draft-ietf-mext-nemo-v4traversal-01.txt   draft-ietf-mext-nemo-v4traversal-02.txt 
MEXT Working Group Hesham Soliman (Ed.) MEXT Working Group H. Soliman, Ed.
INTERNET-DRAFT Elevate Technologies Internet-Draft Elevate Technologies
Intended status: Standards Track Intended status: Standards Track April 29, 2008
Expires: August 2008 Expires: October 31, 2008
February, 2008
Mobile IPv6 support for dual stack Mobile IPv6 Support for Dual Stack Hosts and Routers
Hosts and Routers (DSMIPv6) draft-ietf-mext-nemo-v4travesrsal-02.txt
draft-ietf-mext-nemo-v4traversal-01.txt
Status of this memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
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The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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This Internet-Draft will expire on October 31, 2008.
Abstract Abstract
The current Mobile IPv6 and NEMO specifications support IPv6 only. The current Mobile IPv6 and NEMO specifications support IPv6 only.
This specification extends those standards to allow the registration This specification extends those standards to allow the registration
of IPv4 addresses and prefixes, respectively, and the transport of of IPv4 addresses and prefixes, respectively, and the transport of
both IPv4 and IPv6 packets over the tunnel to the home agent. This both IPv4 and IPv6 packets over the tunnel to the home agent. This
specification also allows the Mobile Node to roam over both IPv6 and specification also allows the Mobile Node to roam over both IPv6 and
IPv4, including the case where Network Address Translation is present IPv4, including the case where Network Address Translation is present
on the path between the mobile node and its home agent. on the path between the mobile node and its home agent.
Table of Contents Table of Contents
1. Introduction.....................................................3 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 4
1.1 Motivation for using Mobile IPv6 only...........................3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Scenarios considered by this specification...................4 2.1. Motivation for Using Mobile IPv6 Only . . . . . . . . . . 5
1.3 Terminology.................................................5 2.2. Scenarios Considered by This Specification . . . . . . . . 6
2. Solution overview................................................5 3. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 8
2.1. Home Agent Address Discovery...................................6 3.1. Home Agent Address Discovery . . . . . . . . . . . . . . . 8
2.2. Mobile Prefix Solicitations and Advertisements..............7 3.2. Mobile Prefix Solicitation and Advertisement . . . . . . . 9
2.3. Binding management.............................................7 3.3. Binding Management . . . . . . . . . . . . . . . . . . . . 9
2.3.1 Foreign network supports IPv6.................................7 3.3.1. Foreign Network Supports IPv6 . . . . . . . . . . . . 10
2.3.2 Foreign network supports IPv4 only............................8 3.3.2. Foreign Network Supports IPv4 Only . . . . . . . . . . 11
2.3.2.2 Visited network supports IPv4 only (private addresses)......9 3.4. Route Optimization . . . . . . . . . . . . . . . . . . . . 13
2.4. Route optimization............................................10 3.5. Dynamic IPv4 Home Address Allocation . . . . . . . . . . . 13
2.5. Dynamic IPv4 home address allocation..........................10 4. Extensions And Modifications To Mobile IPv6 . . . . . . . . . 14
3. Extensions and modifications to Mobile IPv6.....................10 4.1. Binding Update Extensions . . . . . . . . . . . . . . . . 14
3.1. Binding update extensions.....................................11 4.1.1. IPv4 Home Address Option . . . . . . . . . . . . . . . 14
3.1.1 IPv4 home address option.....................................11 4.1.2. The IPv4 Care-of Address Option . . . . . . . . . . . 15
3.1.2 The IPv4 Care-of Address option........................12 4.1.3. The Binding Update Message Extensions . . . . . . . . 16
3.1.3 The Binding Update Message extensions..................12 4.2. Binding Acknowledgement Extensions . . . . . . . . . . . . 16
3.2. Binding Acknowledgement extensions............................13 4.2.1. IPv4 Address Acknowledgement Option . . . . . . . . . 16
3.2.1 IPv4 address acknowledgement option..........................13 4.2.2. The NAT Detection Option . . . . . . . . . . . . . . . 18
3.2.2 The NAT detection option...............................14 4.2.3. Extensions to the Binding Acknowledgement Message . . 19
3.2.3 Extensions to the Binding Acknowledgement message......15 5. Protocol operation . . . . . . . . . . . . . . . . . . . . . . 20
4. Protocol operation..............................................15 5.1. Tunelling Formats . . . . . . . . . . . . . . . . . . . . 20
4.1. Tunnelling formats.........................................15 5.1.1. Tunnelling Impacts on Transport and MTU . . . . . . . 22
4.2. NAT detection and traversal................................17 5.2. NAT Detection . . . . . . . . . . . . . . . . . . . . . . 22
4.3. NAT Keepalives.............................................18 5.3. NAT Keepalives . . . . . . . . . . . . . . . . . . . . . . 24
4.4. Mobile node operation.........................................19 5.4. Mobile Node Operation . . . . . . . . . . . . . . . . . . 25
4.4.1 Sending packets from a visited network.................20 5.4.1. Sending Packets from a Visited Network . . . . . . . . 27
4.4.2 Movement detection in IPv4-only networks...............21 5.4.2. Movement Detection in IPv4-only Networks . . . . . . . 28
4.5. Home agent operations.........................................21 5.5. Home agent operation . . . . . . . . . . . . . . . . . . . 28
4.5.1 Sending packets to the mobile node.....................23 5.5.1. Sending Packets to the Mobile Node . . . . . . . . . . 30
4.6. Correspondent node operations.................................24 5.6. Correspondent Node Operation . . . . . . . . . . . . . . . 31
5. Security considerations.........................................24 6. Security Considerations . . . . . . . . . . . . . . . . . . . 32
5.1 Handover interactions for IPsec and IKE.....................25 6.1. Handover Interactions for IPsec and IKE . . . . . . . . . 33
6. Protocol constants..............................................28 6.2. IKE negotiation messages between the mobile node and
7. Acknowledgements................................................28 Home Agent . . . . . . . . . . . . . . . . . . . . . . . . 35
8. IANA considerations.............................................28 6.2.1. IKEv2 Operation for Securing DSMIPv6 Signaling . . . . 36
9. References......................................................29 6.2.2. IKEv2 Operation for Securing Data over IPv4 . . . . . 38
10. Contributors...................................................30 7. Protocol Constants . . . . . . . . . . . . . . . . . . . . . . 41
Author's Address...................................................30 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 42
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 43
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 44
10.1. Normative References . . . . . . . . . . . . . . . . . . . 44
10.2. Informative . . . . . . . . . . . . . . . . . . . . . . . 44
Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 46
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 47
Intellectual Property and Copyright Statements . . . . . . . . . . 48
1. Introduction 1. Requirements notation
Mobile IPv6 [MIPv6] and [NEMO] allow mobile nodes to move within the The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
Internet while maintaining reachability and ongoing sessions, using "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
an IPv6 home address or prefix. However, since IPv6 is not widely document are to be interpreted as described in [RFC2119].
deployed, it is unlikely that mobile nodes will use IPv6 addresses
only for their connections. It is reasonable to assume that mobile 2. Introduction
nodes will, for a long time, need an IPv4 home address that can be
used by upper layers. It is also reasonable to assume that mobile Mobile IPv6 [RFC3775] and [RFC3963] allow mobile nodes to move within
nodes will move to networks that might not support IPv6 and would the Internet while maintaining reachability and ongoing sessions,
therefore need the capability to support an IPv4 Care-of Address. using an IPv6 home address or prefix. However, since IPv6 is not
Hence, this specification extends Mobile IPv6 capabilities to allow widely deployed, it is unlikely that mobile nodes will use IPv6
dual stack mobile nodes to request that their home agent (also dual addresses only for their connections. It is reasonable to assume
stacked) tunnel IPv4/IPv6 packets addressed to their home addresses, that mobile nodes will, for a long time, need an IPv4 home address
as well as IPv4/IPv6 care-of address(es). that can be used by upper layers. It is also reasonable to assume
that mobile nodes will move to networks that might not support IPv6
and would therefore need the capability to support an IPv4 Care-of
Address. Hence, this specification extends Mobile IPv6 capabilities
to allow dual stack mobile nodes to request that their home agent
(also dual stacked) tunnel IPv4/IPv6 packets addressed to their home
addresses, as well as IPv4/IPv6 care-of address(es).
Using this specification, mobile nodes would only need Mobile IPv6 Using this specification, mobile nodes would only need Mobile IPv6
and [NEMO] to manage mobility while moving within the Internet; hence and [RFC3963] to manage mobility while moving within the Internet;
eliminating the need to run two mobility management protocols hence eliminating the need to run two mobility management protocols
simultaneously. This specification provides the extensions needed in simultaneously. This specification provides the extensions needed in
order to allow IPv6 mobility only to be used by dual stack mobile order to allow IPv6 mobility only to be used by dual stack mobile
nodes. nodes.
This specification will also consider cases where a mobile node moves This specification will also consider cases where a mobile node moves
into a private IPv4 network and gets configured with a private IPv4 into a private IPv4 network and gets configured with a private IPv4
Care-of Address. In these scenarios, the mobile node needs to be able Care-of Address. In these scenarios, the mobile node needs to be
to traverse the IPv4 NAT in order to communicate with the home agent. able to traverse the IPv4 NAT in order to communicate with the home
IPv4 NAT traversal for Mobile IPv6 is presented in this agent. IPv4 NAT traversal for Mobile IPv6 is presented in this
specification. specification.
In this specification, the term mobile node refers to both a mobile In this specification, the term mobile node refers to both a mobile
host and mobile router unless the discussion is specific to either host and mobile router unless the discussion is specific to either
hosts or routers. Similarly, we use the term home address to reflect hosts or routers. Similarly, we use the term home address to reflect
an address/prefix format. an address/prefix format.
In this specification, extensions are defined for the binding update In this specification, extensions are defined for the binding update
and binding acknowledgement. It should be noted that all these and binding acknowledgement. It should be noted that all these
extensions apply to cases where the mobile node communicates with a extensions apply to cases where the mobile node communicates with a
Mobility Anchor Point (MAP) as defined in [HMIPv6]. The requirements Mobility Anchor Point (MAP) as defined in [RFC4140]. The
on the MAP are identical to those stated for the home agent, although requirements on the MAP are identical to those stated for the home
it is unlikely that NAT traversal would be needed with a MAP as it is agent, although it is unlikely that NAT traversal would be needed
expected to be in the same address domain. with a MAP as it is expected to be in the same address domain.
1.1 Motivation for using Mobile IPv6 only 2.1. Motivation for Using Mobile IPv6 Only
IPv6 offers a number of improvements over today's IPv4, primarily due IPv6 offers a number of improvements over today's IPv4, primarily due
to its large address space. Mobile IPv6 offers a number of to its large address space. Mobile IPv6 offers a number of
improvements over Mobile IPv4 [MIPv4], mainly due to capabilities improvements over Mobile IPv4 [RFC3344], mainly due to capabilities
inherited from IPv6. For instance, route optimization and dynamic inherited from IPv6. For instance, route optimization and dynamic
home agent discovery can only be achieved with Mobile IPv6. home agent discovery can only be achieved with Mobile IPv6.
One of the advantages of the large address space provided by IPv6 is One of the advantages of the large address space provided by IPv6 is
that it allows mobile nodes to obtain a globally unique care-of that it allows mobile nodes to obtain a globally unique care-of
address wherever they are. Hence, there is no need for Network address wherever they are. Hence, there is no need for Network
Address Translator (NAT) traversal techniques designed for Mobile Address Translator (NAT) traversal techniques designed for Mobile
IPv4. This allows Mobile IPv6 to be a significantly simpler and more IPv4. This allows Mobile IPv6 to be a significantly simpler and more
bandwidth efficient mobility management protocol. At the same time, bandwidth efficient mobility management protocol. At the same time,
during the transition towards IPv6, NAT traversal for existing during the transition towards IPv6, NAT traversal for existing
private IPv4 networks needs to be considered. This specification private IPv4 networks needs to be considered. This specification
introduces NAT traversal for this purpose. introduces NAT traversal for this purpose.
The above benefits make the case for using Mobile IPv6 only for dual The above benefits make the case for using Mobile IPv6 only for dual
stack mobile nodes in order to allow for a long lasting mobility stack mobile nodes in order to allow for a long lasting mobility
solution and minimize the need to changing the mobility stack due to solution and minimize the need to changing the mobility stack due to
the introduction of IPv6 within a deployed network. the introduction of IPv6 within a deployed network.
1.2 Scenarios considered by this specification 2.2. Scenarios Considered by This Specification
In [SNRIO] several scenarios that illustrate potential There are several scenarios that illustrate potential
incompatibilities for mobile nodes using Mobile IPv6 were discussed. incompatibilities for mobile nodes using Mobile. Some of the
Some of the problems associated with mobility and transition issues problems associated with mobility and transition issues were
were presented in [MIP-PB]. This specification considers a subset of presented in [RFC4977]. This specification considers the scenarios
the scenarios in [SNRIO], which address all the problems discussed in that address all the problems discussed in [RFC4977]. The scenarios
[MIP-PB]. The scenarios considered in this specification are listed considered in this specification are listed below.
below.
All of the following scenarios assume that both the mobile node and All of the following scenarios assume that both the mobile node and
the home agent are IPv4 and IPv6-enabled and that only Mobile IPv6 is the home agent are IPv4 and IPv6-enabled and that only Mobile IPv6 is
used between the mobile node and the home agent. We also assume that used between the mobile node and the home agent. We also assume that
the home agent is always reachable through a globally unique IPv4 the home agent is always reachable through a globally unique IPv4
address. Finally, it's important to note that the following scenarios address. Finally, it's important to note that the following
are not mutually exclusive. scenarios are not mutually exclusive.
Scenario 1: IPv4-only foreign network Scenario 1: IPv4-only foreign network
In this scenario, a mobile node is connected to an IPv4-only foreign In this scenario, a mobile node is connected to an IPv4-only foreign
network. The mobile node can only configure an IPv4 Care-of Address. network. The mobile node can only configure an IPv4 Care-of Address.
Scenario 2: Mobile node behind a NAT Scenario 2: Mobile node behind a NAT
In this scenario, the mobile node is in a private IPv4 foreign In this scenario, the mobile node is in a private IPv4 foreign
network that has a NAT device connecting it to the Internet. If the network that has a NAT device connecting it to the Internet. If the
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network. The mobile node can only configure an IPv4 Care-of Address. network. The mobile node can only configure an IPv4 Care-of Address.
