Requirements for IPv6 Customer Edge Routers to Support IPv4 Connectivity as-a-Service
draft-ietf-v6ops-transition-ipv4aas-01
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| Document | Type | Active Internet-Draft (v6ops WG) | |
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| Authors | Jordi Palet Martinez , Hans M.-H. Liu , Masanobu Kawashima | ||
| Last updated | 2018-05-28 | ||
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draft-ietf-v6ops-transition-ipv4aas-01
IPv6 Operations (v6ops) J. Palet Martinez
Internet-Draft The IPv6 Company
Intended status: Informational H. M.-H. Liu
Expires: November 28, 2018 D-Link Systems, Inc.
M. Kawashima
NEC Platforms, Ltd.
May 27, 2018
Requirements for IPv6 Customer Edge Routers to Support IPv4 Connectivity
as-a-Service
draft-ietf-v6ops-transition-ipv4aas-01
Abstract
This document specifies the IPv4 service continuity requirements for
an IPv6 Customer Edge (CE) router, either provided by the service
provider or thru the retail market.
Specifically, this document extends the "Basic Requirements for IPv6
Customer Edge Routers" in order to allow the provisioning of IPv6
transition services for the support of "IPv4 as-a-Service" (IPv4aaS)
by means of new transition mechanisms. The document only covers
transition technologies for delivering IPv4 in IPv6-only access
networks, commonly called "IPv4 as-a-Service" (IPv4aaS), as required
in a world where IPv4 addresses are no longer available, so hosts in
the customer LANs with IPv4-only or IPv6-only applications or
devices, requiring to communicate with IPv4-only services at the
Internet, are still able to do so.
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 https://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 November 28, 2018.
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Copyright Notice
Copyright (c) 2018 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
(https://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 - Special Note . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. General Requirements . . . . . . . . . . . . . . . . . . 4
3.2. LAN-Side Configuration . . . . . . . . . . . . . . . . . 4
3.3. Transition Technologies Support for IPv4 service
continuity (IPv4 as-a-Service - IPv4aaS) . . . . . 5
3.3.1. 464XLAT . . . . . . . . . . . . . . . . . . . . . . . 5
3.3.2. Dual-Stack Lite (DS-Lite) . . . . . . . . . . . . . . 6
3.3.3. Lightweight 4over6 (lw4o6) . . . . . . . . . . . . . 7
3.3.4. MAP-E . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3.5. MAP-T . . . . . . . . . . . . . . . . . . . . . . . . 8
4. IPv4 Multicast Support . . . . . . . . . . . . . . . . . . . 9
5. UPnP Support . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Differences from RFC7084 . . . . . . . . . . . . . . . . . . 9
7. Code Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
11. Annex A: Usage Scenarios . . . . . . . . . . . . . . . . . . 10
12. Annex B: End-User Network Architecture . . . . . . . . . . . 12
13. ANNEX C: Changes from -00 . . . . . . . . . . . . . . . . . . 15
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
14.1. Normative References . . . . . . . . . . . . . . . . . . 15
14.2. Informative References . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Introduction
This document defines IPv4 service continuity features over an
IPv6-only network, for a residential or small-office router, referred
to as an "IPv6 Transition CE Router", in order to establish an
industry baseline for transition features to be implemented on such a
router.
These routers are likely to rely upon "Basic Requirements for IPv6
Customer Edge Routers" ([RFC7084]), so the scope of this document is
to ensure the IPv4 "service continuity" support, in the LAN side and
the access to IPv4-only Internet services from an IPv6-only access
WAN even from IPv6-only applications or devices in the LAN side.
This document covers a set of IP transition techniques required when
ISPs have an IPv6-only access network. This is a common situation in
a world where IPv4 addresses are no longer available, so the service
providers need to provision IPv6-only WAN access. At the same time,
they need to ensure that both IPv4-only and IPv6-only devices or
applications in the customer networks, can still reach IPv4-only
devices and applications in the Internet.
This document specifies the IPv4 service continuity mechanisms to be
supported by an IPv6 Transition CE Router, and relevant provisioning
or configuration information differences from [RFC7084].
This document is not a recommendation for service providers to use
any specific transition mechanism.
Automatic provisioning of more complex topology than a single router
with multiple LAN interfaces may be handled by means of HNCP
([RFC7788]), which is out of the scope of this document.
