draft-ietf-v6ops-transition-ipv4aas-00.txt   draft-ietf-v6ops-transition-ipv4aas-01.txt 
IPv6 Operations (v6ops) J. Palet Martinez IPv6 Operations (v6ops) J. Palet Martinez
Internet-Draft The IPv6 Company Internet-Draft The IPv6 Company
Updates: RFC7084 (if approved) H. M.-H. Liu Intended status: Informational H. M.-H. Liu
Intended status: Informational D-Link Systems, Inc. Expires: November 28, 2018 D-Link Systems, Inc.
Expires: October 29, 2018 M. Kawashima M. Kawashima
NEC Platforms, Ltd. NEC Platforms, Ltd.
April 27, 2018 May 27, 2018
Requirements for IPv6 Customer Edge Routers to Support IPv4 Connectivity Requirements for IPv6 Customer Edge Routers to Support IPv4 Connectivity
as-a-Service as-a-Service
draft-ietf-v6ops-transition-ipv4aas-00 draft-ietf-v6ops-transition-ipv4aas-01
Abstract Abstract
This document specifies the IPv4 service continuity requirements for This document specifies the IPv4 service continuity requirements for
an IPv6 Customer Edge (CE) router, either provided by the service an IPv6 Customer Edge (CE) router, either provided by the service
provider or thru the retail market. provider or thru the retail market.
Specifically, this document extends the "Basic Requirements for IPv6 Specifically, this document extends the "Basic Requirements for IPv6
Customer Edge Routers" ([RFC7084]) in order to allow the provisioning Customer Edge Routers" in order to allow the provisioning of IPv6
of IPv6 transition services for the support of "IPv4 as-a-Service" transition services for the support of "IPv4 as-a-Service" (IPv4aaS)
(IPv4aaS) by means of new transition mechanisms, which were not by means of new transition mechanisms. The document only covers
available at the time [RFC7084] (Basic Requirements for IPv6 Customer transition technologies for delivering IPv4 in IPv6-only access
Edge Routers) was published. The document only covers transition networks, commonly called "IPv4 as-a-Service" (IPv4aaS), as required
technologies for delivering IPv4 in IPv6-only access networks, in a world where IPv4 addresses are no longer available, so hosts in
commonly called "IPv4 as-a-Service" (IPv4aaS), as required in a world the customer LANs with IPv4-only or IPv6-only applications or
where IPv4 addresses are no longer available, so hosts in the devices, requiring to communicate with IPv4-only services at the
customer LANs with IPv4-only or IPv6-only applications or devices, Internet, are still able to do so.
requiring to communicate with IPv4-only services at the Internet, are
still able to do so.
This document updates section 4.4 (Transition Technologies
Requirements) of [RFC7084].
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 29, 2018. This Internet-Draft will expire on November 28, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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3.1. General Requirements . . . . . . . . . . . . . . . . . . 4 3.1. General Requirements . . . . . . . . . . . . . . . . . . 4
3.2. LAN-Side Configuration . . . . . . . . . . . . . . . . . 4 3.2. LAN-Side Configuration . . . . . . . . . . . . . . . . . 4
3.3. Transition Technologies Support for IPv4 service 3.3. Transition Technologies Support for IPv4 service
continuity (IPv4 as-a-Service - IPv4aaS) . . . . . 5 continuity (IPv4 as-a-Service - IPv4aaS) . . . . . 5
3.3.1. 464XLAT . . . . . . . . . . . . . . . . . . . . . . . 5 3.3.1. 464XLAT . . . . . . . . . . . . . . . . . . . . . . . 5
3.3.2. Dual-Stack Lite (DS-Lite) . . . . . . . . . . . . . . 6 3.3.2. Dual-Stack Lite (DS-Lite) . . . . . . . . . . . . . . 6
3.3.3. Lightweight 4over6 (lw4o6) . . . . . . . . . . . . . 7 3.3.3. Lightweight 4over6 (lw4o6) . . . . . . . . . . . . . 7
3.3.4. MAP-E . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.4. MAP-E . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3.5. MAP-T . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3.5. MAP-T . . . . . . . . . . . . . . . . . . . . . . . . 8
4. IPv4 Multicast Support . . . . . . . . . . . . . . . . . . . 9 4. IPv4 Multicast Support . . . . . . . . . . . . . . . . . . . 9
5. UPnP IGD-PCP IWF Support . . . . . . . . . . . . . . . . . . 9 5. UPnP Support . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Update of RFC7084 . . . . . . . . . . . . . . . . . . . . . . 9 6. Differences from RFC7084 . . . . . . . . . . . . . . . . . . 9
7. Code Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. Code Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Security Considerations . . . . . . . . . . . . . . . . . . . 10 8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
10. Annex A: Usage Scenarios . . . . . . . . . . . . . . . . . . 10 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
11. Annex B: End-User Network Architecture . . . . . . . . . . . 12 11. Annex A: Usage Scenarios . . . . . . . . . . . . . . . . . . 10
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 12. Annex B: End-User Network Architecture . . . . . . . . . . . 12
12.1. Normative References . . . . . . . . . . . . . . . . . . 15 13. ANNEX C: Changes from -00 . . . . . . . . . . . . . . . . . . 15
12.2. Informative References . . . . . . . . . . . . . . . . . 17 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
14.1. Normative References . . . . . . . . . . . . . . . . . . 15
14.2. Informative References . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction 1. Introduction
This document defines IPv4 service continuity features over an This document defines IPv4 service continuity features over an
IPv6-only network, for a residential or small-office router, referred IPv6-only network, for a residential or small-office router, referred
to as an "IPv6 CE Router with IPv4aaS support", in order to establish to as an "IPv6 Transition CE Router", in order to establish an
an industry baseline for transition features to be implemented on industry baseline for transition features to be implemented on such a
such a router. router.
