draft-ietf-softwire-map-01.txt   draft-ietf-softwire-map-02.txt 
Network Working Group O. Troan Network Working Group O. Troan
Internet-Draft W. Dec Internet-Draft W. Dec
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: December 29, 2012 X. Li Expires: March 9, 2013 X. Li
C. Bao C. Bao
Y. Zhai
CERNET Center/Tsinghua CERNET Center/Tsinghua
University University
S. Matsushima S. Matsushima
SoftBank Telecom SoftBank Telecom
T. Murakami T. Murakami
IP Infusion IP Infusion
June 27, 2012 September 5, 2012
Mapping of Address and Port (MAP) Mapping of Address and Port with Encapsulation (MAP)
draft-ietf-softwire-map-01 draft-ietf-softwire-map-02
Abstract Abstract
This document describes a mechanism for transporting IPv4 packets This document describes a mechanism for transporting IPv4 packets
across an IPv6 network, and a generic mechanism for mapping between across an IPv6 network, and a generic mechanism for mapping between
IPv6 addresses and IPv4 addresses and transport layer ports. IPv6 addresses and IPv4 addresses and transport layer ports.
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
skipping to change at page 1, line 41 skipping to change at page 1, line 40
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 http://datatracker.ietf.org/drafts/current/. Drafts is at http://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 December 29, 2012. This Internet-Draft will expire on March 9, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 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
(http://trustee.ietf.org/license-info) in effect on the date of (http://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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Mapping Algorithm . . . . . . . . . . . . . . . . . . . . . . 8 5. Mapping Algorithm . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Port mapping algorithm . . . . . . . . . . . . . . . . . . 10 5.1. Port mapping algorithm . . . . . . . . . . . . . . . . . . 9
5.1.1. Bit Representation of the Algorithm . . . . . . . . . 11 5.1.1. Bit Representation of the Algorithm . . . . . . . . . 9
5.1.2. GMA examples . . . . . . . . . . . . . . . . . . . . . 11 5.1.2. GMA examples . . . . . . . . . . . . . . . . . . . . . 10
5.1.3. Algorithm Provisioning Considerations . . . . . . . . 12 5.1.3. Port Algorithm Provisioning Considerations . . . . . . 11
5.2. Basic mapping rule (BMR) . . . . . . . . . . . . . . . . . 12 5.2. Basic mapping rule (BMR) . . . . . . . . . . . . . . . . . 11
5.3. Forwarding mapping rule (FMR) . . . . . . . . . . . . . . 15 5.3. Forwarding mapping rule (FMR) . . . . . . . . . . . . . . 14
5.4. Default mapping rule (DMR) . . . . . . . . . . . . . . . . 16 5.4. Default mapping rule (DMR) . . . . . . . . . . . . . . . . 15
6. The IPv6 Interface Identifier . . . . . . . . . . . . . . . . 17 6. The IPv6 Interface Identifier . . . . . . . . . . . . . . . . 16
7. MAP Configuration . . . . . . . . . . . . . . . . . . . . . . 18 7. MAP Configuration . . . . . . . . . . . . . . . . . . . . . . 16
7.1. MAP CE . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.1. MAP CE . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7.2. MAP BR . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.2. MAP BR . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7.3. Backwards compatibility . . . . . . . . . . . . . . . . . 19 7.3. Backwards compatibility . . . . . . . . . . . . . . . . . 17
8. Forwarding Considerations . . . . . . . . . . . . . . . . . . 19 8. Forwarding Considerations . . . . . . . . . . . . . . . . . . 18
8.1. Receiving rules . . . . . . . . . . . . . . . . . . . . . 20 8.1. Receiving rules . . . . . . . . . . . . . . . . . . . . . 18
8.2. MAP BR . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8.2. MAP BR . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.2.1. IPv6 to IPv4 . . . . . . . . . . . . . . . . . . . . . 20 8.2.1. IPv6 to IPv4 . . . . . . . . . . . . . . . . . . . . . 18
8.2.2. IPv4 to IPv6 . . . . . . . . . . . . . . . . . . . . . 20 9. ICMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
9. ICMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 10. Fragmentation and Path MTU Discovery . . . . . . . . . . . . . 19
9.1. Translating ICMP/ICMPv6 Headers . . . . . . . . . . . . . 21 10.1. Fragmentation in the MAP domain . . . . . . . . . . . . . 19
10. Fragmentation and Path MTU Discovery . . . . . . . . . . . . . 22 10.2. Receiving IPv4 Fragments on the MAP domain borders . . . . 20
10.1. Fragmentation in the MAP domain . . . . . . . . . . . . . 22 10.3. Sending IPv4 fragments to the outside . . . . . . . . . . 20
10.2. Receiving IPv4 Fragments on the MAP domain borders . . . . 23 11. NAT44 Considerations . . . . . . . . . . . . . . . . . . . . . 20
10.3. Sending IPv4 fragments to the outside . . . . . . . . . . 23 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
11. NAT44 Considerations . . . . . . . . . . . . . . . . . . . . . 23 13. Security Considerations . . . . . . . . . . . . . . . . . . . 21
12. Deployment Considerations . . . . . . . . . . . . . . . . . . 23 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 21
12.1. Use cases . . . . . . . . . . . . . . . . . . . . . . . . 23 15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
12.1.1. Mesh Model . . . . . . . . . . . . . . . . . . . . . . 23 16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
12.1.2. Hub & Spoke Model . . . . . . . . . . . . . . . . . . 24 16.1. Normative References . . . . . . . . . . . . . . . . . . . 23
12.1.3. Communication with IPv6 servers in the MAP-T domain . 24 16.2. Informative References . . . . . . . . . . . . . . . . . . 23
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 Appendix A. Example of MAP . . . . . . . . . . . . . . . . . . . 25
14. Security Considerations . . . . . . . . . . . . . . . . . . . 24 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 28
15. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 25
16. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 26
17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26
17.1. Normative References . . . . . . . . . . . . . . . . . . . 26
17.2. Informative References . . . . . . . . . . . . . . . . . . 27
Appendix A. Example of MAP-T translation . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction 1. Introduction
Mapping IPv4 addresses in IPv6 addresses has been described in Mapping of IPv4 addresses in IPv6 addresses has been described in
numerous mechanisms dating back to 1996 [RFC1933]. The Automatic numerous mechanisms dating back to 1996 [RFC1933]. The Automatic
tunneling mechanism described in RFC1933, assigned a globally unique tunneling mechanism described in RFC1933, assigned a globally unique
IPv6 address to a host by combining the host's IPv4 address with a IPv6 address to a host by combining the host's IPv4 address with a
well-known IPv6 prefix. Given an IPv6 packet with a destination well-known IPv6 prefix. Given an IPv6 packet with a destination
address with an embedded IPv4 address, a node could automatically address with an embedded IPv4 address, a node could automatically
tunnel this packet by extracting the IPv4 tunnel end-point address tunnel this packet by extracting the IPv4 tunnel end-point address
from the IPv6 destination address. from the IPv6 destination address.
There are numerous variations of this idea, described in 6over4 There are numerous variations of this idea, described in 6over4
[RFC2529], 6to4 [RFC3056], ISATAP [RFC5214], and 6rd [RFC5969]. [RFC2529], 6to4 [RFC3056], ISATAP [RFC5214], and 6rd [RFC5969].
The commonalities of all these IPv6 over IPv4 mechanisms are: The commonalities of all these IPv6 over IPv4 mechanisms are:
o Automatically provisions an IPv6 address for a host or an IPv6 o Automatically provisions an IPv6 address for a host or an IPv6
prefix for a site prefix for a site
o Algorithmic or implicit address resolution for tunneling or o Algorithmic or implicit address resolution of tunnel end point
encapsulation. Given an IPv6 destination address, an IPv4 tunnel addresses. Given an IPv6 destination address, an IPv4 tunnel
endpoint address can be calculated. Likewise for translation, an endpoint address can be calculated.
IPv4 address can be calculated from an IPv6 destination address
and vice versa.
o Embedding of an IPv4 address or part thereof and optionally o Embedding of an IPv4 address or part thereof into an IPv6 address.
transport layer ports into an IPv6 address.
In phases of IPv4 to IPv6 migration, IPv6 only networks will be In phases of IPv4 to IPv6 migration, IPv6 only networks will be
common, while there will still be a need for residual IPv4 common, while there will still be a need for residual IPv4
deployment. This document describes a generic mapping of IPv4 to deployment. This document describes a generic mapping of IPv4 to
IPv6, and mechanisms for encapsulation (IPv4 over IPv6) and IPv6, and a mechanism for encapsulating IPv4 over IPv6.
translation between the two protocols that use this mapping.
Just as the IPv6 over IPv4 mechanisms referred to above, the residual Just as the IPv6 over IPv4 mechanisms referred to above, the residual
IPv4 over IPv6 mechanisms must be capable of: IPv4 over IPv6 mechanism must be capable of:
o Provisioning an IPv4 prefix, an IPv4 address or a shared IPv4 o Provisioning an IPv4 prefix, an IPv4 address or a shared IPv4
address. address.
o Algorithmically map between an IPv4 prefix, IPv4 address or a o Algorithmically map between an IPv4 prefix, IPv4 address or a
shared IPv4 address and an IPv6 address. shared IPv4 address and an IPv6 address.
The unified mapping scheme described here supports translation mode, The mapping scheme described here supports encapsulation of IPv4
encapsulation mode, in both mesh and hub and spoke topologies. packets in IPv6 in both mesh and hub and spoke topologies, including
address mappings with full independence between IPv6 and IPv4
addresses.
This document describes delivery of IPv4 unicast service across an This document describes delivery of IPv4 unicast service across an
IPv6 infrastructure. IPv4 multicast is not considered further in IPv6 infrastructure. IPv4 multicast is not considered further in
this document. this document.
