Transition Requirements for IPv6 Customer Edge Routers
draft-palet-v6ops-rfc7084-bis-transition-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Expired".
|
|
|---|---|---|---|
| Author | Jordi Palet Martinez | ||
| Last updated | 2017-06-12 | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-palet-v6ops-rfc7084-bis-transition-00
IPv6 Operations (v6ops) J. Palet Martinez
Internet-Draft Consulintel, S.L.
Intended status: Informational June 11, 2017
Expires: December 13, 2017
Transition Requirements for IPv6 Customer Edge Routers
draft-palet-v6ops-rfc7084-bis-transition-00
Abstract
This document specifies the transition requirements for an IPv6
Customer Edge (CE) router. Specifically, this document extends the
"Minimum Requirements for IPv6-only Customer Edge Routers" (draft-
palet-v6ops-rfc7084-bis2) in order to allow the provisioning of IPv6
transition services for the hosts attached to it and the support of
HNCP ([RFC7788]) for automated provisioning of downstream routers.
The document covers several transition technologies, either for
delivering IPv6 in IPv4-only access networks and specially for
delivering IPv4 "as a service" 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 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 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 December 13, 2017.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Palet Martinez Expires December 13, 2017 [Page 1]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 4
4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Current IPv4 End-User Network Architecture . . . . . . . 5
4.2. IPv6 End-User Network Architecture . . . . . . . . . . . 6
4.2.1. Local Communication . . . . . . . . . . . . . . . . . 8
5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. General Requirements . . . . . . . . . . . . . . . . . . 8
5.2. WAN-Side Configuration . . . . . . . . . . . . . . . . . 8
5.3. LAN-Side Configuration . . . . . . . . . . . . . . . . . 8
5.4. Transition Technologies Support . . . . . . . . . . . . . 8
5.4.1. IPv4 Service Continuity in Customer LANs . . . . . . 9
5.4.1.1. 464XLAT . . . . . . . . . . . . . . . . . . . . . 9
5.4.1.2. Dual-Stack Lite (DS-Lite) . . . . . . . . . . . . 9
5.4.1.3. Lightweight 4over6 (lw4o6) . . . . . . . . . . . 10
5.4.1.4. MAP-E . . . . . . . . . . . . . . . . . . . . . . 11
5.4.1.5. MAP-T . . . . . . . . . . . . . . . . . . . . . . 11
5.4.2. Support of IPv6 in IPv4-only WAN access . . . . . . . 12
5.4.2.1. 6in4 . . . . . . . . . . . . . . . . . . . . . . 12
5.4.2.2. 6rd . . . . . . . . . . . . . . . . . . . . . . . 13
5.5. IPv4 Multicast Support . . . . . . . . . . . . . . . . . 14
5.6. Security Considerations . . . . . . . . . . . . . . . . . 14
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
7. ANNEX A: Code Considerations . . . . . . . . . . . . . . . . 15
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . 17
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
This document defines basic IPv6 transition features for a
residential or small-office router, referred to as an "IPv6
Transition CE router", in order to establish an industry baseline for
dual-stack and transition features to be implemented on such a
Palet Martinez Expires December 13, 2017 [Page 2]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
router.
These routers are based on draft-palet-v6ops-rfc7084-bis2, so the
scope of this documents is to include also support IPv4, at least in
the LAN side.
This document covers the IP transition technologies required when
ISPs have already and IPv4-only access network that they can't turn
to dual-stack or IPv6-only, as well as the situation in a world where
IPv4 addresses are no longer available, so the service providers need
to provision IPv6-only WAN access, while at the same time ensuring
that IPv4-only or IPv6-only devices or applications in the customer
LANs can still reach IPv4-only devices or applications in Internet,
which still don't have IPv6 support.
This document specifies the transition mechanisms to be supported by
an IPv6 transition CE router, relevant provisioning or configuration
information differences from draft-palet-v6ops-rfc7084-bis2.
Automatic provisioning of more complex topology than a single router
with multiple LAN interfaces may be handled by means of HNCP
([RFC7788]). In some cases, manual provisioning may be acceptable,
when intended for a small number of customers.
1.1. Requirements Language
Take careful 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
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 (preferable
in RFC or stable form) 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 access networks.
2. Terminology
This document uses the same terminology as in draft-palet-v6ops-
rfc7084-bis2, with two minor clarifications.
The term "IPv6 transition Customer Edge Router" is defined as an
"IPv6 Customer Edge Router" that provides transition support to allow
IPv4-IPv6 coexistence either in the WAN, the LAN or both.