These routers are likely to rely upon "Basic Requirements for IPv6 These routers are likely to rely upon "Basic Requirements for IPv6
Customer Edge Routers" ([RFC7084]), so the scope of this document is Customer Edge Routers" ([RFC7084]), so the scope of this document is
to ensure the IPv4 "service continuity" support, in the LAN side and to ensure the IPv4 "service continuity" support, in the LAN side and
the access to IPv4-only Internet services from an IPv6-only access the access to IPv4-only Internet services from an IPv6-only access
WAN even from IPv6-only applications or devices in the LAN side. WAN even from IPv6-only applications or devices in the LAN side.
This document covers a set of IP transition techniques required when This document covers a set of IP transition techniques required when
ISPs have an IPv6-only access network. This is a common situation in 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 a world where IPv4 addresses are no longer available, so the service
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supported by an IPv6 Transition CE Router, and relevant provisioning supported by an IPv6 Transition CE Router, and relevant provisioning
or configuration information differences from [RFC7084]. or configuration information differences from [RFC7084].
This document is not a recommendation for service providers to use This document is not a recommendation for service providers to use
any specific transition mechanism. any specific transition mechanism.
Automatic provisioning of more complex topology than a single router Automatic provisioning of more complex topology than a single router
with multiple LAN interfaces may be handled by means of HNCP with multiple LAN interfaces may be handled by means of HNCP
([RFC7788]), which is out of the scope of this document. ([RFC7788]), which is out of the scope of this document.
Service providers who specify feature sets for CE Routers MAY specify Service providers who specify feature sets for IPv6 Transition CE
a different set of features than those included in this document. Router MAY specify a different set of features than those included in
Since it is impossible to know prior to sale which transition this document. Since it is impossible to know prior to sale which
mechanism a device will need over the lifetime of the device, IPv6 CE transition mechanism a device will need over the lifetime of the
Routers intended for the retail market MUST support all of them. 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 A complete description of "Usage Scenarios" and "End-User Network
Architecture" is provided in Annex A and B, respectively. Architecture" is provided in Annex A and B, respectively.
1.1. Requirements Language - Special Note 1.1. Requirements Language - Special Note
Unlike other IETF documents, the key words "MUST", "MUST NOT", Unlike other IETF documents, the key words "MUST", "MUST NOT",
"REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in this document are not used as "RECOMMENDED", "MAY", and "OPTIONAL" in this document are not used as
described in RFC 2119 [RFC2119]. This document uses these keywords described in RFC 2119 [RFC2119]. This document uses these keywords
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2. Terminology 2. Terminology
This document uses the same terms as in [RFC7084], with minor This document uses the same terms as in [RFC7084], with minor
clarifications. clarifications.
"IPv4aaS" stands for "IPv4 as-a-Service", meaning transition "IPv4aaS" stands for "IPv4 as-a-Service", meaning transition
technologies for delivering IPv4 in IPv6-only access networks. technologies for delivering IPv4 in IPv6-only access networks.
The term "IPv6 transition Customer Edge Router with IPv4aaS" The term "IPv6 transition Customer Edge Router with IPv4aaS"
(shortened as "CE Router" or "IPv6 CE Router") is defined as an "IPv6 (shortened as "IPv6 Transition CE Router") is defined as an "IPv6
Customer Edge Router" that provides features for the delivery of IPv4 Customer Edge Router" that provides features for the delivery of IPv4
services over an IPv6-only WAN network including IPv6-IPv4 services over an IPv6-only WAN network including IPv6-IPv4
communications. communications.
The "WAN Interface" term used across this document, means that can The "WAN Interface" term used across this document, means that can
also support link technologies based in Internet-layer (or higher- also support link technologies based in Internet-layer (or higher-
layers) "tunnels", such as IPv4-in-IPv6 tunnels. layers) "tunnels", such as IPv4-in-IPv6 tunnels.
3. Requirements 3. Requirements
The CE Router MUST comply with [RFC7084] (Basic Requirements for IPv6 The IPv6 Transition CE Router MUST comply with [RFC7084] (Basic
Customer Edge Routers), with the exception of Section 4.4, which Requirements for IPv6 Customer Edge Routers).
becomes updated by this document.
3.1. General Requirements 3.1. General Requirements
A new general requirement is added, in order to ensure that the CE A new general requirement is added, in order to ensure that the IPv6
Router respects the IPv6 prefix length as a parameter: Transition CE Router respects the IPv6 prefix length as a parameter:
G-6 The IPv6-only CE Router MUST comply with [RFC7608] (IPv6 Prefix G-6 The IPv6 Transition CE Router MUST comply with [RFC7608] (IPv6
Length Recommendation for Forwarding). Prefix Length Recommendation for Forwarding).
