464XLAT: Combination of Stateful and Stateless Translation
RFC 6877
| Document | Type | RFC - Informational (April 2013) IPR | |
|---|---|---|---|
| Authors | Masataka Mawatari , Masanobu Kawashima , Cameron Byrne | ||
| Last updated | 2015-10-14 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| IESG | Responsible AD | Ron Bonica | |
| Send notices to | (None) |
RFC 6877
Internet Engineering Task Force (IETF) M. Mawatari
Request for Comments: 6877 Japan Internet Exchange
Category: Informational M. Kawashima
ISSN: 2070-1721 NEC AccessTechnica, Ltd.
C. Byrne
T-Mobile USA
April 2013
464XLAT: Combination of Stateful and Stateless Translation
Abstract
This document describes an architecture (464XLAT) for providing
limited IPv4 connectivity across an IPv6-only network by combining
existing and well-known stateful protocol translation (as described
in RFC 6146) in the core and stateless protocol translation (as
described in RFC 6145) at the edge. 464XLAT is a simple and scalable
technique to quickly deploy limited IPv4 access service to IPv6-only
edge networks without encapsulation.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6877.
Mawatari, et al. Informational [Page 1]
RFC 6877 464XLAT April 2013
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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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
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Motivation and Uniqueness of 464XLAT . . . . . . . . . . . . . 4
4. Network Architecture . . . . . . . . . . . . . . . . . . . . . 4
4.1. Wireline Network Architecture . . . . . . . . . . . . . . 4
4.2. Wireless 3GPP Network Architecture . . . . . . . . . . . . 5
5. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Wireline Network Applicability . . . . . . . . . . . . . . 6
5.2. Wireless 3GPP Network Applicability . . . . . . . . . . . 7
6. Implementation Considerations . . . . . . . . . . . . . . . . 7
6.1. IPv6 Address Format . . . . . . . . . . . . . . . . . . . 7
6.2. IPv4/IPv6 Address Translation Chart . . . . . . . . . . . 7
6.3. IPv6 Prefix Handling . . . . . . . . . . . . . . . . . . . 9
6.4. DNS Proxy Implementation . . . . . . . . . . . . . . . . . 9
6.5. CLAT in a Gateway . . . . . . . . . . . . . . . . . . . . 9
6.6. CLAT-to-CLAT Communications . . . . . . . . . . . . . . . 10
7. Deployment Considerations . . . . . . . . . . . . . . . . . . 10
7.1. Traffic Engineering . . . . . . . . . . . . . . . . . . . 10
7.2. Traffic Treatment Scenarios . . . . . . . . . . . . . . . 10
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
10.1. Normative References . . . . . . . . . . . . . . . . . . . 11
10.2. Informative References . . . . . . . . . . . . . . . . . . 12
Appendix A. Examples of IPv4/IPv6 Address Translation . . . . . . 13
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RFC 6877 464XLAT April 2013
1. Introduction
With the exhaustion of the unallocated IPv4 address pools, it will be
difficult for many networks to assign IPv4 addresses to end users.
This document describes an IPv4-over-IPv6 solution as one of the
techniques for IPv4 service extension and encouragement of IPv6
deployment. 464XLAT is not a one-for-one replacement of full IPv4
functionality. The 464XLAT architecture only supports IPv4 in the
client-server model, where the server has a global IPv4 address.
This means it is not fit for IPv4 peer-to-peer communication or
inbound IPv4 connections. 464XLAT builds on IPv6 transport and
includes full any-to-any IPv6 communication.
The 464XLAT architecture described in this document uses IPv4/IPv6
translation standardized in [RFC6145] and [RFC6146]. It does not
require DNS64 [RFC6147] since an IPv4 host may simply send IPv4
packets, including packets to an IPv4 DNS server, that will be
translated to IPv6 on the customer-side translator (CLAT) and back to
IPv4 on the provider-side translator (PLAT). 464XLAT networks may
use DNS64 [RFC6147] to enable single stateful translation [RFC6146]
instead of 464XLAT double translation where possible. The 464XLAT
architecture encourages the IPv6 transition by making IPv4 services
reachable across IPv6-only networks and providing IPv6 and IPv4
connectivity to single-stack IPv4 or IPv6 servers and peers.
2. Terminology
PLAT: PLAT is provider-side translator (XLAT) that complies with
[RFC6146]. It translates N:1 global IPv6 addresses to global
IPv4 addresses, and vice versa.
CLAT: CLAT is customer-side translator (XLAT) that complies with
[RFC6145]. It algorithmically translates 1:1 private IPv4
addresses to global IPv6 addresses, and vice versa. The CLAT
function is applicable to a router or an end-node such as a
mobile phone. The CLAT should perform IP routing and
forwarding to facilitate packets forwarding through the
stateless translation even if it is an end-node. The CLAT as
a common home router or wireless Third Generation Partnership
Project (3GPP) router is expected to perform gateway
functions such as being a DHCP server and DNS proxy for local
clients. The CLAT uses different IPv6 prefixes for CLAT-side
and PLAT-side IPv4 addresses and therefore does not comply
with the sentence "Both IPv4-translatable IPv6 addresses and
IPv4-converted IPv6 addresses SHOULD use the same prefix." in
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RFC 6877 464XLAT April 2013
Section 3.3 of [RFC6052]. The CLAT does not facilitate
communications between a local IPv4-only node and an IPv6-
only node on the Internet.
