draft-ietf-mip6-bootstrap-ps-03.txt   draft-ietf-mip6-bootstrap-ps-04.txt 
MIP6 A. Patel, Editor MIP6 A. Patel, Ed.
Internet-Draft Cisco Internet-Draft Cisco
Expires: January 15, 2006 July 14, 2005 Expires: July 6, 2006 G. Giaretta, Ed.
TILAB
January 2, 2006
Problem Statement for bootstrapping Mobile IPv6 Problem Statement for bootstrapping Mobile IPv6
draft-ietf-mip6-bootstrap-ps-03 draft-ietf-mip6-bootstrap-ps-04
Status of this Memo Status of this Memo
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This Internet-Draft will expire on January 15, 2006. This Internet-Draft will expire on July 6, 2006.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2006).
Abstract Abstract
A mobile node needs at least the following information: a home A mobile node needs at least the following information: a home
address, home agent address and a security association with home address, home agent address and a security association with home
agent to register with the home agent. The process of obtaining this agent to register with the home agent. The process of obtaining this
information is called bootstrapping. This document discuss the information is called bootstrapping. This document discuss the
issues involved with how the mobile node can be bootstrapped for issues involved with how the mobile node can be bootstrapped for
Mobile IPv6 and various potential deployment scenarios for Mobile IPv6 and various potential deployment scenarios for mobile
bootstrapping the mobile node. node bootstrapping.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Overview of the Problem . . . . . . . . . . . . . . . . . 3 1.1. Overview of the Problem . . . . . . . . . . . . . . . . . 3
1.2 What is Bootstrapping? . . . . . . . . . . . . . . . . . . 4 1.2. What is Bootstrapping? . . . . . . . . . . . . . . . . . . 4
1.3 Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 7 2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Design Goals . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. Design Goals . . . . . . . . . . . . . . . . . . . . . . . . . 8
4. Non-Goals . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4. Non-Goals . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5. Motivation for bootstrapping . . . . . . . . . . . . . . . . . 10 5. Motivation for bootstrapping . . . . . . . . . . . . . . . . . 10
5.1 Addressing . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1. Addressing . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1.1 Dynamic Home Address Assignment . . . . . . . . . . . 10 5.1.1. Dynamic Home Address Assignment . . . . . . . . . . . 10
5.1.2 Dynamic Home Agent Assignment . . . . . . . . . . . . 11 5.1.2. Dynamic Home Agent Assignment . . . . . . . . . . . . 11
5.1.3 Management requirements . . . . . . . . . . . . . . . 12 5.1.3. Management requirements . . . . . . . . . . . . . . . 12
5.2 Security Infrastructure . . . . . . . . . . . . . . . . . 13 5.2. Security Infrastructure . . . . . . . . . . . . . . . . . 12
5.2.1 Integration with AAA Infrastructure . . . . . . . . . 13 5.2.1. Integration with AAA Infrastructure . . . . . . . . . 12
5.2.2 "Opportunistic" or "Local" Discovery . . . . . . . . . 13 5.2.2. "Opportunistic" or "Local" Discovery . . . . . . . . . 13
5.3 Topology Change . . . . . . . . . . . . . . . . . . . . . 13 5.3. Topology Change . . . . . . . . . . . . . . . . . . . . . 13
5.3.1 Dormant Mode Mobile Nodes . . . . . . . . . . . . . . 13 5.3.1. Dormant Mode Mobile Nodes . . . . . . . . . . . . . . 13
6. Network Access and Mobility services . . . . . . . . . . . . . 15 6. Network Access and Mobility services . . . . . . . . . . . . . 14
7. Deployment scenarios . . . . . . . . . . . . . . . . . . . . . 17 7. Deployment scenarios . . . . . . . . . . . . . . . . . . . . . 16
7.1 Mobility Service Subscription Scenario . . . . . . . . . . 17 7.1. Mobility Service Subscription Scenario . . . . . . . . . . 16
7.2 Integrated ASP network scenario . . . . . . . . . . . . . 17 7.2. Integrated ASP network scenario . . . . . . . . . . . . . 16
7.3 Third party MSP scenario . . . . . . . . . . . . . . . . . 18 7.3. Third party MSP scenario . . . . . . . . . . . . . . . . . 17
7.4 Infrastructure-less scenario . . . . . . . . . . . . . . . 19 7.4. Infrastructure-less scenario . . . . . . . . . . . . . . . 18
8. Parameters for authentication . . . . . . . . . . . . . . . . 20 8. Parameters for authentication . . . . . . . . . . . . . . . . 19
9. Security Considerations . . . . . . . . . . . . . . . . . . . 22 9. Security Considerations . . . . . . . . . . . . . . . . . . . 21
9.1 Security Requirements of Mobile IPv6 . . . . . . . . . . . 22 9.1. Security Requirements of Mobile IPv6 . . . . . . . . . . . 21
9.2 Threats to the Bootstrapping Process . . . . . . . . . . . 23 9.2. Threats to the Bootstrapping Process . . . . . . . . . . . 22
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . 25 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 26 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 25
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 27 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26
13. IPR Disclosure Acknowledgement . . . . . . . . . . . . . . . 28 13. IPR Disclosure Acknowledgement . . . . . . . . . . . . . . . . 27
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 14. Informative References . . . . . . . . . . . . . . . . . . . . 27
14.1 Normative References . . . . . . . . . . . . . . . . . . . 29 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29
14.2 Informative References . . . . . . . . . . . . . . . . . . 29 Intellectual Property and Copyright Statements . . . . . . . . . . 30
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 30
Intellectual Property and Copyright Statements . . . . . . . . 31
1. Introduction 1. Introduction
Mobile IPv6 [RFC3775] specifies mobility support based on the Mobile IPv6 [RFC3775] specifies mobility support based on the
assumption that a mobile node has a trust relationship with an entity assumption that a mobile node has a trust relationship with an entity
called the home agent. Once the home agent address has been learned called the home agent. Once the home agent address has been learned
for example via manual configuration, via anycast discovery (for example via manual configuration, anycast discovery mechanisms,
mechanisms, via DNS lookup; Mobile IPv6 signaling messages between or DNS lookup), Mobile IPv6 signaling messages between the mobile
the mobile node and the home agent are secured with IPsec or node and the home agent are secured with IPsec or with the
authentication protocol [I-D.ietf-mip6-mn-auth-protocol-02]. The authentication protocol as defined in [RFC4285]. The requirements
requirements for this security architecture are created with for this security architecture are created with [RFC3775] and the
[RFC3775] and the details of this procedure are described in details of this procedure are described in [RFC3776].
[RFC3776].
In [RFC3775] there is an implicit requirement that the MN be In [RFC3775] there is an implicit requirement that the MN be
provisioned with enough information that will permit it to register provisioned with enough information that will permit it to register
successfully with its home agent. However, having this information successfully with its home agent. However, having this information
statically provisioned creates practical deployment issues. statically provisioned creates practical deployment issues.
This document serves to define the problem of bootstrapping. This document serves to define the problem of bootstrapping.
Bootstrapping is defined as the process of the mobile node obtaining Bootstrapping is defined as the process of obtaining enough
enough information, so that it can successfully register with an information at the mobile node so that it can successfully register
appropriate home agent. with an appropriate home agent.
The requirements for bootstrapping could consider various scenarios/ The requirements for bootstrapping could consider various scenarios/
network deployment issues. It is the basic assumption of this network deployment issues. It is the basic assumption of this
document that certain minimal parameters (seed information) is document that certain minimal parameters (seed information) are
available to the mobile node to aid in bootstrapping. The exact seed available to the mobile node to aid in bootstrapping. The exact seed
information available differs depending on the deployment scenario. information available differs depending on the deployment scenario.