Service providers who specify feature sets for IPv6 Transition CE
Router MAY specify a different set of features than those included in
this document. Since it is impossible to know prior to sale which
transition mechanism a device will need over the lifetime of the
device, IPv6 Transition CE Router intended for the retail market MUST
support all of them.
A complete description of "Usage Scenarios" and "End-User Network
Architecture" is provided in Annex A and B, respectively.
1.1. Requirements Language - Special Note
Unlike other IETF documents, the key words "MUST", "MUST NOT",
"REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in this document are not used as
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described in RFC 2119 [RFC2119]. This document uses these keywords
not strictly for the purpose of interoperability, but rather for the
purpose of establishing industry-common baseline functionality. As
such, the document points to several other specifications to provide
additional guidance to implementers regarding any protocol
implementation required to produce a successful IPv6 Transition CE
Router that interoperates successfully with a particular subset of
currently deploying and planned common IPv6-only access networks.
2. Terminology
This document uses the same terms as in [RFC7084], with minor
clarifications.
"IPv4aaS" stands for "IPv4 as-a-Service", meaning transition
technologies for delivering IPv4 in IPv6-only access networks.
The term "IPv6 transition Customer Edge Router with IPv4aaS"
(shortened as "IPv6 Transition CE Router") is defined as an "IPv6
Customer Edge Router" that provides features for the delivery of IPv4
services over an IPv6-only WAN network including IPv6-IPv4
communications.
The "WAN Interface" term used across this document, means that can
also support link technologies based in Internet-layer (or higher-
layers) "tunnels", such as IPv4-in-IPv6 tunnels.
3. Requirements
The IPv6 Transition CE Router MUST comply with [RFC7084] (Basic
Requirements for IPv6 Customer Edge Routers).
3.1. General Requirements
A new general requirement is added, in order to ensure that the IPv6
Transition CE Router respects the IPv6 prefix length as a parameter:
G-6 The IPv6 Transition CE Router MUST comply with [RFC7608] (IPv6
Prefix Length Recommendation for Forwarding).
3.2. LAN-Side Configuration
A new LAN requirement is added, which in fact is common in regular
IPv6 Transition CE Router, and it is required by most of the
transition mechanisms:
L-15 The IPv6 Transition CE Router SHOULD implement a DNS proxy as
described in [RFC5625] (DNS Proxy Implementation Guidelines).
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3.3. Transition Technologies Support for IPv4 service continuity (IPv4
as-a-Service - IPv4aaS)
The main target of this document is the support of IPv6-only WAN
access. To enable legacy IPv4 functionality, this document also
includes the support of IPv4-only devices and applications in the
customers LANs, as well as IPv4-only services on the Internet. Thus,
both IPv4-only and the IPv6-only devices inside the IPv6 Transition
CE Router are able to reach the IPv4-only services.
This document takes no position on simultaneous operation of any
transition mechanism and native IPv4.
In order to seamlessly provide the IPv4 Service Continuity in
Customer LANs, allowing an automated IPv6 transition mechanism
provisioning, general transition requirements are added.
General transition requirements:
TRANS-1: If more than one S46 mechanism is supported, the IPv6
Transition CE Router MUST support the DHCPv6 S46 priority
option described in [RFC8026] (Unified IPv4-in-IPv6
Softwire Customer Premises Equipment (CPE): A DHCPv6-Based
Prioritization Mechanism).
TRANS-2: The IPv6 Transition CE Router MUST verify if the WAN link
supports native IPv4. In that case, transition mechanisms
SHOULD NOT be automatically enabled for that interface.
TRANS-3: If native IPv4 is not available and 464XLAT [RFC6877] is
supported, the IPv6 Transition CE Router MUST enable the
CLAT (in order to automatically configure 464XLAT
[RFC6877]). If 464XLAT [RFC6877] is not supported, and
more than one S46 mechanism is supported, following
Section 1.4 of [RFC8026], MUST check for a valid match in
OPTION_S46_PRIORITY, which will allow configuring any of
the other transition mechanisms.
The following sections describe the requirements for supporting
transition mechanisms.