3.2. LAN-Side Configuration 3.2. LAN-Side Configuration
A new LAN requirement is added, which in fact is common in regular CE A new LAN requirement is added, which in fact is common in regular
Router, and it is required by most of the transition mechanisms: IPv6 Transition CE Router, and it is required by most of the
transition mechanisms:
L-15 The IPv6 CE Router SHOULD implement a DNS proxy as described in L-15 The IPv6 Transition CE Router SHOULD implement a DNS proxy as
[RFC5625] (DNS Proxy Implementation Guidelines). described in [RFC5625] (DNS Proxy Implementation Guidelines).
3.3. Transition Technologies Support for IPv4 service continuity (IPv4 3.3. Transition Technologies Support for IPv4 service continuity (IPv4
as-a-Service - IPv4aaS) as-a-Service - IPv4aaS)
The main target of this document is the support of IPv6-only WAN The main target of this document is the support of IPv6-only WAN
access. To enable legacy IPv4 functionality, this document also access. To enable legacy IPv4 functionality, this document also
includes the support of IPv4-only devices and applications in the includes the support of IPv4-only devices and applications in the
customers LANs, as well as IPv4-only services on the Internet. Thus, customers LANs, as well as IPv4-only services on the Internet. Thus,
both IPv4-only and the IPv6-only devices inside the CE Router are both IPv4-only and the IPv6-only devices inside the IPv6 Transition
able to reach the IPv4-only services. CE Router are able to reach the IPv4-only services.
This document takes no position on simultaneous operation of any This document takes no position on simultaneous operation of any
transition mechanism and native IPv4. transition mechanism and native IPv4.
In order to seamlessly provide the IPv4 Service Continuity in In order to seamlessly provide the IPv4 Service Continuity in
Customer LANs, allowing an automated IPv6 transition mechanism Customer LANs, allowing an automated IPv6 transition mechanism
provisioning, a new general transition requirement is added. provisioning, general transition requirements are added.
General transition requirements: General transition requirements:
TRANS-1: If more than one S46 mechanism is supported, the CE Router TRANS-1: If more than one S46 mechanism is supported, the IPv6
MUST support the DHCPv6 S46 priority option described in Transition CE Router MUST support the DHCPv6 S46 priority
[RFC8026] (Unified IPv4-in-IPv6 Softwire Customer Premises option described in [RFC8026] (Unified IPv4-in-IPv6
Equipment (CPE): A DHCPv6-Based Prioritization Mechanism). Softwire Customer Premises Equipment (CPE): A DHCPv6-Based
Prioritization Mechanism).
TRANS-2: The CE Router MUST verify if the WAN link supports native TRANS-2: The IPv6 Transition CE Router MUST verify if the WAN link
IPv4. In that case, transition mechanisms SHOULD NOT be supports native IPv4. In that case, transition mechanisms
automatically enabled for that interface. SHOULD NOT be automatically enabled for that interface.
TRANS-3: If native IPv4 is not available and 464XLAT [RFC6877] is TRANS-3: If native IPv4 is not available and 464XLAT [RFC6877] is
supported, the CE Router MUST enable the CLAT (in order to supported, the IPv6 Transition CE Router MUST enable the
automatically configure 464XLAT [RFC6877]). If 464XLAT CLAT (in order to automatically configure 464XLAT
[RFC6877] is not supported, and more than one S46 mechanism [RFC6877]). If 464XLAT [RFC6877] is not supported, and
is supported, following Section 1.4 of [RFC8026], MUST more than one S46 mechanism is supported, following
check for a valid match in OPTION_S46_PRIORITY, which will Section 1.4 of [RFC8026], MUST check for a valid match in
allow configuring any of the other transition mechanisms. OPTION_S46_PRIORITY, which will allow configuring any of
the other transition mechanisms.
The following sections describe the requirements for supporting The following sections describe the requirements for supporting
transition mechanisms. transition mechanisms.
3.3.1. 464XLAT 3.3.1. 464XLAT
464XLAT [RFC6877] is a technique to provide IPv4 service over an 464XLAT [RFC6877] is a technique to provide IPv4 service over an
IPv6-only access network without encapsulation. This architecture IPv6-only access network without encapsulation. This architecture
assumes a NAT64 [RFC6146] (Stateful NAT64: Network Address and assumes a NAT64 [RFC6146] (Stateful NAT64: Network Address and
Protocol Translation from IPv6 Clients to IPv4 Servers) function Protocol Translation from IPv6 Clients to IPv4 Servers) function
deployed at the service provider or a third-party network. deployed at the service provider or a third-party network.
The CE Router SHOULD support CLAT functionality. If 464XLAT is The IPv6 Transition CE Router SHOULD support CLAT functionality. If
supported, it MUST be implemented according to [RFC6877]. The 464XLAT is supported, it MUST be implemented according to [RFC6877].
following CE Router requirements also apply: The following IPv6 Transition CE Router requirements also apply:
464XLAT requirements: 464XLAT requirements:
464XLAT-1: The CE Router MUST perform IPv4 Network Address 464XLAT-1: The IPv6 Transition CE Router MUST perform IPv4 Network
Translation (NAT) on IPv4 traffic translated using the Address Translation (NAT) on IPv4 traffic translated
CLAT, unless a dedicated /64 prefix has been acquired using the CLAT, unless a dedicated /64 prefix has been
using DHCPv6-PD [RFC3633] (IPv6 Prefix Options for acquired using DHCPv6-PD [RFC3633] (IPv6 Prefix Options
DHCPv6). for DHCPv6).
