Multiple IPv4 - IPv6 address mapping encapsulation
- fixed prefix (M46E-FP)WIDE ProjectJapannaoki.matsuhira@gmail.comIPv6DraftThis document specifies Multiple IPv4 - IPv6 address mapping
encapsulation - fixed prefix (M46E-FP) specification. M46E-FP makes
backbone network to IPv6 only. And also, M46E-FP can stack many IPv4
networks, i.e. the networks using same IPv4 (private) addresses, without
interdependence.The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.This document provides Multiple IPv4 - IPv6 address maping
encapsulation - fixed prefix (M46E-FP) specification.The basic strategy for IPv6 deployment is dual stack. Viewing this
strategy from operational side, operation cost of dual stack is higher
than single stack operation. Viewing from future, IPv6 only operation is
more reasonable rather than IPv4 only operation. Therefore IPv6 only
operation is desired.M46E-FP makes backbone network to IPv6 only and privide IPv4
connectivities. And also, M46E-FP can stack many IPv4 networks, i.e. the
networks using same IPv4 (private) address, without interdependence.IP address contain two information, one is locator information, and
another is identifier information. This is basic architecture of
internet protocol, and also the Internet, and no difference between IPv4
and IPv6.Locater is a information related "Where", and indentifier is a
information related "Who". That mean, IP address's semantics is "Where's
Who" meaning. Host is identified whole IP address information, that is
"Where's Who", however route to the host is identified just locator
information in IP address, that is "Where". See .In IPv4 address space, some host has IPv4 address, which consist n
bits length identifier and 32 - n bits locator. In Where's Who
representation, 32 - n bits "Where" and n bits "Who".Keeping such "Where's Who" relation, IPv4 address can be represent as
IPv6 address by expanding "Where" information from 32 - n bits to 128 -
n bits. Expanding " Where" information, IPv4 address can be mapped to
IPv6 address. shows such
expanding.IPv4 address space contain private address, that is non globally
unique IP address. If some identifier which distinguish private address
can introduce in IPv6 address space, we can treate IPv4 private address
as different address in IPv6 address space. This document define such
identifier as "IPv4 network plane ID". "IPv6 network plane ID" can
provide VPN (Virtual Private Network) like service.That is M46A. In M46E-FP address, "Where" information's bit length is
128 -n bits, and "Who" information's bit length is n bits. shows summary of IPv4 address
and M46E-FP address relation. shows network configuration with
M46E-FP. The network consists of three parts. Backbone network, stub
network, and M46E-FP.Backbone network is operated with IPv6 only. Stub network has three
cases. IPv4 only, Dual Stack (both IPv4 and IPv6), and IPv6 only.M46E-FP connects backbone network and stub network in case IPv4 still
works in that stub network. If stub network is IPv6 only, M46E-FP is not
needed.Campus network, corporate network, ISP and datacenter network are the
example for such network.M46E-FP has mainly two function. One is IPv4 over IPv6 Encapsulation
/ Decapsulation, and another is advertise route for stub network.M46E-FP encapsulates IPv4 packet to IPv6 from stub network to
backbone network, and decapsulates IPv6 packet to IPv4 from backbone
network to stub network. shows such
movement.M46E-FP MUST support tunnel MTU
discovery. When encapsulated IPv6 Packet size exceed path MTU
and inner IPv4 packet have the Don't Fragment bit is set, M46E-FP MUST
return ICMP Destination unreachable message with Type3 Code4, fragmentation needed and DS set.In case IPv6, M46E-FP just relays IPv6 packet.By IPv4 over IPv6 function, M46E-FP make backbone network to IPv6
only.M46A is a IPv6 address used in outer IPv6 header which encapsulate
IPv4 packet by M46E-FP. M46A is described in M46A. shows M46A address
architectureM46A consists of three parts as follows.M46A prefix.