3.3.1. 464XLAT
464XLAT [RFC6877] is a technique to provide IPv4 service over an
IPv6-only access network without encapsulation. This architecture
assumes a NAT64 [RFC6146] (Stateful NAT64: Network Address and
Protocol Translation from IPv6 Clients to IPv4 Servers) function
deployed at the service provider or a third-party network.
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The IPv6 Transition CE Router SHOULD support CLAT functionality. If
464XLAT is supported, it MUST be implemented according to [RFC6877].
The following IPv6 Transition CE Router requirements also apply:
464XLAT requirements:
464XLAT-1: The IPv6 Transition CE Router MUST perform IPv4 Network
Address Translation (NAT) on IPv4 traffic translated
using the CLAT, unless a dedicated /64 prefix has been
acquired using DHCPv6-PD [RFC3633] (IPv6 Prefix Options
for DHCPv6).
464XLAT-2: The IPv6 Transition CE Router SHOULD support IGD-PCP IWF
[RFC6970] (UPnP Internet Gateway Device - Port Control
Protocol Interworking Function).
464XLAT-3: If PCP ([RFC6887]) is implemented, the IPv6 Transition CE
Router MUST also implement [RFC7291] (DHCP Options for
the PCP). If no PCP server is configured, the IPv6
Transition CE Router MAY verify if the default gateway,
or the NAT64 is the PCP server. A plain IPv6 mode is
used to send PCP requests to the server.
464XLAT-4: The IPv6 Transition CE Router MUST implement [RFC7050]
(Discovery of the IPv6 Prefix Used for IPv6 Address
Synthesis) in order to discover the PLAT-side translation
IPv4 and IPv6 prefix(es)/suffix(es). The IPv6 Transition
CE Router MUST follow [RFC7225] (Discovering NAT64 IPv6
Prefixes Using the PCP), in order to learn the PLAT-side
translation IPv4 and IPv6 prefix(es)/suffix(es) used by
an upstream PCP-controlled NAT64 device.
3.3.2. Dual-Stack Lite (DS-Lite)
Dual-Stack Lite [RFC6333] enables both continued support for IPv4
services and incentives for the deployment of IPv6. It also de-
couples IPv6 deployment in the service provider network from the rest
of the Internet, making incremental deployment easier. Dual-Stack
Lite enables a broadband service provider to share IPv4 addresses
among customers by combining two well-known technologies: IP in IP
(IPv4-in-IPv6) and Network Address Translation (NAT). It is expected
that DS-Lite traffic is forwarded over the IPv6 Transition CE
Router's native IPv6 WAN interface, and not encapsulated in another
tunnel.
The IPv6 Transition CE Router SHOULD implement DS-Lite [RFC6333]
functionality. If DS-Lite is supported, it MUST be implemented
according to [RFC6333]. The following IPv6 Transition CE Router
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requirements also apply:
DS-Lite requirements:
DSLITE-1: The IPv6 Transition CE Router MUST support configuration
of DS-Lite via the DS-Lite DHCPv6 option [RFC6334] (DHCPv6
Option for Dual-Stack Lite). The IPv6 Transition CE
Router MAY use other mechanisms to configure DS-Lite
parameters. Such mechanisms are outside the scope of this
document.
DSLITE-2: The IPv6 Transition CE Router SHOULD support IGD-PCP IWF
[RFC6970] (UPnP Internet Gateway Device - Port Control
Protocol Interworking Function).
DSLITE-3: If PCP ([RFC6887]) is implemented, the IPv6 Transition CE
Router SHOULD also implement [RFC7291] (DHCP Options for
the PCP). If PCP ([RFC6887]) is implemented and a PCP
server is not configured, the IPv6 Transition CE Router
MUST assume, by default, that the AFTR is the PCP server.
A plain IPv6 mode is used to send PCP requests to the
server.
DSLITE-4: The IPv6 Transition CE Router MUST NOT perform IPv4
Network Address Translation (NAT) on IPv4 traffic
encapsulated using DS-Lite ([RFC6333]).
3.3.3. Lightweight 4over6 (lw4o6)
Lw4o6 [RFC7596] specifies an extension to DS-Lite, which moves the
NAPT function from the DS-Lite tunnel concentrator to the tunnel
client located in the IPv6 Transition CE Router, removing the
requirement for a CGN function in the tunnel concentrator and
reducing the amount of centralized state.