This document defines/describes various deployment scenarios and This document describes various deployment scenarios and provides for
provides for a set of minimal parameters that are available in each a set of minimal parameters that are available in each deployment
deployment scenario. scenario.
This document stops short of suggesting the various solutions to This document stops short of suggesting the preferred solutions for
obtaining information on the mobile node. Such details will be how the mobile node should obtain information. Such details will be
available from separate documents. available from separate documents.
1.1 Overview of the Problem 1.1. Overview of the Problem
Mobile IPv6 [RFC3775] expects the mobile node to have a static home Mobile IPv6 [RFC3775] expects the mobile node to have a static home
address, home agent address (or anycast address and do dynamic home address, home agent address (which can be derived from an anycast
agent discovery of Home Agent using ICMP messages) and a security address) and a security association with a home agent (or multiple
association with a home agent (multiple home agents on the home home agents).
network if dynamic home agent discovery is in use and multiple home
agents are deployed.)
This static provisioning of information has various problems as This static provisioning of information has various problems as
discussed in Section 5. discussed in Section 5.
The aim of this draft is to: The aim of this draft is to:
o Define bootstrapping. o Define bootstrapping.
o Identify sample deployment scenarios where MIPv6 will be deployed, o Identify sample deployment scenarios where MIPv6 will be deployed,
taking into account the relationship between the subscriber and taking into account the relationship between the subscriber and
the service provider. the service provider.
o Identify the minimal set of information required on the Mobile o Identify the minimal set of information required on the Mobile
Node (and/or) in the network in order for the mobile node to Node and in the network in order for the mobile node to obtain
obtain address and security credentials, to register with the home address and security credentials, to register with the home agent.
agent.
1.2 What is Bootstrapping? 1.2. What is Bootstrapping?
Bootstrapping is defined as obtaining enough information at the Bootstrapping is defined as obtaining enough information at the
mobile node, so that the mobile node can successfully register with mobile node so that the mobile node can successfully register with an
an appropriate home agent. Specifically, this means obtaining the appropriate home agent. Specifically, this means obtaining the home
home agent address, home address and security credentials for the agent address and home address, and for the mobile node and home
mobile node and home agent to authenticate and mutually construct agent to authenticate and mutually construct security credentials for
security credentials for Mobile IPv6 without requiring Mobile IPv6.
preconfiguration.
Typically, bootstrapping happens when a mobile node does not have all Typically, bootstrapping happens when a mobile node does not have all
the information it needs to setup the Mobile IPv6 service. This the information it needs to setup the Mobile IPv6 service. This
includes, but is not limited to MN not having any information when it includes, but is not limited to, the mobile node (MN) not having any
boots up for the first time (out of the box), it does not retain any information when it boots up for the first time (out of the box), it
information during reboots, is instructed by the Home Agent (via some does not retain any information during reboots, etc.
form of signalling) to do so etc.
Also, in certain scenarios, after the MN bootstraps for the first Also, in certain scenarios, after the MN bootstraps for the first
time (out of the box), subsequent bootstrapping is implementation time (out of the box), subsequent bootstrapping is implementation-
dependent. For instance, the MN may bootstrap everytime it boots, dependent. For instance, the MN may bootstrap everytime it boots,
bootstrap everytime on prefix change, bootstrap periodically to bootstrap everytime on prefix change, bootstrap periodically to
anchor to an optimal (distance, load etc) HA, etc. anchor to an optimal (distance, load etc) HA, etc.
1.3 Terminology 1.3. Terminology
General mobility terminology can be found in [I-D.ietf-seamoby- General mobility terminology can be found in [RFC3753]. The
mobility]. The following additional terms are used here: following additional terms are used here:
Trust relationship Trust relationship
In the context of this draft, trust relationship means that two In the context of this draft, trust relationship means that two
parties in question, typically the user of the mobile host and the parties in question, typically the user of the mobile host and the
mobility or access service provider, have some sort of prior mobility or access service authorizer , have some sort of prior
contact in which the mobile host was provisioned with credentials. contact in which the mobile node was provisioned with credentials.
These credentials allow the mobile host to authenticate itself to These credentials allow the mobile node to authenticate itself to
the mobility or access service authorizer and to prove its the mobility or access service provider and to prove its
authorization to obtain service. authorization to obtain service.
Infrastructureless relationship Infrastructureless relationship
In the context of this draft, an infrastructureless relationship In the context of this draft, an infrastructureless relationship
is one in which the user of the mobile host and the mobility or is one in which the user of the mobile node and the mobility or
access service provider have no previous contact and the mobile access service provider have no previous contact and the mobile
host is not required to supply credentials to authenticate and node is not required to supply credentials to authenticate and
prove authorization for service. Mobility and/or network access prove authorization for service. Mobility and/or network access
service is provided without any authentication or authorization. service is provided without any authentication or authorization.
Infrastructureless in this context does not mean that there is no Infrastructureless in this context does not mean that there is no
network infrastructure, such as would be the case for an ad hoc network infrastructure, such as would be the case for an ad-hoc
network. network.
Credentials Credentials
Data or mechanism used by a mobile host to authenticate itself to Data used by a mobile node to authenticate itself to a mobility or
a mobility or access network service provider and prove access network service authorizer and prove authorization to
authorization to receive service. User name/passwords, one time receive service. User name/passwords, one time password cards,
password cards, public/private key pairs with certificates, public/private key pairs with certificates, biometric information,
biometric information, etc. are some examples. etc. are some examples.
ASA ASA
Access Service Authorizer. A network operator that authenticates Access Service Authorizer. A network operator that authenticates
a mobile host and establishes the mobile host's authorization to a mobile node and establishes the mobile node's authorization to
receive Internet service. receive Internet service.
ASP ASP
Access Service Provider. A network operator that provides direct Access Service Provider. A network operator that provides direct
IP packet forwarding to and from the end host. IP packet forwarding to and from the end host.
Serving Network Access Provider Serving Network Access Provider
A network operator that is the mobile host's ASP but not its ASA. A network operator that is the mobile node's ASP but not its ASA.
The serving network accesss provider may or may not additionally The serving network access provider may or may not additionally
provide mobility service. provide mobility service.
Home Network Access Provider Home Network Access Provider
A network operator that is both the mobile host's ASP and ASA.
A network operator that is both the mobile node's ASP and ASA.
The home network access provider may or may not additionally The home network access provider may or may not additionally
provide mobility service (note that this is a slighlty different provide mobility service (note that this is a slighlty different
definition from RFC 3775). definition from RFC 3775).
IASP IASP
Integrated Access Service Provider. A service provider that Integrated Access Service Provider. A service provider that
provides both authorization for network access and also provides provides both authorization for network access, and mobility
mobility service. service.
MSA MSA
Mobility Service Authorizer. A service provider that authorizes Mobility Service Authorizer. A service provider that authorizes
Mobile IPv6 service. Mobile IPv6 service.
MSP MSP
Mobility Service Provider. A service provider that provides Mobility Service Provider. A service provider that provides
Mobile IPv6 service. In order to obtain such service, the mobile Mobile IPv6 service. In order to obtain such service, the mobile
host must be authenticated and prove authorization to obtain the node must be authenticated and prove authorization to obtain the
service. service.
Home Mobility Service Provider Home Mobility Service Provider
A MSP that both provides mobility service and authorizes it. A MSP that both provides mobility service and authorizes it.
Serving Mobility Service Provider Serving Mobility Service Provider
A MSP that provides mobility service but depends on another A MSP that provides mobility service but depends on another
service provider to authorize it. service provider to authorize it.
