Network Working Group                                      A. Patel, Ed.
Request for Comments: 4640                                         Cisco
Category: Informational                                 G. Giaretta, Ed.
                                                          Telecom Italia
                                                          September 2006
Network Working Group                                      A. Patel, Ed.
Request for Comments: 4640                                         Cisco
Category: Informational                                 G. Giaretta, Ed.
                                                          Telecom Italia
                                                          September 2006

Problem Statement for Bootstrapping Mobile IPv6 (MIPv6)


Status of This Memo


This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.


Copyright Notice


Copyright (C) The Internet Society (2006).




A mobile node needs at least the following information: a home address, a home agent address, and a security association with home agent to register with the home agent. The process of obtaining this information is called bootstrapping. This document discusses issues involved with how the mobile node can be bootstrapped for Mobile IPv6 (MIPv6) and various potential deployment scenarios for mobile node bootstrapping.


Table of Contents


   1. Introduction ....................................................2
      1.1. Overview of the Problem ....................................3
      1.2. Bootstrapping ..............................................3
      1.3. Terminology ................................................4
   2. Assumptions .....................................................5
   3. Design Goals ....................................................6
   4. Non-goals .......................................................7
   5. Motivation for bootstrapping ....................................7
      5.1. Addressing .................................................7
           5.1.1. Dynamic Home Address Assignment .....................7
           5.1.2. Dynamic Home Agent Assignment .......................9
           5.1.3. "Opportunistic" or "Local" Discovery ................9
           5.1.4. Management Requirements .............................9
      5.2. Security Infrastructure ...................................10
           5.2.1. Integration with AAA Infrastructure ................10
      5.3. Topology Change ...........................................10
   1. Introduction ....................................................2
      1.1. Overview of the Problem ....................................3
      1.2. Bootstrapping ..............................................3
      1.3. Terminology ................................................4
   2. Assumptions .....................................................5
   3. Design Goals ....................................................6
   4. Non-goals .......................................................7
   5. Motivation for bootstrapping ....................................7
      5.1. Addressing .................................................7
           5.1.1. Dynamic Home Address Assignment .....................7
           5.1.2. Dynamic Home Agent Assignment .......................9
           5.1.3. "Opportunistic" or "Local" Discovery ................9
           5.1.4. Management Requirements .............................9
      5.2. Security Infrastructure ...................................10
           5.2.1. Integration with AAA Infrastructure ................10
      5.3. Topology Change ...........................................10
           5.3.1. Dormant Mode Mobile Nodes ..........................10
   6. Network Access and Mobility Services ...........................11
   7. Deployment Scenarios ...........................................13
      7.1. Mobility Service Subscription Scenario ....................13
      7.2. Integrated ASP Network Scenario ...........................14
      7.3. Third-Party MSP Scenario ..................................14
      7.4. Infrastructure-less Scenario ..............................15
   8. Parameters for Authentication ..................................15
   9. Security Considerations ........................................17
      9.1. Security Requirements of Mobile IPv6 ......................17
      9.2. Threats to the Bootstrapping Process ......................18
   10. Contributors ..................................................19
   11. Acknowledgements ..............................................20
   12. Informative References ........................................20
           5.3.1. Dormant Mode Mobile Nodes ..........................10
   6. Network Access and Mobility Services ...........................11
   7. Deployment Scenarios ...........................................13
      7.1. Mobility Service Subscription Scenario ....................13
      7.2. Integrated ASP Network Scenario ...........................14
      7.3. Third-Party MSP Scenario ..................................14
      7.4. Infrastructure-less Scenario ..............................15
   8. Parameters for Authentication ..................................15
   9. Security Considerations ........................................17
      9.1. Security Requirements of Mobile IPv6 ......................17
      9.2. Threats to the Bootstrapping Process ......................18
   10. Contributors ..................................................19
   11. Acknowledgements ..............................................20
   12. Informative References ........................................20
1. Introduction
1. 介绍

Mobile IPv6 [RFC3775] specifies mobility support based on the assumption that a mobile node (MN) has a trust relationship with an entity called the home agent. Once the home agent address has been learned (for example, via manual configuration, anycast discovery mechanisms, or DNS lookup), Mobile IPv6 signaling messages between the mobile node and the home agent are secured with IPsec or with the authentication protocol, as defined in [RFC4285]. The requirements for this security architecture are created with [RFC3775], and the details of this procedure are described in [RFC3776].


In [RFC3775], there is an implicit requirement that the MN be provisioned with enough information that will permit it to register successfully with its home agent. However, having this information statically provisioned creates practical deployment issues.


This document serves to define the problem of bootstrapping. Bootstrapping is defined as the process of obtaining enough information at the mobile node that it can successfully register with an appropriate home agent.


The requirements for bootstrapping could consider various scenarios/network deployment issues. It is the basic assumption of this document that certain minimal parameters (seed information) are available to the mobile node to aid in bootstrapping. The exact seed information available differs depending on the deployment scenario. This document describes various deployment scenarios and provides a set of minimal parameters that are available in each deployment scenario.


This document stops short of suggesting the preferred solutions for how the mobile node should obtain information. Such details will be available from separate documents.