The IPv6 Transition CE Router SHOULD implement lw4o6 functionality.
If DS-Lite is implemented, lw4o6 SHOULD be supported as well. If
lw4o6 is supported, it MUST be implemented according to [RFC7596].
The following IPv6 Transition CE Router requirements also apply:
Lw4o6 requirements:
LW4O6-1: The IPv6 Transition CE Router MUST support configuration of
lw4o6 via the lw4o6 DHCPv6 options [RFC7598] (DHCPv6
Options for Configuration of Softwire Address and Port-
Mapped Clients). The IPv6 Transition CE Router MAY use
other mechanisms to configure lw4o6 parameters. Such
mechanisms are outside the scope of this document.
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LW4O6-2: The IPv6 Transition CE Router MUST support the DHCPv4-over-
DHCPv6 (DHCP 4o6) transport described in [RFC7341] (DHCPv4-
over-DHCPv6 Transport).
LW4O6-3: The IPv6 Transition CE Router MAY support Dynamic
Allocation of Shared IPv4 Addresses as described in
[RFC7618] (Dynamic Allocation of Shared IPv4 Addresses).
3.3.4. MAP-E
MAP-E [RFC7597] is a mechanism for transporting IPv4 packets across
an IPv6 network using IP encapsulation, including an algorithmic
mechanism for mapping between IPv6 addresses and IPv4 addresses as
well as transport-layer ports.
The IPv6 Transition CE Router SHOULD support MAP-E functionality. If
MAP-E is supported, it MUST be implemented according to [RFC7597].
The following IPv6 Transition CE Router requirements also apply:
MAP-E requirements:
MAPE-1: The IPv6 Transition CE Router MUST support configuration of
MAP-E via the MAP-E DHCPv6 options [RFC7598] (DHCPv6 Options
for Configuration of Softwire Address and Port-Mapped
Clients). The IPv6 Transition CE Router MAY use other
mechanisms to configure MAP-E parameters. Such mechanisms
are outside the scope of this document.
MAPE-2: The IPv6 Transition CE Router MAY support Dynamic Allocation
of Shared IPv4 Addresses as described in [RFC7618] (Dynamic
Allocation of Shared IPv4 Addresses).
3.3.5. MAP-T
MAP-T [RFC7599] is a mechanism similar to MAP-E, differing from it in
that MAP-T uses IPv4-IPv6 translation, rather than encapsulation, as
the form of IPv6 domain transport.
The IPv6 Transition CE Router SHOULD support MAP-T functionality. If
MAP-T is supported, it MUST be implemented according to [RFC7599].
The following IPv6 Transition CE Router requirements also apply:
MAP-T requirements:
MAPT-1: The IPv6 Transition CE Router MUST support configuration of
MAP-T via the MAP-T DHCPv6 options [RFC7598] (DHCPv6 Options
for Configuration of Softwire Address and Port-Mapped
Clients). The IPv6 Transition CE Router MAY use other
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mechanisms to configure MAP-T parameters. Such mechanisms
are outside the scope of this document.
MAPT-2: The IPv6 Transition CE Router MAY support Dynamic Allocation
of Shared IPv4 Addresses as described in [RFC7618] (Dynamic
Allocation of Shared IPv4 Addresses).
4. IPv4 Multicast Support
Actual deployments support IPv4 multicast for services such as IPTV.
In the transition phase it is expected that multicast services will
still be provided using IPv4 to the customer LANs.
If the IPv6 Transition CE Router supports delivery of IPv4 multicast
services, then it MUST support [RFC8114] (Delivery of IPv4 Multicast
Services to IPv4 Clients over an IPv6 Multicast Network) and
[RFC8115] (DHCPv6 Option for IPv4-Embedded Multicast and Unicast IPv6
Prefixes).
5. UPnP Support
UPnP SHOULD be disabled by default on the IPv6 Transition CE Router
when using an IPv4aaS transition mechanism.
UPnP MAY be enabled when a IPv6 Transition CE Router is configured to
use a stateless mechanism that allows unsolicited inbound packets
through to the CE, such as MAP or LW4o6, or when configured with an a
port set containing all 65535 ports, e.g. with an IPv4 address
sharing ratio of 1.