464XLAT-2: The CE Router SHOULD support IGD-PCP IWF [RFC6970] (UPnP 464XLAT-2: The IPv6 Transition CE Router SHOULD support IGD-PCP IWF
Internet Gateway Device - Port Control Protocol [RFC6970] (UPnP Internet Gateway Device - Port Control
Interworking Function). Protocol Interworking Function).
464XLAT-3: If PCP ([RFC6887]) is implemented, the CE Router MUST 464XLAT-3: If PCP ([RFC6887]) is implemented, the IPv6 Transition CE
also implement [RFC7291] (DHCP Options for the PCP). If Router MUST also implement [RFC7291] (DHCP Options for
no PCP server is configured, the CE Router MAY verify if the PCP). If no PCP server is configured, the IPv6
the default gateway, or the NAT64 is the PCP server. A Transition CE Router MAY verify if the default gateway,
plain IPv6 mode is used to send PCP requests to the or the NAT64 is the PCP server. A plain IPv6 mode is
server. used to send PCP requests to the server.
464XLAT-4: The CE Router MUST implement [RFC7050] (Discovery of the 464XLAT-4: The IPv6 Transition CE Router MUST implement [RFC7050]
IPv6 Prefix Used for IPv6 Address Synthesis) in order to (Discovery of the IPv6 Prefix Used for IPv6 Address
discover the PLAT-side translation IPv4 and IPv6 Synthesis) in order to discover the PLAT-side translation
prefix(es)/suffix(es). The CE Router MUST follow IPv4 and IPv6 prefix(es)/suffix(es). The IPv6 Transition
[RFC7225] (Discovering NAT64 IPv6 Prefixes Using the CE Router MUST follow [RFC7225] (Discovering NAT64 IPv6
PCP), in order to learn the PLAT-side translation IPv4 Prefixes Using the PCP), in order to learn the PLAT-side
and IPv6 prefix(es)/suffix(es) used by an upstream PCP- translation IPv4 and IPv6 prefix(es)/suffix(es) used by
controlled NAT64 device. an upstream PCP-controlled NAT64 device.
3.3.2. Dual-Stack Lite (DS-Lite) 3.3.2. Dual-Stack Lite (DS-Lite)
Dual-Stack Lite [RFC6333] enables both continued support for IPv4 Dual-Stack Lite [RFC6333] enables both continued support for IPv4
services and incentives for the deployment of IPv6. It also de- services and incentives for the deployment of IPv6. It also de-
couples IPv6 deployment in the service provider network from the rest couples IPv6 deployment in the service provider network from the rest
of the Internet, making incremental deployment easier. Dual-Stack of the Internet, making incremental deployment easier. Dual-Stack
Lite enables a broadband service provider to share IPv4 addresses Lite enables a broadband service provider to share IPv4 addresses
among customers by combining two well-known technologies: IP in IP among customers by combining two well-known technologies: IP in IP
(IPv4-in-IPv6) and Network Address Translation (NAT). It is expected (IPv4-in-IPv6) and Network Address Translation (NAT). It is expected
that DS-Lite traffic is forwarded over the IPv6 CE Router's native that DS-Lite traffic is forwarded over the IPv6 Transition CE
IPv6 WAN interface, and not encapsulated in another tunnel. Router's native IPv6 WAN interface, and not encapsulated in another
tunnel.
The IPv6 CE Router SHOULD implement DS-Lite [RFC6333] functionality. The IPv6 Transition CE Router SHOULD implement DS-Lite [RFC6333]
If DS-Lite is supported, it MUST be implemented according to functionality. If DS-Lite is supported, it MUST be implemented
[RFC6333]. The following CE Router requirements also apply: according to [RFC6333]. The following IPv6 Transition CE Router
requirements also apply:
DS-Lite requirements: DS-Lite requirements:
DSLITE-1: The IPv6 CE Router MUST support configuration of DS-Lite DSLITE-1: The IPv6 Transition CE Router MUST support configuration
via the DS-Lite DHCPv6 option [RFC6334] (DHCPv6 Option for of DS-Lite via the DS-Lite DHCPv6 option [RFC6334] (DHCPv6
Dual-Stack Lite). The IPv6 CE Router MAY use other Option for Dual-Stack Lite). The IPv6 Transition CE
mechanisms to configure DS-Lite parameters. Such Router MAY use other mechanisms to configure DS-Lite
mechanisms are outside the scope of this document. parameters. Such mechanisms are outside the scope of this
document.
DSLITE-2: The CE Router SHOULD support IGD-PCP IWF [RFC6970] (UPnP DSLITE-2: The IPv6 Transition CE Router SHOULD support IGD-PCP IWF
Internet Gateway Device - Port Control Protocol [RFC6970] (UPnP Internet Gateway Device - Port Control
Interworking Function). Protocol Interworking Function).