3. Motivation and Uniqueness of 464XLAT
The list below describes the motivation for 464XLAT and its unique
characteristics.
o 464XLAT has minimal IPv4 resource requirements and maximum IPv4
efficiency through statistical multiplexing.
o No new protocols are required; there is quick deployment.
o IPv6-only networks are simpler and therefore less expensive to
operate than dual-stack networks.
o 464XLAT has consistent native IP-based monitoring and traffic
engineering. Capacity-planning techniques can be applied without
the indirection or obfuscation of a tunnel.
4. Network Architecture
Examples of 464XLAT architectures are shown in the figures in the
following sections.
Wireline Network Architecture can be used in situations where there
are clients behind the CLAT, regardless of the type of access service
-- for example, fiber to the home (FTTH), Data Over Cable Service
Interface Specification (DOCSIS), or WiFi.
Wireless 3GPP Network Architecture can be used in situations where a
client terminates the wireless access network and possibly acts as a
router with tethered clients.
4.1. Wireline Network Architecture
The private IPv4 host in this diagram can reach global IPv4 hosts via
translation on both the CLAT and PLAT. On the other hand, the IPv6
host can reach other IPv6 hosts on the Internet directly without
translation. This means that the Customer Premises Equipment (CPE) /
CLAT can not only have the function of a CLAT but also the function
of an IPv6 native router for native IPv6 traffic. In this diagram,
the v4p host behind the CLAT has [RFC1918] addresses.
INTERNET MULTICAST ADDRESSES
Host Extensions for IP Multicasting (RFC-1112) [43] specifies the
extensions required of a host implementation of the Internet Protocol
(IP) to support multicasting. Current addresses are listed below.
224.0.0.0 Reserved [43,JBP]
224.0.0.1 All Systems on this Subnet [43,JBP]
224.0.0.2 All Routers on this Subnet [JBP]
224.0.0.3 Unassigned [JBP]
224.0.0.4 DVMRP Routers [140,JBP]
224.0.0.5 OSPFIGP OSPFIGP All Routers [83,JXM1]
224.0.0.6 OSPFIGP OSPFIGP Designated Routers [83,JXM1]
224.0.0.7 ST Routers [KS14]
224.0.0.8 ST Hosts [KS14]
224.0.0.9 RIP2 Routers [GSM11]
224.0.0.10-224.0.0.255 Unassigned [JBP]
224.0.1.0 VMTP Managers Group [17,DRC3]
224.0.1.1 NTP Network Time Protocol [80,DLM1]
224.0.1.2 SGI-Dogfight [AXC]
224.0.1.3 Rwhod [SXD]
224.0.1.4 VNP [DRC3]
224.0.1.5 Artificial Horizons - Aviator [BXF]
224.0.1.6 NSS - Name Service Server [BXS2]
224.0.1.7 AUDIONEWS - Audio News Multicast [MXF2]
224.0.1.8 SUN NIS+ Information Service [CXM3]
224.0.1.9 MTP Multicast Transport Protocol [SXA]
224.0.1.10-224.0.1.255 Unassigned [JBP]
224.0.2.1 "rwho" Group (BSD) (unofficial) [JBP]
224.0.2.2 SUN RPC PMAPPROC_CALLIT [BXE1]
224.0.3.0-224.0.3.255 RFE Generic Service [DXS3]
224.0.4.0-224.0.4.255 RFE Individual Conferences [DXS3]
224.1.0.0-224.1.255.255 ST Multicast Groups [KS14]
224.2.0.0-224.2.255.255 Multimedia Conference Calls [SC3]
232.x.x.x VMTP transient groups [17,DRC3]
These addresses are listed in the Domain Name Service under
MCAST.NET and 224.IN-ADDR.ARPA.
Note that when used on an Ethernet or IEEE 802 network, the 23
low-order bits of the IP Multicast address are placed in the low-
order 23 bits of the Ethernet or IEEE 802 net multicast address
Reynolds & Postel [Page 27]
RFC 1340 Assigned Numbers July 1992
1.0.94.0.0.0. See the next section on "IANA ETHERNET ADDRESS
BLOCK".
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RFC 1340 Assigned Numbers July 1992
IANA ETHERNET ADDRESS BLOCK
The IANA owns an Ethernet address block which may be used for
multicast address asignments or other special purposes.
The address block in IEEE binary is (which is in bit transmission
order):
0000 0000 0000 0000 0111 1010
In the normal Internet dotted decimal notation this is 0.0.94 since
the bytes are transmitted higher order first and bits within bytes
are transmitted lower order first (see "Data Notation" in the
Introduction).
IEEE CSMA/CD and Token Bus bit transmission order: 00 00 5E
IEEE Token Ring bit transmission order: 00 00 7A
Appearance on the wire (bits transmitted from left to right):
0 23 47
| | |
1000 0000 0000 0000 0111 1010 xxxx xxx0 xxxx xxxx xxxx xxxx
| |
Multicast Bit 0 = Internet Multicast
1 = Assigned by IANA for
other uses
Appearance in memory (bits transmitted right-to-left within octets,
octets transmitted left-to-right):
0 23 47
| | |
0000 0001 0000 0000 0101 1110 0xxx xxxx xxxx xxxx xxxx xxxx
| |
Multicast Bit 0 = Internet Multicast
1 = Assigned by IANA for other uses
The latter representation corresponds to the Internet standard bit-
order, and is the format that most programmers have to deal with.
Using this representation, the range of Internet Multicast addresses
is:
01-00-5E-00-00-00 to 01-00-5E-7F-FF-FF in hex, or
1.0.94.0.0.0 to 1.0.94.127.255.255 in dotted decimal
Reynolds & Postel [Page 29]
RFC 1340 Assigned Numbers July 1992
IP TOS PARAMETERS
This documents the default Type-of-Service values that are currently
recommended for the most important Internet protocols.