If UPnP is enabled on a IPv6 Transition CE Router, the UPnP agent
MUST reject any port mapping requests for ports outside of the port
set allocated to the IPv6 Transition CE Router.
UPnP MAY also be enabled on a IPv6 Transition CE Router configured
for IPv4aaS mechanisms that support PCP [RFC6887], if implemented in
conjunction with a method to control the external port mapping, such
as IGD-PCP IWF [RFC6970].
A IPv6 Transition CE Router that implements a UPnP agent, SHOULD
support the Open Connectivity Foundation's IGD:2 specification,
including the AddAnyPortMapping() function.
6. Differences from RFC7084
This document no longer consider the need to support 6rd ([RFC5969])
and includes slightly different requirements for DS-LITE [RFC6333].
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7. Code Considerations
One of the apparent main issues for vendors to include new
functionalities, such as support for new transition mechanisms, is
the lack of space in the flash (or equivalent) memory. However, it
has been confirmed from existing open source implementations
(OpenWRT/LEDE, Linux, others), that adding the support for the new
transitions mechanisms, requires around 10-12 Kbytes (because most of
the code base is shared among several transition mechanisms already
supported by [RFC7084]), as a single data plane is common to all
them, which typically means about 0,15% of the existing code size in
popular CEs already in the market.
It is also clear that the new requirements don't have extra cost in
terms of RAM memory, neither other hardware requirements such as more
powerful CPUs.
The other issue seems to be the cost of developing the code for those
new functionalities. However, at the time of writing this document,
it has been confirmed that there are several open source versions of
the required code for supporting the new transition mechanisms, and
even several vendors already have implementations and provide it to
ISPs, so the development cost is negligent, and only integration and
testing cost may become a minor issue.
8. Security Considerations
The IPv6 Transition CE Router must comply with the Security
Considerations as stated in [RFC7084], as well as those stated by
each transition mechanism implemented by the IPv6 Transition CE
Router.
9. IANA Considerations
This document has no actions for IANA.
10. Acknowledgements
Thanks to Mikael Abrahamsson, Fred Baker, Mohamed Boucadair, Brian
Carpenter, Lee Howard, Richard Patterson, Barbara Stark, Ole Troan,
James Woodyatt, and "TBD", for their review and comments in this and
previous versions of this document.
11. Annex A: Usage Scenarios
The situation previously described, where there is ongoing IPv6
deployment and lack of IPv4 addresses, is not happening at the same
pace at every country, and even within every country, every ISP. For
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different technical, financial, commercial/marketing and socio-
economic reasons, each network is transitioning at their own pace,
and nobody has a magic crystal ball, to make a guess.
Different studies (for example [IPv6Survey]) also show that this is a
changing situation, because in a single country, it may be that not
all operators provide IPv6 support, and consumers may switch ISPs and
use the same IPv6 Transition CE Router with an ISP that provides
IPv4-only and an ISP that provides IPv6 plus IPv4aaS.
So, it is clear that, to cover all those evolving situations, a IPv6
Transition CE Router is required, at least from the perspective of
the transition support, which can accommodate those changes.
Moreover, because some services will remain IPv4-only for an
undetermined time, and some service providers will remain IPv4-only
for an undetermined period of time, IPv4 will be needed for an
undetermined period of time. There will be a need for CEs with
support "IPv4 as-a-Service" for an undetermined period of time.
This document is consequently, based on those premises, in order to
ensure the continued transition from networks that today may provide
access with dual-stack or IPv6-in-IPv4, as described in [RFC7084],
and as an "extension" to it, evolving to an IPv6-only access with
IPv4-as-a-Service.
Considering that situation and different possible usage cases, the
IPv6 Transition CE Router described in this document is expected to
be used typically, in the following scenarios:
1. Residential/household, Small Office/Home Office (SOHO) and Small/
Medium Enterprise (SME). Common usage is any kind of Internet
access (web, email, streaming, online gaming, etc.).
2. Residential/household and Small/Medium Enterprise (SME) with
advanced requirements. Same basic usage as for the previous
case, however there may be requirements for allowing inbound
connections (IP cameras, web, DNS, email, VPN, etc.).
The above list is not intended to be comprehensive of all the
possible usage scenarios, just an overall view. In fact,
combinations of the above usages are also possible, as well as
situations where the same CE is used at different times in different
scenarios or even different services providers that may use a
different transition mechanism.