Scenario 2: Mobile node behind a NAT Scenario 2: Mobile node behind a NAT
In this scenario, the mobile node is in a private IPv4 foreign In this scenario, the mobile node is in a private IPv4 foreign
network that has a NAT device connecting it to the Internet. If the network that has a NAT device connecting it to the Internet. If the
home agent is located outside the NAT device, the mobile node will home agent is located outside the NAT device, the mobile node will
need a NAT traversal mechanism to communicate with the home agent. need a NAT traversal mechanism to communicate with the home agent.
Scenario 3: Home Agent behind a NAT Scenario 3: Home Agent behind a NAT
In this scenario, the communication between the mobile node and the In this scenario, the communication between the mobile node and the
home agent is further complicated by the fact that the home agent is home agent is further complicated by the fact that the home agent is
located within a private IPv4 network. However, in this scenario, we located within a private IPv4 network. However, in this scenario, we
assume that the home agent is allocated a globally unique IPv4 assume that the home agent is allocated a globally unique IPv4
address. The address might not be physically configured on the home address. The address might not be physically configured on the home
agent interface. Instead, it is associated with the home agent on the agent interface. Instead, it is associated with the home agent on
NAT device, which allows the home agent to be reachable through the NAT device, which allows the home agent to be reachable through
address or port mapping. address or port mapping.
Scenario 4: Use Of IPv4-only applications Scenario 4: Use Of IPv4-only applications
In this scenario, the mobile node may be located in an IPv4, IPv6 or In this scenario, the mobile node may be located in an IPv4, IPv6 or
a dual network. However, the mobile node might be communicating with a dual network. However, the mobile node might be communicating with
an IPv4-only node. In this case, the mobile node would need a stable an IPv4-only node. In this case, the mobile node would need a stable
IPv4 address for its application. The alternative to using an IPv4 IPv4 address for its application. The alternative to using an IPv4
address is the use of protocol translators; however, end-to-end address is the use of protocol translators; however, end-to-end
communication with IPv4 is preferred to the use of protocol communication with IPv4 is preferred to the use of protocol
translators. translators.
The mobile node may also be communicating with an IPv4-only The mobile node may also be communicating with an IPv4-only
application that requires an IPv4 address. application that requires an IPv4 address.
The cases above illustrate the need for the allocation of a stable The cases above illustrate the need for the allocation of a stable
IPv4 home address to the mobile node. This is done using an IPv4 home IPv4 home address to the mobile node. This is done using an IPv4
address. Since running Mobile IPv4 and Mobile IPv6 simultaneously is home address. Since running Mobile IPv4 and Mobile IPv6
problematic (as illustrated in [MIP-PB]), this scenario adds a simultaneously is problematic (as illustrated in [RFC4977]), this
requirement on Mobile IPv6 to support IPv4 home addresses. scenario adds a requirement on Mobile IPv6 to support IPv4 home
addresses.
1.3 Terminology
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 [KEYWORDS].
2. Solution overview 3. Solution Overview
In order to allow Mobile IPv6 to be used by dual stack mobile nodes, In order to allow Mobile IPv6 to be used by dual stack mobile nodes,
the following needs to be done: the following needs to be done:
- Mobile nodes should be able to use an IPv4 and IPv6 home or care-of o Mobile nodes should be able to use an IPv4 and IPv6 home or
address simultaneously and update their home agents accordingly. care-of address simultaneously and update their home agents
accordingly.
- Mobile nodes need to be able to know the IPv4 address of the home o Mobile nodes need to be able to know the IPv4 address of the home
agent as well as its IPv6 address. There is no need for IPv4 prefix agent as well as its IPv6 address. There is no need for IPv4
discovery however. prefix discovery however.
- Mobile nodes need to be able to detect the presence of a NAT device o Mobile nodes need to be able to detect the presence of a NAT
and traverse it in order to communicate with the home agent. device and traverse it in order to communicate with the home
agent.
This section presents an overview of the extensions required in order This section presents an overview of the extensions required in order
to allow mobile nodes to use Mobile IPv6 only for IP mobility to allow mobile nodes to use Mobile IPv6 only for IP mobility
management. management
2.1. Home Agent Address Discovery 3.1. Home Agent Address Discovery
Dynamic home agent Address Discovery (DHAAD) was defined in [MIPv6] Dynamic home agent Address Discovery (DHAAD) was defined in [RFC3775]
to allow mobile nodes to discover their home agents by appending a to allow mobile nodes to discover their home agents by appending a
well-known anycast interface identifier to their home link's prefix. well-known anycast interface identifier to their home link's prefix.
However, this mechanism is based on IPv6-anycast routing. If a mobile However, this mechanism is based on IPv6-anycast routing. If a
node is located in an IPv4-only foreign network, it cannot rely on mobile node is located in an IPv4-only foreign network, it cannot
native IPv6 routing. In this scenario, the solution for discovering rely on native IPv6 routing. In this scenario, the solution for
the home agent's IPv4 address is through the Domain Name System discovering the home agent's IPv4 address is through the Domain Name
(DNS). If the MN is attached to an IPv6-only or dual stack network, System (DNS). If the MN is attached to an IPv6-only or dual stack
it may also use procedures defined in [INTBOOT] to discover home network, it may also use procedures defined in [INTBOOT] to discover
agent information. Note that the use of [INTBOOT] cannot give the home agent information. Note that the use of [INTBOOT] cannot give
mobile node information that allows it to continue to communicate the mobile node information that allows it to continue to communicate
with the home agent if, for example, the mobile node moved from an with the home agent if, for example, the mobile node moved from an
IPv6-enabled network to an IPv4-only network. In this scenario, the IPv6-enabled network to an IPv4-only network. In this scenario, the
mobile node would need to discover the IPv4 address of its home agent mobile node would need to discover the IPv4 address of its home agent
through the DNS. through the DNS.
For DNS lookup by name, the mobile node should be configured with the For DNS lookup by name, the mobile node should be configured with the
name of the home agent. When the mobile node needs to discover a name of the home agent. When the mobile node needs to discover a
home agent, it sends a DNS request with QNAME set to the configured home agent, it sends a DNS request with QNAME set to the configured
name. An example is "ha1.example.com". If a home agent has an IPv4 name. An example is "ha1.example.com". If a home agent has an IPv4
and IPv6 address, the corresponding DNS record should be configured and IPv6 address, the corresponding DNS record should be configured
with both 'AAAA' and 'A' records. Accordingly, the DNS reply will with both 'AAAA' and 'A' records. Accordingly, the DNS reply will
contain 'AAAA' and 'A' records. contain 'AAAA' and 'A' records.
For DNS lookup by service, the SRV record defined in [BOOT] is For DNS lookup by service, the SRV record defined in [RFC5026] is
reused. For instance, if the service name is "mip6" and the protocol reused. For instance, if the service name is "mip6" and the protocol
name is "ipv6" in the SRV record, the mobile node SHOULD send a DNS name is "ipv6" in the SRV record, the mobile node SHOULD send a DNS
request with the QNAME set to "_mip6ha._ipv6.example.com". The request with the QNAME set to "_mip6._ipv6.example.com". The
response should contain the home agent's FQDN(s) and may include the response should contain the home agent's FQDN(s) and may include the
corresponding 'AAAA' and 'A' records as well. corresponding 'AAAA' and 'A' records as well.
If multiple home agents reside on the home link, each configured with If multiple home agents reside on the home link, each configured with
a public IPv4 address, then the operation above applies. In case the a public IPv4 address, then the operation above applies. In case the
home agents are behind a NAT box, there are two options, 1) configure home agents are behind a NAT box, there are two options, 1) configure
a public IPv4 address for each home agent on the NAT box, 2) a public IPv4 address for each home agent on the NAT box, 2)
configure one public address and make the home agents share the configure one public address and make the home agents share the
public address. In either case, the correct DNS entries can be public address. In either case, the correct DNS entries can be
configured. Another possible solution is to designate one home agent configured. Another possible solution is to designate one home agent
on the home link for IPv4 traversal. The NAT device should associate on the home link for IPv4 traversal. The NAT device should associate
that home agent with the public IPv4 address configured on it for v4 that home agent with the public IPv4 address configured on it for v4
traversal. In all cases above, both the 'AAAA' and 'A' records traversal. In all cases above, both the 'AAAA' and 'A' records
returned for a particular name MUST correspond to the same physical returned for a particular name MUST correspond to the same physical
home agent; otherwise the mobile node will not be able to bind its home agent; otherwise the mobile node will not be able to bind its
addresses correctly. addresses correctly.
2.2. Mobile Prefix Solicitations and Advertisements 3.2. Mobile Prefix Solicitation and Advertisement
According to [MIPv6], the mobile node can send a Mobile Prefix According to [RFC3775], the mobile node can send a Mobile Prefix
Solicitation and receive a Mobile Prefix Advertisement containing all Solicitation and receive a Mobile Prefix Advertisement containing all
prefixes advertised on the home link. prefixes advertised on the home link.
A dual stack mobile node MAY send a Mobile Prefix Solicitation A dual stack mobile node MAY send a Mobile Prefix Solicitation
message encapsulated in IPv4 (i.e., IPv6 in IPv4) in the case where message encapsulated in IPv4 (i.e., IPv6 in IPv4) in the case where
the mobile node has no access to IPv6 within the local network. the mobile node has no access to IPv6 within the local network.
Securing these messages requires the mobile node to have a security Securing these messages requires the mobile node to have a security
association with the home agent, using IPsec (AH or ESP) and based on association with the home agent, using IPsec (AH or ESP) and based on
the mobile node's IPv4 care-of address as described in [MIPv6]. Since the mobile node's IPv4 care-of address as described in [RFC3775].
the mobile node needs to encapsulate all IPv6 traffic sent to the Since the mobile node needs to encapsulate all IPv6 traffic sent to
home agent into IPv4 while located in an IPv4-only visited network, the home agent into IPv4 while located in an IPv4-only visited
this SA would match all packets if the selectors were based on the network, this SA would match all packets if the selectors were based
information in the outer header. That is, the SA selectors being the on the information in the outer header. That is, the SA selectors
protocol number (protocol is always IP in IP), as well as, source and being the protocol number (protocol is always IP in IP), as well as,
destination addresses are all common to all packets. If this effect source and destination addresses are all common to all packets. If
is not desired, the mobile node can base the SA on the information in this effect is not desired, the mobile node can base the SA on the
the inner header (i.e., using the home agent's IPv6 address, the information in the inner header (i.e., using the home agent's IPv6
mobile node's home address and the ICMP protocol number). This address, the mobile node's home address and the ICMP protocol
security association would use transport mode ESP protection. number). This security association would use transport mode ESP
protection.
2.3. Binding management 3.3. Binding Management
A dual stack mobile node will need to update its home agent with its A dual stack mobile node will need to update its home agent with its
care-of address. If a mobile node has an IPv4 and an IPv6 home care-of address. If a mobile node has an IPv4 and an IPv6 home
address, it will need to create a binding cache entry for each address, it will need to create a binding cache entry for each
address. The format of the IP packet carrying the binding update and address. The format of the IP packet carrying the binding update and
acknowledgement messages will vary depending on whether the mobile acknowledgement messages will vary depending on whether the mobile
node has access to IPv6 in the visited network. There are three node has access to IPv6 in the visited network. There are three
different scenarios to consider with respect to the visited network: different scenarios to consider with respect to the visited network:
A. The visited network has IPv6 connectivity and provides the mobile o The visited network has IPv6 connectivity and provides the mobile
node with a care-of address (in a stateful or stateless manner). node with a care-of address (in a stateful or stateless manner).
B. The mobile node can only configure a globally unique IPv4 address o The mobile node can only configure a globally unique IPv4 address
in the visited network. in the visited network.
C. The mobile node can only configure a private IPv4 address in the
o The mobile node can only configure a private IPv4 address in the
visited network. visited network.
2.3.1 Foreign network supports IPv6 3.3.1. Foreign Network Supports IPv6
In this case, the mobile node is able to configure a globally unique In this case, the mobile node is able to configure a globally unique
IPv6 address. The mobile node will send a binding update to the IPv6 IPv6 address. The mobile node will send a binding update to the IPv6
address of its home agent, as defined in [MIPv6]. The binding update address of its home agent, as defined in [RFC3775]. The binding
MAY include the IPv4 home address option introduced in this document. update MAY include the IPv4 home address option introduced in this
After receiving the binding update, the home agent creates two document. After receiving the binding update, the home agent creates
binding cache entries, one for the mobile node's IPv4 home address, two binding cache entries, one for the mobile node's IPv4 home
and another for the mobile node's IPv6 home address. Both entries address, and another for the mobile node's IPv6 home address. Both
will point to the mobile node's IPv6 care-of address. Hence, whenever entries will point to the mobile node's IPv6 care-of address. Hence,
a packet is addressed to the mobile node's IPv4 or IPv6 home whenever a packet is addressed to the mobile node's IPv4 or IPv6 home
addresses, the home agent will tunnel it in IPv6 to the mobile node's addresses, the home agent will tunnel it in IPv6 to the mobile node's
IPv6 care-of address included in the binding update. Effectively, the IPv6 care-of address included in the binding update. Effectively,
mobile node establishes two different tunnels, one for its IPv4 the mobile node establishes two different tunnels, one for its IPv4
traffic (IPv4 in IPv6) and one for its IPv6 traffic (IPv6 in IPv6) traffic (IPv4 in IPv6) and one for its IPv6 traffic (IPv6 in IPv6)
with a single binding update. The security implications of this with a single binding update. The security implications of this
mechanism are discussed in the security considerations section. mechanism are discussed in the security considerations section.
In this scenario, the only addition to [MIPv6] is the inclusion of In this scenario, the only addition to [RFC3775] is the inclusion of
the IPv4 home address option in the binding update message. the IPv4 home address option in the binding update message.
After accepting the binding update and creating the corresponding After accepting the binding update and creating the corresponding
binding cache entries, the home agent MUST send a binding binding cache entries, the home agent MUST send a binding
acknowledgement to the mobile node as defined in [MIPv6]. In acknowledgement to the mobile node as defined in [RFC3775]. In
addition, if the binding update included an IPv4 home address option, addition, if the binding update included an IPv4 home address option,
the binding acknowledgement MUST include the IPv4 address the binding acknowledgement MUST include the IPv4 address
acknowledgment option as described later in this specification. This acknowledgment option as described later in this specification. This
option informs the mobile node whether the binding was accepted for option informs the mobile node whether the binding was accepted for
the IPv4 home address. If this option is not included in the binding the IPv4 home address. If this option is not included in the binding
acknowledgement and the IPv4 home address option was included in the acknowledgement and the IPv4 home address option was included in the
binding update, the mobile node MUST assume that the home agent does binding update, the mobile node MUST assume that the home agent does
not support the IPv4 home address option and therefore SHOULD NOT not support the IPv4 home address option and therefore SHOULD NOT
include the option in future binding updates to that home agent include the option in future binding updates to that home agent
address. address.