There are four assigned TOS values: low delay, high throughput, high
reliability, and low cost; in each case, the TOS value is used to
indicate "better". Only one TOS value or property can be requested
in any one IP datagram.
Generally, protocols which are involved in direct interaction with a
human should select low delay, while data transfers which may involve
large blocks of data are need high throughput. Finally, high
reliability is most important for datagram-based Internet management
functions.
Application protocols not included in these tables should be able to
make appropriate choice of low delay (8 decimal, 1000 binary) or high
throughput (4 decimail, 0100 binary).
The following are recommended values for TOS:
----- Type-of-Service Value -----
Protocol TOS Value
TELNET (1) 1000 (minimize delay)
FTP
Control 1000 (minimize delay)
Data (2) 0100 (maximize throughput)
TFTP 1000 (minimize delay)
SMTP (3)
Command phase 1000 (minimize delay)
DATA phase 0100 (maximize throughput)
Domain Name Service
UDP Query 1000 (minimize delay)
TCP Query 0000
Zone Transfer 0100 (maximize throughput)
NNTP 0001 (minimize monetary cost)
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RFC 1340 Assigned Numbers July 1992
ICMP
Errors 0000
Requests 0000 (4)
Responses <same as request> (4)
Any IGP 0010 (maximize reliability)
EGP 0000
SNMP 0010 (maximize reliability)
BOOTP 0000
Notes:
(1) Includes all interactive user protocols (e.g., rlogin).
(2) Includes all bulk data transfer protocols (e.g., rcp).
(3) If the implementation does not support changing the TOS during
the lifetime of the connection, then the recommended TOS on
opening the connection is the default TOS (0000).
(4) Although ICMP request messages are normally sent with the
default TOS, there are sometimes good reasons why they would be
sent with some other TOS value. An ICMP response always uses the
same TOS value as was used in the corresponding ICMP request
message.
An application may (at the request of the user) substitute 0001
(minimize monetary cost) for any of the above values.
Reynolds & Postel [Page 31]
RFC 1340 Assigned Numbers July 1992
IP TIME TO LIVE PARAMETER
The current recommended default time to live (TTL) for the Internet
Protocol (IP) [45,105] is 64.
Reynolds & Postel [Page 32]
RFC 1340 Assigned Numbers July 1992
DOMAIN SYSTEM PARAMETERS
The Internet Domain Naming System (DOMAIN) includes several
parameters. These are documented in RFC-1034, [81] and RFC-1035
[82]. The CLASS parameter is listed here. The per CLASS parameters
are defined in separate RFCs as indicated.
Domain System Parameters:
Decimal Name References
-------- ---- ----------
0 Reserved [PM1]
1 Internet (IN) [81,PM1]
2 Unassigned [PM1]
3 Chaos (CH) [PM1]
4 Hessoid (HS) [PM1]
5-65534 Unassigned [PM1]
65535 Reserved [PM1]
In the Internet (IN) class the following TYPEs and QTYPEs are
defined:
TYPE value and meaning
A 1 a host address [82]
NS 2 an authoritative name server [82]
MD 3 a mail destination (Obsolete - use MX) [82]
MF 4 a mail forwarder (Obsolete - use MX) [82]
CNAME 5 the canonical name for an alias [82]
SOA 6 marks the start of a zone of authority [82]
MB 7 a mailbox domain name (EXPERIMENTAL) [82]
MG 8 a mail group member (EXPERIMENTAL) [82]
MR 9 a mail rename domain name (EXPERIMENTAL) [82]
NULL 10 a null RR (EXPERIMENTAL) [82]
WKS 11 a well known service description [82]
PTR 12 a domain name pointer [82]
HINFO 13 host information [82]
MINFO 14 mailbox or mail list information [82]
MX 15 mail exchange [82]
TXT 16 text strings [82]
RP 17 for Responsible Person [172]
AFSDB 18 for AFS Data Base location [172]
X25 19 for X.25 PSDN address [172]
ISDN 20 for ISDN address [172]
RT 21 for Route Through [172]
Reynolds & Postel [Page 33]
RFC 1340 Assigned Numbers July 1992
NSAP 22 for NSAP address, NSAP style A record [174]
NSAP-PTR 23 for domain name pointer, NSAP style [174]
AXFR 252 transfer of an entire zone [82]
MAILB 253 mailbox-related RRs (MB, MG or MR) [82]
MAILA 254 mail agent RRs (Obsolete - see MX) [82]
* 255 A request for all records [82]
Reynolds & Postel [Page 34]
RFC 1340 Assigned Numbers July 1992
BOOTP PARAMETERS
The Bootstrap Protocol (BOOTP) RFC-951 [36] describes an IP/UDP
bootstrap protocol (BOOTP) which allows a diskless client machine to
discover its own IP address, the address of a server host, and the
name of a file to be loaded into memory and executed. The BOOTP
Vendor Information Extensions RFC-1084 [117] describes an addition to
the Bootstrap Protocol (BOOTP).