The mechanisms for allowing inbound connections are "naturally"
available in any IPv6 router, as when using GUA, unless they are
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blocked by firewall rules, which may require some manual
configuration by means of a GUI and/or CLI.
However, in the case of IPv4aaS, because the usage of private
addresses and NAT and even depending on the specific transition
mechanism, it typically requires some degree of more complex manual
configuration such as setting up a DMZ, virtual servers, or port/
protocol forwarding. In general, IPv4 CE Routers already provide GUI
and/or CLI to manually configure them, or the possibility to setup
the CE in bridge mode, so another CE behind it, takes care of that.
It is out of the scope of this document the definition of any
requirements for that.
The main difference for a CE Router to support the above indicated
scenarios and number of users, is related to the packet processing
capabilities, performance, even other details such as the number of
WAN/LAN interfaces, their maximum speed, memory for keeping tables or
tracking connections, etc. It is out of the scope of this document
to classify them.
The actual bandwidth capabilities of access technologies such as
FTTH, cable and even 3GPP/LTE, allows the support of such scenarios,
and indeed, is a very common situation that access networks and CE
Router provided by the service provider are the same for SMEs and
residential users.
There is also no difference in terms of who actually provides the CE
Router. In most of the cases is the service provider, and in fact is
responsible, typically, of provisioning/managing at least the WAN
side. However, commonly the user has access to configure the LAN
interfaces, firewall, DMZ, and many other features. In fact, in many
cases, the user must supply or may replace the CE Router; this makes
even more relevant that all the CE Routers, support the same
requirements defined in this document.
The IPv6 Transition CE Router described in this document is not
intended for usage in other scenarios such as large Enterprises, Data
Centers, Content Providers, etc. So, even if the documented
requirements meet their needs, they may have additional requirements,
which are out of the scope of this document.
12. Annex B: End-User Network Architecture
According to the descriptions in the preceding sections, an end-user
network will likely support both IPv4 and IPv6. It is not expected
that an end user will change their existing network topology with the
introduction of IPv6. There are some differences in how IPv6 works
and is provisioned; these differences have implications for the
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network architecture.
A typical IPv4 end-user network consists of a "plug and play" router
with NAT functionality and a single link upstream, connected to the
service provider network.
From the perspective of an "IPv4 user" behind an IPv6 transition
Customer Edge Router with IPv4aaS, this doesn't change.
However, while a typical IPv4 NAT deployment by default blocks all
incoming connections and may allow opening of ports using a Universal
Plug and Play Internet Gateway Device (UPnP IGD) [UPnP-IGD] or some
other firewall control protocol, in the case of an IPv6-only access
and IPv4aaS, that may not be feasible depending on specific
transition mechanism details. PCP (Port Control Protocol, [RFC6887])
may be an alternative solution.
Another consequence of using IPv4 private address space in the end-
user network is that it provides stable addressing; that is, it never
changes even when you change service providers, and the addresses are
always there even when the WAN interface is down or the customer edge
router has not yet been provisioned. In the case of an IPv6-only
access, there is no change on that if the transition mechanism keeps
running the NAT interface towards the LAN side.
More advanced routers support dynamic routing (which learns routes
from other routers), and advanced end-users can build arbitrary,
complex networks using manual configuration of address prefixes
combined with a dynamic routing protocol. Once again, this is true
for both, IPv4 and IPv6.
In general, the end-user network architecture for IPv6 should provide
equivalent or better capabilities and functionality than the current
IPv4 architecture.
The end-user network is a stub network, in the sense that is not
providing transit to other external networks. However, HNCP
([RFC7788]) allows support for automatic provisioning of downstream
routers. Figure 1 illustrates the model topology for the end-user
network.