The A+P (Address and Port) architecture of sharing an IPv4 address by The A+P (Address and Port) architecture of sharing an IPv4 address by
distributing the port space is described in [RFC6346]. Specifically distributing the port space is described in [RFC6346]. Specifically
section 4 of [RFC6346] covers stateless mapping. The corresponding section 4 of [RFC6346] covers stateless mapping. The corresponding
stateful solution DS-lite is described in [RFC6333]. The motivation stateful solution DS-lite is described in [RFC6333]. The motivation
for the work is described in for the work is described in
[I-D.ietf-softwire-stateless-4v6-motivation]. [I-D.ietf-softwire-stateless-4v6-motivation].
A companion document defines a DHCPv6 option for provisioning of MAP A companion document defines a DHCPv6 option for provisioning of MAP
[I-D.mdt-softwire-map-dhcp-option]. Other means of provisioning is [I-D.ietf-softwire-map-dhcp]. Other means of provisioning is
possible. Deployment considerations are described in [I-D.mdt- possible. Deployment considerations are described in [I-D.mdt-
softwire-map-deployment]. softwire-map-deployment].
MAP relies on IPv6 and is designed to deliver production-quality MAP relies on IPv6 and is designed to deliver production-quality
dual-stack service while allowing IPv4 to be phased out within the SP dual-stack service while allowing IPv4 to be phased out within the SP
network. The phasing out of IPv4 within the SP network is network. The phasing out of IPv4 within the SP network is
independent of whether the end user disables IPv4 service or not. independent of whether the end user disables IPv4 service or not.
Further, "Greenfield"; IPv6-only networks may use MAP in order to Further, "Greenfield"; IPv6-only networks may use MAP in order to
deliver IPv4 to sites via the IPv6 network. deliver IPv4 to sites via the IPv6 network.
skipping to change at page 6, line 16 skipping to change at page 5, line 14
within the context of MAP. within the context of MAP.
MAP Customer Edge (CE): A device functioning as a Customer Edge MAP Customer Edge (CE): A device functioning as a Customer Edge
router in a MAP deployment. A typical MAP CE router in a MAP deployment. A typical MAP CE
adopting MAP rules will serve a residential adopting MAP rules will serve a residential
site with one WAN side interface, and one or site with one WAN side interface, and one or
more LAN side interfaces. A MAP CE may also more LAN side interfaces. A MAP CE may also
be referred to simply as a "CE" within the be referred to simply as a "CE" within the
context of MAP. context of MAP.
Port-set: Each node has a separate part of the Port-set: The separate part of the transport layer port
transport layer port space; denoted as a space; denoted as a port-set.
port-set.
Port-set ID (PSID): Algorithmically identifies a set of ports Port-set ID (PSID): Algorithmically identifies a set of ports
exclusively assigned to the CE. exclusively assigned to a CE.
Shared IPv4 address: An IPv4 address that is shared among multiple Shared IPv4 address: An IPv4 address that is shared among multiple
CEs. Only ports that belong to the assigned CEs. Only ports that belong to the assigned
port-set can be used for communication. Also port-set can be used for communication. Also
known as a Port-Restricted IPv4 address. known as a Port-Restricted IPv4 address.
End-user IPv6 prefix: The IPv6 prefix assigned to an End-user CE by End-user IPv6 prefix: The IPv6 prefix assigned to an End-user CE by
other means than MAP itself. E.g. other means than MAP itself. E.g.
Provisioned using DHCPv6 PD [RFC3633] or provisioned using DHCPv6 PD [RFC3633] or
configured manually. It is unique for each configured manually. It is unique for each
CE. CE.
MAP IPv6 address: The IPv6 address used to reach the MAP MAP IPv6 address: The IPv6 address used to reach the MAP
function of a CE from other CEs and from BRs. function of a CE from other CEs and from BRs.
Rule IPv6 prefix: An IPv6 prefix assigned by a Service Provider Rule IPv6 prefix: An IPv6 prefix assigned by a Service Provider
for a mapping rule. for a mapping rule.
Rule IPv4 prefix: An IPv4 prefix assigned by a Service Provider Rule IPv4 prefix: An IPv4 prefix assigned by a Service Provider
for a mapping rule. for a mapping rule.
Embedded Address (EA) bits: The IPv4 EA-bits in the IPv6 address Embedded Address (EA) bits: The IPv4 EA-bits in the IPv6 address
identify an IPv4 prefix/address (or part identify an IPv4 prefix/address (or part
thereof) or a shared IPv4 address (or part thereof) or a shared IPv4 address (or part
thereof) and a port-set identifier. thereof) and a port-set identifier.
MRT: MAP Rule table. Address and Port aware data
structure, supporting longest match lookups.
The MRT is used by the MAP forwarding
function.
MAP-T: Mapping of Address and Port - Translation
mode. MAP-T utilizes IPv4/IPv6 translation
as per [RFC6145].
MAP-E: Mapping of Address and Port - Encapsulation
mode. MAP-E utilizes a simple IPv4-in-IPv6
tunneling [RFC2473].
4. Architecture 4. Architecture
The MAP mechanism is largely built up using existing standard The MAP mechanism uses existing standard building blocks. The
building blocks. The existing NAT44 on the CE is used with existing NAT44 on the CE is used with additional support for
additional support for restricting transport protocol ports, ICMP restricting transport protocol ports, ICMP identifiers and fragment
identifiers and fragment identifiers to the configured port set. MAP identifiers to the configured port set. MAP supports the
supports two forwarding modes, one using stateless NAT64 as specified encapsulation mode specified in [RFC2473]. In addition MAP specifies
in [RFC6145] and one encapsulation mode specified in [RFC2473]. In an algorithm to do "address resolution" from an IPv4 address and port
addition MAP specifies an algorithm to do "address resolution" from to an IPv6 address. This algorithmic mapping is specified in
an IPv4 address and port to an IPv6 address. This algorithmic Section 5.
mapping is specified in section 5.
A full IPv4 address or IPv4 prefix can be used like today, e.g. for A full IPv4 address or IPv4 prefix can be used like today, e.g. for
identifying an interface or as a DHCP pool. A shared IPv4 address on identifying an interface or as a DHCP pool. A shared IPv4 address on
the other hand, MUST NOT be used to identify an interface. While it the other hand, MUST NOT be used to identify an interface. While it
is theoretically possible to make host stacks and applications port- is theoretically possible to make host stacks and applications port-
aware, that is considered a too drastic change to the IP model aware, that is considered a too drastic change to the IP model
[RFC6250]. [RFC6250].
The MAP architecture described here, restricts the use of the shared The MAP architecture described here, restricts the use of the shared
IPv4 address to only be used as the global address (outside) of the IPv4 address to only be used as the global address (outside) of the
NAPT [RFC2663] running on the CE. The NAPT MUST in turn be connected NAPT [RFC2663] running on the CE. The NAPT MUST in turn be connected
to a MAP aware forwarding function, that does encapsulation/ to a MAP aware forwarding function, that does encapsulation/
decapsulation or translation to IPv6. decapsulation of IPv4 packets in IPv6.
When MAP is used to provision a full IPv4 address or an IPv4 prefix When MAP is used to provision a full IPv4 address or an IPv4 prefix
to the CE, these restrictions do not apply. to the CE, these restrictions do not apply.
For packets outbound from the private IPv4 network, the CE NAPT MUST For packets outbound from the private IPv4 network, the CE NAPT MUST
translate transport identifiers (e.g. TCP and UDP port numbers) so translate transport identifiers (e.g. TCP and UDP port numbers) so
that they fall within the assigned CE's port-range. that they fall within the assigned CE's port-range.
The forwarding function uses the Mapping Rule Table (MRT) to make The forwarding function uses the Rules table to make forwarding
forwarding decisions. The table consist of the mapping rules. An decisions. The table consists of the mapping rules. An entry in the
entry in the table consists of an IPv4 prefix and PSID. The normal table consists of an IPv4 prefix and PSID.
best matching prefix algorithm is used. With a maximum key length of
48 (Length of IPv4 address (32) + Length of Transport layer port
field (16)). E.g. with a sharing ratio of 64 (6 bit PSID length) a
"host route" for this CE would be a /38 (32 + 6).
User N User N
Private IPv4 Private IPv4
| Network | Network
| |
O--+---------------O O--+---------------O
| | MAP CE | | | MAP CE |
| +-----+--------+ | | +-----+--------+ |
| NAPT44| MAP | | | NAPT44| MAP | |
| +-----+ | | |\ ,-------. .------. | +-----+ | | |\ ,-------. .------.
skipping to change at page 8, line 34 skipping to change at page 7, line 34
| | +--------+ | | | +--------+ |
O---.--------------O O---.--------------O
| |
User M User M
Private IPv4 Private IPv4
Network Network
Figure 1: Network Topology Figure 1: Network Topology
The MAP BR is responsible for connecting external IPv4 networks to The MAP BR is responsible for connecting external IPv4 networks to
all devices in one or more MAP domains. the IPv4 nodes in one or more MAP domains.
The translation mode allows communication between both IPv4-only and
any IPv6 enabled end hosts, with native IPv6-only servers which are
using IPv4-mapped IPv6 address based on DMR in the MAP-T domain. In
this mode, the IPv6-only servers SHOULD have both A and AAAA records
in the authorities DNS server [RFC6219]. DNS64 [RFC6147] become
required only when IPv6 servers in the MAP-T domain are expected
themselves to initiate communication to external IPv4-only hosts.
5. Mapping Algorithm 5. Mapping Algorithm
A MAP node is provisioned with one or more mapping rules. A MAP node is provisioned with one or more mapping rules.
Mapping rules are used differently depending on their function. Mapping rules are used differently depending on their function.