When a mobile node acquires both IPv4 and IPv6 care-of addresses at When a mobile node acquires both IPv4 and IPv6 care-of addresses at
foreign network, it SHOULD prioritize IPv6 care-of address for MIP6 foreign network, it SHOULD prioritize IPv6 care-of address for MIP6
binding registration. The mobile node MUST NOT register both IPv4 and binding registration. The mobile node MUST NOT register both IPv4
IPv6 care-of addresses to its home agent. and IPv6 care-of addresses to its home agent.
2.3.2 Foreign network supports IPv4 only 3.3.2. Foreign Network Supports IPv4 Only
If the mobile node is in a foreign network that only supports IPv4, If the mobile node is in a foreign network that only supports IPv4,
it needs to detect whether a NAT is in its communication path to the it needs to detect whether a NAT is in its communication path to the
home agent. This is done while exchanging the binding update and home agent. This is done while exchanging the binding update and
acknowledgement messages as shown later in this document. If no NAT acknowledgement messages as shown later in this document. If no NAT
is detected between the mobile node and the home agent, the mobile is detected between the mobile node and the home agent, the mobile
node assumes that it is in a foreign network that supports IPv4 node assumes that it is in a foreign network that supports IPv4
public addresses. Otherwise, the mobile node assumes that private public addresses. Otherwise, the mobile node assumes that private
addresses are used in the foreign network. Note that this assumption addresses are used in the foreign network. Note that this assumption
is only valid for the purposes of the signaling presented in this is only valid for the purposes of the signaling presented in this
specification. A mobile node SHOULD NOT assume that its IPv4 address specification. A mobile node SHOULD NOT assume that its IPv4 address
is globally unique if a NAT device was not detected. The operations is globally unique if a NAT device was not detected. The operations
of both cases are discussed below. of both cases are discussed below.
2.3.2.1 Foreign network supports IPv4 only (public addresses) 3.3.2.1. Foreign Network Supports IPv4 Only (Public Addresses
In this scenario the mobile node will need to tunnel IPv6 packets In this scenario the mobile node will need to tunnel IPv6 packets
containing the binding update to the home agent's IPv4 address. The containing the binding update to the home agent's IPv4 address. The
mobile node uses the IPv4 address it gets from the foreign network as mobile node uses the IPv4 address it gets from the foreign network as
a source address in the outer header. The binding update will contain a source address in the outer header. The binding update will
the mobile node's IPv6 home address. However, since the care-of contain the mobile node's IPv6 home address. However, since the
address in this scenario is the mobile node's IPv4 address, the care-of address in this scenario is the mobile node's IPv4 address,
mobile node MUST include its IPv4 care-of address in the IPv6 packet. the mobile node MUST include its IPv4 care-of address in the IPv6
The IPv4 address is represented in the IPv4 Care-of address option packet. The IPv4 address is represented in the IPv4 Care-of address
defined in this specification. If the mobile node had an IPv4 home option defined in this specification. If the mobile node had an IPv4
address, it MUST also include the IPv4 home address option described home address, it MUST also include the IPv4 home address option
in this specification. described in this specification.
After accepting the binding update, the home agent MUST create a new After accepting the binding update, the home agent MUST create a new
binding cache entry for the mobile node's IPv6 home address. If an binding cache entry for the mobile node's IPv6 home address. If an
IPv4 home address option were included, the home agent MUST create IPv4 home address option were included, the home agent MUST create
another entry for that address. All entries MUST point to the mobile another entry for that address. All entries MUST point to the mobile
node's IPv4 care-of address. Hence, all packets addressed to the node's IPv4 care-of address. Hence, all packets addressed to the
mobile node's home address(es) (IPv4 or IPv6) will be encapsulated in mobile node's home address(es) (IPv4 or IPv6) will be encapsulated in
an IPv4 header that includes the home agent's IPv4 address in the an IPv4 header that includes the home agent's IPv4 address in the
source address field and the mobile node's IPv4 care-of address in source address field and the mobile node's IPv4 care-of address in
the destination address field. the destination address field.
After accepting the binding updates and creating the corresponding After accepting the binding updates and creating the corresponding
entries, the home agent MUST send a binding acknowledgement as entries, the home agent MUST send a binding acknowledgement as
specified in [MIPv6]. In addition, if the binding update included an specified in [RFC3775]. In addition, if the binding update included
IPv4 home address option, the binding acknowledgement MUST include an IPv4 home address option, the binding acknowledgement MUST include
the IPv4 address acknowledgment option as described later in this the IPv4 address acknowledgment option as described later in this
specification. The binding acknowledgement is encapsulated to the specification. The binding acknowledgement is encapsulated to the
IPv4 care-of address, which was included in the source address field IPv4 care-of address, which was included in the source address field
of the IPv4 header encapsulating the binding update. of the IPv4 header encapsulating the binding update.
2.3.2.2 Visited network supports IPv4 only (private addresses) 3.3.2.2. Foreign Network Supports IPv4 Only (Private Addresses
In this scenario the mobile node will need to tunnel IPv6 packets n this scenario the mobile node will need to tunnel IPv6 packets
containing the binding update to the home agent's IPv4 address. In containing the binding update to the home agent's IPv4 address. In
order to traverse the NAT device, IPv6 packets are tunneled UDP and order to traverse the NAT device, IPv6 packets are tunneled UDP and
IPv4. The UDP port allocated for the home agent is TBA. IPv4. The UDP port allocated for the home agent is TBA.
The mobile node uses the IPv4 address it gets from the visited The mobile node uses the IPv4 address it gets from the visited
network as a source address in the IPv4 header. The binding update network as a source address in the IPv4 header. The binding update
will contain the mobile node's IPv6 home address. will contain the mobile node's IPv6 home address.
After accepting the binding update, the home agent MUST create a new After accepting the binding update, the home agent MUST create a new
binding cache entry for the mobile node's IPv6 home address. If an binding cache entry for the mobile node's IPv6 home address. If an
skipping to change at page 10, line 7 skipping to change at page 12, line 37
IPv4 header that encapsulated the binding update message. In IPv4 header that encapsulated the binding update message. In
addition, the tunnel used MUST indicate UDP encapsulation for NAT addition, the tunnel used MUST indicate UDP encapsulation for NAT
traversal. Hence, all packets addressed to the mobile node's home traversal. Hence, all packets addressed to the mobile node's home
address(es) (IPv4 or IPv6) will be encapsulated in UDP then address(es) (IPv4 or IPv6) will be encapsulated in UDP then
encapsulated in an IPv4 header that includes the home agent's IPv4 encapsulated in an IPv4 header that includes the home agent's IPv4
address in the source address field and the mobile node's IPv4 care- address in the source address field and the mobile node's IPv4 care-
of address in the destination address field. of address in the destination address field.
After accepting the binding updates and creating the corresponding After accepting the binding updates and creating the corresponding
entries, the home agent MUST send a binding acknowledgement as entries, the home agent MUST send a binding acknowledgement as
specified in [MIPv6]. In addition, if the binding update included an specified in [RFC3775]. In addition, if the binding update included
IPv4 home address option, the binding acknowledgement MUST include an IPv4 home address option, the binding acknowledgement MUST include
the IPv4 address acknowledgment option as described later in this the IPv4 address acknowledgment option as described later in this
specification. The binding acknowledgement is encapsulated in UDP specification. The binding acknowledgement is encapsulated in UDP
then IPv4 with the home agent's IPv4 address in the source address then IPv4 with the home agent's IPv4 address in the source address
field and the mobile node's IPv4 care-of address in the destination field and the mobile node's IPv4 care-of address in the destination
field. The IPv4 address in the destination field of the IPv4 packet field. The IPv4 address in the destination field of the IPv4 packet
is the source address received in the IPv4 header containing the is the source address received in the IPv4 header containing the
binding update message. The inner IPv6 packet will contain the home binding update message. The inner IPv6 packet will contain the home
agent's IPv6 address as a source address and the mobile node's IPv6 agent's IPv6 address as a source address and the mobile node's IPv6
home address in the destination address field. home address in the destination address field.
The mobile node needs to maintain the NAT bindings for its current The mobile node needs to maintain the NAT bindings for its current
IPv4 care-of address. This is done through sending the binding update IPv4 care-of address. This is done through sending the binding
regularly to the home agent. update regularly to the home agent.
2.4. Route optimization 3.4. Route Optimization
Route optimization, as specified in [MIPv6] will operate in an Route optimization, as specified in [RFC3775] will operate in an
identical manner for dual stack mobile nodes when they are located in identical manner for dual stack mobile nodes when they are located in
a visited network that provides IPv6 addresses to the mobile node. a visited network that provides IPv6 addresses to the mobile node.
However, when located in an IPv4-only network, route optimization However, when located in an IPv4-only network, route optimization
will not be possible due to the difficulty of performing the care-of will not be possible due to the difficulty of performing the care-of
address test. Therefore, mobile nodes will need to communicate address test. Therefore, mobile nodes will need to communicate
through the home agent. through the home agent.
Route optimization will not be possible for IPv4 traffic. That is, Route optimization will not be possible for IPv4 traffic. That is,
traffic addressed to the mobile node's IPv4 home address. This is traffic addressed to the mobile node's IPv4 home address. This is
similar to using Mobile IPv4, therefore there is no reduction of similar to using Mobile IPv4, therefore there is no reduction of
features resulting from using this specification. features resulting from using this specification.
2.5. Dynamic IPv4 home address allocation 3.5. Dynamic IPv4 Home Address Allocation
It is possible to allow for the mobile node's IPv4 home address to be It is possible to allow for the mobile node's IPv4 home address to be
allocated dynamically. This is done by including 0.0.0.0 in the IPv4 allocated dynamically. This is done by including 0.0.0.0 in the IPv4
home address option included in the binding update. The home agent home address option included in the binding update. The home agent
SHOULD allocate an IPv4 address to the mobile node and include it in SHOULD allocate an IPv4 address to the mobile node and include it in
the IPv4 address acknowledgement option sent to the mobile node. In the IPv4 address acknowledgement option sent to the mobile node. In
this case, the lifetime of the binding is bound to the minimum of the this case, the lifetime of the binding is bound to the minimum of the
lifetimes of the IPv6 binding and the lease time of the IPv4 home lifetimes of the IPv6 binding and the lease time of the IPv4 home
address. address.
3. Extensions and modifications to Mobile IPv6 4. Extensions And Modifications To Mobile IPv6
This section highlights the protocol and implementation additions This section highlights the protocol and implementation additions
required to support this specification. required to support this specification.
3.1. Binding update extensions 4.1. Binding Update Extensions
3.1.1 IPv4 home address option 4.1.1. IPv4 Home Address Option
This option is included in the Mobility Header including the binding This option is included in the Mobility Header including the binding
update message sent from the mobile node to a home agent or Mobility update message sent from the mobile node to a home agent or Mobility
Anchor Point. The alignment requirement for this option is 4n. Anchor Point. The alignment requirement for this option is 4n.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |Prefix-len |P| Reserved | | Type | Length |Prefix-len |P| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 home address | | IPv4 home address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD Figure 1: IPv4 Home Address Option
Length 6 Type
Prefix-len The length of the prefix allocated to the mobile TBD
node. If only a single address is allocated,
this field MUST be set to 32. In the first
binding update requesting a prefix, the field
contains the prefix length requested. However,
in the following binding updates, this field
must contain the length of the prefix allocated.
A value of zero is invalid and MUST be
considered an error.
P A flag indicating, when set, that the mobile Length
node requests a mobile network prefix. This flag
is only relevant for new requests, and must be
ignored for binding refreshes.
Reserved This field is reserved for future use. It MUST 6
be set to zero by the sender and ignored by the
receiver.
IPv4 home address The mobile node's IPv4 home address that should Prefix-len
be defended by the home agent. This field could
contain any unicast IPv4 address (public or
private) that was assigned to the mobile node.
The value 0.0.0.0 is used to request an IPv4
home address from the home agent. A mobile node
may choose to use this option to request a
prefix by setting the address to the All Zeroes
and setting the P flag. The mobile node could
then form an IPv4 home address based on the
allocated prefix. Alternatively, the mobile node
may use two different options, one for
requesting an address (Static or Dynamic) and
another for requesting a prefix.
3.1.2 The IPv4 Care-of Address option The length of the prefix allocated to the mobile node. If only a
single address is allocated, this field MUST be set to 32. In the
first binding update requesting a prefix, the field contains the
prefix length requested. However, in the following binding
updates, this field must contain the length of the prefix
allocated. A value of zero is invalid and MUST be considered an
error.
P
A flag indicating, when set, that the mobile node requests a
mobile network prefix. This flag is only relevant for new
requests, and must be ignored for binding refreshes.
Reserved
This field is reserved for future use. It MUST be set to zero by
the sender and ignored by the receiver.
IPv4 Home Address
The mobile node's IPv4 home address that should be defended by the
home agent. This field could contain any unicast IPv4 address
(public or private) that was assigned to the mobile node. The
value 0.0.0.0 is used to request an IPv4 home address from the
home agent. A mobile node may choose to use this option to
request a prefix by setting the address to the All Zeroes and
setting the P flag. The mobile node could then form an IPv4 home
address based on the allocated prefix. Alternatively, the mobile
node may use two different options, one for requesting an address
(Static or Dynamic) and another for requesting a prefix.
4.1.2. The IPv4 Care-of Address Option
This option is included in the Mobility Header including the binding This option is included in the Mobility Header including the binding
update message sent from the mobile node to a home agent or Mobility update message sent from the mobile node to a home agent or Mobility
Anchor Point. The alignment requirement for this option is 4n. Anchor Point. The alignment requirement for this option is 4n.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | | Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Care-of address | | IPv4 Care-of address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD Figure 2: The IPv4 CoA Option
Length 6 Type
Reserved This field is set to zero by the sender and TBD
ignored by the receiver.
IPv4 care-of address This field contains the mobile node's IPv4 care- Length
of address. The IPv4 care-of address is used
when the mobile node is located in an IPv4-only
network.
3.1.3 The Binding Update Message extensions 6
Reserved
This field is set to zero by the sender and ignored by the
receiver.
IPv4 Care-of Address
This field contains the mobile node's IPv4 care- of address. The
IPv4 care-of address is used when the mobile node is located in an
IPv4-only network.