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+---------------+ \
| Service | \
| Provider | | Service
| Router | | Provider
+-------+-------+ | Network
| /
| Customer /
| Internet Connection /
|
+------+--------+ \
| IPv6 | \
| Customer Edge | \
| Router | /
+---+-------+---+ /
Network A | | Network B |
---+----------------+-+- --+---+-------------+-- |
| | | | \
+---+------+ | +----+-----+ +-----+----+ \
|IPv6 Host | | | IPv4 Host| |IPv4/IPv6 | /
| | | | | | Host | /
+----------+ | +----------+ +----------+ /
| |
+------+--------+ | End-User
| IPv6 | | Network(s)
| Router | \
+------+--------+ \
Network C | \
---+-------------+--+--- |
| | |
+---+------+ +----+-----+ |
|IPv6 Host | |IPv6 Host | /
| | | | /
+----------+ +----------+ /
Figure 1: An Example of a Typical End-User Network
This architecture describes the:
o Basic capabilities of the IPv6 Transition CE Router
o Provisioning of the WAN interface connecting to the service
provider
o Provisioning of the LAN interfaces
The IPv6 Transition CE Router may be manually configured in an
arbitrary topology with a dynamic routing protocol or using HNCP
([RFC7788]). Automatic provisioning and configuration is described
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for a single IPv6 Transition CE Router only.
13. ANNEX C: Changes from -00
Section to be removed for WGLC. Significant updates are:
1. ID-Nits: IANA section.
2. ID-Nits: RFC7084 reference removed from Abstract.
3. This document no longer updates RFC7084.
4. UPnP section reworded.
5. "CE Router" changed to "IPv6 Transition CE Router".
6. Reduced text in Annex A.
14. References
14.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
DOI 10.17487/RFC3633, December 2003,
<https://www.rfc-editor.org/info/rfc3633>.
[RFC5625] Bellis, R., "DNS Proxy Implementation Guidelines",
BCP 152, RFC 5625, DOI 10.17487/RFC5625, August 2009,
<https://www.rfc-editor.org/info/rfc5625>.
[RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4
Infrastructures (6rd) -- Protocol Specification",
RFC 5969, DOI 10.17487/RFC5969, August 2010,
<https://www.rfc-editor.org/info/rfc5969>.
[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, <https://www.rfc-editor.org/info/rfc6146>.
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[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, DOI 10.17487/RFC6333, August 2011,
<https://www.rfc-editor.org/info/rfc6333>.
[RFC6334] Hankins, D. and T. Mrugalski, "Dynamic Host Configuration
Protocol for IPv6 (DHCPv6) Option for Dual-Stack Lite",
RFC 6334, DOI 10.17487/RFC6334, August 2011,
<https://www.rfc-editor.org/info/rfc6334>.
[RFC6877] Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT:
Combination of Stateful and Stateless Translation",
RFC 6877, DOI 10.17487/RFC6877, April 2013,
<https://www.rfc-editor.org/info/rfc6877>.
[RFC6887] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and
P. Selkirk, "Port Control Protocol (PCP)", RFC 6887,
DOI 10.17487/RFC6887, April 2013,
<https://www.rfc-editor.org/info/rfc6887>.
[RFC6970] Boucadair, M., Penno, R., and D. Wing, "Universal Plug and
Play (UPnP) Internet Gateway Device - Port Control
Protocol Interworking Function (IGD-PCP IWF)", RFC 6970,
DOI 10.17487/RFC6970, July 2013,
<https://www.rfc-editor.org/info/rfc6970>.
[RFC7050] Savolainen, T., Korhonen, J., and D. Wing, "Discovery of
the IPv6 Prefix Used for IPv6 Address Synthesis",
RFC 7050, DOI 10.17487/RFC7050, November 2013,
<https://www.rfc-editor.org/info/rfc7050>.
[RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic
Requirements for IPv6 Customer Edge Routers", RFC 7084,
DOI 10.17487/RFC7084, November 2013,
<https://www.rfc-editor.org/info/rfc7084>.
[RFC7225] Boucadair, M., "Discovering NAT64 IPv6 Prefixes Using the
Port Control Protocol (PCP)", RFC 7225,
DOI 10.17487/RFC7225, May 2014,
<https://www.rfc-editor.org/info/rfc7225>.
[RFC7291] Boucadair, M., Penno, R., and D. Wing, "DHCP Options for
the Port Control Protocol (PCP)", RFC 7291,
DOI 10.17487/RFC7291, July 2014,
<https://www.rfc-editor.org/info/rfc7291>.
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[RFC7341] Sun, Q., Cui, Y., Siodelski, M., Krishnan, S., and I.