2. Assumptions 2. Assumptions
o A basic assumption in the Mobile IPv6 RFC [RFC3775] is that there o A basic assumption in the Mobile IPv6 [RFC3775] is that there is a
is a trust relationship between the mobile node and MSP. This trust relationship between the mobile node and its home agent(s).
trust relationship can be direct, or indirect through, for This trust relationship can be direct, or indirect through, for
instance, an ASP that has a contract with the MSP. This trust instance, an ASP that has a contract with the MSP. This trust
relationship can be used to bootstrap the MN. relationship can be used to bootstrap the MN.
One typical way of verifying the trust relationship is using One typical way of verifying the trust relationship is using
authentication, authorization, and accounting (AAA). authentication, authorization, and accounting (AAA)
infrastructure. In this document, two distinct uses of AAA are infrastructure. In this document, two distinct uses of AAA are
considered: considered:
AAA for Network Access AAA for Network Access
This functionality provides authentication and authorization to This functionality provides authentication and authorization to
access the network (obtain address and send/receive packets). access the network (obtain address and send/receive packets).
AAA for Mobility Service AAA for Mobility Service
This functionality provides authentication and authorization This functionality provides authentication and authorization
for mobility services. for mobility services.
These functionalities may be implemented in a single entity or in These functionalities may be implemented in a single entity or in
different entities, depending on the service models described in different entities, depending on the service models described in
Section 6 or deployment scenarios as described in Section 7. Section 6 or deployment scenarios as described in Section 7.
o Yet another assumption is that some identifier, such as NAI, as o Yet another assumption is that some identifier, such as an NAI, as
defined in [I-D.ietf-mip6-mn-ident-option-02] or [RFC2794] is defined in [RFC4283] or [RFC2794] is provisioned on the MN which
provisioned on the MN which permits the MN to identify itself to permits the MN to identify itself to the ASP and MSP.
the ASP and ASP.
3. Design Goals 3. Design Goals
A solution to the bootstrapping problem has the following design A solution to the bootstrapping problem has the following design
goals: goals:
o The following information must be available at the end of o The following information must be available at the end of
bootstrapping, to enable the MN to register with the HA. bootstrapping, to enable the MN to register with the HA.
* MN's home agent address * MN's home agent address
* MN's home address * MN's home address
* IPsec SA between MN and HA, IKE pre-shared secret between MN * IPsec SA between MN and HA, IKE pre-shared secret between MN
and HA or shared secret/security association for authentication and HA, or shared secret/security association for
protocol [I-D.ietf-mip6-mn-auth-protocol-02] authentication protocol [RFC4285]
o The bootstrapping procedure can be triggered at any time, either o The bootstrapping procedure can be triggered at any time, either
by the MN or by the network. Bootstrapping can occur, for by the MN or by the network. Bootstrapping can occur, for
instance due to administrative action, information going stale, HA instance due to administrative action, information going stale, HA
indicating the MN etc. Bootstrapping may be initiated even when indicating the MN etc. Bootstrapping may be initiated even when
the MN is registered with the HA and has all the required the MN is registered with the HA and has all the required
credentials. This may typically happen to refresh/renew the credentials. This may typically happen to refresh/renew the
credentials. credentials.
o Subsequent protocol interaction (for example updating the IPsec o Subsequent protocol interaction (for example updating the IPsec
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bootstrapping. If the MN executes the bootstrap procedures bootstrapping. If the MN executes the bootstrap procedures
everytime it powers-on (as opposed to caching state information everytime it powers-on (as opposed to caching state information
from previous bootstrap process), then home network renumbering is from previous bootstrap process), then home network renumbering is
taken care of automatically. taken care of automatically.
o Bootstrapping in the absence of a trust relationship between MN o Bootstrapping in the absence of a trust relationship between MN
and any provider is not considered. and any provider is not considered.
5. Motivation for bootstrapping 5. Motivation for bootstrapping
5.1 Addressing 5.1. Addressing
The default bootstrapping described in the Mobile IPv6 base The default bootstrapping described in the Mobile IPv6 base
specification [RFC3775] has a tight binding to the home addresses and specification [RFC3775] has a tight binding to the home addresses and
home agent addresses. home agent addresses.
In this section, we discuss the problems caused by the currently In this section, we discuss the problems caused by the currently
tight binding to home addresses and home agent addresses. tight binding to home addresses and home agent addresses.
5.1.1 Dynamic Home Address Assignment 5.1.1. Dynamic Home Address Assignment
Currently, the home agent uses the mobile node's home address for Currently, the home agent uses the mobile node's home address for
authorization. When manual keying is used, this happens through the authorization. When manual keying is used, this happens through the
security policy database, which specifies that a certain security security policy database, which specifies that a certain security
association may only use a specific home address. When dynamic association may only be used for a specific home address. When
keying is used, the home agent ensures that the IKE Phase 1 identity dynamic keying is used, the home agent ensures that the IKE Phase 1
is authorized to request security associations for the given home identity is authorized to request security associations for the given
address. Mobile IPv6 uses IKEv1, which is unable to update the home address. Mobile IPv6 uses IKEv1, which is unable to update the
security policy database based on a dynamically assigned home security policy database based on a dynamically assigned home
address. As a result, static home address assignment is really the address. As a result, static home address assignment is really the
only home address configuration technique compatible with the current only home address configuration technique compatible with the base
specification. specification.
However, support for dynamic home address assignment would be However, support for dynamic home address assignment would be
desirable for the following reasons: desirable for the following reasons:
DHCP-based address assignment DHCP-based address assignment
Some ASPs may want to use DHCPv6 from the home network to Some providers may want to use DHCPv6 or other dynamic address
configure home addresses. assignment (e.g. IKEv2) from the home network to configure home
addresses.
Recovery from a duplicate address collision Recovery from a duplicate address collision
It may be necessary to recover from a collision of addresses on It may be necessary to recover from a collision of addresses on
the home network. the home network by one of the mobile nodes changing its home
address.
Addressing privacy Addressing privacy
It may be desirable to establish randomly generated addresses as It may be desirable to establish randomly generated addresses as
in RFC 3041 and use them for a short period of time. in [RFC3041] and use them for a short period of time.
Unfortunately, current protocols make it possible to use such Unfortunately, current protocols make it possible to use such
addresses only from the visited network. As a result, these addresses only from the visited network. As a result, these
addresses can not be used for communications lasting longer than addresses can not be used for communications lasting longer than
the attachment to a particular visited network. the attachment to a particular visited network.
Ease of deployment Ease of deployment
In order to simplify the deployment of Mobile IPv6, it is In order to simplify the deployment of Mobile IPv6, it is
desirable to free users and administrators from the task of desirable to free users and administrators from the task of
allocating home addresses and specifying them in the security allocating home addresses and specifying them in the security
policy database. policy database. This is consistent with the general IPv6 design
goal of using autoconfiguration wherever possible.
This is consistent with the general IPv6 design goal of using
autoconfiguration wherever possible.
Prefix changes in the home network Prefix changes in the home network
The Mobile IPv6 specification contains support for a mobile node The Mobile IPv6 specification contains support for a mobile node
to autoconfigure a home address based on its discovery of prefix to autoconfigure a home address based on its discovery of prefix
information on the home subnet [RFC3775]. Autoconfiguration in information on the home subnet [RFC3775]. Autoconfiguration in
case of network renumbering is done by replacing the existing case of network renumbering is done by replacing the existing
network prefix with the new network prefix. network prefix with the new network prefix.
Subsequently, the MN needs to update the mobility binding in the Subsequently, the MN needs to update the mobility binding in the
HA to register the newly configured Home Address. However, the MN HA to register the newly configured Home Address. However, the MN
may not be able to register the newly configured address with the may not be able to register the newly configured address with the
HA if a security association related to that reconfigured Home HA if a security association related to that reconfigured Home
Address does not exist in the MN and the HA. This situation is Address does not exist in the MN and the HA. This situation is
not handled in the current MIPv6 specification [RFC3775]. not handled in the current MIPv6 specification [RFC3775].