1.1. Overview of the Problem
1.1. 问题概述

Mobile IPv6 [RFC3775] expects the mobile node to have a static home address, a home agent address (which can be derived from an anycast address), and a security association with a home agent (or multiple home agents).


This static provisioning of information has various problems, as discussed in Section 5.


The aim of this document is:


o To define bootstrapping;

o 定义引导;

o To identify sample deployment scenarios where Mobile Internet Protocol version 6 (MIPv6) will be deployed, taking into account the relationship between the subscriber and the service provider; and

o 考虑到用户和服务提供商之间的关系,确定将部署移动互联网协议版本6(MIPv6)的示例部署场景;和

o To identify the minimal set of information required on the Mobile Node and in the network in order for the mobile node to obtain address and security credentials, to register with the home agent.

o 为了识别移动节点和网络上所需的最小信息集,以便移动节点获得地址和安全凭据,向归属代理注册。

1.2. Bootstrapping
1.2. 自举

Bootstrapping is defined as obtaining enough information at the mobile node that the mobile node can successfully register with an appropriate home agent. Specifically, this means obtaining the home agent address and home address, and for the mobile node and home agent to authenticate and mutually construct security credentials for Mobile IPv6.


Typically, bootstrapping happens when a mobile node does not have all the information it needs to set up the Mobile IPv6 service. This includes, but is not limited to, situations in which the mobile node does not having any information when it boots up for the first time (out of the box), or does not retain any information during reboots.


Also, in certain scenarios, after the MN bootstraps for the first time (out of the box), the need for subsequent bootstrapping is implementation dependent. For instance, the MN may bootstrap every time it boots, bootstrap every time on prefix change, or bootstrap periodically to anchor to an optimal HA (based on distance, load, etc.).


1.3. Terminology
1.3. 术语

General mobility terminology can be found in [RFC3753]. The following additional terms are used here:


Trust relationship


In the context of this document, trust relationship means that the two parties in question, typically the user of the mobile host and the mobility or access service authorizer, have some sort of prior contact in which the mobile node was provisioned with credentials. These credentials allow the mobile node to authenticate itself to the mobility or access service provider and to prove its authorization to obtain service.


Infrastructureless relationship


In the context of this document, an infrastructureless relationship is one in which the user of the mobile node and the mobility or access service provider have no previous contact and the mobile node is not required to supply credentials to authenticate and prove authorization for service. Mobility and/or network access service is provided without any authentication or authorization. Infrastructureless in this context does not mean that there is no network infrastructure, such as would be the case for an ad hoc network.




Data used by a mobile node to authenticate itself to a mobility or access network service authorizer and to prove authorization to receive service. User name/passwords, one time password cards, public/private key pairs with certificates, and biometric information are some examples.




Access Service Authorizer. A network operator that authenticates a mobile node and establishes the mobile node's authorization to receive Internet service.




Access Service Provider. A network operator that provides direct IP packet forwarding to and from the end host.


Serving Network Access Provider


A network operator that is the mobile node's ASP but not its ASA. The serving network access provider may or may not additionally provide mobility service.


Home Network Access Provider


A network operator that is both the mobile node's ASP and ASA. The home network access provider may or may not additionally provide mobility service (note that this is a slightly different definition from that in RFC 3775).

同时作为移动节点的ASP和ASA的网络运营商。家庭网络接入提供商可以或不可以另外提供移动性服务(注意,这与RFC 3775中的定义稍有不同)。



Integrated Access Service Provider. A service provider that provides both authorization for network access and mobility service.




Mobility Service Authorizer. A service provider that authorizes Mobile IPv6 service.




Mobility Service Provider. A service provider that provides Mobile IPv6 service. In order to obtain such service, the mobile node must be authenticated and prove authorization to obtain the service. Home Mobility Service Provider


A MSP that both provides mobility service and authorizes it.


Serving Mobility Service Provider


A MSP that provides mobility service but depends on another service provider to authorize it.


2. Assumptions
2. 假设

o A basic assumption in Mobile IPv6 [RFC3775] is that there is a trust relationship between the mobile node and its home agent(s). This trust relationship can be direct, or indirect through, for instance, an ASP that has a contract with the MSP. This trust relationship can be used to bootstrap the MN.

o 移动IPv6[RFC3775]中的一个基本假设是移动节点与其归属代理之间存在信任关系。这种信任关系可以是直接的,也可以是通过与MSP签订合同的ASP间接的。此信任关系可用于引导MN。

One typical way of verifying the trust relationship is using authentication, authorization, and accounting (AAA) infrastructure. In this document, two distinct uses of AAA are considered:


AAA for Network Access


This functionality provides authentication and authorization to access the network (obtain address and send/receive packets).


AAA for Mobility Service


This functionality provides authentication and authorization for mobility services.