The "WAN Interface" term used across this document, means that can
Palet Martinez Expires December 13, 2017 [Page 3]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
also support link technologies based in Internet-layer (or higher-
layers) "tunnels", such as tunnels over IPv4 or IPv6 itself.
3. Usage Scenarios
The IPv6 Transition CE router described in this document is expected
to be used typically, in any of the following scenarios:
1. Residential/household users. Common usage is any kind of
Internet access (web, email, streaming, online gaming, etc.).
2. Residential with Small Office/Home Office (SOHO). Same usage as
for the first scenario.
3. Small Office/Home Office (SOHO). Same usage as for the first
scenario.
4. Small and Medium Enterprise (SME). Same usage as for the first
scenario.
5. Residential/household with advanced requirements. Same basic
usage as for the first scenario, however there may be
requirements for exporting services to the WAN (IP cameras, web,
DNS, email, VPN, etc.).
6. Small and Medium Enterprise (SME) with advanced requirements.
Same basic usage as for the first scenario, however there may be
requirements for exporting services to the WAN (IP cameras, web,
DNS, email, VPN, etc.).
The above list is not intended to be comprehensive of all the
possible usage scenarios, just the main ones. In fact, combinations
of the above usages are also possible, for example a residential with
SOHO and advanced requirements.
The mechanisms for exporting IPv6 services are commonly "naturally"
available in any IPv6 router, as when using GUA, unless they are
blocked by firewall rules, which may require some manual
configuration by means of a GUI and/or CLI.
However, in the case of IPv4, because the usage of private addresses
and NAT, it typically requires some degree of manual configuration
such as setting up a DMZ, virtual servers, or port/protocol
forwarding. In general, 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.
Palet Martinez Expires December 13, 2017 [Page 4]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
The main difference for an IPv6 Transition CE router to support one
or several of the above indicated scenarios, 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. So, it is out of the scope of
this document to classify them.
For example, an SME may have just 10 employees (micro-SME), which
commonly will be considered same as a SOHO, but a small SME can have
up to 50 employees, or 250 for a medium one. Depending on the IPv6
Transition CE router capabilities or even how it is being configured
(for instance, using SLAAC or DHCPv6), it may support even a higher
number of employees if the traffic in the LANs is low, or switched by
another device(s), or the WAN bandwidth requirements are low, etc.
The actual bandwidth capabilities of access with technologies such as
FTTH, cable and even 3GPP/LTE, allows the support of such usages, and
indeed, is a very common situation that access networks and the IPv6
Transition CE 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
IPv6 Transition 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
aspects. In fact, in many cases, the user must supply, or at least
can replace the IPv6 Transition CE router, which makes even more
relevant that all the IPv6 Transition 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 bigger Enterprises,
Data Centers, Content Providers, etc. So, even if the documented
requirements meet their needs, may have additional requirements,
which are out of the scope of this document.
4. Architecture
4.1. Current IPv4 End-User Network Architecture
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 network architecture. A typical IPv4 end-user
network consists of a "plug and play" router with NAT functionality
and a single link behind it, connected to the service provider
network.
Palet Martinez Expires December 13, 2017 [Page 5]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
A typical IPv4 NAT deployment by default blocks all incoming
connections. Opening of ports is typically allowed using a Universal
Plug and Play Internet Gateway Device (UPnP IGD) [UPnP-IGD] or some
other firewall control protocol.
Another consequence of using 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.
Many existing 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.
4.2. IPv6 End-User Network Architecture
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.
Palet Martinez Expires December 13, 2017 [Page 6]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
+---------------+ \
| 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 an IPv6 Transition CE router
o Provisioning of the WAN interface connecting to the service
provider
o Provisioning of the LAN interfaces
As indicated in draft-palet-v6ops-rfc7084-bis2, for IPv6 multicast
traffic, the IPv6 Transition CE router may act as a Multicast
Listener Discovery (MLD) proxy [RFC4605] and may support a dynamic
Palet Martinez Expires December 13, 2017 [Page 7]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
multicast routing protocol.
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
for a single IPv6 Transition CE router only.
4.2.1. Local Communication
Section 3.2.1 from draft-palet-v6ops-rfc7084-bis2 apply here without
changes.
Coexistence with IPv4 requires any IPv6 Transition CE router(s) on
the LAN to conform to these recommendations, especially requirements
ULA-5 and L-4 from draft-palet-v6ops-rfc7084-bis2.
5. Requirements
5.1. General Requirements
The IPv6 Transition CE router must comply with the general
requirements stated in draft-palet-v6ops-rfc7084-bis2.