Every MAP node must be provisioned with a Basic mapping rule. This Every MAP node must be provisioned with a Basic mapping rule. This
is used by the node to configure its IPv4 address, IPv4 prefix or is used by the node to configure its IPv4 address, IPv4 prefix or
shared IPv4 address. This same basic rule can also be used for shared IPv4 address. This same basic rule can also be used for
forwarding, where an IPv4 destination address and optionally a forwarding, where an IPv4 destination address and optionally a
destination port is mapped into an IPv6 address or prefix. destination port is mapped into an IPv6 address. Additional mapping
Additional mapping rules are specified to allow for e.g. multiple rules are specified to allow for multiple different IPv4 sub-nets to
different IPv4 subnets to exist within the domain and optimize exist within the domain and optimize forwarding between them.
forwarding between them.
Traffic outside of the domain (i.e. when the destination IPv4 address Traffic outside of the domain (i.e. when the destination IPv4 address
does not match (using longest matching prefix) any Rule IPv4 prefix does not match (using longest matching prefix) any Rule IPv4 prefix
in the Rules database) will be forward using the Default mapping in the Rules database) will be forward using the Default mapping
rule. The Default mapping rule maps outside destinations to the BR's rule. The Default mapping rule maps outside destinations to the BR's
IPv6 address or prefix. IPv6 address.
Note: The forwarding mode is intended to apply uniformly for rules in
a domain - subject to further WG feedback in this area.
There are three types of mapping rules: There are three types of mapping rules:
1. Basic Mapping Rule - used for IPv4 prefix, address or port set 1. Basic Mapping Rule - used for IPv4 prefix, address or port set
assignment. There can only be one Basic Mapping Rule per End- assignment. There can only be one Basic Mapping Rule per End-
user IPv6 prefix. The Basic Mapping Rule is used to configure user IPv6 prefix. The Basic Mapping Rule is used to configure
the MAP IPv6 address or prefix. the MAP IPv6 address or prefix.
* Rule IPv6 prefix (including prefix length) * Rule IPv6 prefix (including prefix length)
* Rule IPv4 prefix (including prefix length) * Rule IPv4 prefix (including prefix length)
* Rule EA-bits length (in bits) * Rule EA-bits length (in bits)
* Rule Port Parameters (optional) * Rule Port Parameters (optional)
* Forwarding mode
2. Forwarding Mapping Rule - used for forwarding. The Basic Mapping 2. Forwarding Mapping Rule - used for forwarding. The Basic Mapping
Rule is also a Forwarding Mapping Rule. Each Forwarding Mapping Rule is also a Forwarding Mapping Rule. Each Forwarding Mapping
Rule will result in an entry in the MRT for the Rule IPv4 prefix. Rule will result in an entry in the Rules table for the Rule IPv4
The FMR consists of the same parameters as the BMR. prefix. The FMR consists of the same parameters as the BMR.
3. Default Mapping Rule - used for destinations outside the MAP 3. Default Mapping Rule - used for destinations outside the MAP
domain. A 0.0.0.0/0 entry is installed in the MRT for this rule. domain. A 0.0.0.0/0 entry is installed in the Rules table for
this rule.
* IPv6 prefix of address of BR
* Forwarding mode * IPv6 address of BR
A MAP node finds its Basic Mapping Rule by doing a longest match A MAP node finds its Basic Mapping Rule by doing a longest match
between the End-user IPv6 prefix and the Rule IPv6 prefix in the between the End-user IPv6 prefix and the Rule IPv6 prefix in the
Mapping Rule database. The rule is then used for IPv4 prefix, Mapping Rules table. The rule is then used for IPv4 prefix, address
address or shared address assignment. or shared address assignment.
A MAP IPv6 address (or prefix) is formed from the BMR Rule IPv6 A MAP IPv6 address is formed from the BMR Rule IPv6 prefix. This
prefix. This address MUST be assigned to an interface of the MAP address MUST be assigned to an interface of the MAP node and is used
node and is used to terminate all MAP traffic being sent or received to terminate all MAP traffic being sent or received to the node.
to the node.
Port-aware IPv4 entries in the MRT are installed for all the Port-aware IPv4 entries in the Rules table are installed for all the
Forwarding Mapping Rules and an IPv4 default route for the Default Forwarding Mapping Rules and an IPv4 default route for the Default
Mapping Rule. Mapping Rule.
In hub and spoke mode, all traffic MUST be forwarded using the In hub and spoke mode, all traffic MUST be forwarded using the
Default Mapping Rule. Default Mapping Rule.
5.1. Port mapping algorithm 5.1. Port mapping algorithm
The port mapping algorithm is used in domains whose rules allow IPv4 The port mapping algorithm is used in domains whose rules allow IPv4
address sharing. Different Port-Set Identifiers (PSID) MUST have address sharing. Different Port-Set Identifiers (PSID) MUST have
skipping to change at page 12, line 15 skipping to change at page 11, line 4
For example, for R = 64, a = 0 (PSID offset = 0 and PSID length = 6 For example, for R = 64, a = 0 (PSID offset = 0 and PSID length = 6
bits): bits):
Port-set Port-set
PSID=0 | [ 0 - 1023] PSID=0 | [ 0 - 1023]
PSID=1 | [1024 - 2047] PSID=1 | [1024 - 2047]
PSID=2 | [2048 - 3071] PSID=2 | [2048 - 3071]
PSID=3 | [3072 - 4095] PSID=3 | [3072 - 4095]
... ...
PSID=63 | [64512 - 65535] PSID=63 | [64512 - 65535]
Example 2: with offset = 0 (a = 0) Example 2: with offset = 0 (a = 0)
5.1.3. Algorithm Provisioning Considerations 5.1.3. Port Algorithm Provisioning Considerations
The number of offset bits (a) and excluded ports are optionally The number of offset bits (a) and excluded ports are optionally
provisioned via the "Rule Port Mapping Parameters" in the Basic provisioned via the "Rule Port Mapping Parameters" in the Basic
Mapping Rule. Mapping Rule.
The defaults are: The defaults are:
o Excluded ports : 0-4095 o Excluded ports : 0-4095
o Offset bits (a) : 4 o Offset bits (a) : 4
To simplify the port mapping algorithm the defaults are chosen so To simplify the GMA port mapping algorithm the defaults are chosen so
that the PSID field starts on a nibble boundary and the excluded port that the PSID field starts on a nibble boundary and the excluded port
range (0-1023) is extended to 0-4095. range (0-1023) is extended to 0-4095.
5.2. Basic mapping rule (BMR) 5.2. Basic mapping rule (BMR)
| n bits | o bits | s bits | 128-n-o-s bits | | n bits | o bits | s bits | 128-n-o-s bits |
+--------------------+-----------+---------+------------+----------+ +--------------------+-----------+---------+------------+----------+
| Rule IPv6 prefix | EA bits |subnet ID| interface ID | | Rule IPv6 prefix | EA bits |subnet ID| interface ID |
+--------------------+-----------+---------+-----------------------+ +--------------------+-----------+---------+-----------------------+
|<--- End-user IPv6 prefix --->| |<--- End-user IPv6 prefix --->|
skipping to change at page 13, line 13 skipping to change at page 11, line 45
Rule within the MAP domain. The EA bits encode the CE specific IPv4 Rule within the MAP domain. The EA bits encode the CE specific IPv4
address and port information. The EA bits can contain a full or part address and port information. The EA bits can contain a full or part
of an IPv4 prefix or address, and in the shared IPv4 address case of an IPv4 prefix or address, and in the shared IPv4 address case
contains a Port-Set Identifier (PSID). contains a Port-Set Identifier (PSID).
The MAP IPv6 address is created by concatenating the End-user IPv6 The MAP IPv6 address is created by concatenating the End-user IPv6
prefix with the MAP subnet-id and the interface-id as specified in prefix with the MAP subnet-id and the interface-id as specified in
Section 6. Section 6.
The MAP subnet ID is defined to be the first subnet (all bits set to The MAP subnet ID is defined to be the first subnet (all bits set to
zero). A MAP node MUST reserve the first IPv6 prefix in a End-user zero). A MAP node MUST reserve the first IPv6 prefix in an End-user
IPv6 prefix for the purpose of MAP. IPv6 prefix for the purpose of MAP.
The MAP IPv6 is created by combining the End-User IPv6 prefix with The MAP IPv6 is created by combining the End-User IPv6 prefix with
the all zeros subnet-id and the MAP IPv6 interface identifier. the all zeros subnet-id and the MAP IPv6 interface identifier.
Shared IPv4 address: Shared IPv4 address:
| r bits | p bits | | q bits | | r bits | p bits | | q bits |
+-------------+---------------------+ +------------+ +-------------+---------------------+ +------------+
| Rule IPv4 | IPv4 Address suffix | |Port-Set ID | | Rule IPv4 | IPv4 Address suffix | |Port-Set ID |
skipping to change at page 14, line 40 skipping to change at page 13, line 20
If o + r is equal to 32, then a full IPv4 address is to be assigned. If o + r is equal to 32, then a full IPv4 address is to be assigned.
The address is created by concatenating the Rule IPv4 prefix and the The address is created by concatenating the Rule IPv4 prefix and the
EA-bits. EA-bits.
If o + r is > 32, then a shared IPv4 address is to be assigned. The If o + r is > 32, then a shared IPv4 address is to be assigned. The
number of IPv4 address suffix bits (p) in the EA bits is given by 32 number of IPv4 address suffix bits (p) in the EA bits is given by 32
- r bits. The PSID bits are used to create a port-set. The length - r bits. The PSID bits are used to create a port-set. The length
of the PSID bit field within EA bits is: o - p. of the PSID bit field within EA bits is: o - p.
The length of r MAY be 32, with no part of the IPv4 address embedded
in the EA bits. This results in a mapping with no dependence between
the IPv4 address and the IPv6 address. In addition the length of o
MAY be zero (no EA bits embedded in the End-User IPv6 prefix),
meaning that also the PSID is provisioned using e.g. the DHCP option.