Vendor Extensions are listed below:
Tag Name Data Length Meaning
--- ---- ----------- -------
0 Pad 0 None
1 Subnet Mask 4 Subnet Mask Value
2 Time Zone 4 Time Offset in
Seconds from UTC
3 Gateways N N/4 Gateway addresses
4 Time Server N N/4 Timeserver addresses
5 Name Server N N/4 IEN-116 Server addresses
6 Domain Server N N/4 DNS Server addresses
7 Log Server N N/4 Logging Server addresses
8 Quotes Server N N/4 Quotes Server addresses
9 LPR Server N N/4 Printer Server addresses
10 Impress Server N N/4 Impress Server addresses
11 RLP Server N N/4 RLP Server addresses
12 Hostname N Hostname string
13 Boot File Size 2 Size of boot file in 512 byte
checks
14 Merit Dump File Client to dump and name
the file to dump it to
15-127 Unassigned
128-154 Reserved
255 End 0 None
Reynolds & Postel [Page 35]
RFC 1340 Assigned Numbers July 1992
NETWORK MANAGEMENT PARAMETERS
For the management of hosts and gateways on the Internet a data
structure for the information has been defined. This data structure
should be used with any of several possible management protocols, such
as the "Simple Network Management Protocol" (SNMP) RFC-1157 [15], or
the "Common Management Information Protocol over TCP" (CMOT) [142].
The data structure is the "Structure and Indentification of Management
Information for TCP/IP-based Internets" (SMI) RFC-1155 [120], and the
"Management Information Base for Network Management of TCP/IP-based
Internets" (MIB-II) [121].
The SMI includes the provision for panrameters or codes to indicate
experimental or private data structures. These parameter assignments
are listed here.
The older "Simple Gateway Monitoring Protocol" (SGMP) RFC-1028 [37]
also defined a data structure. The parameter assignments used with
SGMP are included here for hist orical completeness.
The network management object identifiers are under the iso (1), org
(3), dod (6), internet (1), or 1.3.6.1, branch of the name space.
SMI Network Management Directory Codes:
Prefix: 1.3.6.1.1.
Decimal Name Description References
------- ---- ----------- ----------
all Reserved Reserved for future use [IANA]
SMI Network Management MGMT Codes:
Prefix: 1.3.6.1.2.
Decimal Name Description References
------- ---- ----------- ----------
0 Reserved [IANA]
1 MIB [149,KZM]
Prefix: 1.3.6.1.2.1. (mib-2)
Decimal Name Description References
------- ---- ----------- ----------
0 Reserved Reserved [IANA]
1 system System [150,KZM]
2 interfaces Interfaces [150,KZM]
Reynolds & Postel [Page 36]
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RFC 6877 464XLAT April 2013
+------+
| v6 |
| host |
+--+---+
|
.---+---.
/ \
/ IPv6 \
| Internet |
\ /
`----+----'
|
+------+ | .---+---. .------.
| v6 +---+ +------+ / \ +------+ / \
| host | | | | / IPv6 \ | | / IPv4 \
+------+ +---+ CLAT +---+ Network +---+ PLAT +---+ Internet |
+--------+ | | | \ / | | \ /
| v4p/v6 +-+ +------+ `---------' +------+ `----+----'
| host | | |
+--------+ | +--+---+
+------+ | | v4g |
| v4p +---+ | host |
| host | | +------+
+------+ |
<- v4p -> XLAT <--------- v6 --------> XLAT <- v4g ->
v6 : Global IPv6
v4p : Private IPv4
v4g : Global IPv4
Figure 1: Wireline Network Topology
4.2. Wireless 3GPP Network Architecture
The CLAT function on the User Equipment (UE) provides an [RFC1918]
address and IPv4 default route to the local node's network stack.
The applications on the UE can use the private IPv4 address for
reaching global IPv4 hosts via translation on both the CLAT and the
PLAT. On the other hand, reaching IPv6 hosts (including hosts
presented via DNS64 [RFC6147]) does not require the CLAT function on
the UE.
Presenting a private IPv4 network for tethering via NAT44 and
stateless translation on the UE is also an application of the CLAT.
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RFC 6877 464XLAT April 2013
+------+
| v6 |
| host |
+--+---+
|
.---+---.
/ \
/ IPv6 \
| Internet |
\ /
UE / Mobile Phone `---------'
+----------------------+ |
| +----+ | | .---+---. .------.
| | v6 +----+ +------+ / \ +------+ / \
| +----+ | | | / IPv6 PDP \ | | / IPv4 \
| +---+ CLAT +---+ Mobile Core +---+ PLAT +--+ Internet |
| | | | \ GGSN / | | \ /
| | +------+ \ ' +------+ `----+---'
| +-----+ | | `-------' |
| | v4p +---+ | +--+---+
| +-----+ | | | v4g |
+----------------------+ | host |
+------+
<- v4p -> XLAT <--------- v6 --------> XLAT <- v4g ->
v6 : Global IPv6
v4p : Private IPv4
v4g : Global IPv4
PDP : Packet Data Protocol
GGSN : Gateway GPRS Support Node
Figure 2: Wireless 3GPP Network Topology
5. Applicability
5.1. Wireline Network Applicability
When an Internet Service Provider (ISP) has IPv6 access service and
provides 464XLAT, the ISP can provide outgoing IPv4 service to end
users across an IPv6 access network. The result is that edge network
growth is no longer tightly coupled to the availability of scarce
IPv4 addresses.
If another ISP operates the PLAT, the edge ISP is only required to
deploy an IPv6 access network. All ISPs do not need IPv4 access
networks. They can migrate their access network to a simple and
highly scalable IPv6-only environment.
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RFC 6877 464XLAT April 2013
5.2. Wireless 3GPP Network Applicability
At the time of writing, in April 2013, the vast majority of mobile
networks are compliant to Pre-Release 9 3GPP standards. In Pre-
Release 9 3GPP networks, Global System for Mobile Communications
(GSM) and Universal Mobile Telecommunications System (UMTS) networks
must signal and support both IPv4 and IPv6 Packet Data Protocol (PDP)
attachments to access IPv4 and IPv6 network destinations [RFC6459].