This value is fixed value and preconfigured to all M46E-FP in the
networks.IPv4
network plane ID is an identifier of IPv4 network stack over IPv6
backbone network. This value is preconfigured depend on the
M46E-FP belong which IPv4 network plane. For more detail see .IPv4 address in
inner IPv4 packet.M46A is resolved copying IPv4 address in inner IPv4 packet, and
preconfigured values, M46A prefix and IPv4 network plane ID.M46E-FP converts stub network's IPv4 route to M46E-FP IPv6 route
and advertises to backbone network. And reverse direction, M46E-FP
converts M46E-FP IPv6 route to IPv4 route, that advertises other IPv4
stub networks.The IPv4 route for stub network is map to M46E-FP IPv6 route one to
one, so number of route of IPv4 is same as number of route of M46E-FP
IPv6 route. Total number of route is same as when backbone network
operate dual stack, without M46E-FP.In stub network, usual dynamic routing protocol for IPv4 and IPv6
can be used such as RIPv2, RIPng, OSPFv2,
OSPFv3 and IS-IS. Similarly, in
backbone network, usual dynamic routing protocol for IPv6 can be used
such as RIPng, OSPFv3 and IS-IS
.If want using default route, default M46E-FP advertise the route
[M46E-FP address prefix/( 96 - m )] as default route. If want using
different default route by IPv4 network plane ID, default M46E-FP in
IPv4 network plane #1 advertise the route [ M46E-FP address prefix +
IPv4 network plane ID #1 / 96] as default route. in
show the example using default route.M46E-FP can provide VPN like service to stub networks by using
different IPv4 network plane ID value.If backbone network operator provide IPv4 privates network service to
Organization A, backbone network operator sets IPv4 network plane ID
value =1 to the M46E-FP which connects stub network of organization A.
If there are five stub network of organization A, backbone network
operator sets same IPv4 network plane ID = 1, to five M46E-FPs which
connect stub network of organization A. If there are one hundred stub
network of organization B, backbone network operator sets same IPv4
network plane ID = 2, to one hundred M46E-FPs which connect stub network
of organization B. If a new stub network in organization B join,
backbone network operator configures same IPv4 network plane ID = 2, to
the new stub network only, which connect stub network of organization B,
and no configuration is needed to one hundred M46E-FPs which are already
connected.Such configuration, that means same stub network group to same IPv4
network plane ID value, is simple and easy to understand, so, it is
expected that possibility of misconfiguration is very low. And also,
number of configuration is minimum, that mean, number of configuration
is same as number of stub networks, and add new stub network, configure
to new one only.Describe above, M46E-FP can provide VPN like service, for example,
Intranet or extranet. And, after IPv4 global address running out, some
service provider may want to reuse IPv4 private address. M46E-FP can
provide such IPv4 private address networks over single IPv6 backbone
network. By M46E-FP, some service providers may reuse IPv4 private
address.M46E-FP brings no limit for redundancy. shows such example in case two connection
between backbone network and stub network. Number of link between
backbone network and stub network is not limited, and different type of
link can be used, for example, for wire and wireless.Configuration of M46E-FPs, which connect same stub network, is same.
That mean same M46E-FP prefix and same IPv4 network plane ID value. shows M46E-FP operation which
does not use IPv4 network plane ID. In this example, two stub network
is connected to backbone network via M46E-FP. One stub network is
10.1.1.0/24 sub network, and the other is 10.1.2.0/24 sub network.When M46E-FP receives IPv4 route advertisement, then M46E-FP
convert this IPv4 route to IPv6 route by address resolution to M46E-FP
address, and advertise this IPv6 route to backbone network. When
M46E-FP receives IPv6 route advertisements, then M46E-FP converts this
IPv6 route to IPv4 route if this IPv6 route is match M46E-FP address (
same prefix with M46E-FP), and advertise this IPv4 route to stub
network.In this example. IPv4 route, 10.1.1.0/24 is converted to IPv6
route, <M46E-FPprefix>:10.1.1.0/120,and IPv4 route, 10.1.2.0/24
is converted to IPv6 route, <M46E-FPprefix>:10.1.2.0/120 at
M46E-FP from stub network to backbone network. And, from backbone
network to stub network, IPv6 route,
<M46E-FPprefix>:10.1.1.0/120 is converted to IPv4 route,
10.1.1.0/24, and IPv6 route, <M46E-FPprefix>:10.1.2.0/120 is
converted to IPv4 route, 10.1.2.0/24. shows the example using default
route. Default route is useful in case most packets are routed same
path. Typically, access network is one of the example. Although using
default route, communication between stub networks can be done.