These functionalities may be implemented in a single entity or in different entities, depending on the service models described in Section 6 or deployment scenarios as described in Section 7.


o Some identifier, such as an Network Access Identifier (NAI), as defined in [RFC4283] or [RFC2794], is provisioned on the MN that permits the MN to identify itself to the ASP and MSP.

o 如[RFC4283]或[RFC2794]中所定义的一些标识符(例如网络访问标识符(NAI))被设置在MN上,其允许MN向ASP和MSP标识自己。

3. Design Goals
3. 设计目标

A solution to the bootstrapping problem has the following design goals:


o The following information must be available at the end of bootstrapping, to enable the MN to register with the HA.

o 以下信息必须在引导结束时可用,以使MN能够向HA注册。

* MN's home agent address

* MN的国内代理地址

* MN's home address

* MN的家庭住址

* IPsec Security Association (SA) between MN and HA, Intenet Key Exchange Protocol (IKE) pre-shared secret between MN and HA

* MN和HA之间的IPsec安全关联(SA),MN和HA之间的Intenet密钥交换协议(IKE)预共享秘密

o The bootstrapping procedure can be triggered at any time, either by the MN or by the network. Bootstrapping can occur, for instance, due to administrative action, information going stale, or HA indicating the MN. Bootstrapping may be initiated even when the MN is registered with the HA and has all the required credentials. This may typically happen to refresh/renew the credentials.

o 可以随时由MN或网络触发引导过程。例如,由于管理操作、信息过时或指示MN的HA,可能会发生引导。即使MN已向HA注册并具有所有必需的凭据,也可以启动引导。通常,刷新/续订凭据时可能会发生这种情况。

o Subsequent protocol interaction (for example, updating the IPsec SA) can be executed between the MN and the HA itself without involving the infrastructure that was used during bootstrapping.

o 可以在MN和HA本身之间执行后续协议交互(例如,更新IPsec SA),而不涉及引导期间使用的基础设施。

o Solutions to the bootstrapping problem should enable storage of user-specific information on entities other than the home agent.

o 引导问题的解决方案应支持在除归属代理以外的实体上存储用户特定的信息。

o Solutions to the bootstrapping problem should not exclude storage of user-specific information on entities other than the home agent.

o 引导问题的解决方案不应排除在除归属代理以外的实体上存储用户特定信息。

o Configuration information which is exchanged between the mobile node and the home agent must be secured using integrity and replay protection. Confidentiality protection should be provided if necessary.

o 必须使用完整性和重播保护来保护移动节点和归属代理之间交换的配置信息。如有必要,应提供保密保护。

o The solution should be applicable to all feasible deployment scenarios that can be envisaged, along with the relevant authentication/authorization models.

o 该解决方案应适用于可以设想的所有可行部署场景,以及相关的身份验证/授权模型。

4. Non-goals
4. 非目标

This following issues are clearly outside the scope of bootstrapping:


o Home prefix renumbering is not explicitly supported as part of bootstrapping. If the MN executes the bootstrap procedures every time it powers on (as opposed to caching state information from previous bootstrap process), then home network renumbering is taken care of automatically.

o 引导过程中不明确支持主前缀重新编号。如果MN在每次通电时都执行引导过程(与缓存以前引导过程中的状态信息相反),则家庭网络重新编号将自动完成。

o Bootstrapping in the absence of a trust relationship between MN and any provider is not considered.

o 在MN和任何提供者之间没有信任关系的情况下,不考虑引导。

5. Motivation for bootstrapping
5. 自举的动机
5.1. Addressing
5.1. 寻址

The default bootstrapping described in the Mobile IPv6 base specification [RFC3775] has a tight binding to the home addresses and home agent addresses.


In this section, we discuss the problems caused by the currently tight binding to home addresses and home agent addresses.


5.1.1. Dynamic Home Address Assignment
5.1.1. 动态家庭地址分配

Currently, the home agent uses the mobile node's home address for authorization. When manual keying is used, this happens through the


security policy database, which specifies that a certain security association may only be used for a specific home address. When dynamic keying is used, the home agent ensures that the IKE Phase 1 identity is authorized to request security associations for the given home address. Mobile IPv6 uses IKEv1, which is unable to update the security policy database according to a dynamically assigned home address. As a result, static home address assignment is really the only home address configuration technique compatible with the base specification.


However, support for dynamic home address assignment would be desirable for the following reasons:


Dynamic Host Configuration Protocol (DHCP)-based address assignment. Some providers may want to use DHCPv6 or other dynamic address assignment (e.g., IKEv2) from the home network to configure home addresses.


Recovery from a duplicate address collision. It may be necessary to recover from a collision of addresses on the home network by one of the mobile nodes changing its home address.


Addressing privacy. It may be desirable to establish randomly generated addresses as in [RFC3041] and use them for a short period of time. Unfortunately, current protocols make it possible to use such addresses only from the visited network. As a result, these addresses cannot be used for communications lasting longer than the attachment to a particular visited network.


Ease of deployment. In order to simplify the deployment of Mobile IPv6, it is desirable to free users and administrators from the task of allocating home addresses and specifying them in the security policy database. This is consistent with the general IPv6 design goal of using autoconfiguration wherever possible.


Prefix changes in the home network. The Mobile IPv6 specification contains support for a mobile node to autoconfigure a home address as based on its discovery of prefix information on the home subnet [RFC3775]. Autoconfiguration in case of network renumbering is done by replacing the existing network prefix with the new network prefix.


Subsequently, the MN needs to update the mobility binding in the HA to register the newly configured Home Address. However, the MN may not be able to register the newly configured address with the HA if a security association related to that reconfigured Home Address does not exist in the MN and the HA. This situation is not handled in the current MIPv6 specification [RFC3775].