Since there are two PDPs required to support two address families,
this is double the number of PDPs required to support the status quo
of one address family, which is IPv4.
For the cases of connecting to an IPv4 literal or IPv4 socket that
require IPv4 connectivity, the CLAT function on the UE provides a
private IPv4 address and IPv4 default route on the host for the
applications to reference and bind to. Connections sourced from the
IPv4 interface are immediately routed to the CLAT function and passed
to the IPv6-only mobile network, destined for the PLAT. In summary,
the UE performs the CLAT function that does a stateless translation
[RFC6145], but only when required by an IPv4-only scenario such as
IPv4 literals or IPv4-only sockets. The mobile network has a PLAT
that does stateful translation [RFC6146].
464XLAT works with today's existing systems as much as possible.
464XLAT is compatible with existing solutions for network-based deep
packet inspection like 3GPP standardized Policy and Charging Control
(PCC) [TS.23203].
6. Implementation Considerations
6.1. IPv6 Address Format
The IPv6 address format in 464XLAT is defined in Section 2.2 of
[RFC6052].
6.2. IPv4/IPv6 Address Translation Chart
This chart offers an explanation about address translation
architecture using a combination of stateful translation at the PLAT
and stateless translation at the CLAT. The client on this chart is
delegated an IPv6 prefix from a prefix delegation mechanism such as
DHCPv6 Prefix Delegation (DHCPv6-PD) [RFC3633]; therefore, it has a
dedicated IPv6 prefix for translation.
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RFC 6877 464XLAT April 2013
Destination IPv4 address
+----------------------------+
| Global IPv4 address |
| assigned to IPv4 server |
+--------+ +----------------------------+
| IPv4 | Source IPv4 address
| server | +----------------------------+
+--------+ | Global IPv4 address |
^ | assigned to IPv4 PLAT pool |
| +----------------------------+
+--------+
| PLAT | Stateful XLATE(IPv4:IPv6=1:n)
+--------+
^
|
(IPv6 cloud)
Destination IPv6 address
+--------------------------------------------------------------+
| IPv4-embedded IPv6 address |
| defined in Section 2.2 of RFC 6052 |
+--------------------------------------------------------------+
Source IPv6 address
+--------------------------------------------------------------+
| IPv4-embedded IPv6 address |
| defined in Section 2.2 of RFC 6052 |
+--------------------------------------------------------------+
(IPv6 cloud)
^
|
+--------+
| CLAT | Stateless XLATE(IPv4:IPv6=1:1)
+--------+
^ Destination IPv4 address
| +----------------------------+
+--------+ | Global IPv4 address |
| IPv4 | | assigned to IPv4 server |
| client | +----------------------------+
+--------+ Source IPv4 address
+----------------------------+
| Private IPv4 address |
| assigned to IPv4 client |
+----------------------------+
Figure 3: Case of Enabling Only Stateless XLATE on CLAT
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RFC 6877 464XLAT April 2013
RFC 1340 Assigned Numbers July 1992
3 at Address Translation [150,KZM]
4 ip Internet Protocol [150,KZM]
5 icmp Internet Control Message [150,KZM]
6 tcp Transmission Control Protocol [150,KZM]
7 udp User Datagram Protocol [150,KZM]
8 egp Exterior Gateway Protocol [150,KZM]
9 cmot CMIP over TCP [150,KZM]
10 transmission Transmission [150,KZM]
11 snmp Simple Network Management [150,KZM]
12 GenericIF Generic Interface Extensions [151,163,KZM]
13 Appletalk Appletalk Networking [152,SXW]
14 ospf Open Shortest Path First [153,FB77]
15 bgp Border Gateway Protocol [154,SW159]
16 rmon Remote Network Monitoring [155,SXW]
17 bridge Bridge Objects [156,EXD]
18 DecnetP4 Decnet Phase 4
19 Character Character Streams [165,BS221]
20 snmpParties SNMP Parties [177,KZM]
21 snmpSecrets SNMP Secrets [177,KZM]
Prefix: 1.3.6.1.2.1.10 (transmission)
Decimal Name Description
------- ---- -----------
7 IEEE802.3 CSMACD--like Objects [157,JXC]
8 IEEE802.4 Token Bus-like Objects [158,163,KZM]
9 IEEE802.5 Token Ring-like Objects [159,163,KZM]
15 FDDI FDDI Objects [160,JDC20]
18 DS1 T1 Carrier Objects [161,163,FB77]
30 DS3 DS3 Interface Objects [162,163,TXC]
31 SIP SMDS Interface Objects [164,TXC]
32 FRAME-RELAY Frame Relay Objects [168,CXB]
33 RS-232 RS-232 Objects [166,BS221]
34 Parallel Parallel Printer Objects [167,BS221]
Reynolds & Postel [Page 37]
RFC 1340 Assigned Numbers July 1992
SMI Network Management Experimental Codes:
Prefix: 1.3.6.1.3.