4.1.3. The Binding Update Message Extensions
This specification extends the Binding Update message with two new This specification extends the Binding Update message with two new
flags. The flags are shown and described below. flags. The flags are shown and described below.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # | | Sequence # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|H|L|K|M|R|F|T| Reserved | Lifetime | |A|H|L|K|M|R|F|T| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
F When set, this flag indicates a request for Figure 3: Binding Update message
forcing UDP encapsulation regardless of whether
a NAT is present on the path between the mobile
node and the home agent.
T When set, this flag indicates that the mobile F
node requests the use of the TLV-format for
encapsulating IPv6 in IPv4. The TLV-format is
described later in this document.
3.2. Binding Acknowledgement extensions When set, this flag indicates a request for forcing UDP
encapsulation regardless of whether a NAT is present on the path
between the mobile node and the home agent.
3.2.1 IPv4 address acknowledgement option T
When set, this flag indicates that the mobile node requests the
use of the TLV-format for encapsulating IPv6 in IPv4. The TLV-
format is described later in this document.
4.2. Binding Acknowledgement Extensions
4.2.1. IPv4 Address Acknowledgement Option
This option is included in the Mobility Header including the binding This option is included in the Mobility Header including the binding
acknowledgement message sent from the home agent or Mobility Anchor acknowledgement message sent from the home agent or Mobility Anchor
Point to the mobile node. This option indicates whether a binding Point to the mobile node. This option indicates whether a binding
cache entry was created for the mobile node's IPv4 address. cache entry was created for the mobile node's IPv4 address.
Additionally, this option can include an IPv4 home address in the Additionally, this option can include an IPv4 home address in the
case of Dynamic IPv4 home address configuration (i.e., if the case of Dynamic IPv4 home address configuration (i.e., if the
unspecified IPv4 address was included in the binding update). The unspecified IPv4 address was included in the binding update). The
alignment requirement for this option is 4n. alignment requirement for this option is 4n.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Status |Pref-len |Res| | Type | Length | Status |Pref-len |Res|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 home address | | IPv4 home address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD Figure 4: IPv4 Address Acknowledgement Option
Length 6 Type
Status Indicates success or failure for the IPv4 home TBD
address binding. Values from 0 to 127 indicate
success. Higher values indicate failure. The
following values are reserved:
0 Success
128 Failure, reason unspecified
129 Administratively prohibited
130 Incorrect IPv4 home address
131 Invalid IPv4 address
132 Dynamic IPv4 home address
assignment not available
133 Prefix allocation unauthorized
Pref-len The prefix length of the address allocated. This Length
field is only valid in case of success and MUST
be set to zero and ignored in case of failure.
This field overrides what the mobile node
requested (if not equal to the requested
length).
Res This field is reserved for future use. It MUST 6
be set to zero by the sender and ignored by the
receiver.
IPv4 home address The IPv4 home address that the home agent will Status
use in the binding cache entry. This could be a
public or private address. This field MUST
contain the mobile node's IPv4 home address.
If the address were dynamically allocated the
home agent will add the address to inform the
mobile node. Otherwise, if the address were
statically allocated to the mobile node, the
home agent will copy it from the binding update
message.
3.2.2 The NAT detection option Indicates success or failure for the IPv4 home address binding.
Values from 0 to 127 indicate success. Higher values indicate
failure.
Pref-len
The prefix length of the address allocated. This field is only
valid in case of success and MUST be set to zero and ignored in
case of failure. This field overrides what the mobile node
requested (if not equal to the requested length).
Res
This field is reserved for future use. It MUST be set to zero by
the sender and ignored by the receiver
IPv4 Home Address
he IPv4 home address that the home agent will use in the binding
cache entry. This could be a public or private address. This
field MUST contain the mobile node's IPv4 home address. If the
address were dynamically allocated the home agent will add the
address to inform the mobile node. Otherwise, if the address were
statically allocated to the mobile node, the home agent will copy
it from the binding update message.
The following values are allocated for the Status field:
o 0 Success
o 128 Failure, reason unspecified
o 129 Administratively prohibited
o 130 Incorrect IPv4 home address
o 131 Invalid IPv4 address
o 132 Dynamic IPv4 home address assignment not available
o 133 Prefix allocation unauthorized
4.2.2. The NAT Detection Option
This option is sent from the home agent to the mobile node to This option is sent from the home agent to the mobile node to
indicate whether a NAT was in the path. This option MAY also include indicate whether a NAT was in the path. This option MAY also include
a suggested NAT binding refresh time for the mobile node. The a suggested NAT binding refresh time for the mobile node. The
alignment requirement for this option is 4n. If a NAT is detected, alignment requirement for this option is 4n. If a NAT is detected,
this option MUST be sent by the home agent. this option MUST be sent by the home agent.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |F| Reserved | | Type | Length |F| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Refresh time | | Refresh time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD Figure 5: The NAT Detection Option
Length 6 Type
F This flag indicates to the mobile node that UDP TBD
encapsulation is required. When set, this flag
indicates that the mobile node MUST use UDP
encapsulation even if a NAT is not located
between the mobile node and home agent.
Reserved This field is reserved for future use. It MUST Length
be set to zero by the sender and ignored by the
receiver.
Refresh time A suggested time (in seconds) for the mobile 6
node to refresh the NAT binding. If set to zero,
it is ignored. If this field is set to the all
1s it means that keepalives are not needed,
i.e.,
no NAT was detected.
3.2.3 Extensions to the Binding Acknowledgement message F
This flag indicates to the mobile node that UDP encapsulation is
required. When set, this flag indicates that the mobile node MUST
use UDP encapsulation even if a NAT is not located between the
mobile node and home agent.
Reserved
This field is reserved for future use. It MUST be set to zero by
the sender and ignored by the receiver.
Refresh Time
A suggested time (in seconds) for the mobile node to refresh the
NAT binding. If set to zero, it is ignored. If this field is set
to the all 1s it means that keepalives are not needed, i.e.,no NAT
was detected.
4.2.3. Extensions to the Binding Acknowledgement Message
This specification extends the binding acknowledgement message with a This specification extends the binding acknowledgement message with a
new flag. The new flag is shown and described below. new flag. The new flag is shown and described below.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status |K|R|T| Reserved| | Status |K|R|T| Reserved|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # | Lifetime | | Sequence # | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
T This flag indicates, when set, that the sender Figure 6: Binding Acknowledgement message
of the binding acknowledgement supports the TLV-
tunnel format.
4. Protocol operation T
This flag indicates, when set, that the sender of the binding
acknowledgement supports the TLV- tunnel format.
5. Protocol operation
This section presents the protocol operation and processing for the This section presents the protocol operation and processing for the
messages presented above. In addition, this section introduces the messages presented above. In addition, this section introduces the
NAT detection and traversal mechanism used by this specification. NAT detection and traversal mechanism used by this specification.
4.1. Tunnelling formats 5.1. Tunelling Formats
This specification allows the mobile node to use various tunnelling
formats depending on its location and the visited networ's
capabilities. The mobile node can tunnel IPv6 in IPv4, IPv4 in IPv6
or use UDP encapsulation to tunnel IPv6 in IPv4. Naturally, this
specification also supports tunnelling IPv6 in IPv6.
This speacification allows two different types of UDP-based This speacification allows two different types of UDP-based
tunnelling formats to be used between the mobile node and its home tunnelling formats to be used between the mobile node and its home
agent or MAP. The two formats are vanilla UDP encapsulation and TLV- agent or MAP. The two formats are vanilla UDP encapsulation and TLV-
header UDP encapsulation. A vanilla UDP encapsulation format means header UDP encapsulation. A vanilla UDP encapsulation format means
the following order of headers: the following order of headers:
IPv4 IPv4
UDP UDP
IP (v4 or v6) IP (v4 or v6)
Other headers Other headers
When using this format the receiver would parse the version field When using this format the receiver would parse the version field
following the UDP header in order to determine whether the following following the UDP header in order to determine whether the following
header is IPv4 or IPv6. The rest of the headers are processed header is IPv4 or IPv6. The rest of the headers are processed
normally. The above order of headers does not take IPsec headers into normally. The above order of headers does not take IPsec headers
account as they may be placed in different parts of the packet. The into account as they may be placed in different parts of the packet.
above format MUST be supported by all implementations of this The above format MUST be supported by all implementations of this
specification and MUST always be used to send the binding update specification and MUST always be used to send the binding update
message. message.
A TLV-header UDP encapsulation is represented by the following order A TLV-header UDP encapsulation is represented by the following order
of headers: of headers:
IP (v4 or v6) IP (v4 or v6)
UDP UDP
TLV-header TLV-header
Other headers
The receiver of the TLV-header UDP encapsulated packet expects the Other headers
TLV-header to follow UDP. The TLV header contains the type of the The use of the TLV header is negotiated during the binding update/
following message and its length. Hence, the TLV header can carry acknowledgement exchange. If the TLV header is agreed upon, the
traffic other than IP. receiver of the TLV-header UDP encapsulated packet expects the TLV-
header to follow UDP. The TLV header contains the type of the
following message and its length. The Type field MUST NOT be
assigned the values 4 or 6 to make sure that the receiver can tell
the difference between the Type field and the IP version field in a
packet that contains an IP header after UDP. Hence, the TLV header
can carry traffic other than IP.
The mobile node negotiates the format for tunnelling payload traffic The mobile node negotiates the format for tunnelling payload traffic
during the binding exchange. If a mobile node prefers to use the TLV- during the binding exchange. If a mobile node prefers to use the
header UDP encapsulation, it sets the T flag in the binding update TLV- header UDP encapsulation, it sets the T flag in the binding
sent to the home agent or MAP. If the receiver of the binding update update sent to the home agent or MAP. If the receiver of the binding
supports the TLV-header format, it SHOULD set the T flag in the update supports the TLV-header format, it SHOULD set the T flag in
binding acknowledgement message. Otherwise, the T flag is cleared. the binding acknowledgement message. Otherwise, the T flag is
The setting of the T flag in the binding acknowledgement indicates to cleared. The setting of the T flag in the binding acknowledgement
the mobile node that it must use the TLV-header UDP encapsulation indicates to the mobile node that it must use the TLV-header UDP
format for all packets sent for the duration of the binding or until encapsulation format for all packets sent for the duration of the
a new binding update is sent. Each binding update may renegotiate the binding or until a new binding update is sent. Each binding update
tunnelling format. To avoid interoperability issues, the sender of may renegotiate the tunnelling format. To avoid interoperability
the binding acknowledgement MUST NOT set the T flag unless it was set issues, the sender of the binding acknowledgement MUST NOT set the T
in the binding update sent from the mobile node. flag unless it was set in the binding update sent from the mobile
node.
The TLV-header format is shown below. The TLV-header format is shown below.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | | Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type This field indicates the type of the payload Figure 7: TLV-header format
following this header.
Length This field indicates the length of the payload Type
following the header, excluding the TLV-header
itself.
Reserved This field MUST be set to zero by the sender and This field indicates the type of the payload following this
ignored by the receiver. header.
The following values are assigned to the Type field, other values may Length
This field indicates the length of the payload following the
header, excluding the TLV-header itself.
Reserved
This field MUST be set to zero by the sender and ignored by the
receiver.
The following value is assigned to the Type field, other values may
be assigned in future: be assigned in future:
1 IPv4 1 GRE
2 IPv6
3 IPsec
4 GRE
In addition to the UDP-based tunnelling formats described above, this In addition to the UDP-based tunnelling formats described above, this
specification allows for standard IP in IP tunnelling. This can take specification allows for standard IP in IP tunnelling. This can take
place by tunnelling IPv4 in IPv6 or IPv6 in IPv4. However, whenever a place by tunnelling IPv4 in IPv6 or IPv6 in IPv4. However, whenever
NAT a detected, the mobile node will default to UDP-based a NAT a detected, the mobile node will default to UDP-based
encapsulation. The mobile node can request to always use UDP encapsulation. The mobile node can request to always use UDP
encapsulation by setting the F flag in the binding update. If the encapsulation by setting the F flag in the binding update. If the
home agent does not agree to the request, it MUST reject the binding home agent does not agree to the request, it MUST reject the binding
update with the new Status code: update with the new Status code:
144 Cannot force UDP encapsulation 144 Cannot force UDP encapsulation
Alternatively, the home agent can force UDP encapsulation by setting Alternatively, the home agent can force UDP encapsulation by setting
the F flag in the NAT detection option included in the binding the F flag in the NAT detection option included in the binding
acknowledgement. acknowledgement.
4.2. NAT detection and traversal 5.1.1. Tunnelling Impacts on Transport and MTU
Changing the tunnel format may occur due to movement of the mobile
node from one network to another. This can have impacts on the link
and path MTU, which may affect the amount of bandwidth available to
the applications. It is recommended that the mobile node use PLMTUD
as specified in [RFC4459].
To accomodate traffic that uses Explicit Congestion Notification
(ECN), it is RECOMMENDED that the ECN information is copied between
the inner and outer header as defined in [RFC3168].
5.2. NAT Detection
NAT detection is done when the initial binding update message is sent NAT detection is done when the initial binding update message is sent
from the mobile node to the home agent. When located in an IPv4-only from the mobile node to the home agent. When located in an IPv4-only
foreign link, the mobile node sends the binding update message foreign link, the mobile node sends the binding update message
encapsulated in UDP and IPv4. The source address of the IPv6 packet encapsulated in UDP and IPv4. The source address of the IPv6 packet
is the mobile node's IPv6 home address. The destination address is is the mobile node's IPv6 home address. The destination address is
the IPv6 address of the home agent. The IPv4 header contains the IPv4 the IPv6 address of the home agent. The IPv4 header contains the
care-of address in the source address field and the IPv4 address of IPv4 care-of address in the source address field and the IPv4 address
the home agent in the destination address field. of the home agent in the destination address field.
When the home agent receives the encapsulated binding update it When the home agent receives the encapsulated binding update it
compares the IPv4 address of the source address field in the IPv4 compares the IPv4 address of the source address field in the IPv4
header with the IPv4 address included in the IPv4 care-of address header with the IPv4 address included in the IPv4 care-of address
option. If the two addresses match, no NAT device was in the path. option. If the two addresses match, no NAT device was in the path.
