example a local host called apple
and (if it is registered) an apple gTLD, so some local name space is
probably required, which should also be configurable to something
else by a home user, e.g. ".home", if desired. There is also
potential ambiguity if, for example, a mobile device should move
between two local name spaces called ".home".
For service discovery, support may be required for IPv6 multicast
across the scope of the home network. This would be the case if an
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approach to create Extended mDNS (xmDNS) is followed as described in
[I-D.lynn-homenet-site-mdns].
SD1) The homenet must support naming and service discovery
functions.
SD2) All naming and service discovery functions should be able to
function across the entire homenet site if required.
SD3) Disconnected operation ("fate sharing"): name resolution for
reachable devices continues if the local network is
disconnected from the global Internet.
SD4) Message utilisation should be efficient considering the network
technologies the service may need to operate over.
SD5) Devices represented in the homenet name space may also be
represented in the global DNS namespace.
SD6) Site scope IPv6 multicast should be supported across the
homenet.
3.4.10. Proxy or Extend?
Related to the above, the architecture proposes that any existing
protocols (e.g. service discovery) that are designed to only work
within a subnet should be modified/extended to work across subnets,
rather than defining proxy capabilities for each of those functions.
Some protocols already have proxy functions defined and in use, e.g.
DHCPv6 relays, in which case those protocols would be expected to
continue to operate that way.
Feedback is desirable on which other functions/protocols assume
subnet-only operation, in the context of existing home networks.
Some experience from enterprises may be relevant here.
SD1) Prefer to extend protocols to site scope operation rather than
providing proxy functions on subnet boundaries.
3.4.11. Adapt to ISP constraints
Different homenets may be subject to different behaviour by its
ISP(s). The home network may receive an arbitrary length IPv6 prefix
from its provider, e.g. /60 or /56. The offered prefix may be stable
over time or change from time to time. Some ISPs may offer
relatively stable prefixes, while others may change the prefix
whenever the CER is reset. Some discussion of IPv6 prefix allocation
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policies is included in [RFC6177], which discusses why, for example,
a one-size-fits-all /48 allocation is not appropriate. The home
network needs to be adaptable to such ISP policies.
The internal operation of the home network should also not depend on
the availability of the ISP network at any given time, other than for
connectivity to services or systems off the home network. This
implies the use of ULAs as supported in RFC6204. If used, ULA
addresses should be stable so that they can always be used
internally, independent of the link to the ISP.
It is expected that ISPs will deliver a relatively stable home prefix
to customers. The norm for residential customers of large ISPs may
be similar to their single IPv4 address provision; by default it is
likely to remain persistent for some time, but changes in the ISP's
own provisioning systems may lead to the customer's IP (and in the
IPv6 case their prefix pool) changing. It is not expected that ISPs
will support Provider Independent (PI) addressing in general
residential homenets.
When an ISP needs to restructure and in doing so renumber its
customer homenets, "flash" renumbering is likely to be imposed. This
implies a need for the homenet to be able to handle a sudden
renumbering event which, unlike the process described in [RFC4192],
would be a "flag day" event, which means that a graceful renumbering
process moving through a state with two active prefixes in use would
not be possible. While renumbering is an extended version of an
initial numbering process, the difference between flash renumbering
and an initial "cold start" is the need to provide service
continuity. The customer may of course also choose to move to a new
ISP, and thus begin using a new prefix, though in such cases the
customer may expect a discontinuity. Regardless, it's desirable that
homenet protocols support rapid renumbering and operational processes
don't add unnecessary complexity for the renumbering process.
The 6renum WG is studying IPv6 renumbering for enterprise networks.
It is not currently targetting homenets, but may produce outputs that
are relevant.
AD1) The homenet should make no assumptions about the stability of
the prefix received from an ISP, or the length of the prefix
that may be offered.
AD2) The operation of the homenet must not depend on the
availability of the ISP connection.
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AD3) The homenet should support "flash" renumbering. Applications
and services operating within or to/from the homenet should be
as resilient as possible to an external change of delegated
prefix(es).
3.5. Implementing the Architecture on IPv6
This architecture text encourages re-use of existing protocols. Thus
the necessary mechanisms are largely already part of the IPv6
protocol set and common implementations. There are though some
exceptions. For automatic routing, it is expected that existing
routing protocols can be used as is. However, a new mechanism may be
needed in order to turn a selected protocol on by default.
Some functionality, if required by the architecture, would add
significant changes or require development of new protocols, e.g.
support for multihoming with multiple exit routers would require
extensions to support source and destination address based routing
within the homenet.
Some protocol changes are however required in the architecture, e.g.
for name resolution and service discovery, extensions to existing
multicast-based name resolution protocols are needed to enable them
to work across subnets, within the scope of the home network site.