Decimal Name Description References
------- ---- ----------- ----------
0 Reserved [JKR1]
1 CLNS ISO CLNS Objects [GS2]
* 2 T1-Carrier T1 Carrier Objects [FB77]
* 3 IEEE802.3 Ethernet-like Objects [JXC]
* 4 IEEE802.5 Token Ring-like Objects [EXD]
* 5 DECNet-PHIV DECNet Phase IV [JXS2]
* 6 Interface Generic Interface Objects [KZM]
* 7 IEEE802.4 Token Bus-like Objects [KZM]
* 8 FDDI FDDI Objects [JDC20]
9 LANMGR-1 LAN Manager V1 Objects [JXG1]
10 LANMGR-TRAPS LAN Manager Trap Objects [JXG1]
11 Views SNMP View Objects [CXD]
12 SNMP-AUTH SNMP Authentication Objects [KZM]
* 13 BGP Border Gateway Protocol [SW159]
* 14 Bridge Bridge MIB [FB77]
* 15 DS3 DS3 Interface Type [TXC]
* 16 SIP SMDS Interface Protocol [TXC]
* 17 Appletalk Appletalk Networking [SXW]
18 PPP PPP Objects [FJK2]
* 19 Character MIB Character MIB [BS221]
* 20 RS-232 MIB RS-232 MIB [BS221]
* 21 Parallel MIB Parallel MIB [BS221]
22 atsign-proxy Proxy via Community [RXF]
* 23 OSPF OSPF MIB [FB77]
24 Alert-Man Alert-Man [LS8]
25 FDDI-Synoptics FDDI-Synoptics [DXP1]
* 26 Frame Relay Frame Relay MIB [CXB]
* 27 rmon Remote Network Management MIB [SXW]
28 IDPR IDPR MIB [RAW44]
29 HUBMIB IEEE 802.3 Hub MIB [DXM5]
30 IPFWDTBLMIB IP Forwarding Table MIB [FB77]
31 LATM MIB [TXC]
32 SONET MIB [TXC]
33 IDENT [MTR]
34 MIME-MHS [MTR]
* = obsoleted
Reynolds & Postel [Page 38]
RFC 1340 Assigned Numbers July 1992
SMI Network Management Private Enterprise Codes:
Prefix: 1.3.6.1.4.1.
Decimal Name References
------- ---- ----------
0 Reserved [JKR1]
1 Proteon [JS28]
2 IBM [VXC]
3 CMU [SXW]
4 Unix [KXS]
5 ACC [AB20]
6 TWG [KZM]
7 CAYMAN [BP52]
8 PSI [MS9]
9 cisco [GXS]
10 NSC [GS123]
11 HP [RDXS]
12 Epilogue [KA4]
13 U of Tennessee [JDC20]
14 BBN [RH6]
15 Xylogics, Inc. [JRL3]
16 Timeplex [LXB1]
17 Canstar [SXP]
18 Wellfleet [JCB1]
19 TRW [HXL]
20 MIT [JR35]
21 EON [MXW]
22 Spartacus [YXK]
23 Excelan [RXB]
24 Spider Systems [VXW]
25 NSFNET [HWB]
26 Hughes LAN Systems [KZM]
27 Intergraph [GS91]
28 Interlan [BXT]
29 Vitalink Communications [FXB]
30 Ulana [BXA]
31 NSWC [SRN1]
32 Santa Cruz Operation [KR35]
33 Xyplex [BXS]
34 Cray [HXE]
35 Bell Northern Research [GXW]
36 DEC [RXB1]
37 Touch [BXB]
38 Network Research Corp. [BXV]
39 Baylor College of Medicine [SB98]
40 NMFECC-LLNL [SXH]
41 SRI [DW181]
Reynolds & Postel [Page 39]
RFC 1340 Assigned Numbers July 1992
42 Sun Microsystems [DXY]
43 3Com [TB6]
44 CMC [DXP]
45 SynOptics [DXP1]
46 Cheyenne Software [RXH]
47 Prime Computer [MXS]
48 MCNC/North Carolina Data Network [KXW]
49 Chipcom [JXC]
50 Optical Data Systems [JXF]
51 gated [JXH]
52 Cabletron Systems [RXD]
53 Apollo Computers [JXB]
54 DeskTalk Systems, Inc. [DXK]
55 SSDS [RXS]
56 Castle Rock Computing [JXS1]
57 MIPS Computer Systems [CXM]
58 TGV, Inc. [KAA]
59 Silicon Graphics, Inc. [RXJ]
60 University of British Columbia [DXM354]
61 Merit [BXN]
62 FiberCom [EXR]
63 Apple Computer Inc [JXH1]
64 Gandalf [HXK]
65 Dartmouth [PXK]
66 David Systems [KXD1]
67 Reuter [BXZ]
68 Cornell [DC126]
69 LMS [MLS34]
70 Locus Computing Corp. [AXS]
71 NASA [SS92]
72 Retix [AXM]
73 Boeing [JXG]
74 AT&T [RXB2]
75 Ungermann-Bass [DXM]
76 Digital Analysis Corp. [SXK]
77 LAN Manager [DXK]
78 Netlabs [JB478]
79 ICL [JXI]
80 Auspex Systems [BXE]
81 Lannet Company [EXR]
82 Network Computing Devices [DM280]
83 Raycom Systems [BXW1]
84 Pirelli Focom Ltd. [SXL]
85 Datability Software Systems [LXF]
86 Network Application Technology [YXW]
87 LINK (Lokales Informatik-Netz Karlsruhe) [GXS]
88 NYU [BJR2]
89 RND [RXN]
Reynolds & Postel [Page 40]
RFC 1340 Assigned Numbers July 1992
90 InterCon Systems Corporation [AW90]
91 LearningTree Systems [JXG2]
92 Webster Computer Corporation [RXE]
93 Frontier Technologies Corporation [PXA]
94 Nokia Data Communications [DXE]
95 Allen-Bradely Company [BXK]
96 CERN [JXR]
97 Sigma Network Systems, Inc. [KXV]
98 Emerging Technologies, Inc. [DXB2]
99 SNMP Research [JDC20]
100 Ohio State University [SXA1]
101 Ultra Network Technologies [JXD]
102 Microcom [AXF]
103 Martin Marietta Astronautic Group [DR137]
104 Micro Technology [MXE]
105 Process Software Corporation [BV15]
106 Data General Corporation [JXK]
107 Bull Company [AXB]
108 Emulex Corporation [JXF1]
109 Warwick University Computing Services [IXD]
110 Network General Corporation [JXD1]
111 Oracle [JPH17]
112 Control Data Corporation [NXR]
113 Hughes Aircraft Company [KZM]
114 Synernetics, Inc. [JXP1]
115 Mitre [BM60]
116 Hitachi, Ltd. [HXU]
117 Telebit [MXL2]
118 Salomon Technology Services [PXM]
119 NEC Corporation [YXA]
120 Fibermux [KH157]
121 FTP Software Inc. [SXK1]
122 Sony [TXH]
123 Newbridge Networks Corporation [JXW]
124 Racal-Milgo Information Systems [MXR]
125 CR SYSTEMS [SXS2]
126 DSET Corporation [DXS]
127 Computone [BXV]
128 Tektronix, Inc. [DT167]
129 Interactive Systems Corporation [SXA2]
130 Banyan Systems Inc. [DXT]
131 Sintrom Datanet Limited [SXW]
132 Bell Canada [MXF]
133 Crosscomm Corporation [RXS1]
134 Rice University [CXF]
135 T3Plus Networking, Inc. [HXF]
136 Concurrent Computer Corporation [JRL3]
137 Basser [PXO]
Reynolds & Postel [Page 41]
6.3. IPv6 Prefix Handling
There are two relevant IPv6 prefixes that the CLAT must be aware of.