5.1.2. Dynamic Home Agent Assignment
5.1.2. 动态归属代理分配

Currently, the address of the home agent is specified in the security policy database. Support for multiple home agents requires the configuration of multiple security policy database entries.


However, support for dynamic home agent assignment would be desirable for the following reasons:


Home agent discovery. The Mobile IPv6 specification contains support for a mobile node to autoconfigure a home agent address as based on a discovery protocol [RFC3775].

Home agent discovery。移动IPv6规范支持移动节点根据发现协议自动配置归属代理地址[RFC3775]。

Independent network management. An MSP may want to assign home agents dynamically in different subnets; for instance, not require that a roaming mobile node have a fixed home subnet.


Local home agents. The mobile node's MSP may want to allow the serving MSP to assign a local home agent for the mobile node. This is useful from the point of view of communications efficiency and has also been mentioned as one approach to support location privacy.


Ease of deployment. In order to simplify the deployment of Mobile IPv6, it is desirable to free users and administrators from the task of 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. "Opportunistic" or "Local" Discovery
5.1.3. “机会主义”或“局部”发现

The home agent discovery protocol does not support an "opportunistic" 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 subnet in order to be able to discover a home agent. It must either obtain that information through prefix update or have it statically configured. A more typical pattern for inter-domain service discovery in the Internet is that the client (mobile node in this case) knows the domain name of the service and uses DNS to find the server in the visited domain. For local service discovery, DHCP is typically used.


5.1.4. Management Requirements
5.1.4. 管理要求

As described earlier, new addresses invalidate configured security policy databases and authorization tables. Regardless of the specific protocols used, there is a need for either an automatic system for updating the security policy entries or manual configuration. These requirements apply to both home agents and


mobile nodes, but it cannot be expected that mobile node users are capable of performing the required tasks.


5.2. Security Infrastructure
5.2. 安全基础设施
5.2.1. Integration with AAA Infrastructure
5.2.1. 与AAA基础架构的集成

The current IKEv1-based dynamic key exchange protocol, described in [RFC3776], has no integration with backend authentication, authorization, and accounting techniques unless the authentication credentials and trust relationships use certificates or pre-shared secrets.


Certificates are not easily supported by traditional AAA infrastructures. Where a traditional AAA infrastructure is used, the home agent is not able to leverage authentication and authorization information established between the mobile node, the foreign AAA server, and the home AAA server. This would be desirable when the mobile node gains access to the foreign network, in order to authenticate the mobile node's identity and determine whether the mobile node is authorized for mobility service.


The lack of connection to the AAA infrastructure also means that the home agent does not know where to send accounting records at appropriate times during the mobile node's session, as determined by the business relationship between the MSP and the mobile node's owner.


Presumably, some backend AAA protocol between the home agent and home AAA could be utilized, but IKEv1 does not contain support for exchanging full AAA credentials with the mobile node. It is worthwhile to note that IKEv2 provides this feature.


5.3. Topology Change
5.3. 拓扑变化
5.3.1. Dormant Mode Mobile Nodes
5.3.1. 休眠模式移动节点

The description of the protocol to push prefix information to mobile nodes in Section 10.6 of [RFC3775] has an implicit assumption that 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 save battery power, or will even be switched off, so they will miss any propagation of prefix information. As a practical matter, if this 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 subnet, whereby the mobile node asks for a new home agent as 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


long periods, some owners would need to be contacted by other means, reducing the utility of the protocol.


Bootstrapping does not explicitly try to solve this problem of home network renumbering when MN is in dormant mode. If the MN can configure itself after it 'comes back on' by reinitiating the bootstrapping process, then network renumbering problem is fixed as a side effect.


6. Network Access and Mobility Services
6. 网络接入和移动服务

This section defines some terms as they pertain to authentication and practical network deployment/roaming scenarios. This description lays the groundwork for Section 7. The focus is on the 'service' model since, ultimately, it is the provider providing the service that wants to authenticate the mobile (and vice versa for mutual authentication between provider and the user of the service).


Network access service enables a host to send and receive IP packets on the Internet or an intranet. IP address configuration and IP packet forwarding capabilities are required to deliver this 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 department of an enterprise network, or the maintainer of a home (residential) network.


If the mobile node is not directly usable for communication at the current location of the MN in which network access service is provided by its home ASP, the mobile node is roaming. In this case, the home ASP acts as the access service authorizer, but the actual network access is provided by the serving network access provider. During the authentication and authorization prior to the mobile nodes having Internet access, the serving network access provider may simply act as a routing agent for authentication and authorization back to the access service authorizer, or it may require an additional authentication and authorization step itself. 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 roaming agreement with the business person's cellular provider. In that case, the hotspot network is acting as the serving network access provider, and the cellular network is acting as the access service authorizer. When the business person moves from the hotspot network to the cellular network, the cellular network is both the home access service provider and the access service authorizer.