Communication between host 10.1.1.1 and host 10.1.2.1 can be done
inside in access network, and does not pass over default M46E-FP. shows M46E-FP operation which
uses IPv4 network plane ID. In this example, there are two planes, and
two stub network in each plane is connected to backbone network via
M46E-FP. In each plane, one stub network is 10.1.1.0/24 sub network,
and the other is 10.1.2.0/24 sub network, that means same IPv4 address
is used in different plane.When M46E-FP receives IPv4 route advertisements, then M46E-FP
converts this IPv4 route to IPv6 route by address resolution to
M46E-FP address, and advertise this IPv6 route to backbone network.
When M46E-FP receives IPv6 route advertisements, then M46E-FP converts
this IPv6 route to IPv4 route if this IPv6 route is match M46E-FP
address ( same prefix with M46E-FP), and advertises this IPv4 route to
stub network.In this example in plane #1. IPv4 route, 10.1.1.0/24 is converted
to IPv6 route, <M46E-FPprefix><#1>:10.1.1.0/120,and IPv4
route, 10.1.2.0/24 is converted to IPv6 route,
<M46E-FPprefix><#1>:10.1.2.0/120 at M46E-FP from stub
network to backbone network. And, from backbone network to stub
network, IPv6 route, <M46E-FPprefix><#1>:10.1.1.0/120 is
converted to IPv4 route, 10.1.1.0/24, and IPv6 route,
<M46E-FPprefix><#1>:10.1.2.0/120 is converted to IPv4
route, 10.1.2.0/24.And also, In this example in plane #2. IPv4 route, 10.1.1.0/24 is
converted to IPv6 route,
<M46E-FPprefix><#2>:10.1.1.0/120,and IPv4 route,
10.1.2.0/24 is converted to IPv6 route,
<M46E-FPprefix><#2>:10.1.2.0/120 at M46E-FP from stub
network to backbone network. And, from backbone network to stub
network, IPv6 route, <M46E-FPprefix><#2>:10.1.1.0/120 is
converted to IPv4 route, 10.1.1.0/24, and IPv6 route,
<M46E-FPprefix><#2>:10.1.2.0/120 is converted to IPv4
route, 10.1.2.0/24.In IPv6 space, address <M46E-FPprefix><#1>:10.1.1.1 and
address <M46E-FPprefix><#2>:10.1.1.1 are different
address, route <M46E-FPprefix><#1>:10.1.1.0/120 and route
<M46E-FPprefix><#2>:10.1.1.0/120 are different route,
although in IPv4 space, address 10.1.1.1 in plane #1 and 10.1.1.1 in
plane#2 are same address, route 10.1.1.0/24 in plane#1 and route
10.1.1.0/24 in plane#2 are same route.shows the example using default
route with IPv4 network plane. In this case, default M46E-FP may
configure different by each IPv4 network plane.M46E-FP has following useful characteristics.Reduce backbone network operation cost with IPv6 single stack (
at least less than Dual Stack)Can allocate IPv4 address to stub networks, which used in
backbone network before installing M46E-FPLess configurationNo need for special protocolNo dependent Layer 2 networkCan Stack IPv4 Private networksEasy stop IPv4 operation in stub network for future ( just remove
M46E-FP)Provide redundancyThis document makes no request of IANA.Note to RFC Editor: this section may be removed on publication as an
RFC.M46E-FP use automatic Encapsulation / Decapsulation technologies.
Security consideration related tunneling technologies are discussed in
RFC2893, RFC2267,
etc.Multiple IPv4 - IPv6 mapped IPv6 address