In the following examples, only the suffix (last 8 bits) of the IPv4 In the following examples, only the suffix (last 8 bits) of the IPv4
address is embedded in the EA bits (r = 24), while the IPv4 prefix address is embedded in the EA bits (r = 24), while the IPv4 prefix
(first 24 bits) is given in the BMR Rule IPv4 prefix. (first 24 bits) is given in the BMR Rule IPv4 prefix.
Example: Example:
Given: Given:
End-user IPv6 prefix: 2001:db8:0012:3400::/56 End-user IPv6 prefix: 2001:db8:0012:3400::/56
Basic Mapping Rule: {2001:db8:0000::/40 (Rule IPv6 prefix), Basic Mapping Rule: {2001:db8:0000::/40 (Rule IPv6 prefix),
192.0.2.0/24 (Rule IPv4 prefix), 192.0.2.0/24 (Rule IPv4 prefix),
16 (Rule EA-bits length)} 16 (Rule EA-bits length)}
Sharing ratio: 256 (16 - (32 - 24) = 8. 2^8 = 256) Sharing ratio: 256 (16 - (32 - 24) = 8 2^8 = 256)
PSID offset: 4 (default value as per section 5.1.3) PSID offset: 4 (default value as per section 5.1.3)
We get IPv4 address and port-set: We get IPv4 address and port-set:
EA bits offset: 40 EA bits offset: 40
IPv4 suffix bits (p): Length of IPv4 address (32) - IPv4 suffix bits (p): Length of IPv4 address (32) -
IPv4 prefix length (24) = 8 IPv4 prefix length (24) = 8
IPv4 address: 192.0.2.18 (0x12) IPv4 address: 192.0.2.18 (18: 0x12)
PSID start: 40 + p = 40 + 8 = 48 PSID start: 40 + p = 40 + 8 = 48
PSID length: o - p = 16 (56 - 40) - 8 = 8 PSID length: o - p = 16 (56 - 40) - 8 = 8
PSID: 0x34 PSID: 0x34
Port-set-1: 4928, 4929, 4930, 4931, 4932, 4933, 4934, 4935, Port-set-1: 4928, 4929, 4930, 4931, 4932, 4933, 4934, 4935,
4936, 4937, 4938, 4939, 4940, 4941, 4942, 4943 4936, 4937, 4938, 4939, 4940, 4941, 4942, 4943
Port-set-2: 9024, 9025, 9026, 9027, 9028, 9029, 9030, 9031, Port-set-2: 9024, 9025, 9026, 9027, 9028, 9029, 9030, 9031,
9032, 9033, 9034, 9035, 9036, 9037, 9038, 9039 9032, 9033, 9034, 9035, 9036, 9037, 9038, 9039
... ...
Port-set-15: 62272, 62273, 62274, 62275, Port-set-15: 62272, 62273, 62274, 62275,
62276, 62277, 62278, 62279, 62276, 62277, 62278, 62279,
62280, 62281, 62282, 62283, 62280, 62281, 62282, 62283,
62284, 62285, 62286, 62287, 62284, 62285, 62286, 62287,
5.3. Forwarding mapping rule (FMR) 5.3. Forwarding mapping rule (FMR)
On adding an FMR rule, an IPv4 route is installed in the MRT for the On adding an FMR rule, an IPv4 route is installed in the Rules table
Rule IPv4 prefix. for the Rule IPv4 prefix.
On forwarding an IPv4 packet, a best matching prefix lookup is done On forwarding an IPv4 packet, a best matching prefix look up is done
in the MRT and the correct FMR is chosen. in the Rules table and the correct FMR is chosen.
| 32 bits | | 16 bits | | 32 bits | | 16 bits |
+--------------------------+ +-------------------+ +--------------------------+ +-------------------+
| IPv4 destination address | | IPv4 dest port | | IPv4 destination address | | IPv4 dest port |
+--------------------------+ +-------------------+ +--------------------------+ +-------------------+
: : ___/ : : : ___/ :
| p bits | / q bits : | p bits | / q bits :
+----------+ +------------+ +----------+ +------------+
|IPv4 sufx| |Port-Set ID | |IPv4 sufx| |Port-Set ID |
+----------+ +------------+ +----------+ +------------+
skipping to change at page 16, line 48 skipping to change at page 15, line 48
PSID: 0x34 (9030 (0x2346)) PSID: 0x34 (9030 (0x2346))
EA bits: 0x1234 EA bits: 0x1234
MAP IPv6 address: 2001:db8:0012:3400:00c0:0002:1200:3400 MAP IPv6 address: 2001:db8:0012:3400:00c0:0002:1200:3400
5.4. Default mapping rule (DMR) 5.4. Default mapping rule (DMR)
The Default Mapping rule is used to reach IPv4 destinations outside The Default Mapping rule is used to reach IPv4 destinations outside
of the MAP domain. Traffic using this rule will be sent from a CE to of the MAP domain. Traffic using this rule will be sent from a CE to
a BR. a BR.
The DMR consist of the IPv6 address or IPv6 prefix of the BR. Which The DMR consist of the IPv6 address of the BR.
is used, is dependent on the forwarding mode used. Translation mode
requires that the IPv4 destination address is encoded in the BR IPv6
address, so only a prefix is used in the DMR to allow for a generated
interface identifier. For the encapsulation mode the complete IPv6
address of the BR is used.
6. The IPv6 Interface Identifier 6. The IPv6 Interface Identifier
The Interface identifier format of a MAP node is based on the format The Interface identifier format of a MAP node is based on the format
specified in section 2.2 of [RFC6052], with the added PSID field if specified in section 2.2 of [RFC6052], with the added PSID field if
present, as shown in figure Figure 8. present, as shown in figure Figure 8.
+--+---+---+---+---+---+---+---+---+ +--+---+---+---+---+---+---+---+---+
|PL| 8 16 24 32 40 48 56 | |PL| 8 16 24 32 40 48 56 |
+--+---+---+---+---+---+---+---+---+ +--+---+---+---+---+---+---+---+---+
|64| u | IPv4 address | PSID | 0 | |64| u | IPv4 address | PSID | 0 |
+--+---+---+---+---+---+---+---+---+ +--+---+---+---+---+---+---+---+---+
Figure 8 Figure 8
For traffic destined outside of a MAP domain (i.e. for traffic
following the default mapping rule), the destination IPv4 address is
mapped to the IPv6 address or prefix of the BR. For MAP-E this is
the IPv6 tunnel end point address of the BR, while for MAP-T this is
the IPv6 converted representation of the IPv6 address per RFC6052,
shown in the form of an example in figure Figure 9 below. Note that
the BR prefix-length is variable and can be both shorter or longer
than 64 bits, up to 96 bits.
<---------- 64 ------------>< 8 ><----- 32 -----><--- 24 --->
+--------------------------+----+---------------+-----------+
| BR prefix | u | IPv4 address | 0 |
+--------------------------+----+---------------+-----------+
Figure 9
The encoding of the full IPv4 address into the interface identifier,
both for the source and destination IPv6 addresses have been shown to
be useful for troubleshooting.
In the case of an IPv4 prefix, the IPv4 address field is right-padded In the case of an IPv4 prefix, the IPv4 address field is right-padded
with zeroes up to 32 bits. The PSID field is left-padded to create a with zeroes up to 32 bits. The PSID field is left-padded to create a
16 bit field. For an IPv4 prefix or a complete IPv4 address, the 16 bit field. For an IPv4 prefix or a complete IPv4 address, the
PSID field is zero. PSID field is zero.
If the End-user IPv6 prefix length is larger than 64, the most If the End-user IPv6 prefix length is larger than 64, the most
significant parts of the interface identifier is overwritten by the significant parts of the interface identifier is overwritten by the
prefix. prefix.
7. MAP Configuration 7. MAP Configuration
For a given MAP domain, the BR and CE MUST be configured with the For a given MAP domain, the BR and CE MUST be configured with the
following MAP elements. The configured values for these elements are following MAP elements. The configured values for these elements are
identical for all CEs and BRs within a given MAP domain. identical for all CEs and BRs within a given MAP domain.
o The End-User IPv6 prefix (Part of the normal IPv6 provisioning). o The End-User IPv6 prefix (Part of the normal IPv6 provisioning).
o The Basic Mapping Rule and optionally the Forwarding Mapping o The Basic Mapping Rule and optionally the Forwarding Mapping
Rules, including the Rule IPv6 prefix, Rule IPv4 prefix, Length of Rules, including the Rule IPv6 prefix, Rule IPv4 prefix, and
EA bits, and Forwarding mode Length of EA bits
o The Default Mapping Rule with the BR IPv6 prefix or address o The Default Mapping Rule with the BR IPv6 address
o The domain's MAP-E or MAP-T forwarding mode. o Hub and spoke mode or Mesh mode. (If all traffic should be sent
to the BR, or if direct CE to CE traffic should be supported).
7.1. MAP CE 7.1. MAP CE
The MAP elements are set to values that are the same across all CEs The MAP elements are set to values that are the same across all CEs
within a MAP domain. The values may be configured in a variety of within a MAP domain. The values may be configured in a variety of
manners, including provisioning methods such as the Broadband Forum's manners, including provisioning methods such as the Broadband Forum's
"TR-69" Residential Gateway management interface, an XML-based object "TR-69" Residential Gateway management interface, an XML-based object
retrieved after IPv6 connectivity is established, or manual retrieved after IPv6 connectivity is established, or manual
configuration by an administrator. This document describes how to configuration by an administrator. This document describes how to
configure the necessary parameters via a single DHCPv6 option. A CE configure the necessary parameters via a single DHCPv6 option. A CE
skipping to change at page 18, line 51 skipping to change at page 17, line 31
IPv6 prefix for the CE. The End-user IPv6 prefix is configured as IPv6 prefix for the CE. The End-user IPv6 prefix is configured as
part of obtaining IPv6 Internet access. part of obtaining IPv6 Internet access.