Mobility service using Mobile IPv6 is conceptually and possibly also in practice separate from network access service, though of course network access is required prior to providing mobility. Mobile IPv6


service enables an IPv6 host to maintain its reachability despite changing its network attachment point (subnets). A network operator providing Mobile IPv6 service is called a mobility service provider (MSP). Granting Mobile IPv6 service requires that a host authenticate and prove authorization for the service. A network operator that authenticates a mobile node and authorizes mobility service is called a mobility service authorizer (MSA). If both types of operation are performed by the same operator, that operator is called a home mobility service provider. If authentication and authorization is provided by one operator and the actual service is provided by another, the operator providing the service is called the serving mobility service provider. The serving MSP must contact the mobile node's mobility service authorizer to check the mobile node's authorization prior to granting mobility service.


The service model defined here clearly separates the entity providing the service from the entity that authenticates and authorizes the service. In the case of basic network access, this supports the traditional and well-known roaming model, in which inter-operator roaming agreements allow a host to obtain network access in areas where their home network access provider does not have coverage. In the case of mobility service, this allows a roaming mobile node to obtain mobility service in the local operator's network while having that service authorized by the home operator. The service model also allows mobility service and network access service to be provided by different entities. This allows a network operator with no wireless access, such as, for example, an enterprise network operator, to deploy a Mobile IPv6 home agent for mobility service while the actual wireless network access is provided by the serving network access providers with which the enterprise operator has a contract. Here are some other possible combinations of ASPs and MSPs:


o The serving ASP might be the home ASP. Similarly, the serving MSP might be the home MSP.

o 服务ASP可能是主ASP。类似地,服务MSP可以是主MSP。

o The home ASP and the home MSP may be the same operator, or not. When they are the same, the same set of credentials may be used for both services.

o 家庭ASP和家庭MSP可能是同一个操作员,也可能不是。当它们相同时,两个服务可以使用相同的凭据集。

o The serving ASP and the serving MSP may be the same operator, or not.

o 服务ASP和服务MSP可以是相同的操作员,也可以不是。

o It is possible that serving ASP and home MSP are the same operator.

o 服务ASP和家庭MSP可能是同一个操作员。

Similarly the home ASP and serving MSP may be the same. Also, the ASA and MSA may be the same.


These entities and all combinations that are reasonable from a deployment perspective must be taken into consideration to solve the Mobile IPv6 bootstrapping problem. They impact home agent discovery, home address configuration, and mobile node-to-home agent authentication aspects.


7. Deployment Scenarios
7. 部署场景

This section describes the various network deployment scenarios. The various combinations of service providers described in Section 6 are considered.


For each scenario, the underlying assumptions are described. The basic assumption is that there is a trust relationship between mobile user and the MSA. Typically, this trust relationship is between the mobile user and AAA in the MSA's network. Seed information needed to bootstrap the mobile node is considered in two cases:


o AAA authentication is mandatory for network access.

o AAA身份验证对于网络访问是强制性的。

o AAA authentication is not part of network access.

o AAA身份验证不是网络访问的一部分。

The seed information is described further in Section 8.


7.1. Mobility Service Subscription Scenario
7.1. 移动服务订阅场景

Many commercial deployments are based on the assumption that mobile nodes have a subscription with a service provider. In this scenario the MN has a subscription with an MSA, also called the home MSP, for Mobile IPv6 service. As stated in Section 6, the MSP is responsible for setting up a home agent on a subnet that acts as a Mobile IPv6 home link. As a consequence, the home MSP should explicitly authorize and control the whole bootstrapping procedure.


Since the MN is assumed to have a pre-established trust relationship 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-band means (i.e., manual configuration) before bootstrapping.


In order to guarantee ubiquitous service, the MN should be able to bootstrap MIPv6 operations with its home MSP from any possible access location, such as an open network or a network managed by an ASP, that may be different from the MSP and that may not have any pre-established trust relationship with it.


7.2. Integrated ASP Network Scenario
7.2. 集成ASP网络方案

In this scenario, the ASA and MSA are the same entity. The MN has security credentials for access to the network, and these credentials can also be used to bootstrap MIPv6.


Figure 1 describes an AAA design example for integrated ASP scenario.


                     | IASP(ASA+MSA)              |
        +----+    +-----+         +----+          |
        | MN |--- | NAS |         | HA |          |
        +----+    +-----+         +----+          |
                     | \            \             |
                     |  \ +------+   \ +-------+  |
                     |   -|AAA-NA|    -|AAA-MIP|  |
                     |    +------+     +-------+  |
                     | IASP(ASA+MSA)              |
        +----+    +-----+         +----+          |
        | MN |--- | NAS |         | HA |          |
        +----+    +-----+         +----+          |
                     | \            \             |
                     |  \ +------+   \ +-------+  |
                     |   -|AAA-NA|    -|AAA-MIP|  |
                     |    +------+     +-------+  |

NAS: Network Access Server AAA-NA: AAA for network access AAA-MIP: AAA for Mobile IP service


Figure 1. Integrated ASP network


7.3. Third-Party MSP Scenario
7.3. 第三方MSP场景

Mobility service has traditionally been provided by the same entity that authenticates and authorizes the subscriber for network access. This is certainly the only model supported by the base Mobile IPv6 specification.