Farrer, "DHCPv4-over-DHCPv6 (DHCP 4o6) Transport",
RFC 7341, DOI 10.17487/RFC7341, August 2014,
<https://www.rfc-editor.org/info/rfc7341>.
[RFC7596] Cui, Y., Sun, Q., Boucadair, M., Tsou, T., Lee, Y., and I.
Farrer, "Lightweight 4over6: An Extension to the Dual-
Stack Lite Architecture", RFC 7596, DOI 10.17487/RFC7596,
July 2015, <https://www.rfc-editor.org/info/rfc7596>.
[RFC7597] Troan, O., Ed., Dec, W., Li, X., Bao, C., Matsushima, S.,
Murakami, T., and T. Taylor, Ed., "Mapping of Address and
Port with Encapsulation (MAP-E)", RFC 7597,
DOI 10.17487/RFC7597, July 2015,
<https://www.rfc-editor.org/info/rfc7597>.
[RFC7598] Mrugalski, T., Troan, O., Farrer, I., Perreault, S., Dec,
W., Bao, C., Yeh, L., and X. Deng, "DHCPv6 Options for
Configuration of Softwire Address and Port-Mapped
Clients", RFC 7598, DOI 10.17487/RFC7598, July 2015,
<https://www.rfc-editor.org/info/rfc7598>.
[RFC7599] Li, X., Bao, C., Dec, W., Ed., Troan, O., Matsushima, S.,
and T. Murakami, "Mapping of Address and Port using
Translation (MAP-T)", RFC 7599, DOI 10.17487/RFC7599, July
2015, <https://www.rfc-editor.org/info/rfc7599>.
[RFC7608] Boucadair, M., Petrescu, A., and F. Baker, "IPv6 Prefix
Length Recommendation for Forwarding", BCP 198, RFC 7608,
DOI 10.17487/RFC7608, July 2015,
<https://www.rfc-editor.org/info/rfc7608>.
[RFC7618] Cui, Y., Sun, Q., Farrer, I., Lee, Y., Sun, Q., and M.
Boucadair, "Dynamic Allocation of Shared IPv4 Addresses",
RFC 7618, DOI 10.17487/RFC7618, August 2015,
<https://www.rfc-editor.org/info/rfc7618>.
[RFC8026] Boucadair, M. and I. Farrer, "Unified IPv4-in-IPv6
Softwire Customer Premises Equipment (CPE): A DHCPv6-Based
Prioritization Mechanism", RFC 8026, DOI 10.17487/RFC8026,
November 2016, <https://www.rfc-editor.org/info/rfc8026>.
[RFC8114] Boucadair, M., Qin, C., Jacquenet, C., Lee, Y., and Q.
Wang, "Delivery of IPv4 Multicast Services to IPv4 Clients
over an IPv6 Multicast Network", RFC 8114,
DOI 10.17487/RFC8114, March 2017,
<https://www.rfc-editor.org/info/rfc8114>.
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[RFC8115] Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6
Option for IPv4-Embedded Multicast and Unicast IPv6
Prefixes", RFC 8115, DOI 10.17487/RFC8115, March 2017,
<https://www.rfc-editor.org/info/rfc8115>.
14.2. Informative References
[IPv6Survey]
Palet Martinez, J., "IPv6 Deployment Survey", January
2018,
<https://indico.uknof.org.uk/event/41/contribution/5/
material/slides/0.pdf>.
[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <https://www.rfc-editor.org/info/rfc7788>.
[UPnP-IGD]
UPnP Forum, "InternetGatewayDevice:2 Device Template
Version 1.01", December 2010,
<http://upnp.org/specs/gw/igd2/>.
Authors' Addresses
Jordi Palet Martinez
The IPv6 Company
Molino de la Navata, 75
La Navata - Galapagar, Madrid 28420
Spain
EMail: jordi.palet@theipv6company.com
URI: http://www.theipv6company.com/
Hans M.-H. Liu
D-Link Systems, Inc.
17595 Mount Herrmann St.
Fountain Valley, California 92708
US
EMail: hans.liu@dlinkcorp.com
URI: http://www.dlink.com/
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Masanobu Kawashima
NEC Platforms, Ltd.
800, Shimomata
Kakegawa-shi, Shizuoka 436-8501
Japan
EMail: kawashimam@vx.jp.nec.com
URI: https://www.necplatforms.co.jp/en/
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