5.1.2 Dynamic Home Agent Assignment 5.1.2. Dynamic Home Agent Assignment
Currently, the address of the home agent is specified in the security Currently, the address of the home agent is specified in the security
policy database. Support for multiple home agents requires the policy database. Support for multiple home agents requires the
configuration of multiple security policy database entries. configuration of multiple security policy database entries.
However, support for dynamic home agent assignment would be desirable However, support for dynamic home agent assignment would be desirable
for the following reasons: for the following reasons:
Home agent discovery Home agent discovery
The Mobile IPv6 specification contains support for a mobile node The Mobile IPv6 specification contains support for a mobile node
to autoconfigure a home agent address based on a discovery to autoconfigure a home agent address based on a discovery
protocol [RFC3775]. protocol [RFC3775].
Independent network management Independent network management
An ASP may want to dynamically assign home agents in different An MSP may want to dynamically assign home agents in different
subnets, that is, not require that a roaming mobile node have a subnets; for istance, not require that a roaming mobile node have
fixed home subnet. a fixed home subnet.
Local home agents Local home agents
The mobile node's home ASP may want to allow a local roaming The mobile node's MSP may want to allow the serving ASP to assign
partner ASP to assign a local home agent for the mobile node. a local home agent for the mobile node. This is useful both from
This is useful both from the point of view of communications the point of view of communications efficiency, and has also been
efficiency, and has also been mentioned as one approach to support mentioned as one approach to support location privacy.
location privacy.
Ease of deployment Ease of deployment
MSP may want to allow "opportunistic" discovery and utilization of In order to simplify the deployment of Mobile IPv6, it is
its mobility services without any prearranged contact. These desirable to free users and administrators from the task of
scenarios will require dynamic home address assignment. allocating home agent addresses in a static manner. Moreover, an
MSP may want to have a dynamic home agent assignment mechanism to
load balance users among home agents located on different links.
5.1.3 Management requirements 5.1.3. Management requirements
As described earlier, new addresses invalidate configured security As described earlier, new addresses invalidate configured security
policy databases and authorization tables. Regardless of the policy databases and authorization tables. Regardless of the
specific protocols used, there is a need for either an automatic specific protocols used, there is a need for either an automatic
system for updating the security policy entries, or manual system for updating the security policy entries, or manual
configuration. These requirements apply to both home agents and configuration. These requirements apply to both home agents and
mobile nodes, but it can not be expected that mobile node users are mobile nodes, but it can not be expected that mobile node users are
capable of performing the required tasks. capable of performing the required tasks.
5.2 Security Infrastructure 5.2. Security Infrastructure
5.2.1 Integration with AAA Infrastructure 5.2.1. Integration with AAA Infrastructure
The current IKEv1-based dynamic key exchange protocol described in The current IKEv1-based dynamic key exchange protocol described in
[RFC3776] has no integration with backend authentication, [RFC3776] has no integration with backend authentication,
authorization and accounting techniques unless the authentication authorization and accounting techniques unless the authentication
credentials and trust relationships use certificates or pre-shared credentials and trust relationships use certificates or pre-shared
secrets. secrets.
Using certificates may require the ASP to deploy a PKI, which may not Using certificates may require the MSP to deploy a PKI, which may not
be possible or desirable in certain circumstances. Where a be possible or desirable in certain circumstances. Where a
traditional AAA infrastructure is used, the home agent is not able to traditional AAA infrastructure is used, the home agent is not able to
leverage authentication and authorization information established leverage authentication and authorization information established
between the mobile node, the foreign AAA server, and the home AAA between the mobile node, the foreign AAA server, and the home AAA
server when the mobile node gains access to the foreign network, in server. This would be desirable when the mobile node gains access to
order to authenticate the mobile node's identity and determine if the the foreign network, in order to authenticate the mobile node's
mobile node is authorized for mobility service. identity and determine if the mobile node is authorized for mobility
service.
The lack of connection to the AAA infrastructure also means the home The lack of connection to the AAA infrastructure also means the home
agent does not know where to issue accounting records at appropriate agent does not know where to issue accounting records at appropriate
times during the mobile node's session, as determined by the business times during the mobile node's session, as determined by the business
relationship between the home ASP and the mobile node's owner. relationship between the MSP and the mobile node's owner.
Presumably, some backend AAA protocol between the home agent and home Presumably, some backend AAA protocol between the home agent and home
AAA could be utilized, but IKEv1 does not contain support for AAA could be utilized, but IKEv1 does not contain support for
exchanging full AAA credentials with the mobile node. It is exchanging full AAA credentials with the mobile node. It is
worthwhile to note that IKEv2 provides this feature. worthwhile to note that IKEv2 provides this feature.
5.2.2 "Opportunistic" or "Local" Discovery 5.2.2. "Opportunistic" or "Local" Discovery
The home agent discovery protocol does not support an "opportunistic" The home agent discovery protocol does not support an "opportunistic"
or local discovery mechanisms in an ASP's local access network. It or local discovery mechanisms in an ASP's local access network. It
is expected that the mobile node must know the prefix of the home is expected that the mobile node must know the prefix of the home
subnet in order to be able to discover a home agent. It must either subnet in order to be able to discover a home agent. It must either
obtain that information through prefix update or have it statically obtain that information through prefix update or have it statically
configured. A more typical pattern for interdomain service discovery configured. A more typical pattern for inter-domain service
in the Internet is that the client (mobile node in this case) knows discovery in the Internet is that the client (mobile node in this
the domain name of the service, and uses DNS in some manner to find case) knows the domain name of the service, and uses DNS to find the
the server in the other domain. For local service discovery, DHCP is server in the visited domain. For local service discovery, DHCP is
typically used. typically used.
5.3 Topology Change 5.3. Topology Change
5.3.1 Dormant Mode Mobile Nodes 5.3.1. Dormant Mode Mobile Nodes
The description of the protocol to push prefix information to mobile The description of the protocol to push prefix information to mobile
nodes in Section 10.6 in [RFC3775] has an implicit assumption that nodes in Section 10.6 in [RFC3775] has an implicit assumption that
the mobile node is active and taking IP traffic. In fact, many, if the mobile node is active and taking IP traffic. In fact, many, if
not most, mobile devices will be in a low power "dormant mode" to not most, mobile devices will be in a low power "dormant mode" to
save battery power, or even switched off, so they will miss any save battery power, or even switched off, so they will miss any
propagation of prefix information. As a practical matter, if this propagation of prefix information. As a practical matter, if this
protocol is used, an ASP will need to keep the old prefix around and protocol is used, an MSP will need to keep the old prefix around and
handle any queries to the old home agent anycast address on the old handle any queries to the old home agent anycast address on the old
subnet, whereby the mobile node asks for a new home agent as subnet, whereby the mobile node asks for a new home agent as
described in Section 11.4, until all mobile nodes are accounted for. described in Section 11.4, until all mobile nodes are accounted for.
Even then, since some mobile nodes are likely to be turned off for Even then, since some mobile nodes are likely to be turned off for
long periods, some owners would need to be contacted by other means, long periods, some owners would need to be contacted by other means,
reducing the utility of the protocol. reducing the utility of the protocol.
Bootstrapping does not explicitly try to solve this problem of home Bootstrapping does not explicitly try to solve this problem of home
network renumbering when MN is in dormant mode. If the MN can network renumbering when MN is in dormant mode. If the MN can
configure itself after it 'comes back on' by reinitiating the configure itself after it 'comes back on' by reinitiating the
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authentication between provider and the user of the service). authentication between provider and the user of the service).