A single MAP CE MAY be connected to more than one MAP domain, just as A single MAP CE MAY be connected to more than one MAP domain, just as
any router may have more than one IPv4-enabled service provider any router may have more than one IPv4-enabled service provider
facing interface and more than one set of associated addresses facing interface and more than one set of associated addresses
assigned by DHCP. Each domain a given CE operates within would assigned by DHCP. Each domain a given CE operates within would
require its own set of MAP configuration elements and would generate require its own set of MAP configuration elements and would generate
its own IPv4 address. its own IPv4 address.
The MAP DHCP option is specified in The MAP DHCP option is specified in [I-D.ietf-softwire-map-dhcp].
[I-D.mdt-softwire-map-dhcp-option].
7.2. MAP BR 7.2. MAP BR
The MAP BR MUST be configured with the same MAP elements as the MAP The MAP BR MUST be configured with the same MAP elements as the MAP
CEs operating within the same domain. CEs operating within the same domain.
For increased reliability and load balancing, the BR IPv6 address may For increased reliability and load balancing, the BR IPv6 address MAY
be an anycast address shared across a given MAP domain. As MAP is be an anycast address shared across a given MAP domain. As MAP is
stateless, any BR may be used at any time. If the BR IPv6 address is stateless, any BR may be used at any time. If the BR IPv6 address is
anycast the relay MUST use this anycast IPv6 address as the source anycast the relay MUST use this anycast IPv6 address as the source
address in packets relayed to CEs. address in packets relayed to CEs.
Since MAP uses provider address space, no specific routes need to be Since MAP uses provider address space, no specific routes need to be
advertised externally for MAP to operate, neither in IPv6 nor IPv4 advertised externally for MAP to operate, neither in IPv6 nor IPv4
BGP. However, if anycast is used for the MAP IPv6 relays, the BGP. However, if anycast is used for the MAP IPv6 relays, the
anycast addresses must be advertised in the service provider's IGP. anycast addresses must be advertised in the service provider's IGP.
7.3. Backwards compatibility 7.3. Backwards compatibility
A MAP-E CE provisioned with only a Default Mapping Rule makes a MAP-E A MAP-E CE provisioned with only a Default Mapping Rule, and with no
CE compatible for use with DS-Lite [RFC6333] AFTRs, whose addresses IPv4 address and port range configured by other means, MUST disable
are configured as the MAP BR. its NAT44 functionality. This characteristic makes a MAP CE
compatible with DS-Lite [RFC6333] AFTRs, whose addresses are
A MAP-T CE, in all configuration modes, is by default compatible with configured as the MAP BR.
stateful NAT64 gateways, whose prefixes are passed as the BR
prefixes. Furthermore, when a MAP-T CE configured to operate without
address sharing (no PSID), is compatible with stateless NAT64
elements acting as BRs.
8. Forwarding Considerations 8. Forwarding Considerations
Figure 1 depicts the overall MAP architecture with IPv4 users (N and Figure 1 depicts the overall MAP architecture with IPv4 users (N and
M) networks connected to a routed IPv6 network. M) networks connected to a routed IPv6 network.
MAP supports two forwarding modes. Translation mode as specified in MAP supports Encapsulation mode as specified in [RFC2473].
[RFC6145] and Encapsulation mode as specified in [RFC2473].
A MAP CE forwarding IPv4 packets from the LAN SHOULD perform NAT44 A MAP CE forwarding IPv4 packets from the LAN performs NAT44
functions first and create appropriate NAT44 bindings. The resulting functions first and create appropriate NAT44 bindings. The resulting
IPv4 packets MUST contain the source IPv4 address and source IPv4 packets MUST contain the source IPv4 address and source
transport number defined by MAP. The resulting IPv4 packet is transport number defined by MAP. The resulting IPv4 packet is
forwarded to the CE's MAP forwarding function. The IPv6 source and forwarded to the CE's MAP forwarding function. The IPv6 source and
destination addresses MUST then be derived as per Section 5 of this destination addresses MUST then be derived as per Section 5 of this
draft. draft.
A MAP CE receiving an IPv6 packet to its MAP IPv6 address are A MAP CE receiving an IPv6 packet to its MAP IPv6 address sends this
forwarded to the CE's MAP function. All other IPv6 traffic is packet to the CE's MAP function. All other IPv6 traffic is forwarded
forwarded as per the CE's IPv6 routing rules. In other cases, the as per the CE's IPv6 routing rules. The resulting IPv4 packet is
MAP-T function MUST derive the IPv4 source and destination addresses then forwarded to the CE's NAT44 function where the destination port
as per Section 6 of this draft and MUST replace the IPv6 header with number MUST be checked against the stateful port mapping session
an IPv4 header in accordance with [RFC6145]. The resulting IPv4 table and the destination port number MUST be mapped to its original
packet is then forwarded to the CE's NAT44 function where the value.
destination port number MUST be checked against the stateful port
mapping session table and the destination port number MUST be mapped
to its original value.
8.1. Receiving rules 8.1. Receiving rules
The CE SHOULD check that MAP received packets' transport-layer The CE SHOULD check that MAP received packets' transport-layer
destination port number is in the range configured by MAP for the CE destination port number is in the range configured by MAP for the CE
and the CE SHOULD drop any non conforming packet and respond with an and the CE SHOULD drop any non conforming packet and respond with an
ICMPv6 "Address Unreachable" (Type 1, Code 3). ICMPv6 "Address Unreachable" (Type 1, Code 3).
8.2. MAP BR 8.2. MAP BR
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the packet destination address against the configured BR prefixes or the packet destination address against the configured BR prefixes or
FMR prefix(es). The selected MAP rule allows the BR to determine the FMR prefix(es). The selected MAP rule allows the BR to determine the
EA-bits from the source IPv6 address. The BR MUST perform a EA-bits from the source IPv6 address. The BR MUST perform a
validation of the consistency of the source IPv6 address and source validation of the consistency of the source IPv6 address and source
port number for the packet using BMR. If the packets source port port number for the packet using BMR. If the packets source port
number is found to be outside the range allowed for this CE and the number is found to be outside the range allowed for this CE and the
BMR, the BR MUST drop the packet and respond with an ICMPv6 BMR, the BR MUST drop the packet and respond with an ICMPv6
"Destination Unreachable, Source address failed ingress/egress "Destination Unreachable, Source address failed ingress/egress
policy" (Type 1, Code 5). policy" (Type 1, Code 5).
For packets that are to be forwarded outside of a MAP domain, the BR
MUST derive the source and destination IPv4 addresses as per Section
7 of this draft and translate the IPv6 to IPv4 headers following
[RFC6145]. The resulting IPv4 packets are then passed to regular
IPv4 forwarding.
8.2.2. IPv4 to IPv6
A MAP BR receiving IPv4 packets uses a longest match IPv4 lookup to
select the target MAP domain and rule. The BR MUST then derive the
IPv6 source and destination addresses from the IPv4 source and
destination address and port as per Section 7 of this draft.
Following this, the BR MUST translate the IPv4 to IPv6 headers
following [RFC6145]. The resulting IPv6 packets are then passed to
regular IPv6 forwarding.
Note that the operation of a BR when forwarding to MAP domains that
do not utilize IPv4 address sharing, is the same as stateless IPv4/
IPv6 translation.
9. ICMP 9. ICMP
ICMP message should be supported in MAP domain. Hence, the NAT44 in ICMP message should be supported in MAP domain. Hence, the NAT44 in
MAP CE must implement the behavior for ICMP message conforming to the MAP CE must implement the behavior for ICMP message conforming to the
best current practice documented in [RFC5508]. best current practice documented in [RFC5508].
If a MAP CE receives an ICMP message having ICMP identifier field in If a MAP CE receives an ICMP message having ICMP identifier field in
ICMP header, NAT44 in the MAP CE must rewrite this field to a ICMP header, NAT44 in the MAP CE must rewrite this field to a
specific value assigned from the port-set. BR and other CEs must specific value assigned from the port-set. BR and other CEs must
handle this field similar to the port number in the TCP/UDP header handle this field similar to the port number in the TCP/UDP header
upon receiving the ICMP message with ICMP identifier field. upon receiving the ICMP message with ICMP identifier field.
If a MAP node receives an ICMP error message without the ICMP If a MAP node receives an ICMP error message without the ICMP
identifier field for some errors that is detected inside a IPv6 identifier field for errors that is detected inside a IPv6 tunnel, a
tunnel, a MAP BR and CE should replay the ICMP error message to the node should relay the ICMP error message to the original source.
original source. This behavior should be implemented conforming to This behavior should be implemented conforming to the section 8 of
the section 8 of [RFC2473]. The MAP-E BR and CE obtain the original [RFC2473].
IPv6 tunnel packet storing in ICMP payload and then decapsulate IPv4
packet. Finally the MAP-E BR and CE generate a new ICMP error
message from the decapsulated IPv4 packet and then forward it.
9.1. Translating ICMP/ICMPv6 Headers
MAP-T CEs and BRs MUST follow ICMP/ICMPv6 translation as per
[RFC6145], with the following extension to cover the address sharing/
port-range feature.