Otherwise, a NAT device was in the path and the NAT detection option Otherwise, a NAT device was in the path and the NAT detection option
is included in the binding acknowledgement. The binding is included in the binding acknowledgement. The binding
acknowledgement, and all future packets, are then encapsulated in UDP acknowledgement, and all future packets, are then encapsulated in UDP
and IPv4. The source address in the IPv4 header is the IPv4 address and IPv4. The source address in the IPv4 header is the IPv4 address
of the home agent. The destination address is the IPv4 address of the home agent. The destination address is the IPv4 address
skipping to change at page 17, line 43 skipping to change at page 23, line 24
source port. The destination port is the source port received in the source port. The destination port is the source port received in the
binding update message. Note that the home agent stores the port binding update message. Note that the home agent stores the port
numbers and associates them with the mobile node's tunnel in order to numbers and associates them with the mobile node's tunnel in order to
forward future packets. forward future packets.
Upon receiving the binding acknowledgement with the NAT detection Upon receiving the binding acknowledgement with the NAT detection
option, the mobile node sets the tunnel to the home agent to UDP option, the mobile node sets the tunnel to the home agent to UDP
encapsulation. Hence, all future packets to the home agent are encapsulation. Hence, all future packets to the home agent are
tunneled in UDP and IPv4. For all tunneled IPv6 packets, the source tunneled in UDP and IPv4. For all tunneled IPv6 packets, the source
address in the IPv6 header is the mobile node's IPv6 home address and address in the IPv6 header is the mobile node's IPv6 home address and
the destination address is the correspondent node's IPv6 address. All the destination address is the correspondent node's IPv6 address.
tunneled IPv4 packets will contain the mobile node's IPv4 home All tunneled IPv4 packets will contain the mobile node's IPv4 home
address in the source address field of the inner IPv4 packet and the address in the source address field of the inner IPv4 packet and the
correspondent node's IPv4 address in the destination address field. correspondent node's IPv4 address in the destination address field.
The outer IPv4 header is the same whether the inner packet is IPv4 or The outer IPv4 header is the same whether the inner packet is IPv4 or
IPv6. IPv6.
If no NAT device was detected in the path between the mobile node and If no NAT device was detected in the path between the mobile node and
the home agent then IPv6 packets are tunneled in an IPv4 header, the home agent then IPv6 packets are tunneled in an IPv4 header,
unless the home agent forces UDP encapsulation using the F flag. The unless the home agent forces UDP encapsulation using the F flag. The
content of the inner and outer headers are identical to the UDP content of the inner and outer headers are identical to the UDP
encapsulation case. encapsulation case.
A mobile node MUST always tunnel binding updates in UDP when located A mobile node MUST always tunnel binding updates in UDP when located
in an IPv4-only network. Essentially, this process allows for in an IPv4-only network. Essentially, this process allows for
perpetual NAT detection. Similarly, the home agent MUST encapsulate perpetual NAT detection. Similarly, the home agent MUST encapsulate
binding acknowledgements in a UDP header whenever the binding update binding acknowledgements in a UDP header whenever the binding update
is encapsulated in UDP. is encapsulated in UDP.
In conclusion, the packet formats for the binding update and In conclusion, the packet formats for the binding update and
acknowledgement messages are shown below: acknowledgement messages are shown below:
A. Binding update received by the home agent: Binding update received by the home agent:
IPv4 header (src=V4ADDR, dst=HA_V4ADDR) IPv4 header (src=V4ADDR, dst=HA_V4ADDR)
UDP header UDP header
IPv6 header (src=V6HOA, dst=HAADDR) IPv6 header (src=V6HOA, dst=HAADDR)
ESP-header
ESP Header
Mobility header Mobility header
BU [IPv4 HAO] BU [IPv4 HAO]
IPv4 CoA option IPv4 CoA option
Where V4ADDR is either the IPv4 care-of address or the address Where V4ADDR is either the IPv4 care-of address or the address
provided by the NAT device. V6HOA is the IPv6 home address of the provided by the NAT device. V6HOA is the IPv6 home address of the
mobile node. The binding update MAY also contain the IPv4 home mobile node. The binding update MAY also contain the IPv4 home
address option IPv4 HAO. address option IPv4 HAO.
B. Binding acknowledgement sent by the home agent: Binding acknowledgement sent by the home agent:
IPv4 header (src= HA_V4ADDR, dst=V4ADDR) IPv4 header (src= HA_V4ADDR, dst=V4ADDR)
UDP header
UDP Header
IPv6 header (src=HAADDR, dst=V6HOA) IPv6 header (src=HAADDR, dst=V6HOA)
ESP-header
Mobility header ESP Header
Mobility Header
BA ([IPv4 ACK], NAT DET) BA ([IPv4 ACK], NAT DET)
Where V6HOA is IPv6 home address of the mobile node. The IPv4 ACK is Where V6HOA is IPv6 home address of the mobile node. The IPv4 ACK is
the IPv4 address acknowledgement option, which is only included if the IPv4 address acknowledgement option, which is only included if
the IPv4 home address option were present in the BU. The NAT DET is the IPv4 home address option were present in the BU. The NAT DET is
the NAT detection option, which MUST be present in the binding the NAT detection option, which MUST be present in the binding
acknowledgement message if the binding update was encapsulated in acknowledgement message if the binding update was encapsulated in
UDP. UDP.
4.3. NAT Keepalives 5.3. NAT Keepalives
If a NAT is detected, the mobile node will need to refresh the NAT If a NAT is detected, the mobile node will need to refresh the NAT
bindings in order to be reachable from the home agent. NAT bindings bindings in order to be reachable from the home agent. NAT bindings
can be refreshed through sending and receiving traffic encapsulated can be refreshed through sending and receiving traffic encapsulated
in UDP. However, if the mobile node is not active, it will need to in UDP. However, if the mobile node is not active, it will need to
periodically send a message to the home agent in order to refresh the periodically send a message to the home agent in order to refresh the
NAT binding. This can be done using the binding update message. The NAT binding. This can be done using the binding update message. The
binding update/acknowledgement pair will ensure that the NAT bindings binding update/acknowledgement pair will ensure that the NAT bindings
are refreshed in a reliable manner. There is no way for the mobile are refreshed in a reliable manner. There is no way for the mobile
node to know the exact time of the NAT binding. The default time node to know the exact time of the NAT binding. The default time
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reachable (i.e., only cares about the session continuity aspect of reachable (i.e., only cares about the session continuity aspect of
Mobile IP) does not need to refresh NAT binding. In this case, the Mobile IP) does not need to refresh NAT binding. In this case, the
mobile node would only be able to initiate communication with other mobile node would only be able to initiate communication with other
nodes. However, this is likely to imply that the mobile node will nodes. However, this is likely to imply that the mobile node will
need to send a binding update before initiating communication after a need to send a binding update before initiating communication after a
long idle period as it is likely to be assigned a different port and long idle period as it is likely to be assigned a different port and
IPv4 address when it initiates communication. Hence, an IPv4 address when it initiates communication. Hence, an
implementation may choose, for the sake of simplicity, to always implementation may choose, for the sake of simplicity, to always
maintain the NAT bindings even when it does not need reachability. maintain the NAT bindings even when it does not need reachability.
4.4. Mobile node operation 5.4. Mobile Node Operation
In addition to the operations specified in [MIPv6] and [NEMO], this In addition to the operations specified in [RFC3775] and [RFC3963],
specification requires mobile nodes to be able to support an IPv4 this specification requires mobile nodes to be able to support an
home address. IPv4 home address.
When sending an IPv6 packet containing a binding update while When sending an IPv6 packet containing a binding update while
connected to an IPv4-only access network, mobile nodes MUST ensure connected to an IPv4-only access network, mobile nodes MUST ensure
the following: the following:
- The IPv6 packet is encapsulated in the vanilla UDP encapsulation o The IPv6 packet is encapsulated in the vanilla UDP encapsulation
format. format.
- The source address in the IPv4 header is the mobile node's IPv4
care-of address o The source address in the IPv4 header is the mobile node's IPv4
- The destination address in the IPv4 header is the home agent's care-of address.
o The destination address in the IPv4 header is the home agent's
IPv4 address. IPv4 address.
- The source address in the IPv6 header is the mobile node's IPv6
o The source address in the IPv6 header is the mobile node's IPv6
home address. home address.
- The IPv4 home address option MAY be included in the mobility
header. This option contains the IPv4 home address. If the mobile o The IPv4 home address option MAY be included in the mobility
node did not have a static home address it MAY include the header. This option contains the IPv4 home address. If the
mobile node did not have a static home address it MAY include the
unspecified IPv4 address, which acts as a request for a dynamic unspecified IPv4 address, which acts as a request for a dynamic
IPv4 home address. Alternatively, one or more IPv4 home address IPv4 home address. Alternatively, one or more IPv4 home address
options may be included with requests for IPv4 prefixes (i.e., with options may be included with requests for IPv4 prefixes (i.e.,
the P flag set.). with the P flag set).
- If the mobile node wishes to use UDP encapsulation only, it should
o If the mobile node wishes to use UDP encapsulation only, it should
set the F flag in the binding update message. set the F flag in the binding update message.
- If the mobile node prefers to use the TLV-header format, it should
o If the mobile node prefers to use the TLV-header format, it should
set the T flag in the binding update. set the T flag in the binding update.
- The IPv6 packet MUST be authenticated as per [MIPv6], based on the
mobile node's IPv6 home address. o The IPv6 packet MUST be authenticated as per [RFC3775], based on
the mobile node's IPv6 home address.
When sending a binding update from a visited network that supports When sending a binding update from a visited network that supports
IPv6, the mobile node MUST follow the rules specified in [MIPv6]. In IPv6, the mobile node MUST follow the rules specified in [RFC3775].
addition, if the mobile node has an IPv4 home address or needs one, In addition, if the mobile node has an IPv4 home address or needs
it MUST include the IPv4 home address option in the mobility header. one, it MUST include the IPv4 home address option in the mobility
If the mobile node already has a static IPv4 home address, this header. If the mobile node already has a static IPv4 home address,
address MUST be included in the IPv4 home address option. Otherwise, this address MUST be included in the IPv4 home address option.
if the mobile node needs a dynamic IPv4 address, it MUST include the Otherwise, if the mobile node needs a dynamic IPv4 address, it MUST
IPv4 0.0.0.0 address in the IPv4 home address option. include the IPv4 0.0.0.0 address in the IPv4 home address option.
When the mobile node receives a binding acknowledgement from the home When the mobile node receives a binding acknowledgement from the home
agent, it follows the rules in [MIPv6] and [NEMO]. In addition, the agent, it follows the rules in [RFC3775] and [RFC3963]. In addition,
following actions MUST be made: the following actions MUST be made:
- If the status field indicated failure with error code 144, the o If the status field indicated failure with error code 144, the
mobile node MAY resend the binding update without setting the F mobile node MAY resend the binding update without setting the F
flag. flag.
- If the mobility header includes an IPv4 address acknowledgement
o If the mobility header includes an IPv4 address acknowledgement
option indicating success, the mobile node should create two option indicating success, the mobile node should create two
entries in its binding update list, one for the IPv6 home address entries in its binding update list, one for the IPv6 home address
and another for the IPv4 home address. and another for the IPv4 home address.
- If the NAT detection option were present, the mobile node
MUST tunnel future packets in UDP and IPv4. This MUST be indicated o If the NAT detection option were present, the mobile node MUST
in the binding update list. tunnel future packets in UDP and IPv4. This MUST be indicated in
- If no IPv4 address acknowledgement option were present, and an the binding update list.
o If no IPv4 address acknowledgement option were present, and an
IPv4 home address option was present in the binding update, the IPv4 home address option was present in the binding update, the
mobile node MUST only create one binding update list entry for its mobile node MUST only create one binding update list entry for its
IPv6 home address. The mobile node MAY include the IPv4 home IPv6 home address. The mobile node MAY include the IPv4 home
address option in future binding updates. address option in future binding updates.
- If an IPv4 address acknowledgement option were present and it
o If an IPv4 address acknowledgement option were present and it
indicates failure for the IPv4 home address binding, the mobile indicates failure for the IPv4 home address binding, the mobile
node MUST NOT create an entry for that address in its binding node MUST NOT create an entry for that address in its binding
update list. The mobile node MAY include the IPv4 home address update list. The mobile node MAY include the IPv4 home address
option in future binding updates. option in future binding updates.
- If the T flag was set in the binding update and the binding
o If the T flag was set in the binding update and the binding
acknowledgement included the T flag set, the mobile node MUST use acknowledgement included the T flag set, the mobile node MUST use
the TLV-header UDP encapsulation format. the TLV-header UDP encapsulation format.
4.4.1 Sending packets from a visited network. 5.4.1. Sending Packets from a Visited Network
When the mobile node is located in an IPv6-enabled network it sends When the mobile node is located in an IPv6-enabled network it sends
and receives IPv6 packets as described in [MIPv6]. IPv4 traffic is and receives IPv6 packets as described in [RFC3775]. IPv4 traffic is
encapsulated in IPv6 packets to the home agent. encapsulated in IPv6 packets to the home agent.
When the mobile node is located in an IPv4 only network, it will send When the mobile node is located in an IPv4 only network, it will send
IPv6 packets to its home agent according to the following format: IPv6 packets to its home agent according to the following format:
IPv4 header (src=V4CoA, dst=HA_V4ADDR) IPv4 header (src=V4CoA, dst=HA_V4ADDR)
[UDP header]
[TLV-header] [UDP Header]
[TLV Header]
IPv6 header (src=V6HoA, dst=CN) IPv6 header (src=V6HoA, dst=CN)
Upper layer protocols
Upper Layer protocols
Where the UDP header is only used if a NAT were detected between the Where the UDP header is only used if a NAT were detected between the
mobile node and the home agent, or if the home agent forced UDP mobile node and the home agent, or if the home agent forced UDP
encapsulation. V4CoA is the IPv4 care-of address configured by the encapsulation. V4CoA is the IPv4 care-of address configured by the
mobile node in the visited network. mobile node in the visited network.
Similarly, IPv4 packets are sent according to the following format: Similarly, IPv4 packets are sent according to the following format:
IPv4 header (src=V4CoA, dst=HA_V4ADDR) IPv4 header (src=V4CoA, dst=HA_V4ADDR)
[UDP header]
[TLV-header] [UDP Header]
[TLV Header]
IPv4 header (src=V4HoA, dst=V4CN) IPv4 header (src=V4HoA, dst=V4CN)
Upper layer protocols
Upper Layer protocols
Where the UDP header is only used if a NAT were detected between the Where the UDP header is only used if a NAT were detected between the
mobile node and the home agent, or if the home agent forced UDP mobile node and the home agent, or if the home agent forced UDP
encapsulation. encapsulation.
If the mobile node and the home agent negotiated the use of the TLV- If the mobile node and the home agent negotiated the use of the TLV-
header UDP encapsulation format, then the TLV-header would be used header UDP encapsulation format, then the TLV-header would be used
after the UDP header. after the UDP header.