DSLITE-3: If PCP ([RFC6887]) is implemented, the CE Router SHOULD DSLITE-3: If PCP ([RFC6887]) is implemented, the IPv6 Transition CE
also implement [RFC7291] (DHCP Options for the PCP). If Router SHOULD also implement [RFC7291] (DHCP Options for
PCP ([RFC6887]) is implemented and a PCP server is not the PCP). If PCP ([RFC6887]) is implemented and a PCP
configured, the CE Router MUST assume, by default, that server is not configured, the IPv6 Transition CE Router
the AFTR is the PCP server. A plain IPv6 mode is used to MUST assume, by default, that the AFTR is the PCP server.
send PCP requests to the server. A plain IPv6 mode is used to send PCP requests to the
server.
DSLITE-4: The IPv6 CE Router MUST NOT perform IPv4 Network Address DSLITE-4: The IPv6 Transition CE Router MUST NOT perform IPv4
Translation (NAT) on IPv4 traffic encapsulated using DS- Network Address Translation (NAT) on IPv4 traffic
Lite ([RFC6333]). encapsulated using DS-Lite ([RFC6333]).
3.3.3. Lightweight 4over6 (lw4o6) 3.3.3. Lightweight 4over6 (lw4o6)
Lw4o6 [RFC7596] specifies an extension to DS-Lite, which moves the Lw4o6 [RFC7596] specifies an extension to DS-Lite, which moves the
NAPT function from the DS-Lite tunnel concentrator to the tunnel NAPT function from the DS-Lite tunnel concentrator to the tunnel
client located in the CE Router, removing the requirement for a CGN client located in the IPv6 Transition CE Router, removing the
function in the tunnel concentrator and reducing the amount of requirement for a CGN function in the tunnel concentrator and
centralized state. reducing the amount of centralized state.
The CE Router SHOULD implement lw4o6 functionality. If DS-Lite is The IPv6 Transition CE Router SHOULD implement lw4o6 functionality.
implemented, lw4o6 SHOULD be supported as well. If lw4o6 is If DS-Lite is implemented, lw4o6 SHOULD be supported as well. If
supported, it MUST be implemented according to [RFC7596]. The lw4o6 is supported, it MUST be implemented according to [RFC7596].
following CE Router requirements also apply: The following IPv6 Transition CE Router requirements also apply:
Lw4o6 requirements: Lw4o6 requirements:
LW4O6-1: The CE Router MUST support configuration of lw4o6 via the LW4O6-1: The IPv6 Transition CE Router MUST support configuration of
lw4o6 DHCPv6 options [RFC7598] (DHCPv6 Options for lw4o6 via the lw4o6 DHCPv6 options [RFC7598] (DHCPv6
Configuration of Softwire Address and Port-Mapped Clients). Options for Configuration of Softwire Address and Port-
The CE Router MAY use other mechanisms to configure lw4o6 Mapped Clients). The IPv6 Transition CE Router MAY use
parameters. Such mechanisms are outside the scope of this other mechanisms to configure lw4o6 parameters. Such
document. mechanisms are outside the scope of this document.
LW4O6-2: The CE Router MUST support the DHCPv4-over-DHCPv6 (DHCP LW4O6-2: The IPv6 Transition CE Router MUST support the DHCPv4-over-
4o6) transport described in [RFC7341] (DHCPv4-over-DHCPv6 DHCPv6 (DHCP 4o6) transport described in [RFC7341] (DHCPv4-
Transport). over-DHCPv6 Transport).
LW4O6-3: The CE Router MAY support Dynamic Allocation of Shared IPv4 LW4O6-3: The IPv6 Transition CE Router MAY support Dynamic
Addresses as described in [RFC7618] (Dynamic Allocation of Allocation of Shared IPv4 Addresses as described in
Shared IPv4 Addresses). [RFC7618] (Dynamic Allocation of Shared IPv4 Addresses).
3.3.4. MAP-E 3.3.4. MAP-E
MAP-E [RFC7597] is a mechanism for transporting IPv4 packets across MAP-E [RFC7597] is a mechanism for transporting IPv4 packets across
an IPv6 network using IP encapsulation, including an algorithmic an IPv6 network using IP encapsulation, including an algorithmic
mechanism for mapping between IPv6 addresses and IPv4 addresses as mechanism for mapping between IPv6 addresses and IPv4 addresses as
well as transport-layer ports. well as transport-layer ports.
The CE Router SHOULD support MAP-E functionality. If MAP-E is The IPv6 Transition CE Router SHOULD support MAP-E functionality. If
supported, it MUST be implemented according to [RFC7597]. The MAP-E is supported, it MUST be implemented according to [RFC7597].
following CE Router requirements also apply: The following IPv6 Transition CE Router requirements also apply:
MAP-E requirements: MAP-E requirements:
MAPE-1: The CE Router MUST support configuration of MAP-E via the MAPE-1: The IPv6 Transition CE Router MUST support configuration of
MAP-E DHCPv6 options [RFC7598] (DHCPv6 Options for MAP-E via the MAP-E DHCPv6 options [RFC7598] (DHCPv6 Options
Configuration of Softwire Address and Port-Mapped Clients). for Configuration of Softwire Address and Port-Mapped
The CE Router MAY use other mechanisms to configure MAP-E Clients). The IPv6 Transition CE Router MAY use other
parameters. Such mechanisms are outside the scope of this mechanisms to configure MAP-E parameters. Such mechanisms
document. are outside the scope of this document.