Network access service enables a host to send and receive IP packets Network access service enables a host to send and receive IP packets
on the Internet or an intranet. IP address configuration and IP on the Internet or an intranet. IP address configuration and IP
packet forwarding capabilities are required to deliver this service. packet forwarding capabilities are required to deliver this service.
A network operator providing this service is called an access service A network operator providing this service is called an access service
provider (ASP). An ASP can, for example, be a commercial ASP, the IT provider (ASP). An ASP can, for example, be a commercial ASP, the IT
department of an enterprise network, or the maintainer of a home department of an enterprise network, or the maintainer of a home
(residential) network. (residential) network.
If the mobile host is within the geographical area in which network If the mobile node is not within the geographical area in which
access service is not provided by its home network access service network access service is provided by its home ASP, the mobile node
provider, the mobile host is roaming. The home network access is roaming. In this case, the home ASP acts as the access service
service provider in this case acts as the access service authorizer, authorizer, but the actual network access is provided by the serving
but the actual network access is provided by the serving network network access provider. During the authentication and authorization
access provider. During the authentication and authorization prior prior to the mobile node having Internet access, the serving network
to the mobile host having Internet access, the serving network access access provider may simply act as a routing agent for authentication
provider may simply act as a routing agent for authentication and and authorization back to the access service authorizer, or it may
authorization back to the access service authorizer, or it may
require an additional authentication and authorization step itself. require an additional authentication and authorization step itself.
An example of a roaming situation is when a business person is using An example of a roaming situation is when a business person is using
a hotspot service in an airport, and the hotspot service provider has a hotspot service in an airport, and the hotspot service provider has
a roaming agreement with the business person's cellular provider. In a roaming agreement with the business person's cellular provider. In
that case, the hotspot network is acting as the serving network that case, the hotspot network is acting as the serving network
access provider, while the cellular network is acting as the access access provider, while the cellular network is acting as the access
service authorizer. When the business person moves from the hotspot service authorizer. When the business person moves from the hotspot
network to the cellular network, the cellular network is both the network to the cellular network, the cellular network is both the
home access service provider and the access service authorizer. home access service provider and the access service authorizer.
Mobility service using Mobile IPv6 is conceptually and possibly also Mobility service using Mobile IPv6 is conceptually and possibly also
in practice separate from network access service, though of course in practice separate from network access service, though of course
network access is required prior to providing mobility. Mobile IPv6 network access is required prior to providing mobility. Mobile IPv6
service enables an IPv6 host to maintain its reachability despite service enables an IPv6 host to maintain its reachability despite
changing its network attachment point (subnets). A network operator changing its network attachment point (subnets). A network operator
providing Mobile IPv6 service is called a mobility service provider providing Mobile IPv6 service is called a mobility service provider
(MSP). Granting Mobile IPv6 service requires a host to authenticate (MSP). Granting Mobile IPv6 service requires a host to authenticate
and prove authorization for the service. A network operator that and prove authorization for the service. A network operator that
authenticates a mobile host and authorizes mobility service is called authenticates a mobile node and authorizes mobility service is called
a mobility service authorizer. If both types of operation are a mobility service authorizer (MSA). If both types of operation are
performed by the same operator, that operator is called a home performed by the same operator, that operator is called a home
mobility service provider. If authentication and authorization is mobility service provider. If authentication and authorization is
provided by one operator and the actual service is provider by provided by one operator and the actual service is provider by
another, the operator providing the service is called the serving another, the operator providing the service is called the serving
mobility service provider. The serving MSP must contact the mobile mobility service provider. The serving MSP must contact the mobile
host's mobility service authorizer to check the mobile host's node's mobility service authorizer to check the mobile node's
authorization prior to granting mobility service. authorization prior to granting mobility service.
The service model defined here clearly separates the entity providing The service model defined here clearly separates the entity providing
the service from the entity that authentications and authorizes the the service from the entity that authenticates and authorizes the
service. In the case of basic network access, this supports the service. In the case of basic network access, this supports the
traditional and well-known roaming model, in which inter-operator traditional and well-known roaming model, in which inter-operator
roaming agreements allow a host to obtain network access in areas roaming agreements allow a host to obtain network access in areas
where their home network access provider does not have coverage. In where their home network access provider does not have coverage. In
the case of mobility service, this allows a roaming mobile host to the case of mobility service, this allows a roaming mobile node to
obtain mobility service in the local operator's network while having obtain mobility service in the local operator's network while having
that service authorized by the home operator. The service model also that service authorized by the home operator. The service model also
allows mobility service and network access service to be provided by allows mobility service and network access service to be provided by
different entities. This allows a network operator with no wireless different entities. This allows a network operator with no wireless
access, like, for example, an enterprise network operator, to deploy access, like, for example, an enterprise network operator, to deploy
a Mobile IPv6 home agent for mobility service while the actual a Mobile IPv6 home agent for mobility service while the actual
wireless network access is provided by the serving network access wireless network access is provided by the serving network access
providers with which the enterprise operator has a contract. Here providers with which the enterprise operator has a contract. Here
are some other possible combinations of ASPs and MSPs: are some other possible combinations of ASPs and MSPs:
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o The serving ASP and the serving MSP may be the same operator, or o The serving ASP and the serving MSP may be the same operator, or
not. not.
o It is possible that serving ASP and home MSP are the same o It is possible that serving ASP and home MSP are the same
operator. operator.
Similarly the home ASP and serving MSP may be the same. Also, the Similarly the home ASP and serving MSP may be the same. Also, the
ASA and MSA may be the same. ASA and MSA may be the same.
These entities and possible combinations must be taken into These entities and all combinations that are reasonable from a
consideration when solving the Mobile IPv6 bootstraping problem. deployment perspective must be taken into consideration when solving
They impact home agent discovery, home address configuration, and the Mobile IPv6 bootstraping problem. They impact home agent
mobile node to home agent authentication aspects. discovery, home address configuration, and mobile node to home agent
authentication aspects.
7. Deployment scenarios 7. Deployment scenarios
This section describes the various network deployment scenarios. The This section describes the various network deployment scenarios. The
various combinations of service providers as described in Section 6 various combinations of service providers as described in Section 6
are considered. are considered.
For each scenario, the underlying assumptions are described. The For each scenario, the underlying assumptions are described. The
basic assumption is that there is a trust relationship between mobile basic assumption is that there is a trust relationship between mobile
user and the MSP. Typically, this trust relationship is between the user and the MSA . Typically, this trust relationship is between the
mobile user and AAA in the MSA's network. Seed information needed to mobile user and AAA in the MSA's network. Seed information needed to
bootstrap the mobile node is considered in two cases: bootstrap the mobile node is considered in two cases:
o AAA authentication is mandatory for network access o AAA authentication is mandatory for network access
o AAA authentication is not part of network access. The seed o AAA authentication is not part of network access. The seed
information is described further in Section 8. information is described further in Section 8.
7.1 Mobility Service Subscription Scenario 7.1. Mobility Service Subscription Scenario
Many commercial deployments are based on the assumption that mobile Many commercial deployments are based on the assumption that mobile
nodes have a subscription with a service provider. In particular, in nodes have a subscription with a service provider. In this scenario
this scenario the MN has a subscription with an MSP, called the home the MN has a subscription with an MSA , called also the home MSP, for
MSP, for Mobile IPv6 service. As stated in Section 6, the MSP is Mobile IPv6 service. As stated in Section 6, the MSP is responsible
responsible of setting up a home agent on a subnet that acts as a of setting up a home agent on a subnet that acts as a Mobile IPv6
Mobile IPv6 home link. As a consequence, the home MSP should home link. As a consequence, the home MSP should explicitly
explicitly authorize and control the whole bootstrapping procedure. authorize and control the whole bootstrapping procedure.