First, CLAT must know its own IPv6 prefixes. The CLAT should acquire
a /64 for the uplink interface, a /64 for all downlink interfaces,
and a dedicated /64 prefix for the purpose of sending and receiving
statelessly translated packets. When a dedicated /64 prefix is not
available for translation from DHCPv6-PD [RFC3633], the CLAT may
perform NAT44 for all IPv4 LAN packets so that all the LAN-originated
IPv4 packets appear from a single IPv4 address and are then
statelessly translated to one interface IPv6 address that is claimed
by the CLAT via the Neighbor Discovery Protocol (NDP) and defended
with Duplicate Address Detection (DAD).
Second, the CLAT must discover the PLAT-side translation IPv6 prefix
used as a destination of the PLAT. The CLAT will use this prefix as
the destination of all translation packets that require stateful
translation to the IPv4 Internet. It may discover the PLAT-side
translation prefix using [Discovery-Heuristic]. In the future, some
other mechanisms, such as a new DHCPv6 option, will possibly be
defined to communicate the PLAT-side translation prefix.
6.4. DNS Proxy Implementation
The CLAT should implement a DNS proxy as defined in [RFC5625]. The
case of an IPv4-only node behind the CLAT querying an IPv4 DNS server
is undesirable since it requires both stateful and stateless
translation for each DNS lookup. The CLAT should set itself as the
DNS server via DHCP or other means and should proxy DNS queries for
IPv4 and IPv6 LAN clients. Using the CLAT-enabled home router or UE
as a DNS proxy is a normal consumer gateway function and simplifies
the traffic flow so that only IPv6 native queries are made across the
access network. DNS queries from the client that are not sent to the
DNS proxy on the CLAT must be allowed and are translated and
forwarded just like any other IP traffic.
6.5. CLAT in a Gateway
The CLAT feature can be implemented in a common home router or mobile
phone that has a tethering feature. Routers with a CLAT feature
should also provide common router services such as DHCP of [RFC1918]
addresses, DHCPv6, NDP with Router Advertisement, and DNS service.
Mawatari, et al. Informational [Page 9]
RFC 6877 464XLAT April 2013
6.6. CLAT-to-CLAT Communications
464XLAT is a hub and spoke architecture focused on enabling IPv4-only
services over IPv6-only networks. Interactive Connectivity
Establishment (ICE) [RFC5245] may be used to support peer-to-peer
communication within a 464XLAT network.
7. Deployment Considerations
7.1. Traffic Engineering
Even if the ISP for end users is different from the PLAT provider
(e.g., another ISP), it can implement traffic engineering
independently from the PLAT provider. Detailed reasons are below:
1. The ISP for end users can figure out the IPv4 destination address
from the translated IPv6 packet header, so it can implement
traffic engineering based on the IPv4 destination address (e.g.,
traffic monitoring for each IPv4 destination address, packet
filtering for each IPv4 destination address, etc.). The
tunneling methods do not have such an advantage, without any deep
packet inspection for processing the inner IPv4 packet of the
tunnel packet.
2. If the ISP for end users can assign an IPv6 prefix greater than
/64 to each subscriber, this 464XLAT architecture can separate
the IPv6 prefix for native IPv6 packets and the XLAT prefixes for
IPv4/IPv6 translation packets. Accordingly, it can identify the
type of packets ("native IPv6 packets" and "IPv4/IPv6 translation
packets") and implement traffic engineering based on the IPv6
prefix.
7.2. Traffic Treatment Scenarios
The below table outlines how different permutations of connectivity
are treated in the 464XLAT architecture.
Note: 464XLAT double translation treatment will be stateless when a
dedicated /64 is available for translation on the CLAT. Otherwise,
the CLAT will have both stateful and stateless since it requires
NAT44 from the LAN to a single IPv4 address and then stateless
translation to a single IPv6 address.