4.4.2 Movement detection in IPv4-only networks 5.4.2. Movement Detection in IPv4-only Networks
[MIPv6] describes movement detection mostly based on IPv6-specific [RFC3775] describes movement detection mostly based on IPv6-specific
triggers. These triggers would not be available in an IPv4-only triggers. These triggers would not be available in an IPv4-only
network. Hence, a mobile node located in an IPv4-only network SHOULD network. Hence, a mobile node located in an IPv4-only network SHOULD
use [DNAv4] for guidance on movement detection mechanisms in IPv4- use [RFC4436] for guidance on movement detection mechanisms in IPv4-
only networks. only networks.
4.5. Home agent operations 5.5. Home agent operation
In addition to the home agent specification in [MIPv6] and [NEMO], In addition to the home agent specification in [RFC3775] and
the home agent needs to be able to process the IPv4 home address [RFC3963], the home agent needs to be able to process the IPv4 home
option and generate the IPv4 address acknowledgement option. Both address option and generate the IPv4 address acknowledgement option.
options are included in the mobility header. Furthermore, the home Both options are included in the mobility header. Furthermore, the
agent MUST be able to detect the presence of a NAT device and home agent MUST be able to detect the presence of a NAT device and
indicate that in the NAT detection option included in the binding indicate that in the NAT detection option included in the binding
acknowledgement. acknowledgement.
A home agent must also act as a proxy for address resolution in IPv4 A home agent must also act as a proxy for address resolution in IPv4
for the registered IPv4 home addresses of mobile nodes it is serving. for the registered IPv4 home addresses of mobile nodes it is serving.
Moreover, the administrative domain of the home agent is responsible Moreover, the administrative domain of the home agent is responsible
for advertising the routing information of registered IPv4 mobile for advertising the routing information of registered IPv4 mobile
network prefixes of the mobile nodes. network prefixes of the mobile nodes.
In order to comply with this specification, the home agent MUST be In order to comply with this specification, the home agent MUST be
able to find the IPv4 home address of a mobile node when given the able to find the IPv4 home address of a mobile node when given the
IPv6 home address. That is, given an IPv6 home address, the home IPv6 home address. That is, given an IPv6 home address, the home
agent MUST store the corresponding IPv4 home address if a static one agent MUST store the corresponding IPv4 home address if a static one
is present. If a dynamic address were requested by the mobile node, is present. If a dynamic address were requested by the mobile node,
the home agent MUST store that address (associated with the IPv6 home the home agent MUST store that address (associated with the IPv6 home
address) after it's allocated to the mobile node. address) after it's allocated to the mobile node.
When the home agent receives a binding update encapsulated in UDP and When the home agent receives a binding update encapsulated in UDP and
containing the IPv4 home address option, it needs to follow all the containing the IPv4 home address option, it needs to follow all the
steps in [MIPv6] and [NEMO]. In addition, the following checks MUST steps in [RFC3775] and [RFC3963]. In addition, the following checks
be done: MUST be done:
- If the IPv4 care-of address in the IPv4 CoA option is not the same o If the IPv4 care-of address in the IPv4 CoA option is not the same
as the IPv4 address in the source address in the IPv4 header then as the IPv4 address in the source address in the IPv4 header then
a NAT was in the path. This information should be flagged for the a NAT was in the path. This information should be flagged for the
binding acknowledgement. binding acknowledgement.
- If the F flag in the binding update were set, the home agent needs o If the F flag in the binding update were set, the home agent needs
to determine whether it accepts forcing UDP encapsulation. If it to determine whether it accepts forcing UDP encapsulation. If it
does not, the binding acknowledgement is sent with error code 144. does not, the binding acknowledgement is sent with error code 144.
UDP encapsulation MUST NOT be used when the mobile node is located UDP encapsulation MUST NOT be used when the mobile node is located
in an IPv6-enabled link. in an IPv6-enabled link.
- If the T flag was set in the binding update, the home agent needs o If the T flag was set in the binding update, the home agent needs
to determine whether it can accept the TLV-header encapsulation to determine whether it can accept the TLV-header encapsulation
format. If it does, it should set the T flag in the binding format. If it does, it should set the T flag in the binding
acknowledgement. Otherwise, the home agent MUST NOT set the T flag acknowledgement. Otherwise, the home agent MUST NOT set the T
in the binding acknowledgement. flag in the binding acknowledgement.
- If the IPv4 home address option contains a valid unicast IPv4 o If the IPv4 home address option contains a valid unicast IPv4
address, the home agent MUST check that this address is allocated address, the home agent MUST check that this address is allocated
to the mobile node that has the IPv6 home address included in the to the mobile node that has the IPv6 home address included in the
home address option. The same MUST be done for an IPv4 prefix. home address option. The same MUST be done for an IPv4 prefix.
- If the IPv4 home address option contained the unspecified IPv4 o If the IPv4 home address option contained the unspecified IPv4
address, the home agent SHOULD dynamically allocate an IPv4 home address, the home agent SHOULD dynamically allocate an IPv4 home
address to the mobile node. If none is available, the home agent address to the mobile node. If none is available, the home agent
MUST return error code 132 in the status field of the IPv4 address MUST return error code 132 in the status field of the IPv4 address
acknowledgement option. If a prefix were requested, the home agent acknowledgement option. If a prefix were requested, the home
MUST allocate a prefix with the requested length; otherwise the agent MUST allocate a prefix with the requested length; otherwise
home agent MUST indicate failure of the operation with the the home agent MUST indicate failure of the operation with the
appropriate error code. appropriate error code.
- If the binding update is accepted for the IPv4 home address, the o If the binding update is accepted for the IPv4 home address, the
home agent creates a binding cache entry for the IPv4 home home agent creates a binding cache entry for the IPv4 home
address/prefix. The home agent MUST include an IPv4 acknowledgement address/prefix. The home agent MUST include an IPv4
option in the mobility header containing the binding acknowledgement option in the mobility header containing the
acknowledgement. binding acknowledgement.
If the binding update is accepted for both IPv4 and IPv6 home o If the binding update is accepted for both IPv4 and IPv6 home
addresses, the home agent creates separate binding cache entries, one addresses, the home agent creates separate binding cache entries,
for each home address. The care-of address is the one included in the one for each home address. The care-of address is the one
binding update. If the care-of address is an IPv4 address, the home included in the binding update. If the care-of address is an IPv4
agent MUST setup a tunnel to the IPv4 care-of address of the mobile address, the home agent MUST setup a tunnel to the IPv4 care-of
node. address of the mobile node.
When sending a binding acknowledgement to the mobile node, the home When sending a binding acknowledgement to the mobile node, the home
agent constructs the message according to [MIPv6] and [NEMO]. Note agent constructs the message according to [RFC3775] and [RFC3963].
that the routing header MUST always contain the IPv6 home address as Note that the routing header MUST always contain the IPv6 home
specified in [MIPv6]. address as specified in [RFC3775].
If the care-of address of the mobile node were an IPv4 address, the If the care-of address of the mobile node were an IPv4 address, the
home agent includes the mobile node's IPv6 home address in the home agent includes the mobile node's IPv6 home address in the
destination address field in the IPv6 header. If a NAT were detected, destination address field in the IPv6 header. If a NAT were
the home agent MUST then encapsulate the packet in UDP and an IPv4 detected, the home agent MUST then encapsulate the packet in UDP and
header. The source address is set to the home agent's IPv4 address an IPv4 header. The source address is set to the home agent's IPv4
and the destination address is set to the address received in the address and the destination address is set to the address received in
source address of the IPv4 header encapsulating the binding update. the source address of the IPv4 header encapsulating the binding
update.
After creating a binding cache entry for the mobile node's home After creating a binding cache entry for the mobile node's home
addresses, all packets sent to the mobile node's home addresses are addresses, all packets sent to the mobile node's home addresses are
tunneled by the home agent to the mobile node's care-of address. If a tunneled by the home agent to the mobile node's care-of address. If
NAT were detected, packets are encapsulated in UDP and IPv4. a NAT were detected, packets are encapsulated in UDP and IPv4.
Otherwise, if the care-of address is an IPv4 address, and no NAT were Otherwise, if the care-of address is an IPv4 address, and no NAT were
detected, packets are encapsulated in an IPv4 header unless UDP detected, packets are encapsulated in an IPv4 header unless UDP
encapsulation is forced by the home agent. encapsulation is forced by the home agent.
4.5.1 Sending packets to the mobile node 5.5.1. Sending Packets to the Mobile Node
The home agent follows the rules specified in [MIPv6] for sending The home agent follows the rules specified in [RFC3775] for sending
IPv6 packets to mobile nodes located in IPv6 networks. When sending IPv6 packets to mobile nodes located in IPv6 networks. When sending
IPv4 packets to When mobile nodes in an IPv6 network, the home agent IPv4 packets to When mobile nodes in an IPv6 network, the home agent
must encapsulate the IPv4 packets in IPv6. must encapsulate the IPv4 packets in IPv6.
When sending IPv6 packets to a mobile node located in an IPv4 When sending IPv6 packets to a mobile node located in an IPv4
network, the home agent must follow the format negotiated in the network, the home agent must follow the format negotiated in the
binding update/acknowledgement exchange. In the absence of a binding update/acknowledgement exchange. In the absence of a
negotiated format, the default format that MUST be supported by all negotiated format, the default format that MUST be supported by all
implementations is: implementations is:
IPv4 header (src= HA_V4ADDR, dst= V4ADDR) IPv4 header (src= HA_V4ADDR, dst= V4ADDR)
[UDP header]
UDP Header
IPv6 header (src=CN, dst= V6HoA) IPv6 header (src=CN, dst= V6HoA)
Upper layer protocols Upper layer protocols
Where the UDP header is only included if a NAT were detected between Where the UDP header is only included if a NAT were detected between
the mobile node and the home agent, or if the home agent forced UDP the mobile node and the home agent, or if the home agent forced UDP
encapsulation. V4ADDR is the IPv4 address received in the source encapsulation. V4ADDR is the IPv4 address received in the source
address field of the IPv4 packet containing the binding update. address field of the IPv4 packet containing the binding update.
When sending IPv4 packets to a mobile node located in an IPv4 When sending IPv4 packets to a mobile node located in an IPv4
network, the home agent must follow the format negotiated in the network, the home agent must follow the format negotiated in the
binding update/acknowledgement exchange. In the absence of a binding update/acknowledgement exchange. In the absence of a
skipping to change at page 24, line 8 skipping to change at page 30, line 46
encapsulation. V4ADDR is the IPv4 address received in the source encapsulation. V4ADDR is the IPv4 address received in the source
address field of the IPv4 packet containing the binding update. address field of the IPv4 packet containing the binding update.
When sending IPv4 packets to a mobile node located in an IPv4 When sending IPv4 packets to a mobile node located in an IPv4
network, the home agent must follow the format negotiated in the network, the home agent must follow the format negotiated in the
binding update/acknowledgement exchange. In the absence of a binding update/acknowledgement exchange. In the absence of a
negotiated format, the default format that MUST be supported by all negotiated format, the default format that MUST be supported by all
implementations is: implementations is:
IPv4 header (src= HA_V4ADDR, dst= V4ADDR) IPv4 header (src= HA_V4ADDR, dst= V4ADDR)
[UDP header]
[UDP Header]
IPv4 header (src=V4CN, dst= V4HoA) IPv4 header (src=V4CN, dst= V4HoA)
Upper layer protocols
Upper layer protocols
Where the UDP header is only included if a NAT were detected between Where the UDP header is only included if a NAT were detected between
the mobile node and home agent, or if the home agent forced UDP the mobile node and home agent, or if the home agent forced UDP
encapsulation. encapsulation.
4.6. Correspondent node operations 5.6. Correspondent Node Operation
This specification has no impact on IPv4 or IPv6 correspondent nodes. This specification has no impact on IPv4 or IPv6 correspondent nodes.
5. Security considerations 6. Security Considerations
This specification allows a mobile node to send one binding update This specification allows a mobile node to send one binding update
for its IPv6 and IPv4 home addresses. This is a slight deviation from for its IPv6 and IPv4 home addresses. This is a slight deviation
[MIPv6] which requires one binding update per home address. However, from [RFC3775] which requires one binding update per home address.
like [MIPv6], the IPsec security association needed to authenticate However, like [RFC3775], the IPsec security association needed to
the binding update is still based on the mobile node's IPv6 home authenticate the binding update is still based on the mobile node's
address. Therefore, in order to authorize the mobile node's IPv4 home IPv6 home address. Therefore, in order to authorize the mobile
address binding, the home agent MUST store the IPv4 address node's IPv4 home address binding, the home agent MUST store the IPv4
corresponding to the IPv6 address that is allocated to a mobile node. address corresponding to the IPv6 address that is allocated to a
Therefore, it is sufficient for the home agent to know that the IPsec mobile node. Therefore, it is sufficient for the home agent to know
verification for the packet containing the binding update was valid that the IPsec verification for the packet containing the binding
provided that it knows which IPv4 home address is associated with update was valid provided that it knows which IPv4 home address is
which IPv6 home address. Hence, the security of the IPv4 home address associated with which IPv6 home address. Hence, the security of the
binding is the same as the IPv6 binding. IPv4 home address binding is the same as the IPv6 binding.
In effect, associating the mobile node's IPv4 home address with its In effect, associating the mobile node's IPv4 home address with its
IPv6 home address moves the authorization of the binding update for IPv6 home address moves the authorization of the binding update for
the IPv4 address to the Mobile IPv6 implementation, which infers it the IPv4 address to the Mobile IPv6 implementation, which infers it
from the fact that mobile node has an IPv6 home address and the right from the fact that mobile node has an IPv6 home address and the right
credentials for sending an authentic binding update for the IPv6 credentials for sending an authentic binding update for the IPv6
address. address.
In cases where this specification is used for NAT traversal, it is In cases where this specification is used for NAT traversal, it is
important to note that it has the same vulnerabilities associated important to note that it has the same vulnerabilities associated
with RFC 3519 [TRAV]. An attacker is able to hijack the mobile node's with [RFC3519]. An attacker is able to hijack the mobile node's
session with the home agent if it can modify the contents of the session with the home agent if it can modify the contents of the
outer IPv4 header. The contents of the header are not authenticated outer IPv4 header. The contents of the header are not authenticated
and there is no way for the home agent to verify their validity. and there is no way for the home agent to verify their validity.