Since the MN is assumed to have a pre-established trust relationship Since the MN is assumed to have a pre-established trust relationship
with its home provider, it must be configured with an identity and with its home provider, it must be configured with an identity and
credentials, for instance an NAI and a shared secret by some out-of- credentials, for instance an NAI and a shared secret by some out-of-
band means before bootstrapping, for example by manual configuration. band means (i.e. manual configuration) before bootstrapping.
In order to guarantee ubiquitous service, the MN should be able to In order to guarantee ubiquitous service, the MN should be able to
bootstrap MIPv6 operations with its home MSP from any possible access bootstrap MIPv6 operations with its home MSP from any possible access
location, such as an open network or a network managed by an ASP, location, such as an open network or a network managed by an ASP,
that may be different from the MSP and may not have any pre- that may be different from the MSP and may not have any pre-
established trust relationship with it. established trust relationship with it.
7.2 Integrated ASP network scenario 7.2. Integrated ASP network scenario
In this scenario, the ASP and MSP are the same ASP. MN shares In this scenario, the ASA and MSA are the same entity. The MN has
security credentials for access to the network and these credentials security credentials for access to the network and these credentials
can be used to bootstrap MIPv6. This bootstrapping can be done can be used to bootstrap MIPv6. This bootstrapping can be done
during the same phase as access authentication/authorization or at a during the same phase as access authentication/authorization or at a
later time (probably based on some state created during access later time (probably based on some state created during access
authentication/authorization). authentication/authorization).
Figure 1 describes an example AAA design for integrated ASP scenario. Figure 1 describes an example AAA design for integrated ASP scenario.
+----------------------------+ +----------------------------+
| IASP(ASP+MSP) | | IASP(ASA+MSA) |
+----+ +-----+ +----+ | +----+ +-----+ +----+ |
| MN |--- | NAS | | HA | | | MN |--- | NAS | | HA | |
+----+ +-----+ +----+ | +----+ +-----+ +----+ |
| \ \ | | \ \ |
| \ +------+ \ +-------+ | | \ +------+ \ +-------+ |
| -|AAA-NA| -|AAA-MIP| | | -|AAA-NA| -|AAA-MIP| |
| +------+ +-------+ | | +------+ +-------+ |
+----------------------------+ +----------------------------+
NAS: Network Access Server NAS: Network Access Server
AAA-NA: AAA for network access AAA-NA: AAA for network access
AAA-MIP: AAA for Mobile IP service AAA-MIP: AAA for Mobile IP service
Figure 1: Integrated ASP network Figure 1: Integrated ASP network
7.3 Third party MSP scenario 7.3. Third party MSP scenario
Mobility service has traditionally been provided by the same entity Mobility service has traditionally been provided by the same entity
that authenticates and authorizes the subscriber for network access. that authenticates and authorizes the subscriber for network access.
This is certainly the only model support by the base Mobile IPv6 This is certainly the only model support by the base Mobile IPv6
specification. specification.
In the 3rd party mobility service provider scenario, the subscription In the 3rd party mobility service provider scenario, the subscription
for mobility service is made with one entity (home MSA for instance a for mobility service is made with one entity (MSA for instance a
corporate network), but the actual mobility service is provided by corporate network), but the actual mobility service is provided by
yet another entity (such as an operator specializing on this service, yet another entity (such as an operator specializing on this service,
the serving MSP). These two entities have a trust relationship. the serving MSP). These two entities have a trust relationship.
Transitive trust among the mobile node and these two entities may be Transitive trust among the mobile node and these two entities may be
used to assure the participants that they are dealing with, are used to assure the participants that they are dealing with, are
trustworthy peers. trustworthy peers.
This arrangement is similar to the visited - home operator roaming This arrangement is similar to the visited - home operator roaming
arrangement for network access. arrangement for network access.
Figure 2 describes an example network for third party MSP scenario. Figure 2 describes an example network for third party MSP scenario.
+--------------+ +--------+ +--------------+ +--------+
| | |Serving | | | |Serving |
| ASP | | MSP | | ASP | | MSP |
+----+ +-----+ | | +----+ | +----+ +-----+ | | +----+ |
| MN |--- | NAS | | | | HA | | +-------------------+ | MN |--- | NAS | | | | HA | | +-------------------+
+----+ +-----+ |===| +----+ | | Home MSP | +----+ +-----+ |===| +----+ | | MSA |
| \ | | \ | | (e.g.corporate NW)| | \ | | \ | | (e.g.corporate NW)|
| \ +------+ | | \ | +-------+ | | \ +------+ | | \ | +-------+ |
| -|AAA-NA| | | -------|AAA-MIP| | | -|AAA-NA| | | -------|AAA-MIP| |
| +------+ | | | | +-------+ | | +------+ | | | | +-------+ |
+------------ + +--------+ +-------------------+ +------------ + +--------+ +-------------------+
Figure 2: Third Party MSP network Figure 2: Third Party MSP network
7.4 Infrastructure-less scenario 7.4. Infrastructure-less scenario
Infrastructure refers to network entities like AAA, PKI, HLR etc. Infrastructure refers to network entities like AAA, PKI, HLR etc.
Infrastructure-less implies that there is no dependency on any Infrastructure-less implies that there is no dependency on any
elements in the network with which the user has any form of trust elements in the network with which the user has any form of trust
relationship. relationship.
In such a scenario, there is absolutely no relationship between host In such a scenario, there is absolutely no relationship between host
and infrastructure. and infrastructure.
A good example of infrastructure-less environment for MIP6 A good example of infrastructure-less environment for MIP6
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has with any entity in the network. has with any entity in the network.
This specific scenario is not supported in this document. The reason This specific scenario is not supported in this document. The reason
for this is described in Section 9. for this is described in Section 9.
8. Parameters for authentication 8. Parameters for authentication
The following is a list of parameters that are used as the seed for The following is a list of parameters that are used as the seed for
the bootstrapping procedure. The parameters vary depending on the bootstrapping procedure. The parameters vary depending on
whether authentication for network access is independent of whether authentication for network access is independent of
authentication for mobility services or not. Authentication for authentication for mobility services or not.If different client
network access is always independent of authentication for mobility identities are used for network access and mobility services,
services if different client identities are used for network access authentication for network access is independent of authentication
and mobility services. for mobility services..
o Parameter Set 1 o Parameter Set 1
In this case, authentication for network access is independent of In this case, authentication for network access is independent of
authentication for mobility services. authentication for mobility services.
If the home agent address is not known to the mobile node the If the home agent address is not known to the mobile node the
following parameter is needed for discovering the home agent following parameter is needed for discovering the home agent
address: address:
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If the home agent address is not known but the home subnet prefix If the home agent address is not known but the home subnet prefix
is known, Dynamic Home Agent Address Discovery of Mobile IPv6 may is known, Dynamic Home Agent Address Discovery of Mobile IPv6 may
be used for discovering the home agent address and the above be used for discovering the home agent address and the above
parameter may not be used. parameter may not be used.
When the home agent address is known to the mobile node, the When the home agent address is known to the mobile node, the
following parameter is needed for performing mutual authentication following parameter is needed for performing mutual authentication
between the mobile node and the home agent by using IKE: between the mobile node and the home agent by using IKE:
* IKE credentials(*) * IKE credentials(*)
In the case where the home agent does not have the entire set of In the case where the home agent does not have the entire set of
IKE credentials, the home agent may communicate with other entity IKE credentials, the home agent may communicate with other entity
(for example a AAA server) to perform mutual authentication in (for example a AAA server) to perform mutual authentication in
IKE. In such a case, the IKE credentials include the credentials IKE. In such a case, the IKE credentials include the credentials
used between the mobile node and the other entity. In the case used between the mobile node and the other entity. In the case
where a AAA protocol is used for the communication between the where a AAA protocol is used for the communication between the
home agent and the other entity during the IKE procedure, AAA for home agent and the other entity during the IKE procedure, AAA for
Mobile IPv6 service may be involved in IKE. Mobile IPv6 service may be involved in IKE.