Unlike TCP and UDP, which each provide two port fields to represent
both source and destination, the ICMP/ICMPv6 Query message header has
only one ID field [RFC0792], [RFC4443]. Thus, if the ICMP Query
message is originated from an IPv4 host behind a MAP-T CE, the ICMP
ID field SHOULD be used to exclusively identify that IPv4 host. This
means that the MAP-T CE SHOULD rewrite the ID field to a port-set
value obtained via the BMR during the IPv4 to IPv6 ICMPv6 translation
operation. A BR can translate the resulting ICMPv6 packets back to
ICMP preserving the ID field on its way to an IPv4 destination. In
the return path, when MAP-T BR receives an ICMP packet containing an
ID field which is bound for a shared address in the MAP-T domain, the
MAP-T BR SHOULD use the ID value as a substitute for the destination
port in determining the IPv6 destination address according to Section
5.1. In all other cases, the MAP-T BR MUST derive the destination
IPv6 address by simply mapping the destination IPv4 address without
additional port info.
If a MAP BR receives an ICMP error message on its IPv4 interface, the
MAP BR should replay the ICMP message to an appropriate MAP CE. If
IPv4 address is not shared, the MAP BR generates a CE IPv6 address
from the IPv4 destination address in the ICMP error message and
encapsulates the ICMP message in IPv6. If IPv4 address is shared,
the MAP BR derives an original IPv4 packet from the ICMP payload and
generates a CE IPv6 address from the source address and the source
port in the original IPv4 packet. If the MAP BR can generate the CE
IPv6 address, the MAP BR encapsulates the ICMP error message in IPv6
and then forward it to its IPv6 interface.
10. Fragmentation and Path MTU Discovery 10. Fragmentation and Path MTU Discovery
Due to the different sizes of the IPv4 and IPv6 header, handling the Due to the different sizes of the IPv4 and IPv6 header, handling the
maximum packet size is relevant for the operation of any system maximum packet size is relevant for the operation of any system
connecting the two address families. There are three mechanisms to connecting the two address families. There are three mechanisms to
handle this issue: Path MTU discovery (PMTUD), fragmentation, and handle this issue: Path MTU discovery (PMTUD), fragmentation, and
transport-layer negotiation such as the TCP Maximum Segment Size transport-layer negotiation such as the TCP Maximum Segment Size
(MSS) option [RFC0897]. MAP uses all three mechanisms to deal with (MSS) option [RFC0897]. MAP uses all three mechanisms to deal with
different cases. different cases.
10.1. Fragmentation in the MAP domain 10.1. Fragmentation in the MAP domain
Encapsulating or translating an IPv4 packet to carry it across the Encapsulating an IPv4 packet to carry it across the MAP domain will
MAP domain will increase its size (40 bytes and 20 bytes increase its size (40 bytes). It is strongly recommended that the
respectively). It is strongly recommended that the MTU in the MAP MTU in the MAP domain is well managed and that the IPv6 MTU on the CE
domain is well managed and that the IPv6 MTU on the CE WAN side WAN side interface is set so that no fragmentation occurs within the
interface is set so that no fragmentation occurs within the boundary boundary of the MAP domain.
of the MAP domain.
Fragmentation on MAP domain entry is described for encapsulation in Fragmentation on MAP domain entry is described in section 7.2 of
section 7.2 of [RFC2473] and in section 4 and 5 of of [RFC6145] for [RFC2473]
translation mode.
The use of an anycast source address could lead to any ICMP error The use of an anycast source address could lead to any ICMP error
message generated on the path being sent to a different BR. message generated on the path being sent to a different BR.
Therefore, using dynamic tunnel MTU Section 6.7 of [RFC2473] is Therefore, using dynamic tunnel MTU Section 6.7 of [RFC2473] is
subject to IPv6 Path MTU blackholes. subject to IPv6 Path MTU black-holes.
Multiple BRs using the same anycast source address could send Multiple BRs using the same anycast source address could send
fragmented packets to the same CE at the same time. If the fragmented packets to the same CE at the same time. If the
fragmented packets from different BRs happen to use the same fragment fragmented packets from different BRs happen to use the same fragment
ID, incorrect reassembly might occur. ID, incorrect reassembly might occur.
10.2. Receiving IPv4 Fragments on the MAP domain borders 10.2. Receiving IPv4 Fragments on the MAP domain borders
Forwarding of an IPv4 packet received from the outside of the MAP Forwarding of an IPv4 packet received from the outside of the MAP
domain requires the IPv4 destination address and the transport domain requires the IPv4 destination address and the transport
protocol destination port. The transport protocol information is protocol destination port. The transport protocol information is
only available in the first fragment received. As described in only available in the first fragment received. As described in
section 5.3.3 of [RFC6346] a MAP node receiving an IPv4 fragmented section 5.3.3 of [RFC6346] a MAP node receiving an IPv4 fragmented
packet from outside has to reassemble the packet before sending the packet from outside has to reassemble the packet before sending the
packet onto the MAP link. If the first packet received contains the packet onto the MAP link. If the first packet received contains the
transport protocol information, it is possible to optimize this transport protocol information, it is possible to optimize this
behaviour by using a cache and forwarding the fragments unchanged. A behavior by using a cache and forwarding the fragments unchanged. A
description of this algorithm is outside the scope of this document. description of this algorithm is outside the scope of this document.
10.3. Sending IPv4 fragments to the outside 10.3. Sending IPv4 fragments to the outside
If two IPv4 host behind two different MAP CE's with the same IPv4 If two IPv4 host behind two different MAP CE's with the same IPv4
address sends fragments to an IPv4 destination host outside the address sends fragments to an IPv4 destination host outside the
domain. Those hosts may use the same IPv4 fragmentation identifier, domain. Those hosts may use the same IPv4 fragmentation identifier,
resulting in incorrect reassembly of the fragments at the destination resulting in incorrect reassembly of the fragments at the destination
host. Given that the IPv4 fragmentation identifier is a 16 bit host. Given that the IPv4 fragmentation identifier is a 16 bit
field, it could be used similarly to port ranges. A MAP CE SHOULD field, it could be used similarly to port ranges. A MAP CE SHOULD
skipping to change at page 23, line 38 skipping to change at page 20, line 44
11. NAT44 Considerations 11. NAT44 Considerations
The NAT44 implemented in the MAP CE SHOULD conform with the behavior The NAT44 implemented in the MAP CE SHOULD conform with the behavior
and best current practice documented in [RFC4787], [RFC5508], and best current practice documented in [RFC4787], [RFC5508],
[RFC5382] and [RFC5383]. In MAP address sharing mode (determined by [RFC5382] and [RFC5383]. In MAP address sharing mode (determined by
the MAP domain/rule configuration parameters) the operation of the the MAP domain/rule configuration parameters) the operation of the
NAT44 MUST be restricted to the available port numbers derived via NAT44 MUST be restricted to the available port numbers derived via
the basic mapping rule. the basic mapping rule.
12. Deployment Considerations 12. IANA Considerations
12.1. Use cases
Editorial Note: Carried over from Use-cases/forwarding considerations
in previous drafts.
12.1.1. Mesh Model
MAP allows the mesh model in order for all CEs to communicate each
others directly. If one mapping rules is applied to a given MAP
domain, all CEs can communicate each others directly. If multiple
mapping rules are applied to a given MAP domain, or if multiple MAP
domains exist, CE can communicate with each other directly when the
CEs know the respective mapping rules. When a CE receives an IPv4
packet from its LAN side, the CE looks up a mapping rule
corresponding to an IPv4 destination address in the received IPv4
packet. If the corresponding mapping rule is found, CE can
communicate to another CE directly based on the Forwarding mapping
rule (FMR). If the corresponding mapping rule is not found, CE must
forward the packet to a given BR using the Default Mapping rule
(DMR).
12.1.2. Hub & Spoke Model
In order to achieve the hub & spoke mode fully, Forwarding mapping
rule (FMR) should be disabled. In this case, all CEs do not look up
the mapping rules upon receiving an IPv4 packet from its LAN side and
then CE must encapsulate the IPv4 packet with IPv6 whose destination
must be a given BR using the Default Mapping Rule (DMR).
12.1.3. Communication with IPv6 servers in the MAP-T domain
MAP-T allows communication between both IPv4-only and any IPv6
enabled end hosts, with native IPv6-only servers which are using
IPv4-mapped IPv6 address based on DMR in the MAP-T domain. In this
mode, the IPv6-only servers SHOULD have both A and AAAA records in
DNS [RFC6219]. DNS64 [RFC6147] become required only when IPv6
servers in the MAP-T domain are expected themselves to initiate
communication to external IPv4-only hosts.
13. IANA Considerations
This specification does not require any IANA actions. This specification does not require any IANA actions.
14. Security Considerations 13. Security Considerations
Spoofing attacks: With consistency checks between IPv4 and IPv6 Spoofing attacks: With consistency checks between IPv4 and IPv6
sources that are performed on IPv4/IPv6 packets received by MAP sources that are performed on IPv4/IPv6 packets received by MAP
nodes, MAP does not introduce any new opportunity for spoofing nodes, MAP does not introduce any new opportunity for spoofing
attacks that would not already exist in IPv6. attacks that would not already exist in IPv6.
Denial-of-service attacks: In MAP domains where IPv4 addresses are Denial-of-service attacks: In MAP domains where IPv4 addresses are
shared, the fact that IPv4 datagram reassembly may be necessary shared, the fact that IPv4 datagram reassembly may be necessary
introduces an opportunity for DOS attacks. This is inherent to introduces an opportunity for DOS attacks. This is inherent to
address sharing, and is common with other address sharing address sharing, and is common with other address sharing
skipping to change at page 25, line 23 skipping to change at page 21, line 38
subject to ingress filtering of [RFC2827], some attacks are subject to ingress filtering of [RFC2827], some attacks are
possible by an attacker injecting spoofed packets during ongoing possible by an attacker injecting spoofed packets during ongoing
transport connections ([RFC4953], [RFC5961], [RFC6056]. The transport connections ([RFC4953], [RFC5961], [RFC6056]. The
attacks depend on guessing which ports are currently used by attacks depend on guessing which ports are currently used by
target hosts, and using an unrestricted port set is preferable, target hosts, and using an unrestricted port set is preferable,
i.e. using native IPv6 connections that are not subject to MAP i.e. using native IPv6 connections that are not subject to MAP
port range restrictions. To minimize this type of attacks when port range restrictions. To minimize this type of attacks when
using a restricted port set, the MAP CE's NAT44 filtering behavior using a restricted port set, the MAP CE's NAT44 filtering behavior
SHOULD be "Address-Dependent Filtering". Furthermore, the MAP CEs SHOULD be "Address-Dependent Filtering". Furthermore, the MAP CEs
SHOULD use a DNS transport proxy function to handle DNS traffic, SHOULD use a DNS transport proxy function to handle DNS traffic,
and source such traffic from IPv6 interfaces not assigned to and source such traffic from IPv6 interfaces not assigned to MAP.