Hence, a man in the middle attack where a change in the contents of Hence, a man in the middle attack where a change in the contents of
the IPv4 header can cause a legitimate mobile node's traffic to be the IPv4 header can cause a legitimate mobile node's traffic to be
diverted to an illegitimate receiver independently of the diverted to an illegitimate receiver independently of the
authenticity of the binding update message. authenticity of the binding update message.
In this specification, the binding update message MUST be protected In this specification, the binding update message MUST be protected
using ESP transport mode. When the mobile node is located in an IPv4- using ESP transport mode. When the mobile node is located in an
only network, the binding update message is encapsulated in UDP as IPv4- only network, the binding update message is encapsulated in UDP
described earlier. However, UDP MUST NOT be used to encapsulate the as described earlier. However, UDP MUST NOT be used to encapsulate
binding update message when the mobile node is located in an IPv6- the binding update message when the mobile node is located in an
enabled network. If protection of payload traffic is needed when the IPv6- enabled network. If protection of payload traffic is needed
mobile node is located in an IPv4-only network, encapsulation is done when the mobile node is located in an IPv4-only network,
using tunnel mode ESP over port 4500 as described in [TUNSEC]. When encapsulation is done using tunnel mode ESP over port 4500 as
negotiating the security association with the home agent, while described in [RFC3948]. During the IKE negotiation with the home
located in an IPv4-only network, if the mobile node and home agent agent, if the mobile node and home agent support the use of port
support the use of port 4500, the mobile node MUST establish the 4500, the mobile node MUST establish the security association over
security association over port 4500, regardless of the presence of a port 4500, regardless of the presence of a NAT. This is done to
NAT. This is done to avoid the switching between ports 500 and 4500 avoid the switching between ports 500 and 4500 and the potential
and the potential traffic disruption resulting from this switch. traffic disruption resulting from this switch.
When located in an IPv4-only network, the mobile node MUST NOT
negotiate a security association that uses the following tunnel
formats: IPv4/IP(v4 or v6) and IPv4/ESP/IP(v4 or v6). These formats
will not work in the presence of a NAT. There is no restriction on
the tunnel format when the mobile node is located in an IPv6-enabled
network.
Handovers within private IPv4 networks or from IPv6 to IPv4 networks Handovers within private IPv4 networks or from IPv6 to IPv4 networks
will have impacts on the security association between the mobile node will have impacts on the security association between the mobile node
and the home agent. The following section presents the expected and the home agent. The following section presents the expected
behaviour of the mobile node and home agent in those situations. behaviour of the mobile node and home agent in those situations. The
details of the IKE negotiations and messages are illustrated in
Section 6.2
5.1 Handover interactions for IPsec and IKE 6.1. Handover Interactions for IPsec and IKE
After the mobile node detects movement it configures a new care-of After the mobile node detects movement it configures a new care-of
address. If the mobile node is in an IPv4-only network, it removes address. If the mobile node is in an IPv4-only network, it removes
binding update list entries for correspondent nodes since route binding update list entries for correspondent nodes since route
optimisation cannot be supported. This may cause inbound packet optimisation cannot be supported. This may cause inbound packet
losses as remote correspondent node are unaware of such movement. To losses as remote correspondent node are unaware of such movement. To
avoid confusion in the correspondent node, the mobile node SHOULD avoid confusion in the correspondent node, the mobile node SHOULD
deregister its binding with each correspondent node by sending a deregister its binding with each correspondent node by sending a
deregistration binding update. The deregistration binding update deregistration binding update. The deregistration binding update
message is tunnelled to the home agent and onto the correspondent message is tunnelled to the home agent and onto the correspondent
skipping to change at page 25, line 54 skipping to change at page 33, line 34
its new location as discussed below. its new location as discussed below.
The mobile node sends the binding update message to the home agent. The mobile node sends the binding update message to the home agent.
If the mobile node is in an IPv6-enabled network, the binding update If the mobile node is in an IPv6-enabled network, the binding update
is sent without IPv4/UDP encapsulation. If the mobile node is in an is sent without IPv4/UDP encapsulation. If the mobile node is in an
IPv4-only network, then after IPsec processing of the BU message, it IPv4-only network, then after IPsec processing of the BU message, it
encapsulates the BU in UDP/IPv4 as discussed in sections 4.2 and 4.4. encapsulates the BU in UDP/IPv4 as discussed in sections 4.2 and 4.4.
In order to be able to send the binding update while in an IPv4-only In order to be able to send the binding update while in an IPv4-only
network, the mobile node needs to use the new IPv4 care-of address in network, the mobile node needs to use the new IPv4 care-of address in
the outer header, which is different from the care-of address used in the outer header, which is different from the care-of address used in
the existing tunnel. This should be done without permanently updating the existing tunnel. This should be done without permanently
the tunnel within the mobile node's implementation in order to allow updating the tunnel within the mobile node's implementation in order
the mobile node to receive packets on the old care-of address until to allow the mobile node to receive packets on the old care-of
the binding acknowledgement is received. The method used to achieve address until the binding acknowledgement is received. The method
this effect is implementation dependent and is outside the scope of used to achieve this effect is implementation dependent and is
this specification. This implies that the IP forwarding function outside the scope of this specification. This implies that the IP
(which selects the interface or tunnel through which a packet is forwarding function (which selects the interface or tunnel through
sent) is not based solely on the destination address: some IPv6 which a packet is sent) is not based solely on the destination
packets destined to the home agent are sent via the existing tunnel, address: some IPv6 packets destined to the home agent are sent via
while BUs are sent using the new care-of address. Since BUs are the existing tunnel, while BUs are sent using the new care-of
protected by IPsec, the forwarding function cannot necessarily address. Since BUs are protected by IPsec, the forwarding function
determine the correct treatment from the packet headers. Thus, the cannot necessarily determine the correct treatment from the packet
DSMIPv6 implementation has to attach additional information to BUs, headers. Thus, the DSMIPv6 implementation has to attach additional
and this information has to be preserved after IPsec processing and information to BUs, and this information has to be preserved after
made available to the forwarding function, or additional DSMIP IPsec processing and made available to the forwarding function, or
processing added to the forwarding function. Depending on the mobile additional DSMIP processing added to the forwarding function.
node's implementation, meeting this requirement may require changes Depending on the mobile node's implementation, meeting this
to the IPsec implementation. requirement may require changes to the IPsec implementation.
Upon receiving the binding update message encapsulated in UDP/IPv4, Upon receiving the binding update message encapsulated in UDP/IPv4,
the home agent processes it as follows. In order to allow the DSMIPv6 the home agent processes it as follows. In order to allow the
implementation in the home agent to detect the presence of a NAT on DSMIPv6 implementation in the home agent to detect the presence of a
the path to the mobile node, it needs to compare the outer IPv4 NAT on the path to the mobile node, it needs to compare the outer
source address with the IPv4 address in the IPv4 care-of address IPv4 source address with the IPv4 address in the IPv4 care-of address
option. This implies that the information in the outer header will be option. This implies that the information in the outer header will
preserved after IPsec processing and made available to the DSMIPv6 be preserved after IPsec processing and made available to the DSMIPv6
implementation in the home agent. Depending on the home agent's implementation in the home agent. Depending on the home agent's
implementation, meeting this requirement may require changes to the implementation, meeting this requirement may require changes to the
IPsec implementation. IPsec implementation.
The home agent updates its tunnel mode security association to The home agent updates its tunnel mode security association to
include the mobile node's care-of address as the remote tunnel header include the mobile node's care-of address as the remote tunnel header
address, and 4500 as the port number. If the mobile node were located address, and 4500 as the port number. The IPv4 address and port
in a private IPv4 network the address and port number are likely to number are likely to be wrong; the mobile node provides the correct
be wrong as the NAT would likely allocate a different address and information in a separate exchange as described below. When the
port number to traffic encapsulated in IPsec tunnels or to IKE mobile node is located in a private IPv4 network (which is detected
messages; the mobile node provides the correct information in a as described above), the new address and port number are allocated by
separate exchange as described below. When the mobile node is located the NAT. The home agent will also enable or disable UDP
in a private IPv4 network (which is detected as described above), the encapsulation for outgoing ESP packets for the purpose of NAT
new address and port number are allocated by the NAT. The home agent traversal.
will also enable or disable UDP encapsulation for outgoing ESP
packets for the purpose of NAT traversal.
If the Key Management Mobility Capability (K) bit was set in the If the Key Management Mobility Capability (K) bit was set in the
binding update, and the home agent supports this feature, the home binding update, and the home agent supports this feature, the home
agent updates its IKE security associations to include the mobile agent updates its IKE security associations to include the mobile
node's care-of address as the peer address and 4500 as the port node's care-of address as the peer address and 4500 as the port
number. The home agent may also need to change NAT traversal fields number. The home agent may also need to change NAT traversal fields
in the IKE_SA to enable the dyanmic update of the IP address and port in the IKE_SA to enable the dyanmic update of the IP address and port
number based on the reception of authenticated IKE messages, or number based on the reception of authenticated IKE messages, or
authenticated packets using tunnel mode ESP. The dynamic updates are authenticated packets using tunnel mode ESP. The dynamic updates are
described in section 2.23 of RFC 4306. As described above, when the described in section 2.23 of RFC 4306. As described above, when the
mobile node is located in a private IPv4 network, the address and mobile node is located in a private IPv4 network, the address and
port number used for IPsec and IKE traffic is not yet known by the port number used for IPsec and IKE traffic is not yet known by the
home agent at this point. home agent at this point.
The mobile node updates the IKE SA in one of two ways. If the K flag The mobile node updates the IKE SA in one of two ways. If the K flag
was set in the binding acknowledgement message, the mobile node was set in the binding acknowledgement message, the mobile node
SHOULD send an empty informational message, which results in the IKE SHOULD send an empty informational message, which results in the IKE
module in the home agent to dynamically update the SA information. module in the home agent to dynamically update the SA information.
The IKE implementation in the home agent is REQUIRED to support this The IKE implementation in the home agent is REQUIRED to support this
feature. Alternatively, the IKE SA should be re-negotiated. Note that feature. Alternatively, the IKE SA should be re-negotiated. Note
updating the IKE SA MUST take place after the mobile node has sent that updating the IKE SA MUST take place after the mobile node has
the binding update and received the acknowledgement from the home sent the binding update and received the acknowledgement from the
agent. home agent.
It is important to note that if the mobile node is located behind a It is important to note that the mobile node's IPv4 care-of address
NAT, its IPv4 care-of address seen by the DSMIPv6 module in the home seen by the DSMIPv6 module in the home agent upon receiving the
agent upon receiving the binding update will differ from the IPv4 binding update may differ from the IPv4 care-of address seen by the
care-of address seen by the IKE module and the care-of address used IKE module and the care-of address used for forwarding IPsec tunnel
for forwarding IPsec tunnel mode traffic. This is due to the fact mode traffic. Hence, it is probable that different modules in the
that the NAT will probably allocate a different IP address and port home agent will have a different care-of address that should be used
number to each traffic stream. Hence, it is probable that different for encapsulating traffic to the mobile node.
modules in the home agent will have a different care-of address that
should be used for encapsulating traffic to the mobile node.
After successfully processing the binding update, the home agent After successfully processing the binding update, the home agent
sends the binding acknowledgement to the mobile node's care-of sends the binding acknowledgement to the mobile node's care-of
address as received in the outer header of the packet containing the address as received in the outer header of the packet containing the
binding update. Note that if the BU was rejected, the BAck is sent to binding update. Note that if the BU was rejected, the BAck is sent
the same address where the BU was received from. This may require to the same address where the BU was received from. This may require
special treatment in IP forwarding and/or IPsec processing which special treatment in IP forwarding and/or IPsec processing which
resembles sending of BUs in the mobile node (described above). resembles sending of BUs in the mobile node (described above).
Upon receiving the binding acknowledgement the mobile node updates Upon receiving the binding acknowledgement the mobile node updates
its local tunnel mode Security Association information to include the its local tunnel mode Security Association information to include the
tunnel header IP source address, which is the the home agent's tunnel header IP source address, which is the the home agent's
address and the tunnel header IP destination, which is the mobile address and the tunnel header IP destination, which is the mobile
node's care-of address. The mobile node may also need to enable or node's care-of address. The mobile node may also need to enable or
disable UDP encapsulation for outgoing ESP packets for the purpose disable UDP encapsulation for outgoing ESP packets for the purpose of
of NAT traversal and the sending of keep alives. NAT traversal and the sending of keep alives.
The mobile node MAY use [MOBIKE] to update its IKE SA with the home The mobile node MAY use [RFC4555] to update its IKE SA with the home
agent. Using MOBIKE requires negotiating this capability with the agent. Using MOBIKE requires negotiating this capability with the
home agent when establishing the SA. In this case, the mobile node home agent when establishing the SA. In this case, the mobile node
and the home agent MUST NOT update their IPsec SAs locally as this and the home agent MUST NOT update their IPsec SAs locally as this
step is performed by MOBIKE. Furthermore, the use of MOBIKE allows step is performed by MOBIKE. Furthermore, the use of MOBIKE allows
the mobile node to update the SA independently of the binding update the mobile node to update the SA independently of the binding update
exchange. Hence, there is no need for the mobile node to wait for a exchange. Hence, there is no need for the mobile node to wait for a
binding acknowledgement before performing MOBIKE. The use of MOBIKE binding acknowledgement before performing MOBIKE. The use of MOBIKE
is OPTIONAL in this specification. is OPTIONAL in this specification.
6. Protocol constants 6.2. IKE negotiation messages between the mobile node and Home Agent
This specification defines a number of possible data encapsulation
formats depending on the mobile node's connectivity to the visited
network. When connected to an IPv6-enabled network, the tunnelling
formats are clear. However, when connected to an IPv4-only network,
care should be taken when negotiationg the IKE association and the
consequential tunnelling formats used for secure and insecure
traffic. This section illustrates the IKE message exchange between
the mobile node and home agent when the mobile node is located in an
IPv4-only network. Two different IKE negotiations are considered:
o IKEv2 operation for securing DSMIPv6 Signaling.
o IKEv2 operation for securing Data over IPv4
6.2.1. IKEv2 Operation for Securing DSMIPv6 Signaling
A mobile node connected to an IPv4-only network SHOULD follow the
procedures described below in order to establish an SA for the
protection of binding update and binding acknowledgement messages.