If authentication protocol [I-D.ietf-mip6-mn-auth-protocol-02] is If authentication protocol [RFC4285] is used, the shared key based
used, the shared key based security association with home agent is security association with home agent is needed.
needed.
o Parameter Set 2 o Parameter Set 2
In this case, some dependency exists between authentication for In this case, some dependency exists between authentication for
network access and authentication for mobility services in that a network access and authentication for mobility services in that a
security association that is established as a result of security association that is established as a result of
authentication for network access is re-used for authentication authentication for network access is re-used for authentication
for mobility services. for mobility services.
All required information including IKE credentials are All required information including IKE credentials are
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problem: problem:
1. The security requirements imposed on the outcome of the 1. The security requirements imposed on the outcome of the
bootstrapping process by RFC 3775 and other RFCs used by Mobile bootstrapping process by RFC 3775 and other RFCs used by Mobile
IPv6 for security. IPv6 for security.
2. The security of the bootstrapping process itself, in the sense of 2. The security of the bootstrapping process itself, in the sense of
threats to the bootstrapping process imposed by active or passive threats to the bootstrapping process imposed by active or passive
attackers. attackers.
Note that the two are related, in that if the bootstrapping process Note that the two are related; if the bootstrapping process is
is compromised, the level of security required by RFC 3775 may not be compromised, the level of security required by RFC 3775 may not be
obtained. achieved.
The following two sections discuss these issues. The following two sections discuss these issues.
9.1 Security Requirements of Mobile IPv6 9.1. Security Requirements of Mobile IPv6
The Mobile IPv6 specification in RFC 3775 requires the establishment The Mobile IPv6 specification in RFC 3775 requires the establishment
of a collection of IPsec SAs between the home agent and mobile host of a collection of IPsec SAs between the home agent and mobile node
to secure the signaling traffic for Mobile IP, and, optionally, also to secure the signaling traffic for Mobile IP, and, optionally, also
to secure data traffic. The security of an IPsec SA required by the to secure data traffic. The security of an IPsec SA required by the
relevent IPsec RFCs must be quite strong. Provisioning of keys and relevant IPsec RFCs must be quite strong. Provisioning of keys and
other cryptographic material during the establishment of the SA other cryptographic material during the establishment of the SA
through bootstrapping must be done in a manner such that authenticity through bootstrapping must be done in a manner such that authenticity
is proved and confidentiality is ensured. In addition, the is proved and confidentiality is ensured. In addition, the
generation of any keying material or other cryptographic material for generation of any keying material or other cryptographic material for
the SA must be done in a way such that the probability of compromise the SA must be done in a way such that the probability of compromise
after the SA is in place is minimized. The best way to minimize the after the SA is in place is minimized. The best way to minimize the
probability of such a compromise is to have the cryptographic probability of such a compromise is to have the cryptographic
material only known or calculable by the two end nodes that share the material only known or calculable by the two end nodes that share the
SA, in this case, the home agent and mobile host. If other parties SA -- in this case, the home agent and mobile node. If other parties
are involved in the establishing the SA, through key distribution for are involved in the establishing the SA, through key distribution for
example, the process should follow the constraints [eap_keying] example, the process should follow the constraints [I-D.ietf-eap-
designed to provide equivalent security. keying-08] designed to provide equivalent security.
RFC 3775 also requires a trust relationship as defined in Section 1.3 RFC 3775 also requires a trust relationship as defined in Section 1.3
between the mobile host and mobility service provider. This is between the mobile node and its home agent(s) . This is necessary,
necessary, for instance, to ensure that fradulent mobile hosts which for instance, to ensure that fradulent mobile nodes which attempt to
attempt to flood other mobile hosts with traffic can not only be shut flood other mobile nodes with traffic can not only be shut off but
off but tracked down [I-D.rosec]. An infrastructureless relationship tracked down [I-D.rosec]. An infrastructureless relationship as
as defined in Section 1.3 does not satisfy this requirement. Any defined in Section 1.3 does not satisfy this requirement. Any
bootstrapping solution must include a trust relationship between bootstrapping solution must include a trust relationship between
mobile host and mobility service provider. Solutions that depend on mobile node and mobility service provider. Solutions that depend on
an infrastructureless relationship are out of scope for an infrastructureless relationship are out of scope for
bootstrapping. bootstrapping.
Another requirement is that a home address is authorized to one Another requirement is that a home address is authorized to one
specific host at a time. RFC 3775 requires this in order to that specific host at a time. RFC 3775 requires this in order to that
misbehaving mobile hosts can be shut down. This implies that, in misbehaving mobile nodes can be shut down. This implies that, in
addition to the IPsec SA, the home agent must somehow authorize the addition to the IPsec SA, the home agent must somehow authorize the
mobile host for a home address. The authorization can be either mobile node for a home address. The authorization can be either
implicit (for example, as a side effect of the authentication for implicit (for example, as a side effect of the authentication for
mobility service) or explicit. The authorization can either be done mobility service) or explicit. The authorization can either be done
at the time the SA is created or dynamically managed through a first at the time the SA is created or dynamically managed through a first
come, first served allocation policy. come, first served allocation policy.
9.2 Threats to the Bootstrapping Process 9.2. Threats to the Bootstrapping Process
Various attacks are possible on the bootstrapping process itself. Various attacks are possible on the bootstrapping process itself.
These attacks can compromise the process such that the RFC 3775 These attacks can compromise the process such that the RFC 3775
requirements for Mobile IP security are not met, or they can serve to requirements for Mobile IP security are not met, or they can serve to
simply disrupt the process such that bootstrapping cannot complete. simply disrupt the process such that bootstrapping cannot complete.
Here are some possible attacks: Here are some possible attacks:
o An attacking network entity purporting to offer the mobile host a o An attacking network entity purporting to offer the mobile node a
legitimate home agent address or boostrapping for the IPsec SAs legitimate home agent address or bootstrapping for the IPsec SAs
may, instead, offer a bogus home agent address or configure bogus may, instead, offer a bogus home agent address or configure bogus
SAs that allow the home agent to steal the mobile host's traffic SAs that allow the home agent to steal the mobile node's traffic
or otherwise disrupts the mobile host's mobility service. or otherwise disrupts the mobile node's mobility service.
o An attacking mobile host may attempt to steal mobility service by o An attacking mobile node may attempt to steal mobility service by
offering up fake credentials to a bootstrapping network entity or offering up fake credentials to a bootstrapping network entity or
otherwise disrupt the home agent's ability to offer mobility otherwise disrupt the home agent's ability to offer mobility
service. service.
o A man in the middle on the link between the mobile host and the o A man in the middle on the link between the mobile node and the
bootstrapping network entity could steal credentials or other bootstrapping network entity could steal credentials or other
sensitive information and use that to steal mobility service or sensitive information and use that to steal mobility service or
deny it to the legitimate owner of the credentials. Refer to deny it to the legitimate owner of the credentials. Refer to
Section 7.15 in [2284bis] and [I-D.mariblanca-aaa-eap-lla-00] for Section 7.15 in [2284bis] and [I-D.mariblanca-aaa-eap-lla-00] for
further information. further information.
o An attacker could arrange for a distributed denial of service o An attacker could arrange for a distributed denial of service
attack on the bootstrapping entity, to disrupt legitimate users attack on the bootstrapping entity, to disrupt legitimate users
from bootstrapping. from bootstrapping.