MAP-T. Practicalities of these methods are discussed in Section Practicalities of these methods are discussed in Section 5.9 of
5.9 of [I-D.dec-stateless-4v6]. [I-D.dec-stateless-4v6].
[RFC6269] outlines general issues with IPv4 address sharing. [RFC6269] outlines general issues with IPv4 address sharing.
15. Contributors 14. Contributors
Mohamed Boucadair, Gang Chen, Maoke Chen, Wojciech Dec, Xiaohong
Deng, Jouni Korhonen, Tomasz Mrugalski, Jacni Qin, Chunfa Sun, Qiong
Sun, Leaf Yeh.
This document is the result of the IETF Softwire MAP design team This document is the result of the IETF Softwire MAP design team
effort and numerous previous individual contributions in this area effort and numerous previous individual contributions in this area:
initiated by dIVI [I-D.xli-behave-divi] along with a similar idea
proposed by [I-D.murakami-softwire-4v6-translation]. The following
are the authors who contributed in a major way to this document:
Chongfeng Xie (China Telecom)
Room 708, No.118, Xizhimennei Street Beijing 100035 CN
Phone: +86-10-58552116
Email: xiechf@ctbri.com.cn
Qiong Sun (China Telecom)
Room 708, No.118, Xizhimennei Street Beijing 100035 CN
Phone: +86-10-58552936
Email: sunqiong@ctbri.com.cn
Gang Chen (China Mobile)
53A,Xibianmennei Ave. Beijing 100053 P.R.China
Email: chengang@chinamobile.com
Wentao Shang (CERNET Center/Tsinghua University)
Room 225, Main Building, Tsinghua University Beijing 100084 CN
Email: wentaoshang@gmail.com Chongfeng Xie (China Telecom)
Room 708, No.118, Xizhimennei Street Beijing 100035 CN
Phone: +86-10-58552116
Email: xiechf@ctbri.com.cn
Guoliang Han (CERNET Center/Tsinghua University) Qiong Sun (China Telecom)
Room 708, No.118, Xizhimennei Street Beijing 100035 CN
Phone: +86-10-58552936
Email: sunqiong@ctbri.com.cn
Room 225, Main Building, Tsinghua University Beijing 100084 CN Gang Chen (China Mobile)
53A,Xibianmennei Ave. Beijing 100053 P.R.China
Email: chengang@chinamobile.com
Email: bupthgl@gmail.com Yu Zhai
CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University
Beijing 100084
CN
Email: jacky.zhai@gmail.com
Rajiv Asati (Cisco Systems) Wentao Shang (CERNET Center/Tsinghua University)
Room 225, Main Building, Tsinghua University Beijing 100084
CN
Email: wentaoshang@gmail.com
7025-6 Kit Creek Road Research Triangle Park NC 27709 USA Guoliang Han (CERNET Center/Tsinghua University)
Room 225, Main Building, Tsinghua University Beijing 100084
CN
Email: bupthgl@gmail.com
Email: rajiva@cisco.com Rajiv Asati (Cisco Systems)
7025-6 Kit Creek Road Research Triangle Park NC 27709 USA
Email: rajiva@cisco.com
16. Acknowledgements 15. Acknowledgements
This document is based on the ideas of many. In particular Remi This document is based on the ideas of many, including Mohamed
Despres, who has tirelessly worked on generalized mechanisms for Boucadair, Gang Chen, Maoke Chen, Wojciech Dec, Xiaohong Deng, Jouni
stateless address mapping. Korhonen, Tomasz Mrugalski, Jacni Qin, Chunfa Sun, Qiong Sun, and
Leaf Yeh. The authors want in particular to recognize Remi Despres,
who has tirelessly worked on generalized mechanisms for stateless
address mapping.
The authors would like to thank Guillaume Gottard, Dan Wing, Jan The authors would like to thank Guillaume Gottard, Dan Wing, Jan
Zorz, Necj Scoberne, Tina Tsou for their thorough review and Zorz, Necj Scoberne, Tina Tsou for their thorough review and
comments. comments.
17. References 16. References
17.1. Normative References
[I-D.mdt-softwire-map-dhcp-option] 16.1. Normative References
Mrugalski, T., Boucadair, M., Deng, X., Troan, O., and C.
Bao, "DHCPv6 Options for Mapping of Address and Port", [I-D.ietf-softwire-map-dhcp]
draft-mdt-softwire-map-dhcp-option-02 (work in progress), Mrugalski, T., Troan, O., Bao, C., Dec, W., and L. Yeh,
January 2012. "DHCPv6 Options for Mapping of Address and Port",
draft-ietf-softwire-map-dhcp-01 (work in progress),
August 2012.
[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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, December 1998. IPv6 Specification", RFC 2473, December 1998.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
October 2010. October 2010.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011.
[RFC6346] Bush, R., "The Address plus Port (A+P) Approach to the [RFC6346] Bush, R., "The Address plus Port (A+P) Approach to the
IPv4 Address Shortage", RFC 6346, August 2011. IPv4 Address Shortage", RFC 6346, August 2011.
17.2. Informative References 16.2. Informative References
[I-D.dec-stateless-4v6] [I-D.dec-stateless-4v6]
Dec, W., Asati, R., and H. Deng, "Stateless 4Via6 Address Dec, W., Asati, R., and H. Deng, "Stateless 4Via6 Address
Sharing", draft-dec-stateless-4v6-04 (work in progress), Sharing", draft-dec-stateless-4v6-04 (work in progress),
October 2011. October 2011.
[I-D.ietf-softwire-stateless-4v6-motivation] [I-D.ietf-softwire-stateless-4v6-motivation]
Boucadair, M., Matsushima, S., Lee, Y., Bonness, O., Boucadair, M., Matsushima, S., Lee, Y., Bonness, O.,
Borges, I., and G. Chen, "Motivations for Carrier-side Borges, I., and G. Chen, "Motivations for Carrier-side
Stateless IPv4 over IPv6 Migration Solutions", Stateless IPv4 over IPv6 Migration Solutions",
draft-ietf-softwire-stateless-4v6-motivation-03 (work in draft-ietf-softwire-stateless-4v6-motivation-04 (work in
progress), June 2012. progress), August 2012.
[I-D.ietf-tsvwg-iana-ports] [I-D.ietf-tsvwg-iana-ports]
Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA) Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", Transport Protocol Port Number Registry",
draft-ietf-tsvwg-iana-ports-10 (work in progress), draft-ietf-tsvwg-iana-ports-10 (work in progress),
February 2011. February 2011.
[I-D.murakami-softwire-4v6-translation]
Murakami, T., Chen, G., Deng, H., Dec, W., and S.
Matsushima, "4via6 Stateless Translation",
draft-murakami-softwire-4v6-translation-00 (work in
progress), July 2011.
[I-D.xli-behave-divi]
Shang, W., Li, X., Zhai, Y., and C. Bao, "dIVI: Dual-
Stateless IPv4/IPv6 Translation", draft-xli-behave-divi-04
(work in progress), October 2011.
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, September 1981.
[RFC0897] Postel, J., "Domain name system implementation schedule", [RFC0897] Postel, J., "Domain name system implementation schedule",
RFC 897, February 1984. RFC 897, February 1984.
[RFC1933] Gilligan, R. and E. Nordmark, "Transition Mechanisms for [RFC1933] Gilligan, R. and E. Nordmark, "Transition Mechanisms for
IPv6 Hosts and Routers", RFC 1933, April 1996. IPv6 Hosts and Routers", RFC 1933, April 1996.
[RFC2529] Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4 [RFC2529] Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4
Domains without Explicit Tunnels", RFC 2529, March 1999. Domains without Explicit Tunnels", RFC 2529, March 1999.
[RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address [RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address
skipping to change at page 28, line 37 skipping to change at page 24, line 33
Defeating Denial of Service Attacks which employ IP Source Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, May 2000. Address Spoofing", BCP 38, RFC 2827, May 2000.
[RFC3056] Carpenter, B. and K. Moore, "Connection of IPv6 Domains [RFC3056] Carpenter, B. and K. Moore, "Connection of IPv6 Domains
via IPv4 Clouds", RFC 3056, February 2001. via IPv4 Clouds", RFC 3056, February 2001.
[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,
December 2003. December 2003.
[RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control
Message Protocol (ICMPv6) for the Internet Protocol
Version 6 (IPv6) Specification", RFC 4443, March 2006.
[RFC4787] Audet, F. and C. Jennings, "Network Address Translation [RFC4787] Audet, F. and C. Jennings, "Network Address Translation
(NAT) Behavioral Requirements for Unicast UDP", BCP 127, (NAT) Behavioral Requirements for Unicast UDP", BCP 127,
RFC 4787, January 2007. RFC 4787, January 2007.
[RFC4953] Touch, J., "Defending TCP Against Spoofing Attacks", [RFC4953] Touch, J., "Defending TCP Against Spoofing Attacks",
RFC 4953, July 2007. RFC 4953, July 2007.
[RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site [RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site
Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214, Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214,
March 2008. March 2008.
skipping to change at page 29, line 27 skipping to change at page 25, line 19
August 2010. August 2010.
[RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4 [RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4
Infrastructures (6rd) -- Protocol Specification", Infrastructures (6rd) -- Protocol Specification",
RFC 5969, August 2010. RFC 5969, August 2010.
[RFC6056] Larsen, M. and F. Gont, "Recommendations for Transport- [RFC6056] Larsen, M. and F. Gont, "Recommendations for Transport-
Protocol Port Randomization", BCP 156, RFC 6056, Protocol Port Randomization", BCP 156, RFC 6056,
January 2011. 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.
[RFC6219] Li, X., Bao, C., Chen, M., Zhang, H., and J. Wu, "The
China Education and Research Network (CERNET) IVI
Translation Design and Deployment for the IPv4/IPv6
Coexistence and Transition", RFC 6219, May 2011.
[RFC6250] Thaler, D., "Evolution of the IP Model", RFC 6250, [RFC6250] Thaler, D., "Evolution of the IP Model", RFC 6250,
May 2011. May 2011.
[RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P. [RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P.
Roberts, "Issues with IP Address Sharing", RFC 6269, Roberts, "Issues with IP Address Sharing", RFC 6269,
June 2011. June 2011.
[RFC6324] Nakibly, G. and F. Templin, "Routing Loop Attack Using [RFC6324] Nakibly, G. and F. Templin, "Routing Loop Attack Using
IPv6 Automatic Tunnels: Problem Statement and Proposed IPv6 Automatic Tunnels: Problem Statement and Proposed
Mitigations", RFC 6324, August 2011. Mitigations", RFC 6324, August 2011.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4 Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, August 2011. Exhaustion", RFC 6333, August 2011.
Appendix A. Example of MAP-T translation Appendix A. Example of MAP
Example 1: Example 1:
Given the MAP domain information and an IPv6 address of Given the MAP domain information and an IPv6 address of
an endpoint: an endpoint:
IPv6 prefix assigned to the end user: 2001:db8:0012:3400::/56 IPv6 prefix assigned to the end user: 2001:db8:0012:3400::/56
Basic Mapping Rule: {2001:db8:0000::/40 (Rule IPv6 prefix), Basic Mapping Rule: {2001:db8:0000::/40 (Rule IPv6 prefix),
192.0.2.0/24 (Rule IPv4 prefix), 16 (Rule EA-bits length)} 192.0.2.0/24 (Rule IPv4 prefix), 16 (Rule EA-bits length)}
Sharing ratio: 256 (16 - (32 - 24) = 8. 2^8 = 256) Sharing ratio: 256 (16 - (32 - 24) = 8. 2^8 = 256)
PSID offset: 4 PSID offset: 4
skipping to change at page 30, line 40 skipping to change at page 26, line 37
4937, 4938, 4939, 4940, 4941, 4942, 4943 4937, 4938, 4939, 4940, 4941, 4942, 4943
Port-set-2: 9024, 9025, 9026, 9027, 9028, 9029, 9030, 9031, 9032, Port-set-2: 9024, 9025, 9026, 9027, 9028, 9029, 9030, 9031, 9032,
9033, 9034, 9035, 9036, 9037, 9038, 9039 9033, 9034, 9035, 9036, 9037, 9038, 9039
... ... ... ...
Port-set-15 62272, 62273, 62274, 62275, 62276, 62277, 62278, Port-set-15 62272, 62273, 62274, 62275, 62276, 62277, 62278,
62279, 62280, 62281, 62282, 62283, 62284, 62285, 62286, 62287 62279, 62280, 62281, 62282, 62283, 62284, 62285, 62286, 62287
The BMR information allows a MAP CE also to determine (complete) The BMR information allows a MAP CE also to determine (complete)
its IPv6 address within the indicated IPv6 prefix. its IPv6 address within the indicated IPv6 prefix.
IPv6 address of MAP-T CE: 2001:db8:0012:3400:00c0:0002:1200:3400 IPv6 address of MAP CE: 2001:db8:0012:3400:00c0:0002:1200:3400
Example 2: Example 2:
Another example can be made of a hypothetical MAP-T BR, Another example can be made of a hypothetical MAP BR,
configured with the following FMR when receiving a packet configured with the following FMR when receiving a packet
with the following characteristics: with the following characteristics:
IPv4 source address: 1.2.3.4 (0x01020304) IPv4 source address: 1.2.3.4 (0x01020304)
IPv4 source port: 80 IPv4 source port: 80
IPv4 destination address: 192.0.2.18 (0xc0000212) IPv4 destination address: 192.0.2.18 (0xc0000212)
IPv4 destination port: 9030 IPv4 destination port: 9030
Configured Forwarding Mapping Rule: {2001:db8:0000::/40 Configured Forwarding Mapping Rule: {2001:db8:0000::/40
(Rule IPv6 prefix), 192.0.2.0/24 (Rule IPv4 prefix), (Rule IPv6 prefix), 192.0.2.0/24 (Rule IPv4 prefix),
16 (Rule EA-bits length)} 16 (Rule EA-bits length)}
MAP-T BR Prefix 2001:db8:ffff::/64 MAP BR Prefix 2001:db8:ffff::/64
The above information allows the BR to derive as follows The above information allows the BR to derive as follows
the mapped destination IPv6 address for the corresponding the mapped destination IPv6 address for the corresponding
MAP-T CE, and also the mapped source IPv6 address for MAP CE, and also the mapped source IPv6 address for
the IPv4 source. the IPv4 source.
IPv4 suffix bits (p) 32 - 24 = 8 (18 (0x12)) IPv4 suffix bits (p) 32 - 24 = 8 (18 (0x12))
PSID length: 8 PSID length: 8
PSID: 0x34 (9030 (0x2346)) PSID: 0x34 (9030 (0x2346))
The resulting IPv6 packet will have the following key fields: The resulting IPv6 packet will have the following key fields:
IPv6 source address 2001:db8:ffff:0:0001:0203:0400:: IPv6 source address 2001:db8:ffff:0:0001:0203:0400::
IPv6 destination address: 2001:db8:0012:3400:00c0:0002:1200:3400 IPv6 destination address: 2001:db8:0012:3400:00c0:0002:1200:3400
IPv6 source Port: 80 IPv6 source Port: 80
IPv6 destination Port: 9030 IPv6 destination Port: 9030
Example 3: Example 3:
An IPv4 host behind the MAP-T CE (addressed as per the previous An IPv4 host behind the MAP CE (addressed as per the previous
examples) corresponding with IPv4 host 1.2.3.4 will have its examples) corresponding with IPv4 host 1.2.3.4 will have its
packets converted into IPv6 using the DMR configured on the MAP-T packets converted into IPv6 using the DMR configured on the MAP
CE as follows: CE as follows:
Default Mapping Rule used by MAP-T CE: {2001:db8:ffff::/64 Default Mapping Rule used by MAP CE: {2001:db8:ffff::/64
(Rule IPv6 prefix), 0.0.0.0/0 (Rule IPv4 prefix), null (BR IPv4 (Rule IPv6 prefix), 0.0.0.0/0 (Rule IPv4 prefix), null (BR IPv4
address)} address)}
IPv4 source address (post NAT44 if present) 192.0.2.18 IPv4 source address (post NAT44 if present) 192.0.2.18
IPv4 destination address: 1.2.3.4 IPv4 destination address: 1.2.3.4
IPv4 source port (post NAT44 if present): 9030 IPv4 source port (post NAT44 if present): 9030
IPv4 destination port: 80 IPv4 destination port: 80
IPv6 source address of MAP-T CE: IPv6 source address of MAP CE:
2001:db8:0012:3400:00c0:0002:1200:3400 2001:db8:0012:3400:00c0:0002:1200:3400
IPv6 destination address: 2001:db8:ffff:0:0001:0203:0400:: IPv6 destination address: 2001:db8:ffff:0:0001:0203:0400::
Authors' Addresses Authors' Addresses
Ole Troan Ole Troan
Cisco Systems Cisco Systems
Oslo Philip Pedersens vei 1
Lysaker 1366
Norway Norway
Email: ot@cisco.com Email: ot@cisco.com
Wojciech Dec Wojciech Dec
Cisco Systems Cisco Systems
Haarlerbergpark Haarlerbergweg 13-19 Haarlerbergpark Haarlerbergweg 13-19
Amsterdam, NOORD-HOLLAND 1101 CH Amsterdam, NOORD-HOLLAND 1101 CH
Netherlands Netherlands
Phone: Phone:
Email: wdec@cisco.com Email: wdec@cisco.com
Xing Li Xing Li
CERNET Center/Tsinghua University CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University Room 225, Main Building, Tsinghua University
Beijing 100084 Beijing 100084
CN CN
Email: xing@cernet.edu.cn Email: xing@cernet.edu.cn
Congxiao Bao Congxiao Bao
CERNET Center/Tsinghua University CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University Room 225, Main Building, Tsinghua University
Beijing 100084 Beijing 100084
CN CN
Email: congxiao@cernet.edu.cn Email: congxiao@cernet.edu.cn
Yu Zhai
CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University
Beijing 100084
CN
Email: jacky.zhai@gmail.com
Satoru Matsushima Satoru Matsushima
SoftBank Telecom SoftBank Telecom
1-9-1 Higashi-Shinbashi, Munato-ku 1-9-1 Higashi-Shinbashi, Munato-ku
Tokyo Tokyo
Japan Japan
Email: satoru.matsushima@tm.softbank.co.jp Email: satoru.matsushima@g.softbank.co.jp
Tetsuya Murakami Tetsuya Murakami
IP Infusion IP Infusion
1188 East Arques Avenue 1188 East Arques Avenue
Sunnyvale Sunnyvale
USA USA
Email: tetsuya@ipinfusion.com Email: tetsuya@ipinfusion.com
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