MAPE-2: The CE Router MAY support Dynamic Allocation of Shared IPv4 MAPE-2: The IPv6 Transition CE Router MAY support Dynamic Allocation
Addresses as described in [RFC7618] (Dynamic Allocation of of Shared IPv4 Addresses as described in [RFC7618] (Dynamic
Shared IPv4 Addresses). Allocation of Shared IPv4 Addresses).
3.3.5. MAP-T 3.3.5. MAP-T
MAP-T [RFC7599] is a mechanism similar to MAP-E, differing from it in 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 that MAP-T uses IPv4-IPv6 translation, rather than encapsulation, as
the form of IPv6 domain transport. the form of IPv6 domain transport.
The CE Router SHOULD support MAP-T functionality. If MAP-T is The IPv6 Transition CE Router SHOULD support MAP-T functionality. If
supported, it MUST be implemented according to [RFC7599]. The MAP-T is supported, it MUST be implemented according to [RFC7599].
following CE Router requirements also apply: The following IPv6 Transition CE Router requirements also apply:
MAP-T requirements: MAP-T requirements:
MAPT-1: The CE Router MUST support configuration of MAP-T via the MAPT-1: The IPv6 Transition CE Router MUST support configuration of
MAP-T DHCPv6 options [RFC7598] (DHCPv6 Options for MAP-T via the MAP-T DHCPv6 options [RFC7598] (DHCPv6 Options
Configuration of Softwire Address and Port-Mapped Clients). for Configuration of Softwire Address and Port-Mapped
The CE Router MAY use other mechanisms to configure MAP-T Clients). The IPv6 Transition CE Router MAY use other
parameters. Such mechanisms are outside the scope of this mechanisms to configure MAP-T parameters. Such mechanisms
document. are outside the scope of this document.
MAPT-2: The CE Router MAY support Dynamic Allocation of Shared IPv4 MAPT-2: The IPv6 Transition CE Router MAY support Dynamic Allocation
Addresses as described in [RFC7618] (Dynamic Allocation of of Shared IPv4 Addresses as described in [RFC7618] (Dynamic
Shared IPv4 Addresses). Allocation of Shared IPv4 Addresses).
4. IPv4 Multicast Support 4. IPv4 Multicast Support
Actual deployments support IPv4 multicast for services such as IPTV. Actual deployments support IPv4 multicast for services such as IPTV.
In the transition phase it is expected that multicast services will In the transition phase it is expected that multicast services will
still be provided using IPv4 to the customer LANs. still be provided using IPv4 to the customer LANs.
If the CE Router supports delivery of IPv4 multicast services, then If the IPv6 Transition CE Router supports delivery of IPv4 multicast
it MUST support [RFC8114] (Delivery of IPv4 Multicast Services to services, then it MUST support [RFC8114] (Delivery of IPv4 Multicast
IPv4 Clients over an IPv6 Multicast Network) and [RFC8115] (DHCPv6 Services to IPv4 Clients over an IPv6 Multicast Network) and
Option for IPv4-Embedded Multicast and Unicast IPv6 Prefixes). [RFC8115] (DHCPv6 Option for IPv4-Embedded Multicast and Unicast IPv6
Prefixes).
5. UPnP IGD-PCP IWF Support 5. UPnP Support
UPnP MAY be enabled on the CE Router for stateless mechanisms that UPnP SHOULD be disabled by default on the IPv6 Transition CE Router
forward unsolicited inbound packets through to the CE. If UPnP is when using an IPv4aaS transition mechanism.
enabled, the agent MUST reject any port mapping requests for ports
outside of the range(s) allocated to the CE Router.
UPnP SHOULD be disabled by default for stateful mechanisms that do UPnP MAY be enabled when a IPv6 Transition CE Router is configured to
not forward unsolicited inbound packets to the CE Router, unless use a stateless mechanism that allows unsolicited inbound packets
implemented in conjunction with a method to control the external port through to the CE, such as MAP or LW4o6, or when configured with an a
mapping, such as IGD-PCP IWF [RFC6970]. port set containing all 65535 ports, e.g. with an IPv4 address
sharing ratio of 1.
6. Update of RFC7084 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.
This document updates [RFC7084], by removing section 4.4 (Transition UPnP MAY also be enabled on a IPv6 Transition CE Router configured
Technology Support), so all the transition related references of this for IPv4aaS mechanisms that support PCP [RFC6887], if implemented in
document take preference over those in RFC7084. conjunction with a method to control the external port mapping, such
as IGD-PCP IWF [RFC6970].
Namely, that means that 6rd [RFC5969]) is no longer considered and A IPv6 Transition CE Router that implements a UPnP agent, SHOULD
DS-LITE [RFC6333] requirements have been updated. 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].