In the third-party mobility service provider scenario, the subscription for mobility service is made with one entity (the MSA, is for instance, a corporate), but the actual mobility service is provided by yet another entity (such as an operator specializing in this service, the serving MSP). These two entities have a trust relationship. Transitive trust among the mobile node and these two entities may be used to assure the participants that they are dealing with trustworthy peers.


This arrangement is similar to the visited - home operator roaming arrangement for network access.


Figure 2 describes an example of a network for the third-party MSP scenario.


                +--------------+   +--------+
                |              |   |Serving |
                | ASP          |   | MSP    |
   +----+    +-----+           |   | +----+ |
   | MN |--- | NAS |           |   | | HA | |  +-------------------+
   +----+    +-----+           |===| +----+ |  | MSA               |
                | \            |   |    \   || (e.g., corporate NW)|
                |  \ +------+  |   |     \     | +-------+         |
                |   -|AAA-NA|  |   |      -------|AAA-MIP|         |
                |    +------+  |   |        |  | +-------+         |
                +------------  +   +--------+  +-------------------+
                +--------------+   +--------+
                |              |   |Serving |
                | ASP          |   | MSP    |
   +----+    +-----+           |   | +----+ |
   | MN |--- | NAS |           |   | | HA | |  +-------------------+
   +----+    +-----+           |===| +----+ |  | MSA               |
                | \            |   |    \   || (e.g., corporate NW)|
                |  \ +------+  |   |     \     | +-------+         |
                |   -|AAA-NA|  |   |      -------|AAA-MIP|         |
                |    +------+  |   |        |  | +-------+         |
                +------------  +   +--------+  +-------------------+

Figure 2. Third-Party MSP network


7.4. Infrastructure-less Scenario
7.4. 无基础设施方案

Infrastructure refers to network entities like AAA, Public-Key Infrastructure (PKI), and Home Location Register (HLR). "Infrastructure-less" implies that there is no dependency on any elements in the network with which the user has any form of trust relationship.


In such a scenario, there is absolutely no relationship between host and infrastructure.


A good example of infrastructure-less environment for MIPv6 bootstrapping is the IETF network at IETF meetings. It is possible that there could be MIP6 service available on this network (i.e., a MIPv6 HA). However, there is not really any AAA infrastructure or, for that matter, any trust relationship that a user attending the meeting has with any entity in the network.

MIPv6引导的无基础设施环境的一个很好的例子是IETF会议上的IETF网络。此网络上可能有MIP6服务可用(即,MIPv6 HA)。然而,实际上并不存在任何AAA基础设施,或者,就这一点而言,出席会议的用户与网络中的任何实体都没有任何信任关系。

This specific scenario is not supported in this document. The reason for this is described in Section 9.


8. Parameters for Authentication
8. 用于身份验证的参数

The following is a list of parameters that are used as the seed for the bootstrapping procedure. The parameters vary depending on whether authentication for network access is independent of authentication for mobility services. If different client identities are used for network access and mobility services, authentication for network access is independent of authentication for mobility services.


o Parameter Set 1

o 参数集1

In this case, authentication for network access is independent of authentication for mobility services.


If the home agent address is not known to the mobile node, the following parameter is needed for discovering the home agent address:


* The domain name or Fully Qualified Domain Name (FQDN) of the home agent

* 归属代理的域名或完全限定域名(FQDN)

This parameter may be derived in various ways, such as (but not limited to) static configuration, use of the domain name from the network access NAI (even if AAA for network access is not otherwise used), or use of the domain name of the serving ASP, where the domain name may be obtained via DHCP in the serving ASP.


If the home agent address is not known but the home subnet prefix is known, Dynamic Home Agent Address Discovery of Mobile IPv6 may be used for discovering the home agent address, and the above parameter may not be used.


When the home agent address is known to the mobile node, the following parameter is needed for performing mutual authentication between the mobile node and the home agent by using IKE:


* IKE credentials (*)

* IKE凭据(*)

In the case where the home agent does not have the entire set of IKE credentials, the home agent may communicate with another entity (for example, an AAA server) to perform mutual authentication in IKE. In such a case, the IKE credentials include the credentials used between the mobile node and the other entity. In the case where an AAA protocol is used for the communication between the home agent and the other entity during the IKE procedure, AAA for Mobile IPv6 service may be involved in IKE. If the authentication protocol [RFC4285] is used, the shared key-based security association with the home agent is needed.


o Parameter Set 2

o 参数集2

In this case, some dependency exists between authentication for network access and authentication for mobility services in that a security association that is established as a result of authentication for network access is re-used for authentication for mobility services.


All required information, including IKE credentials, is bootstrapped from the following parameter:


* Network access credentials(*)

* 网络访问凭据(*)

(*) A pair of an NAI and a pre-shared secret is an example of a set of credentials. A pair of an NAI and a public key, which may be provided as a digital certificate, is another example of a set of credentials.


9. Security Considerations
9. 安全考虑

There are two aspects of security for the Mobile IPv6 bootstrapping problem:


1. The security requirements imposed on the outcome of the bootstrapping process by RFC 3775 and other RFCs used by Mobile IPv6 for security.

1. RFC 3775和移动IPv6用于安全的其他RFC对引导过程结果施加的安全要求。

2. The security of the bootstrapping process itself, in the sense of threats to the bootstrapping process imposed by active or passive attackers.