5.2. WAN-Side Configuration
The IPv6 Transition CE router must comply with WAN-Side Configuration
as stated in draft-palet-v6ops-rfc7084-bis2.
5.3. LAN-Side Configuration
The IPv6 Transition CE router must comply with LAN-Side Configuration
as stated in draft-palet-v6ops-rfc7084-bis2.
In addition, a new LAN Requirement is:
L-16 The IPv6 CE router SHOULD provide HNCP (Home Networking Control
Protocol) services, as specified in [RFC7788].
5.4. Transition Technologies Support
Even if the main target of this document is the support of IPv6-only
WAN access, for some time, there will be a need to support IPv4-only
devices and applications in the customers LANs, in one side of the
picture. In the other side, some Service Providers willing to deploy
IPv6, may not be able to do so in the first stage, neither as
IPv6-only or dual-stack in the WAN. Consequently, transition
technologies to resolve both issues should be taken in consideration.
Palet Martinez Expires December 13, 2017 [Page 8]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
5.4.1. IPv4 Service Continuity in Customer LANs
5.4.1.1. 464XLAT
464XLAT [RFC6877] is a technique to provide IPv4 access service to
IPv6-only edge networks without encapsulation.
The IPv6 Transition CE router SHOULD support CLAT functionality. If
464XLAT is supported, it MUST be implemented according to [RFC6877].
The following CE 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].
464XLAT-2: The IPv6 Transition CE router MUST implement [RFC7050] in
order to discover the PLAT-side translation IPv4 and IPv6
prefix(es)/suffix(es). In environments with PCP support,
the IPv6 Transition CE SHOULD follow [RFC7225] to learn
the PLAT-side translation IPv4 and IPv6
prefix(es)/suffix(es) used by an upstream PCP-controlled
NAT64 device.
5.4.1.2. 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 functionality.
If DS-Lite is supported, it MUST be implemented according to
[RFC6333]. This document takes no position on simultaneous operation
of Dual-Stack Lite and native IPv4. The following IPv6 Transition CE
router requirements also apply:
DS-Lite requirements:
DSLITE-1: The IPv6 Transition CE router MUST support configuration
Palet Martinez Expires December 13, 2017 [Page 9]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
of DS-Lite via the DS-Lite DHCPv6 option [RFC6334]. 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 MUST support the DHCPv6 S46
priority option described in [RFC8026].
DSLITE-3: The IPv6 Transition CE router MUST NOT perform IPv4
Network Address Translation (NAT) on IPv4 traffic
encapsulated using DS-Lite.
DSLITE-4: If the IPv6 Transition CE router is configured with an
IPv4 address on its WAN interface, then the IPv6
Transition CE router SHOULD disable the DS-Lite Basic
Bridging BroadBand (B4) element.
5.4.1.3. 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 MUST be supported as well. If lw4o6
is supported, it MUST be implemented according to [RFC7596]. This
document takes no position on simultaneous operation of lw4o6 and
native IPv4. 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]. The IPv6
Transition CE router MAY use other mechanisms to configure
lw4o6 parameters. Such mechanisms are outside the scope of
this document.
LW4O6-2: The IPv6 Transition CE router MUST support the DHCPv6 S46
priority option described in [RFC8026].
LW4O6-3: The IPv6 Transition CE router MUST support the DHCPv4-over-
DHCPv6 (DHCP 4o6) transport described in [RFC7341].
LW4O6-4: The IPv6 Transition CE router MAY support Dynamic
Allocation of Shared IPv4 Addresses as described in
Palet Martinez Expires December 13, 2017 [Page 10]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
[RFC7618].
5.4.1.4. MAP-E
MAP-E [RFC7597] is a mechanism for transporting IPv4 packets across
an IPv6 network using IP encapsulation, including a generic 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 CE 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]. 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 MUST support the DHCPv6 S46
priority option described in [RFC8026].
5.4.1.5. 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 Requirements also apply:
MAP-T requirements:
MAPT-1: The CE router MUST support configuration of MAP-T via the
MAP-E DHCPv6 options [RFC7598]. The IPv6 Transition CE
router MAY use other mechanisms to configure MAP-E
parameters. Such mechanisms are outside the scope of this
document.
MAPT-2: The IPv6 Transition CE router MUST support the DHCPv6 S46
priority option described in [RFC8026].
Palet Martinez Expires December 13, 2017 [Page 11]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
5.4.2. Support of IPv6 in IPv4-only WAN access
5.4.2.1. 6in4
6in4 [RFC4213] specifies a tunneling mechanism to allow end-users to
manually configure IPv6 support via a service provider's IPv4 network
infrastructure.