Mobile Node Home Agent
----------- ----------
IPv4(source_addr=V4ADDR, dest_addr=HAADDR)
UDP (500, 500) HDR, SAi1, KEi, Ni
NAT-D, NAT-D -->
<- IPv4(source_addr=HAADDR, dest_addr=V4ADDR)
UDP(500,X) HDR, SAr1, KEr, Nr, [CERTREQ]
NAT-D, NAT-D
IPv4(source_addr=V4ADDR, dest_addr=HAADDR)
UDP (4500,4500) <non-ESP Marker > HDR, SK
{IDi, [CERT,] [CERTREQ,] [IDr,] AUTH, N(USE_TRANSPORT_MODE),
SAi2, TSi, TSr}
-->
<-- IPv4(source_addr=HAADDR, dest_addr=V4ADDR)
UDP (4500,Y) <non-ESP Marker > HDR, SK
{IDr, [CERT,] AUTH, N(USE_TRANSPORT_MODE),
SAr2, TSi, TSr}
The corresponding SPD entries are shown below.
Mobile node SPD-S:
IF local_address = home_address_1 &
remote_address = home_agent_1 &
proto = MH & local_mh_type = BU & remote_mh_type = BAck Then use
SA ESP transport mode
Initiate using IDi = user_1 to address home_agent_1
Home Agent SPD-S:
F local_address = home_agent_1 &
remote_address = home_address_1 &
proto = MH & local_mh_type = BAck & remote_mh_type = BU Then use
SA ESP transport mode
where home_address_1 is the mobile node's registered IPv6 home
address and home_agent_1 is the IP address of the home agent
The above should result in BU/BA messages with the following BU
received by the home agent.
Pv4 header (src=V4ADDR, dst=HA_V4ADDR)
UDP header (sport=Z, dport=DSMIPv6)
IPv6 header (src=V6HOA, dst=HAADDR)
ESP Header in Transport Mode
Mobility header
BU [IPv4 HAO]
IPv4 CoA option
(+ other as needed)
At the home agent, following UDP de-capsulation, the binding update
is delivered to the IPsec module as shown below:
IPv6 header (src=V6HOA, dst=HAADDR)
ESP Header in Transport Mode
Mobility header
BU [IPv4 HAO]
IPv4 CoA option
(+other as needed)
In addition, V4ADDR and the sport (Z) need to be passed with the
packet to ensure correct processing.
Following IPsec processing, the binding update is delivered to the
DSMIPv6 home agent module as follows:
IPv6 header (src=V6HOA, dst=HAADDR)
Mobility Header
BU [IPv4 HAO]
IPv4 CoA option
(+other as needed)
In addition, V4ADDR and the sport (Z) need to be passed with the
packet to ensure correct processing.
The binding acknowledgement sent by the home agent module to the
IPsec module is as follows:
IPv6 header (src=HAADDR, dst=V6HOA)
Mobility Header
BA ([IPv4 ACK], NAT DET)
(+ other as needed)
In addition, V4ADDR, the sport from the BU (Z), and aindication that
vanilla UDP encapsulation must be used, need to be passed with the
packet to ensure correct processing.
The binding acknowledgement sent by the home agent to the mobile node
is as follows:
IPv4 header (src= HA_V4ADDR, dst=V4ADDR)
UDP Header (sport=DSMIPv6, dport=Z)
IPv6 header (src=HAADDR, dst=V6HOA)
ESP Header in Transport Mode
Mobility Header
BA ([IPv4 ACK], NAT DET)
6.2.2. IKEv2 Operation for Securing Data over IPv4
To secure data traffic when the mobile node is located in an IPv4-
only network, the mobile node MUST establish a child_SA for that
purpose. The procedure is as follows:
Mobile Node Home Agent
----------- ----------
IPv4(source_addr=V4ADDR, dest_addr=HAADDR)
UDP (4500,4500) < non-ESP Marker > HDR, SK
{[N], SA, Ni, [KEi], TSi, TSr} -->
<--IPv4(source_addr=HAADDR, dest_addr=V4ADDR)
UDP (4500,Y) < non-ESP Marker > HDR, SK
SA, Nr, [KEr], TSi, TSr}
If no NAT is detected, the encapsulation used will be:
IPv4 (source_addr=v4CoA, dest_addr=HAAddr)
ESP
IP (source_addr=HoA, set_addr=CNAddr)
Upper_layer_HDR
where IP=IPv4 or IPv6 and HoA=v4HoA or v6HoA
If a NAT were detected, the encapsulation used will be:
IPv4 (source_addr=v4Addr, dest_addr=HAAddr)
UDP (sport=Y, dport=4500)
ESP
IP (source_addr=HoA, set_addr=CNAddr)
Upper_layer_HDR
Where v4CoA may be the external IPv4 address of the NAT, IP is either
IPv4 or IPv6 header and HoA is either the IPv4 or the IPv6 HoA. The
above format shows the packet as seen by the home agent.
The SPD, whether a NAT were detected or not, is set as follows. Note
that this rule is designed to match all data from the MN to nodes
other than the home agent. This is done so that this rule does not
overlap with the earlier rule securing BU/BA signaling between the MN
and the HA.
Mobile Node SPD-S:
IF local_address = home_address &
remote_address != home_agent &
proto=any, then use SA ESP tunnel mode
Initiate using IDi = user_1 to address home_agent_1
home agent SPD-S:
IF local_address != home_agent &
remote_address = home_address &
proto=any, then use SA ESP tunnel mode
Where home_address is the MN's registered IPv6 or IPv4 home address
and home_agent is the IPv6 or the IPv4 address of the home agent.
7. Protocol Constants
NATKATIMEOUT 110 seconds NATKATIMEOUT 110 seconds
7. Acknowledgements 8. Acknowledgements
Thanks to the following members (in alphabetical order) of the MIP6 Thanks to the following members (in alphabetical order) of the MIP6
and NEMO Working Groups for their contributions, discussion, and and NEMO Working Groups for their contributions, discussion, and
review: Jari Arkko, Sri Gundavelli, Wassim Haddad, Conny Larsson, review: Jari Arkko, Sri Gundavelli, Wassim Haddad, Conny Larsson,
Acee Lindem, Ahmad Muhanna, Vidya Narayanan, Karen Nielsen and Acee Lindem, Ahmad Muhanna, Vidya Narayanan, Karen Nielsen and
Keiichi Shima. Thanks to Karen Nielsen, Pasi Eronen and Christian Keiichi Shima. Thanks to Karen Nielsen, Pasi Eronen and Christian
Kaas-Petersen for raising the issue of IKEv2 interactions and Kaas-Petersen for raising the issue of IKEv2 interactions and
proposing the solution included in this document. proposing the solution included in this document.
8. IANA considerations 9. IANA Considerations
The specification requires the following allocations from IANA: The specification requires the following allocations from IANA:
- A UDP port is needed for the NAT traversal mechanism described in
A UDP port is needed for the NAT traversal mechanism described in
section 4.1. section 4.1.
- The IPv4 home address option described in section 3.1.1 requires an
option type. This option is included in the Mobility header The IPv4 home address option described in section 3.1.1 requires
described in [MIPv6].
- The IPv4 address acknowledgement option described in section 3.2.1
requires a new option type. This option is included in the Mobility
header described in [MIPv6].
- The NAT detection option described in section 3.2.2 requires a new
option type. This option is included in the Mobility header
described in [MIPv6].
- The IPv4 Care-of address option described in section 3.1.2 requires
an option type. This option is included in the Mobility header an option type. This option is included in the Mobility header
described in [MIPv6]. described in [RFC3775].
The IPv4 address acknowledgement option described in section 3.2.1
requires a new option type. This option is included in the
Mobility header described in [RFC3775].
The NAT detection option described in section 3.2.2 requires a new
option type. This option is included in the Mobility header
described in [RFC3775].
The IPv4 Care-of address option described in section 3.1.2
requires an option type. This option is included in the Mobility
header described in [RFC3775].
This specification introduces a new TLV-header to be used with UDP This specification introduces a new TLV-header to be used with UDP
encapsulation. The Types of the TLV-header should be allocated by encapsulation. The Types of the TLV-header should be allocated by
IANA under a new registry: "DSMIPv6 TLV-header Types". IANA under a new registry: "DSMIPv6 TLV-header Types".
The Status field in the IPv4 home address option should be allocated The Status field in the IPv4 home address option should be allocated
by IANA under the new registry: "DSMIPv6 IPv4 home address option by IANA under the new registry: "DSMIPv6 IPv4 home address option
status codes". status codes".
The TLV-header types and status field values are allocated using the The TLV-header types and status field values are allocated using the
following procedure: following procedure:
1. The IANA should allocate and permanently register new TLV-header 1. The IANA should allocate and permanently register new TLV-header
types and Status field values from IETF RFC publication. This is for types and Status field values from IETF RFC publication. This is
all RFC types including standards track, informational, and for all RFC types including standards track, informational, and
experimental status that originate from the IETF and have been experimental status that originate from the IETF and have been
approved by the IESG for approved by the IESG for publication.
publication.
2. Requests for new option type value assignments from outside the 2. Requests for new option type value assignments from outside the
IETF are only made through the publication of an IETF document, per IETF are only made through the publication of an IETF document,
1) above. Note also that documents published as "RFC Editor per 1) above. Note also that documents published as "RFC Editor
contributions" [RFC3667] are not considered to be IETF documents. contributions" [RFC3667] are not considered to be IETF documents.
9. References 10. References
NORMATIVE 10.1. Normative References
[DNAv4] Aboba, B., Carlsson, J., and S. Cheshire, "Detecting Network [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Attachment for IPv4 (DNAv4)", RFC 4436, March 2006. Requirement Levels", BCP 14, RFC 2119, March 1997.
[MIPv6] D. Johnson, Perkins, C. and J. Arkko, "Mobility Support in [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
IPv6", RFC 3775, June 2004. Listener Discovery (MLD) for IPv6", RFC 2710,
October 1999.
[NEMO] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
"Network Mobility (NEMO) Basic Support protocol", RFC 3963, in IPv6", RFC 3775, June 2004.
January 2005.
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate [RFC3948] Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and M.
Requirement Levels", BCP 14, RFC 2119, March 1997. Stenberg, "UDP Encapsulation of IPsec ESP Packets",
RFC 3948, January 2005.
[TUNSEC] Huttunen, A., Swander, B., Volpe, V., DiBurro, L. and M. [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
Stenberg, "UDP Encapsulation for IPsec ESP Packets", RFC Thubert, "Network Mobility (NEMO) Basic Support Protocol",
3948, January 2005. RFC 3963, January 2005.
INFORMATIVE [RFC4436] Aboba, B., Carlson, J., and S. Cheshire, "Detecting
Network Attachment in IPv4 (DNAv4)", RFC 4436, March 2006.
[BOOT] Giaretta, G. (Ed.), Kempf J., and V. Devarapalli, " Mobile [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
IPv6 bootstrapping in split scenario", RFC 5026, October 2007. "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[HMIPv6] Soliman, H., Castelluccia, C., ElMalki, K., and L. Bellier, 10.2. Informative
"Hierarchical Mobile IPv6 Mobility Management (HMIPv6)",
Draftietf-mipshop-4140bis-04 November 2007.
[INTBOOT] K. Chowdhury and A. Yegin, "MIP6-bootstrapping for the [RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
Integrated Scenario", draft-ietf-mip6-bootstrapping- of Explicit Congestion Notification (ECN) to IP",
integrated-dhc-02, Work in Progress. RFC 3168, September 2001.
[MIP-PB] Tsirtsis, G., and H. Soliman, "Mobility management for [RFC3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344,
Dual stack mobile nodes, A Problem Statement", August 2002.
RFC 4977, August 2007.
[MIPv4] C. Perkins, "Mobility Support for IPv4", RFC3344 [RFC3519] Levkowetz, H. and S. Vaarala, "Mobile IP Traversal of
Network Address Translation (NAT) Devices", RFC 3519,
May 2003.
[MOBIKE] P. Eronen,"IKEv2 Mobility and Multihoming Protocol (MOBIKE)" [RFC3667] Bradner, S., "IETF Rights in Contributions", RFC 3667,
, RFC 4555, June 2006. February 2004.
[SNRIO] Larsson, T., Gustafsson, E., and H. Levkowetz, "Use of MIPv6 [RFC4140] Soliman, H., Castelluccia, C., El Malki, K., and L.
in IPv4 and MIPv4 in IPv6 networks", draft-larsson-v6ops- Bellier, "Hierarchical Mobile IPv6 Mobility Management
mip-scenarios-01.txt, February 2004. (HMIPv6)", RFC 4140, August 2005.
[TRAV] H. Levkowetz and S. Vaarala, "Mobile IP Traversal for Network [RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
Address Translation (NAT) Devices", RFC 3519, April 2003. for IPv6 Hosts and Routers", RFC 4213, October 2005.
10. Contributors [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC4459] Savola, P., "MTU and Fragmentation Issues with In-the-
Network Tunneling", RFC 4459, April 2006.
[RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol
(MOBIKE)", RFC 4555, June 2006.
[RFC4977] Tsirtsis, G. and H. Soliman, "Problem Statement: Dual
Stack Mobility", RFC 4977, August 2007.
[RFC5026] Giaretta, G., Kempf, J., and V. Devarapalli, "Mobile IPv6
Bootstrapping in Split Scenario", RFC 5026, October 2007.
Appendix A. Contributors
This document reflects discussions and contributions from several This document reflects discussions and contributions from several
people including (in alphabetical order): people including (in alphabetical order):
Vijay Devarapalli Vijay Devarapalli: vijay.devarapalli@azairenet.com
E-mail: vijay.devarapalli@azairenet.com
James Kempf James Kempf: kempf@docomolabs-usa.com
E-mail: kempf@docomolabs-usa.com
Henrik Levkowetz Henrik Levkowetz: henrik@levkowetz.com
E-mail: henrik@levkowetz.com
Pascal Thubert Pascal Thubert: pthubert@cisco.com
E-mail: pthubert@cisco.com
George Tsirtsis George Tsirtsis: G.Tsirtsis@Qualcomm.com
E-mail1: G.Tsirtsis@Qualcomm.com
E-mail2: tsirtsisg@yahoo.com
Wakikawa Ryuji Wakikawa Ryuji: ryuji@sfc.wide.ad.jp
ryuji@sfc.wide.ad.jp
Author's Address Author's Address
Hesham Soliman Hesham Soliman (editor)
Elevate Technologies Elevate Technologies
E-mail: Hesham@elevatemobile.com
Intellectual Property Statement Email: hesham@elevatemobile.com
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
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skipping to change at page 31, line 10 skipping to change at line 1875
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The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
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this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
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Full Copyright Statement
Copyright (C) The IETF Trust (2008). This document is subject to the
rights, licenses and restrictions contained in BCP 78, and except as
set forth therein, the authors retain all their rights.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
This Internet-Draft expires August, 2008.
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