2. 引导过程本身的安全性,从主动或被动攻击者对引导过程造成威胁的角度来看。

Note that the two are related; if the bootstrapping process is compromised, the level of security required by RFC 3775 may not be achieved.

请注意,这两者是相关的;如果引导过程被破坏,可能无法达到RFC 3775所要求的安全级别。

The following two sections discuss these issues.


9.1. Security Requirements of Mobile IPv6
9.1. 移动IPv6的安全要求

The Mobile IPv6 specification in RFC 3775 requires the establishment 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 data traffic. The security of an IPsec SA required by the relevant IPsec RFCs must be quite strong. Provisioning of keys and other cryptographic material during the establishment of the SA through bootstrapping must be done in a manner such that authenticity is proved and confidentiality is ensured. In addition, the generation of any keying material or other cryptographic material for 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 probability of such a compromise is to have the cryptographic material only known or calculable by the two end nodes that share the SA -- in this case, the home agent and mobile node. If other parties are involved in establishing the SA (through key distribution, for example) the process should follow the constraints designed to provide equivalent security.

RFC 3775中的移动IPv6规范要求在归属代理和移动节点之间建立IPsec SA的集合,以保护移动IP的信令流量,并且还可以选择保护数据流量。相关IPsec RFC所要求的IPsec SA的安全性必须非常强。在通过自举建立SA期间,密钥和其他加密材料的提供必须以证明真实性和确保机密性的方式进行。此外,为SA生成任何键控材料或其他密码材料的方式必须确保SA就位后的泄露概率最小化。将这种妥协的可能性降至最低的最佳方法是让共享SA的两个终端节点(在本例中为归属代理和移动节点)只知道或可计算加密材料。如果其他各方参与建立SA(例如,通过密钥分发),则流程应遵循旨在提供同等安全性的约束。

RFC 3775 also requires a trust relationship, as defined in Section 1.3, between the mobile node and its home agent(s). This is necessary, for instance, to ensure that fraudulent mobile nodes that attempt to flood other mobile nodes with traffic be not only shut off but tracked down. An infrastructureless relationship as defined in Section 1.3 does not satisfy this requirement. Any bootstrapping solution must include a trust relationship between mobile node and mobility service provider. Solutions that depend on an infrastructureless relationship are out of scope for bootstrapping.

RFC 3775还要求在移动节点及其归属代理之间建立第1.3节中定义的信任关系。例如,这是必要的,以确保尝试向其他移动节点大量发送流量的欺诈性移动节点不仅被关闭,而且被跟踪。第1.3节中定义的无基础设施关系不满足此要求。任何引导解决方案都必须包括移动节点和移动服务提供商之间的信任关系。依赖于无基础结构关系的解决方案不适用于引导。

Another requirement is that a home address be authorized to one specific host at a time. RFC 3775 requires this so that misbehaving mobile nodes can be shut down. This implies that, in addition to the IPsec SA, the home agent must somehow authorize the mobile node for a home address. The authorization can be either implicit (for example, as a side effect of the authentication for mobility service) or explicit. The authorization can either be done at the time the SA is created or be dynamically managed through a first come, first served allocation policy.

另一个要求是家庭地址必须一次授权给一个特定的主机。RFC3775要求这样才能关闭行为不端的移动节点。这意味着,除了IPsec SA之外,归属代理还必须以某种方式授权移动节点获得归属地址。授权可以是隐式的(例如,作为移动服务认证的副作用),也可以是显式的。授权可以在创建SA时完成,也可以通过先到先服务的分配策略进行动态管理。

9.2. Threats to the Bootstrapping Process
9.2. 对引导过程的威胁

Various attacks are possible on the bootstrapping process itself. These attacks can compromise the process such that the RFC 3775 requirements for Mobile IP security are not met, or they can serve simply to disrupt the process such that bootstrapping cannot be completed. Here are some possible attacks:

引导过程本身可能受到各种攻击。这些攻击可能会破坏该过程,从而无法满足RFC 3775对移动IP安全的要求,或者它们可能只是破坏该过程,从而无法完成引导。以下是一些可能的攻击:

o An attacking network entity purporting to offer the mobile node a legitimate home agent address or bootstrapping for the IPsec SAs may instead offer a bogus home agent address or configure bogus SAs that allow the home agent to steal the mobile node's traffic or otherwise disrupt the mobile node's mobility service.

o 声称为移动节点提供合法的归属代理地址或IPsec SAs引导的攻击网络实体可以改为提供虚假的归属代理地址或配置虚假的SAs,以允许归属代理窃取移动节点的流量或以其他方式中断移动节点的移动服务。

o An attacking mobile node may attempt to steal mobility service by offering up fake credentials to a bootstrapping network entity or otherwise disrupting the home agent's ability to offer mobility service.

o 攻击移动节点可能试图通过向自举网络实体提供虚假凭证或以其他方式破坏归属代理提供移动服务的能力来窃取移动服务。

o A man in the middle on the link between the mobile node and the bootstrapping network entity could steal credentials or other sensitive information and use that to steal mobility service or deny it to the legitimate owner of the credentials. Refer to Section 7.15 in [RFC3748] and [AAA-EAP-LLA] for further information.