Mawatari, et al. Informational [Page 10]
RFC 6877 464XLAT April 2013
+--------+-------------+-----------------------+-------------+
| Server | Application | Traffic Treatment | Location of |
| | and Host | | Translation |
+--------+-------------+-----------------------+-------------+
| IPv6 | IPv6 | End-to-End IPv6 | None |
+--------+-------------+-----------------------+-------------+
| IPv4 | IPv6 | Stateful Translation | PLAT |
+--------+-------------+-----------------------+-------------+
| IPv4 | IPv4 | 464XLAT | PLAT/CLAT |
+--------+-------------+-----------------------+-------------+
Traffic Treatment Scenarios
8. Security Considerations
To implement a PLAT, see the security considerations presented in
Section 5 of [RFC6146].
To implement a CLAT, see the security considerations presented in
Section 7 of [RFC6145]. The CLAT may comply with [RFC6092].
9. Acknowledgements
The authors would like to thank JPIX NOC members, JPIX 464XLAT trial
service members, Seiichi Kawamura, Dan Drown, Brian Carpenter, Rajiv
Asati, Washam Fan, Behcet Sarikaya, Jan Zorz, Tatsuya Oishi, Lorenzo
Colitti, Erik Kline, Ole Troan, Maoke Chen, Gang Chen, Tom Petch,
Jouni Korhonen, Bjoern A. Zeeb, Hemant Singh, Vizdal Ales, Mark ZZZ
Smith, Mikael Abrahamsson, Tore Anderson, Teemu Savolainen, Alexandru
Petrescu, Gert Doering, Victor Kuarsingh, Ray Hunter, James Woodyatt,
Tom Taylor, and Remi Despres for their helpful comments. We also
would like to thank Fred Baker and Joel Jaeggli for their support.
10. References
10.1. Normative References
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
October 2010.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, April 2011.
Mawatari, et al. Informational [Page 11]
RFC 6877 464XLAT April 2013
10.2. Informative References
[Discovery-Heuristic]
Savolainen, T., Korhonen, J., and D. Wing, "Discovery of
the IPv6 Prefix Used for IPv6 Address Synthesis", Work
in Progress, March 2013.
[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
E. Lear, "Address Allocation for Private Internets",
BCP 5, RFC 1918, February 1996.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245,
April 2010.
[RFC5625] Bellis, R., "DNS Proxy Implementation Guidelines",
BCP 152, RFC 5625, August 2009.
[RFC6092] Woodyatt, J., "Recommended Simple Security Capabilities in
Customer Premises Equipment (CPE) for Providing
Residential IPv6 Internet Service", RFC 6092,
January 2011.
[RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van
Beijnum, "DNS64: DNS Extensions for Network Address
Translation from IPv6 Clients to IPv4 Servers", RFC 6147,
April 2011.
[RFC6459] Korhonen, J., Soininen, J., Patil, B., Savolainen, T.,
Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
Partnership Project (3GPP) Evolved Packet System (EPS)",
RFC 6459, January 2012.
[TS.23203] 3GPP, "Policy and charging control architecture", 3GPP
TS 23.203 10.7.0, June 2012.
Mawatari, et al. Informational [Page 12]
RFC 6877 464XLAT April 2013
Appendix A. Examples of IPv4/IPv6 Address Translation
The following is an example of IPv4/IPv6 address translation on the
464XLAT architecture.
In the case that an IPv6 prefix greater than /64 is assigned to an
end user by such as DHCPv6-PD [RFC3633], the CLAT can use a dedicated
/64 from the assigned IPv6 prefix.
Host & configuration value
+------------------------------+
| IPv4 server |
| [198.51.100.1] | IP packet header
+------------------------------+ +--------------------------------+
^ | Destination IP address |
| | [198.51.100.1] |
| | Source IP address |
| | [192.0.2.1] |
+------------------------------+ +--------------------------------+
| PLAT | ^
| IPv4 pool address | |
| [192.0.2.1 - 192.0.2.100] | |
| PLAT-side XLATE IPv6 prefix | |
| [2001:db8:1234::/96] | |
+------------------------------+ +--------------------------------+
^ | Destination IP address |
| | [2001:db8:1234::198.51.100.1] |
| | Source IP address |
| | [2001:db8:aaaa::192.168.1.2] |
+------------------------------+ +--------------------------------+
| CLAT | ^
| PLAT-side XLATE IPv6 prefix | |
| [2001:db8:1234::/96] | |
| CLAT-side XLATE IPv6 prefix | |
| [2001:db8:aaaa::/96] | |
+------------------------------+ +--------------------------------+
^ | Destination IP address |
| | [198.51.100.1] |
| | Source IP address |
| | [192.168.1.2] |
+------------------------------+ +--------------------------------+
| IPv4 client |
| [192.168.1.2/24] |
+------------------------------+
Delegated IPv6 prefix for client: 2001:db8:aaaa::/56
Mawatari, et al. Informational [Page 13]
RFC 6877 464XLAT April 2013
Authors' Addresses
Masataka Mawatari
Japan Internet Exchange Co., Ltd.
KDDI Otemachi Building 19F, 1-8-1 Otemachi,
Chiyoda-ku, Tokyo 100-0004
JAPAN
Phone: +81 3 3243 9579
EMail: mawatari@jpix.ad.jp
Masanobu Kawashima
NEC AccessTechnica, Ltd.
800, Shimomata
Kakegawa-shi, Shizuoka 436-8501
JAPAN
Phone: +81 537 22 8274
EMail: kawashimam@vx.jp.nec.com
Cameron Byrne
T-Mobile USA
Bellevue, Washington 98006
USA
EMail: cameron.byrne@t-mobile.com
Mawatari, et al. Informational [Page 14]