The IPv6 Transition CE router MAY support 6in4 functionality. 6in4
used for a manually configured tunnel requires a subset of the 6rd
parameters (delegated prefix and remote IPv4 end-point). The on-wire
and forwarding plane is identical for both mechanisms, however 6in4
doesn't support mesh traffic and requires manually provisioning.
Thus, if the device supports either 6rd or 6in4, it's commonly a
minor UI addition to support both. If 6in4 is supported, it MUST be
implemented according to [RFC4213]. The following CE Requirements
also apply:
6in4 requirements:
6IN4-1: The IPv6 Transition CE router SHOULD support 6in4 automated
configuration by means of the 6rd DHCPv4 Option 212. If the
IPv6 Transition CE router has obtained an IPv4 network
address through some other means such as PPP, it SHOULD use
the DHCPINFORM request message [RFC2131] to request the 6rd
DHCPv4 Option. The IPv6 Transition CE router MAY use other
mechanisms to configure 6in4 parameters. Such mechanisms
are outside the scope of this document.
6IN4-2: If the IPv6 Transition CE router is capable of automated
configuration of IPv4 through IPCP (i.e., over a PPP
connection), it MUST support user-entered configuration of
6in4.
6IN4-3: If the IPv6 Transition CE router supports configuration
mechanisms other than the 6rd DHCPv4 Option 212 (user-
entered, TR-069 [TR-069], etc.), the IPv6 Transition CE
router MUST support 6in4 in "hub and spoke" mode. 6in4 in
"hub and spoke" requires all IPv6 traffic to go to the 6rd
Border Relay, which in this case is the tunnel-end-point.
In effect, this requirement removes the "direct connect to
6rd" route defined in Section 7.1.1 of [RFC5969].
6IN4-4: The IPv6 Transition CE router MUST allow 6in4 and native
IPv6 WAN interfaces to be active alone as well as
simultaneously in order to support coexistence of the two
technologies during an incremental transition period such as
a transition from 6in4 to native IPv6.
Palet Martinez Expires December 13, 2017 [Page 12]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
6IN4-5: Each packet sent on a 6in4 or native WAN interface MUST be
directed such that its source IP address is derived from the
delegated prefix associated with the particular interface
from which the packet is being sent (Section 4.3 of
[RFC3704]).
6IN4-6: The IPv6 Transition CE router MUST allow different as well
as identical delegated prefixes to be configured via each
(6in4 or native) WAN interface.
6IN4-7: In the event that forwarding rules produce a tie between
6in4 and native IPv6, by default, the IPv6 Transition CE
router MUST prefer native IPv6.
5.4.2.2. 6rd
6rd [RFC5969] specifies an automatic tunneling mechanism tailored to
advance deployment of IPv6 to end users via a service provider's IPv4
network infrastructure. Key aspects include automatic IPv6 prefix
delegation to sites, stateless operation, simple provisioning, and
service that is equivalent to native IPv6 at the sites that are
served by the mechanism. It is expected that such traffic is
forwarded over the IPv6 Transition CE router's native IPv4 WAN
interface and not encapsulated in another tunnel.
The IPv6 Transition CE router MAY support 6rd functionality. If 6rd
is supported, it MUST be implemented according to [RFC5969]. The
following CE Requirements also apply:
6rd requirements:
6RD-1: The IPv6 Transition CE router MUST support 6rd configuration
via the 6rd DHCPv4 Option 212. If the IPv6 Transition CE
router has obtained an IPv4 network address through some
other means such as PPP, it SHOULD use the DHCPINFORM request
message [RFC2131] to request the 6rd DHCPv4 Option. The IPv6
Transition CE router MAY use other mechanisms to configure
6rd parameters. Such mechanisms are outside the scope of
this document.
6RD-2: If the IPv6 Transition CE router is capable of automated
configuration of IPv4 through IPCP (i.e., over a PPP
connection), it MUST support user-entered configuration of
6rd.
6RD-3: If the IPv6 Transition CE router supports configuration
mechanisms other than the 6rd DHCPv4 Option 212 (user-
entered, TR-069 [TR-069], etc.), the IPv6 Transition CE
Palet Martinez Expires December 13, 2017 [Page 13]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
router MUST support 6rd in "hub and spoke" mode. 6rd in "hub
and spoke" requires all IPv6 traffic to go to the 6rd Border
Relay. In effect, this requirement removes the "direct
connect to 6rd" route defined in Section 7.1.1 of [RFC5969].
6RD-4: The IPv6 Transition CE router MUST allow 6rd and native IPv6
WAN interfaces to be active alone as well as simultaneously
in order to support coexistence of the two technologies
during an incremental transition period such as a transition
from 6rd to native IPv6.