In addition to these attacks, there are other considerations that are In addition to these attacks, there are other considerations that are
important in achieving a good security design. As mobility and important in achieving a good security design. As mobility and
network access authentication are separate services, keys generated network access authentication are separate services, keys generated
for these services need to be cryptographically separate, separately for these services need to be cryptographically separate, separately
named, and have separate lifetimes, including if the keys are named, and have separate lifetimes, including if the keys are
generated from the same authentication credentials This is necessary generated from the same authentication credentials This is necessary
because a mobile host must be able to move from one serving (or because a mobile node must be able to move from one serving (or
roaming) network access provider to another without needing to change roaming) network access provider to another without needing to change
its mobility access provider. Finally, basic cryptographic processes its mobility access provider. Finally, basic cryptographic processes
must provide for multiple algorithms in order to accommodate the must provide for multiple algorithms in order to accommodate the
widely varying deployment needs. widely varying deployment needs.
10. IANA Considerations 10. IANA Considerations
No new protocol numbers are required. No new protocol numbers are required.
11. Contributors 11. Contributors
skipping to change at page 26, line 44 skipping to change at page 25, line 44
Gopal Dommety gdommety@cisco.com Gopal Dommety gdommety@cisco.com
Kent Leung kleung@cisco.com Kent Leung kleung@cisco.com
Alper Yegin alper.yegin@samsung.com Alper Yegin alper.yegin@samsung.com
Hannes Tschofenig hannes.tschofenig@siemens.com Hannes Tschofenig hannes.tschofenig@siemens.com
Vijay Devarapalli vijayd@iprg.nokia.com Vijay Devarapalli vijayd@iprg.nokia.com
Kuntal Chowdury kchowdury@starentnetworks.com Kuntal Chowdhury kchowdhury@starentnetworks.com
12. Acknowledgments 12. Acknowledgments
Special thanks to James Kempf and Jari Arkko for writing the initial Special thanks to James Kempf and Jari Arkko for writing the initial
version of the bootstrapping statement. Thanks to John Loughney for version of the bootstrapping statement. Thanks to John Loughney and
a detailed editorial review. T.J. Kniveton for their detailed reviews.
13. IPR Disclosure Acknowledgement 13. IPR Disclosure Acknowledgement
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
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
14. References 14. Informative References
14.1 Normative References
[I-D.ietf-mip6-mn-auth-protocol-02]
Patel et. al., A., "Authentication Protocol for Mobile
IPv6", draft-ietf-mip6-auth-protocol-02.txt (work in
progress), November 2004,
<draft-ietf-mip6-auth-protocol-02.txt>.
[I-D.ietf-seamoby-mobility]
Manner, J. and M. Kojo, "Mobility Related Terminology",
draft-ietf-seamoby-mobility-terminology-06 (work in
progress), February 2004,
<draft-ietf-seamoby-mobility-terminology-06.txt>.
[RFC2794] Calhoun, P. and C. Perkins, "Mobile IP Network Access
Identifier Extension for IPv4", RFC 2794, March 2000.
[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
[RFC3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to
Protect Mobile IPv6 Signaling Between Mobile Nodes and
Home Agents", RFC 3776, June 2004.
14.2 Informative References
[2284bis] Levkowetz, Ed., H., "Extensible Authentication Protocol [2284bis] Levkowetz, Ed., H., "Extensible Authentication Protocol
(EAP)", February 2004, <draft-ietf-eap-rfc2284bis-09.txt>. (EAP)", February 2004, <draft-ietf-eap-rfc2284bis-09.txt>.
[I-D.giaretta-mip6-authorization-eap] [I-D.giaretta-mip6-authorization-eap]
Giaretta, G., "MIPv6 Authorization and Configuration based Giaretta, G., "MIPv6 Authorization and Configuration based
on EAP", draft-giaretta-mip6-authorization-eap-00 (work in on EAP", draft-giaretta-mip6-authorization-eap-02 (work in
progress), February 2004, progress), February 2004,
<draft-giaretta-mip6-authorization-eap-00.txt>. <draft-giaretta-mip6-authorization-eap-02.txt>.
[I-D.ietf-mip6-mn-ident-option-02] [I-D.ietf-eap-keying-08]
Patel, A., Leung, K., Akthar, H., Khalil, M., and K. Aboba et. al., B., "Extensible Authentication Protocol
Chowdhury, "Mobile Node Identifier Option for Mobile (EAP) Key Management Framework",
IPv6", draft-ietf-mip6-mn-ident-option-02.txt (work in draft-ietf-eap-keying-08.txt (work in progress),
progress), February 2004, October 2005, <draft-ietf-eap-keying-08.txt>.
<draft-ietf-mip6-mn-ident-option-02.txt>.
[I-D.kempf-mip6-bootstrap] [I-D.kempf-mip6-bootstrap]
Kempf, J. and J. Arkko, "The Mobile IPv6 Bootstrapping Kempf, J. and J. Arkko, "The Mobile IPv6 Bootstrapping
Problem", draft-kempf-mip6-bootstrap-00 (work in Problem", draft-kempf-mip6-bootstrap-00 (work in
progress), March 2004, progress), March 2004,
<draft-kempf-mip6-bootstrap-00.txt>. <draft-kempf-mip6-bootstrap-00.txt>.
[I-D.mariblanca-aaa-eap-lla-00] [I-D.mariblanca-aaa-eap-lla-00]
Mariblanca, D., "EAP lower layer attributes for AAA Mariblanca, D., "EAP lower layer attributes for AAA
protocols", May 2004, protocols", May 2004,
<draft-mariblanca-aaa-eap-lla-00.txt>. <draft-mariblanca-aaa-eap-lla-00.txt>.
[I-D.rosec] [I-D.rosec]
Nikander, P., Arkko, J., Aura, T., Montenegro, G., and E. Nikander, P., Arkko, J., Aura, T., Montenegro, G., and E.
Nordmark, "Mobile IP version 6 Route Optimization Security Nordmark, "Mobile IP version 6 Route Optimization Security
Design Background", draft-ietf-mip6-ro-sec-02 (work in Design Background", draft-ietf-mip6-ro-sec-02 (work in
progress), October 2004, <draft-ietf-mip6-ro-sec-02.txt>. progress), October 2004, <draft-ietf-mip6-ro-sec-02.txt>.
[eap_keying] [RFC2794] Calhoun, P. and C. Perkins, "Mobile IP Network Access
Aboba et. al., B., "Extensible Authentication Protocol Identifier Extension for IPv4", RFC 2794, March 2000.
(EAP) Key Management Framework",
draft-ietf-eap-keying-05.txt (work in progress),
February 2005, <draft-ietf-eap-keying-05.txt>.
Author's Address [RFC3041] Narten, T. and R. Draves, "Privacy Extensions for
Stateless Address Autoconfiguration in IPv6", RFC 3041,
January 2001.
[RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology",
RFC 3753, June 2004.
[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
[RFC3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to
Protect Mobile IPv6 Signaling Between Mobile Nodes and
Home Agents", RFC 3776, June 2004.
[RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
Chowdhury, "Mobile Node Identifier Option for Mobile IPv6
(MIPv6)", RFC 4283, November 2005.
[RFC4285] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
Chowdhury, "Authentication Protocol for Mobile IPv6",
RFC 4285, January 2006.
Authors' Addresses
Alpesh Patel Alpesh Patel
Cisco Cisco
170 W. Tasman Drive 170 W. Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
Phone: +1 408 853 9580 Phone: +1 408 853 9580
Email: alpesh@cisco.com Email: alpesh@cisco.com
Gerardo Giaretta
Telecom Italia LAB
via Reiss Romoli 274
Torino 10148
Italy
Phone: +39 011 228 6904
Email: gerardo.giaretta@telecomitalia.it
Intellectual Property Statement Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
skipping to change at page 31, line 41 skipping to change at page 30, line 41
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
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