o 中间人在移动节点和引导网络实体之间的链路上可以窃取凭据或其他敏感信息,并使用该信息来窃取移动性服务或将其拒绝给凭证的合法所有者。更多信息,请参阅[RFC3748]和[AAA-EAP-LLA]中的第7.15节。

o An attacker could arrange for a distributed denial-of-service attack on the bootstrapping entity, to disrupt legitimate users from bootstrapping.

o 攻击者可以在引导实体上安排分布式拒绝服务攻击,以中断合法用户的引导。

In addition to these attacks, there are other considerations that are important in achieving a good security design. As mobility and network access authentication are separate services, keys generated for these services need to be cryptographically separate, to be separately named, and to have separate lifetimes. This needs to be achieved even though the keys are generated from the same authentication credentials. This is necessary because a mobile node must be able to move from one serving (or roaming) network access provider to another without needing to change its mobility access provider. Finally, basic cryptographic processes must provide for multiple algorithms in order to accommodate the widely varying deployment needs; the need for replacement of algorithms when attacks become possible must also be considered in the design.


10. Contributors
10. 贡献者

This contribution is a joint effort of the problem statement design team of the Mobile IPv6 WG. The contributors include Basavaraj Patil, Gerardo Giaretta, Jari Arkko, James Kempf, Yoshihiro Ohba, Ryuji Wakikawa, Hiroyuki Ohnishi, Mayumi Yanagiya Samita Chakrabarti, Gopal Dommety, Kent Leung, Alper Yegin, Hannes Tschofenig, Vijay Devarapalli, and Kuntal Chowdury.


The design team members can be reached at the following email addresses:


Basavaraj Patil:


Gerardo Giaretta:


Jari Arkko:


James Kempf:


Yoshihiro Ohba:


Ryuji Wakikawa:


Hiroyuki Ohnishi:


Mayumi Yanagiya:


Samita Chakrabarti:


Gopal Dommety:


Kent Leung:


Alper Yegin:


Hannes Tschofenig:


Vijay Devarapalli:


Kuntal Chowdhury:


11. Acknowledgements
11. 致谢

Special thanks to James Kempf and Jari Arkko for writing the initial version of the bootstrapping statement. Thanks to John Loughney and T.J. Kniveton for their detailed reviews.

特别感谢James Kempf和Jari Arkko编写了bootstrapping声明的初始版本。感谢John Loughney和T.J.Kniveton的详细评论。

12. Informative References
12. 资料性引用

[RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H. Levkowetz, "Extensible Authentication Protocol (EAP)", RFC 3748, June 2004.

[RFC3748]Aboba,B.,Blunk,L.,Vollbrecht,J.,Carlson,J.,和H.Levkowetz,“可扩展身份验证协议(EAP)”,RFC 3748,2004年6月。

[AAA-EAP-LLA] Mariblanca, D., "EAP lower layer attributes for AAA protocols", Work in Progress, May 2004.


[RFC2794] Calhoun, P. and C. Perkins, "Mobile IP Network Access Identifier Extension for IPv4", RFC 2794, March 2000.

[RFC2794]Calhoun,P.和C.Perkins,“IPv4移动IP网络访问标识符扩展”,RFC 27942000年3月。

[RFC3041] Narten, T. and R. Draves, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 3041, January 2001.

[RFC3041]Narten,T.和R.Draves,“IPv6中无状态地址自动配置的隐私扩展”,RFC 3041,2001年1月。

[RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC 3753, June 2004.

[RFC3753]Way,J.和M.Kojo,“机动性相关术语”,RFC 3753,2004年6月。

[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004.

[RFC3775]Johnson,D.,Perkins,C.,和J.Arkko,“IPv6中的移动支持”,RFC 37752004年6月。

[RFC3776] Galvin, J., "IAB and IESG Selection, Confirmation, and Recall Process: Operation of the Nominating and Recall Committees", BCP 10, RFC 3777, June 2004.

[RFC3776]Galvin,J.,“IAB和IESG选择、确认和召回流程:提名和召回委员会的运作”,BCP 10,RFC 3777,2004年6月。

[RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K. Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 (MIPv6)", RFC 4283, November 2005.

[RFC4283]Patel,A.,Leung,K.,Khalil,M.,Akhtar,H.,和K.Chowdhury,“移动IPv6的移动节点标识符选项(MIPv6)”,RFC 4283,2005年11月。

[RFC4285] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K. Chowdhury, "Authentication Protocol for Mobile IPv6", RFC 4285, January 2006.

[RFC4285]Patel,A.,Leung,K.,Khalil,M.,Akhtar,H.,和K.Chowdhury,“移动IPv6认证协议”,RFC 4285,2006年1月。

Authors' Addresses


Alpesh Patel Cisco 170 W. Tasman Drive San Jose, CA 95134 USA


   Phone: +1 408 853 9580
   Phone: +1 408 853 9580

Gerardo Giaretta Telecom Italia via Reiss Romoli 274 Torino 10148 Italy

Gerardo Giaretta Telecom Italia via Reiss Romoli 274意大利都灵10148

   Phone: +39 011 228 6904
   Phone: +39 011 228 6904

Full Copyright Statement


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