6RD-5: Each packet sent on a 6rd or native WAN interface MUST be
directed such that its source IP address is derived from the
delegated prefix associated with the particular interface
from which the packet is being sent (Section 4.3 of
[RFC3704]).
6RD-6: The IPv6 Transition CE router MUST allow different as well as
identical delegated prefixes to be configured via each (6rd
or native) WAN interface.
6RD-7: In the event that forwarding rules produce a tie between 6rd
and native IPv6, by default, the IPv6 Transition CE router
MUST prefer native IPv6.
5.5. 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.
In order to support the delivery of IPv4 multicast services to IPv4
clients over an IPv6 multicast network, the IPv6 Transition CE router
SHOULD support [RFC8114] and [RFC8115].
5.6. Security Considerations
The IPv6 Transition CE router must comply with the Security
Considerations as stated in draft-palet-v6ops-rfc7084-bis2.
6. Acknowledgements
Thanks to James Woodyatt, Mohamed Boucadair, Masanobu Kawashima,
Mikael Abrahamsson, Barbara Stark, Ole Troan and Brian Carpenter for
their review and comments.
Palet Martinez Expires December 13, 2017 [Page 14]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
7. ANNEX A: 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), that adding the support for the new transitions
mechanisms, requires around 10-12 Kbytes (because most of the code is
shared among several transition mechanisms), which typically means
about 0,15% of the existing code size in popular CEs 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, so
the development cost is negligent, and only integration and testing
cost may become a minor issue.
8. References
8.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, DOI 10.17487/RFC2131, March 1997,
<http://www.rfc-editor.org/info/rfc2131>.
[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,
<http://www.rfc-editor.org/info/rfc3633>.
[RFC3704] Baker, F. and P. Savola, "Ingress Filtering for Multihomed
Networks", BCP 84, RFC 3704, DOI 10.17487/RFC3704, March
2004, <http://www.rfc-editor.org/info/rfc3704>.
[RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
for IPv6 Hosts and Routers", RFC 4213,
DOI 10.17487/RFC4213, October 2005,
<http://www.rfc-editor.org/info/rfc4213>.
Palet Martinez Expires December 13, 2017 [Page 15]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
[RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick,
"Internet Group Management Protocol (IGMP) / Multicast
Listener Discovery (MLD)-Based Multicast Forwarding
("IGMP/MLD Proxying")", RFC 4605, DOI 10.17487/RFC4605,
August 2006, <http://www.rfc-editor.org/info/rfc4605>.
[RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4
Infrastructures (6rd) -- Protocol Specification",
RFC 5969, DOI 10.17487/RFC5969, August 2010,
<http://www.rfc-editor.org/info/rfc5969>.
[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,
<http://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,
<http://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,
<http://www.rfc-editor.org/info/rfc6877>.
[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,
<http://www.rfc-editor.org/info/rfc7050>.
[RFC7225] Boucadair, M., "Discovering NAT64 IPv6 Prefixes Using the
Port Control Protocol (PCP)", RFC 7225,
DOI 10.17487/RFC7225, May 2014,
<http://www.rfc-editor.org/info/rfc7225>.
[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,
<http://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, <http://www.rfc-editor.org/info/rfc7596>.
Palet Martinez Expires December 13, 2017 [Page 16]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
[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,
<http://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,
<http://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, <http://www.rfc-editor.org/info/rfc7599>.
[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,
<http://www.rfc-editor.org/info/rfc7618>.
[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <http://www.rfc-editor.org/info/rfc7788>.
[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, <http://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,
<http://www.rfc-editor.org/info/rfc8114>.
[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,
<http://www.rfc-editor.org/info/rfc8115>.
8.2. Informative References
[TR-069] Broadband Forum, "CPE WAN Management Protocol", TR-069
Amendment 4, July 2011,
<http://www.broadband-forum.org/technical/trlist.php>.
Palet Martinez Expires December 13, 2017 [Page 17]
Internet-Draft IPv6 Transition CE Router Requirements June 2017
[UPnP-IGD]
UPnP Forum, "InternetGatewayDevice:2 Device Template
Version 1.01", December 2010,
<http://upnp.org/specs/gw/igd2/>.
Author's Address
Jordi Palet Martinez
Consulintel, S.L.
Molino de la Navata, 75
La Navata - Galapagar, Madrid 28420
Spain
EMail: jordi.palet@consulintel.es
URI: http://www.consulintel.es/
Palet Martinez Expires December 13, 2017 [Page 18]