Some of the hardest problems in developing solutions for home
networking IPv6 architectures include discovering the right borders
where the domain "home" ends and the service provider domain begins,
deciding whether some of the necessary discovery mechanism extensions
should affect only the network infrastructure or also hosts, and the
ability to turn on routing, prefix delegation and other functions in
a backwards compatible manner.
4. Conclusions
This text defines principles and requirements for a homenet
architecture. (More to be added.)
5. References
5.1. Normative References
[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
E. Lear, "Address Allocation for Private Internets",
BCP 5, RFC 1918, February 1996.
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[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, December 1998.
[RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network
Address Translator (Traditional NAT)", RFC 3022,
January 2001.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
December 2002.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for
Renumbering an IPv6 Network without a Flag Day", RFC 4192,
September 2005.
[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, October 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC4864] Van de Velde, G., Hain, T., Droms, R., Carpenter, B., and
E. Klein, "Local Network Protection for IPv6", RFC 4864,
May 2007.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007.
[RFC5533] Nordmark, E. and M. Bagnulo, "Shim6: Level 3 Multihoming
Shim Protocol for IPv6", RFC 5533, June 2009.
[RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4
Infrastructures (6rd) -- Protocol Specification",
RFC 5969, August 2010.
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[RFC6092] Woodyatt, J., "Recommended Simple Security Capabilities in
Customer Premises Equipment (CPE) for Providing
Residential IPv6 Internet Service", RFC 6092,
January 2011.
[RFC6204] Singh, H., Beebee, W., Donley, C., Stark, B., and O.
Troan, "Basic Requirements for IPv6 Customer Edge
Routers", RFC 6204, April 2011.
[RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix
Translation", RFC 6296, June 2011.
5.2. Informative References
[RFC2775] Carpenter, B., "Internet Transparency", RFC 2775,
February 2000.
[RFC3646] Droms, R., "DNS Configuration options for Dynamic Host
Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
December 2003.
[RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol
(DHCP) Service for IPv6", RFC 3736, April 2004.
[RFC6106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Options for DNS Configuration",
RFC 6106, November 2010.
[RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for
IPv4/IPv6 Translation", RFC 6144, April 2011.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011.
[RFC6177] Narten, T., Huston, G., and L. Roberts, "IPv6 Address
Assignment to End Sites", BCP 157, RFC 6177, March 2011.
[I-D.baker-fun-multi-router]
Baker, F., "Exploring the multi-router SOHO network",
draft-baker-fun-multi-router-00 (work in progress),
July 2011.
[I-D.lynn-homenet-site-mdns]
Lynn, K. and D. Sturek, "Extended Multicast DNS",
draft-lynn-homenet-site-mdns-00 (work in progress),
March 2012.
[I-D.townsley-troan-ipv6-ce-transitioning]
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Townsley, M. and O. Troan, "Basic Requirements for
Customer Edge Routers - multihoming and transition",
draft-townsley-troan-ipv6-ce-transitioning-02 (work in
progress), December 2011.
[I-D.baker-fun-routing-class]
Baker, F., "Routing a Traffic Class",
draft-baker-fun-routing-class-00 (work in progress),
July 2011.
[I-D.howard-homenet-routing-comparison]
Howard, L., "Evaluation of Proposed Homenet Routing
Solutions", draft-howard-homenet-routing-comparison-00
(work in progress), December 2011.
[I-D.howard-homenet-routing-requirements]
Howard, L., "Homenet Routing Requirements",
draft-howard-homenet-routing-requirements-00 (work in
progress), December 2011.
[I-D.herbst-v6ops-cpeenhancements]
Herbst, T. and D. Sturek, "CPE Considerations in IPv6
Deployments", draft-herbst-v6ops-cpeenhancements-00 (work
in progress), October 2010.
[I-D.vyncke-advanced-ipv6-security]
Vyncke, E., Yourtchenko, A., and M. Townsley, "Advanced
Security for IPv6 CPE",
draft-vyncke-advanced-ipv6-security-03 (work in progress),
October 2011.
[I-D.ietf-v6ops-ipv6-cpe-router-bis]
Singh, H., Beebee, W., Donley, C., Stark, B., and O.
Troan, "Advanced Requirements for IPv6 Customer Edge
Routers", draft-ietf-v6ops-ipv6-cpe-router-bis-01 (work in
progress), July 2011.
[I-D.ietf-6man-rfc3484bis]
Thaler, D., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol version 6
(IPv6)", draft-ietf-6man-rfc3484bis-01 (work in progress),
March 2012.
[I-D.v6ops-multihoming-without-ipv6nat]
Troan, O., Miles, D., Matsushima, S., Okimoto, T., and D.