7. Code Considerations 7. Code Considerations
One of the apparent main issues for vendors to include new One of the apparent main issues for vendors to include new
functionalities, such as support for new transition mechanisms, is functionalities, such as support for new transition mechanisms, is
the lack of space in the flash (or equivalent) memory. However, it the lack of space in the flash (or equivalent) memory. However, it
has been confirmed from existing open source implementations has been confirmed from existing open source implementations
(OpenWRT/LEDE, Linux, others), that adding the support for the new (OpenWRT/LEDE, Linux, others), that adding the support for the new
transitions mechanisms, requires around 10-12 Kbytes (because most of transitions mechanisms, requires around 10-12 Kbytes (because most of
the code base is shared among several transition mechanisms already the code base is shared among several transition mechanisms already
skipping to change at page 10, line 17 skipping to change at page 10, line 32
The other issue seems to be the cost of developing the code for those The other issue seems to be the cost of developing the code for those
new functionalities. However, at the time of writing this document, new functionalities. However, at the time of writing this document,
it has been confirmed that there are several open source versions of it has been confirmed that there are several open source versions of
the required code for supporting the new transition mechanisms, and the required code for supporting the new transition mechanisms, and
even several vendors already have implementations and provide it to even several vendors already have implementations and provide it to
ISPs, so the development cost is negligent, and only integration and ISPs, so the development cost is negligent, and only integration and
testing cost may become a minor issue. testing cost may become a minor issue.
8. Security Considerations 8. Security Considerations
The CE Router must comply with the Security Considerations as stated The IPv6 Transition CE Router must comply with the Security
in [RFC7084], as well as those stated by each transition mechanism Considerations as stated in [RFC7084], as well as those stated by
implemented by the CE Router. each transition mechanism implemented by the IPv6 Transition CE
Router.
9. Acknowledgements 9. IANA Considerations
Thanks to Mikael Abrahamsson, Mohamed Boucadair, Brian Carpenter, Lee This document has no actions for IANA.
Howard, Richard Patterson, Barbara Stark, Ole Troan, James Woodyatt,
and "TBD", for their review and comments in this and previous
versions of this document.
10. Annex A: Usage Scenarios 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 The situation previously described, where there is ongoing IPv6
deployment and lack of IPv4 addresses, is not happening at the same deployment and lack of IPv4 addresses, is not happening at the same
pace at every country, and even within every country, every ISP. For pace at every country, and even within every country, every ISP. For
different technical, financial, commercial/marketing and socio- different technical, financial, commercial/marketing and socio-
economic reasons, each network is transitioning at their own pace, economic reasons, each network is transitioning at their own pace,
and nobody has a magic crystal ball, to make a guess. and nobody has a magic crystal ball, to make a guess.
Different studies (for example [IPv6Survey]) also show that this is a Different studies (for example [IPv6Survey]) also show that this is a
changing situation, because in a single country, it may be that not changing situation, because in a single country, it may be that not
all operators provide IPv6 support, and consumers may switch ISPs and all operators provide IPv6 support, and consumers may switch ISPs and
use the same CE Router with an ISP that provides IPv4-only and an ISP use the same IPv6 Transition CE Router with an ISP that provides
that provides IPv6 plus IPv4aaS. IPv4-only and an ISP that provides IPv6 plus IPv4aaS.
So, it is clear that, to cover all those evolving situations, a CE So, it is clear that, to cover all those evolving situations, a IPv6
Router is required, at least from the perspective of the transition Transition CE Router is required, at least from the perspective of
support, which can accommodate those changes. the transition support, which can accommodate those changes.
Moreover, because some services will remain IPv4-only for an Moreover, because some services will remain IPv4-only for an
undetermined time, and some service providers will remain IPv4-only undetermined time, and some service providers will remain IPv4-only
for an undetermined period of time, IPv4 will be needed for an for an undetermined period of time, IPv4 will be needed for an
undetermined period of time. There will be a need for CEs with undetermined period of time. There will be a need for CEs with
support "IPv4 as-a-Service" for an undetermined period of time. support "IPv4 as-a-Service" for an undetermined period of time.
This document is consequently, based on those premises, in order to This document is consequently, based on those premises, in order to
ensure the continued transition from networks that today may provide ensure the continued transition from networks that today may provide
access with dual-stack or IPv6-in-IPv4, as described in [RFC7084], 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 and as an "extension" to it, evolving to an IPv6-only access with
IPv4-as-a-Service. IPv4-as-a-Service.
Considering that situation and different possible usage cases, the CE Considering that situation and different possible usage cases, the
Router described in this document is expected to be used typically, IPv6 Transition CE Router described in this document is expected to
in the following scenarios: be used typically, in the following scenarios:
1. Residential/household, Small Office/Home Office (SOHO) and Small/ 1. Residential/household, Small Office/Home Office (SOHO) and Small/
Medium Enterprise (SME). Common usage is any kind of Internet Medium Enterprise (SME). Common usage is any kind of Internet
access (web, email, streaming, online gaming, etc.). access (web, email, streaming, online gaming, etc.).
2. Residential/household and Small/Medium Enterprise (SME) with 2. Residential/household and Small/Medium Enterprise (SME) with
advanced requirements. Same basic usage as for the previous advanced requirements. Same basic usage as for the previous
case, however there may be requirements for allowing inbound case, however there may be requirements for allowing inbound
connections (IP cameras, web, DNS, email, VPN, etc.). connections (IP cameras, web, DNS, email, VPN, etc.).
skipping to change at page 12, line 20 skipping to change at page 12, line 39
There is also no difference in terms of who actually provides the CE 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 Router. In most of the cases is the service provider, and in fact is
responsible, typically, of provisioning/managing at least the WAN responsible, typically, of provisioning/managing at least the WAN
side. However, commonly the user has access to configure the LAN side. However, commonly the user has access to configure the LAN
interfaces, firewall, DMZ, and many other features. In fact, in many interfaces, firewall, DMZ, and many other features. In fact, in many
cases, the user must supply or may replace the CE Router; this makes cases, the user must supply or may replace the CE Router; this makes
even more relevant that all the CE Routers, support the same even more relevant that all the CE Routers, support the same
requirements defined in this document. requirements defined in this document.
The CE Router described in this document is not intended for usage in The IPv6 Transition CE Router described in this document is not
other scenarios such as large Enterprises, Data Centers, Content intended for usage in other scenarios such as large Enterprises, Data
Providers, etc. So, even if the documented requirements meet their Centers, Content Providers, etc. So, even if the documented
needs, they may have additional requirements, which are out of the requirements meet their needs, they may have additional requirements,
scope of this document. which are out of the scope of this document.
11. Annex B: End-User Network Architecture 12. Annex B: End-User Network Architecture
According to the descriptions in the preceding sections, an end-user According to the descriptions in the preceding sections, an end-user
network will likely support both IPv4 and IPv6. It is not expected network will likely support both IPv4 and IPv6. It is not expected
that an end user will change their existing network topology with the that an end user will change their existing network topology with the
introduction of IPv6. There are some differences in how IPv6 works introduction of IPv6. There are some differences in how IPv6 works
and is provisioned; these differences have implications for the and is provisioned; these differences have implications for the
network architecture. network architecture.
A typical IPv4 end-user network consists of a "plug and play" router A typical IPv4 end-user network consists of a "plug and play" router
with NAT functionality and a single link upstream, connected to the with NAT functionality and a single link upstream, connected to the
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| | | | | |
+---+------+ +----+-----+ | +---+------+ +----+-----+ |
|IPv6 Host | |IPv6 Host | / |IPv6 Host | |IPv6 Host | /
| | | | / | | | | /
+----------+ +----------+ / +----------+ +----------+ /
Figure 1: An Example of a Typical End-User Network Figure 1: An Example of a Typical End-User Network
This architecture describes the: This architecture describes the:
o Basic capabilities of the CE Router o Basic capabilities of the IPv6 Transition CE Router
o Provisioning of the WAN interface connecting to the service o Provisioning of the WAN interface connecting to the service
provider provider
o Provisioning of the LAN interfaces o Provisioning of the LAN interfaces
The CE Router may be manually configured in an arbitrary topology The IPv6 Transition CE Router may be manually configured in an
with a dynamic routing protocol or using HNCP ([RFC7788]). Automatic arbitrary topology with a dynamic routing protocol or using HNCP
provisioning and configuration is described for a single CE Router ([RFC7788]). Automatic provisioning and configuration is described
only. for a single IPv6 Transition CE Router only.
12. References 13. ANNEX C: Changes from -00
12.1. Normative References 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 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633, Host Configuration Protocol (DHCP) version 6", RFC 3633,
DOI 10.17487/RFC3633, December 2003, DOI 10.17487/RFC3633, December 2003,
<https://www.rfc-editor.org/info/rfc3633>. <https://www.rfc-editor.org/info/rfc3633>.
skipping to change at page 17, line 42 skipping to change at page 18, line 10
Wang, "Delivery of IPv4 Multicast Services to IPv4 Clients Wang, "Delivery of IPv4 Multicast Services to IPv4 Clients
over an IPv6 Multicast Network", RFC 8114, over an IPv6 Multicast Network", RFC 8114,
DOI 10.17487/RFC8114, March 2017, DOI 10.17487/RFC8114, March 2017,
<https://www.rfc-editor.org/info/rfc8114>. <https://www.rfc-editor.org/info/rfc8114>.
[RFC8115] Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6 [RFC8115] Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6
Option for IPv4-Embedded Multicast and Unicast IPv6 Option for IPv4-Embedded Multicast and Unicast IPv6
Prefixes", RFC 8115, DOI 10.17487/RFC8115, March 2017, Prefixes", RFC 8115, DOI 10.17487/RFC8115, March 2017,
<https://www.rfc-editor.org/info/rfc8115>. <https://www.rfc-editor.org/info/rfc8115>.
12.2. Informative References 14.2. Informative References
[IPv6Survey] [IPv6Survey]
Palet Martinez, J., "IPv6 Deployment Survey", January Palet Martinez, J., "IPv6 Deployment Survey", January
2018, 2018,
<https://indico.uknof.org.uk/event/41/contribution/5/ <https://indico.uknof.org.uk/event/41/contribution/5/
material/slides/0.pdf>. material/slides/0.pdf>.
[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking [RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <https://www.rfc-editor.org/info/rfc7788>. 2016, <https://www.rfc-editor.org/info/rfc7788>.
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