Wing, "IPv6 Multihoming without Network Address
Translation", draft-v6ops-multihoming-without-ipv6nat-00
(work in progress), March 2011.
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[I-D.baker-homenet-prefix-assignment]
Baker, F. and R. Droms, "IPv6 Prefix Assignment in Small
Networks", draft-baker-homenet-prefix-assignment-01 (work
in progress), March 2012.
[I-D.arkko-homenet-prefix-assignment]
Arkko, J. and A. Lindem, "Prefix Assignment in a Home
Network", draft-arkko-homenet-prefix-assignment-01 (work
in progress), October 2011.
[I-D.acee-ospf-ospfv3-autoconfig]
Lindem, A. and J. Arkko, "OSPFv3 Auto-Configuration",
draft-acee-ospf-ospfv3-autoconfig-01 (work in progress),
March 2012.
[I-D.ietf-pcp-base]
Cheshire, S., Boucadair, M., Selkirk, P., Wing, D., and R.
Penno, "Port Control Protocol (PCP)",
draft-ietf-pcp-base-23 (work in progress), February 2012.
[I-D.ietf-v6ops-happy-eyeballs]
Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with
Dual-Stack Hosts", draft-ietf-v6ops-happy-eyeballs-07
(work in progress), December 2011.
[I-D.chakrabarti-homenet-prefix-alloc]
Nordmark, E., Chakrabarti, S., Krishnan, S., and W.
Haddad, "Simple Approach to Prefix Distribution in Basic
Home Networks", draft-chakrabarti-homenet-prefix-alloc-01
(work in progress), October 2011.
[I-D.arkko-homenet-physical-standard]
Arkko, J. and A. Keranen, "Minimum Requirements for
Physical Layout of Home Networks",
draft-arkko-homenet-physical-standard-00 (work in
progress), March 2012.
[Gettys11]
Gettys, J., "Bufferbloat: Dark Buffers in the Internet",
March 2011,
<http://www.ietf.org/proceedings/80/slides/tsvarea-1.pdf>.
[IGD-2] UPnP Gateway Committee, "Internet Gateway Device (IGD) V
2.0", September 2010, <http://upnp.org/specs/gw/
UPnP-gw-WANIPConnection-v2-Service.pdf>.
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Appendix A. Acknowledgments
The authors would like to thank Brian Carpenter, Mark Andrews, Fred
Baker, Ray Bellis, Cameron Byrne, Brian Carpenter, Stuart Cheshire,
Lorenzo Colitti, Ralph Droms, Lars Eggert, Jim Gettys, Wassim Haddad,
Joel M. Halpern, David Harrington, Lee Howard, Ray Hunter, Joel
Jaeggli, Heather Kirksey, Ted Lemon, Kerry Lynn, Erik Nordmark,
Michael Richardson, Barbara Stark, Sander Steffann, Dave Thaler, JP
Vasseur, Curtis Villamizar, Dan Wing, Russ White, and James Woodyatt
for their contributions within homenet WG meetings and the mailing
list, and Mark Townsley for being an initial editor/author of this
text before taking his position as homenet WG co-chair.
Appendix B. Changes
This section will be removed in the final version of the text.
B.1. Version 02
Changes made include:
o Made the IPv6 implications section briefer.
o Changed Network Models section to describe properties of the
homent with illustrative examples, rather than implying the number
of models was fixed to the six shown in 01.
o Text to state multihoming support focused on single CER model.
Multiple CER support is desirable, but not required.
o Stated that NPTv6 not supported.
o Added considerations section for operations and management.
o Added bullet point principles/requirements to Section 3.4.
o Changed IPv6 solutions must not adversely affect IPv4 to should
not.
o End-to-end section expanded to talk about "Simple Security" and
borders.
o Extended text on naming and service discovery.
o Added reference to RFC 2775, RFC 6177.
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o Added reference to the new xmDNS draft.
o Added naming/SD requirements from Ralph Droms.
Authors' Addresses
Tim Chown (editor)
University of Southampton
Highfield
Southampton, Hampshire SO17 1BJ
United Kingdom
Email: tjc@ecs.soton.ac.uk
Jari Arkko
Ericsson
Jorvas 02420
Finland
Email: jari.arkko@piuha.net
Anders Brandt
Sigma Designs
Emdrupvej 26A, 1
Copenhagen DK-2100
Denmark
Email: abr@sdesigns.dk
Ole Troan
Cisco Systems, Inc.
Drammensveien 145A
Oslo N-0212
Norway
Email: ot@cisco.com
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Jason Weil
Time Warner Cable
13820 Sunrise Valley Drive
Herndon, VA 20171
USA
Email: jason.weil@twcable.com
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