PANA Working Group                                          P. Jayaraman
Internet-Draft                                                   Net.Com
Expires: September 4, 2006                                      R. Lopez
                                                         Univ. of Murcia
                                                           Y. Ohba (Ed.)
                                                                 Toshiba
                                                        M. Parthasarathy
                                                                   Nokia
                                                                A. Yegin
                                                                 Samsung
                                                           March 3, 2006


                             PANA Framework
                      draft-ietf-pana-framework-06

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   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
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on September 4, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   PANA (Protocol for carrying Authentication for Network Access) design



Jayaraman, et al.       Expires September 4, 2006               [Page 1]


Internet-Draft               PANA Framework                   March 2006


   provides support for various types of deployments.  Access networks
   can differ based on the availability of lower-layer security,
   placement of PANA entities, choice of client IP configuration and
   authentication methods, etc.  This document defines a general
   framework for describing how these various deployment choices are
   handled by PANA and the access network architectures.  Additionally,
   two possible deployments are described in detail: using PANA over DSL
   networks and wireless LANs.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Specification of Requirements  . . . . . . . . . . . . . .  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  General PANA Framework . . . . . . . . . . . . . . . . . . . .  6
   4.  Environments . . . . . . . . . . . . . . . . . . . . . . . . . 10
   5.  IP Address Configuration . . . . . . . . . . . . . . . . . . . 12
   6.  Data Traffic Protection  . . . . . . . . . . . . . . . . . . . 15
   7.  PAA-EP Protocol  . . . . . . . . . . . . . . . . . . . . . . . 16
     7.1.  PAA and EP Locations . . . . . . . . . . . . . . . . . . . 16
     7.2.  Notification of PaC Presence . . . . . . . . . . . . . . . 17
     7.3.  Filter Rule Installation . . . . . . . . . . . . . . . . . 18
   8.  Network Selection  . . . . . . . . . . . . . . . . . . . . . . 19
   9.  Authentication Method Choice . . . . . . . . . . . . . . . . . 21
   10. Example Cases  . . . . . . . . . . . . . . . . . . . . . . . . 22
     10.1. DSL Access Network . . . . . . . . . . . . . . . . . . . . 22
       10.1.1.  Bridging Mode . . . . . . . . . . . . . . . . . . . . 22
       10.1.2.  Router Mode . . . . . . . . . . . . . . . . . . . . . 23
       10.1.3.  PANA and Dynamic ISP Selection  . . . . . . . . . . . 24
     10.2. Wireless LAN Example . . . . . . . . . . . . . . . . . . . 25
       10.2.1.  PANA with Bootstrapping IPsec . . . . . . . . . . . . 25
       10.2.2.  PANA with Bootstrapping WPA/IEEE 802.11i  . . . . . . 29
       10.2.3.  Capability Discovery  . . . . . . . . . . . . . . . . 31
   11. Security Considerations  . . . . . . . . . . . . . . . . . . . 32
   12. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 33
   13. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 34
   14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 35
     14.1. Normative References . . . . . . . . . . . . . . . . . . . 35
     14.2. Informative References . . . . . . . . . . . . . . . . . . 36
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 38
   Intellectual Property and Copyright Statements . . . . . . . . . . 39









Jayaraman, et al.       Expires September 4, 2006               [Page 2]


Internet-Draft               PANA Framework                   March 2006


1.  Introduction

   PANA (Protocol for carrying Authentication for Network Access) is a
   link-layer agnostic network access authentication protocol that runs
   between a client that wants to gain access to the network and a
   server on the network side.  PANA defines a new EAP [RFC3748] lower
   layer that uses IP between the protocol end points.

   The motivation to define such a protocol and the requirements are
   described in [RFC4058].  Protocol details are documented in
   [I-D.ietf-pana-pana].  [I-D.ietf-pana-ipsec] describes use of IPsec
   for access control following PANA-based authentication.  IPsec can be
   used for per-packet security, but nevertheless it is not the only way
   to achieve this functionality.  Alternatives include reliance on
   physical security and link-layer ciphering.  The server for PANA may
   or may not be co-located with the entity enforcing the per-packet
   access control function.  When the server for PANA and per-packet
   access control entities are separate, SNMP [I-D.ietf-pana-snmp] may
   be used to carry information between the two nodes.

   PANA design provides support for various types of deployments.
   Access networks can differ based on the availability of lower-layer
   security, placement of PANA entities, choice of client IP
   configuration and authentication methods, etc.

   PANA is intended to be used in any access network regardless of the
   underlying security.  For example, the network might be physically
   secured, or secured by means of cryptographic mechanisms after the
   successful client-network authentication.

   The server for PANA and per-packet access control entities can be
   placed on various elements in the access network (e.g., access point,
   access router, dedicated host).

   IP address configuration mechanisms vary as well.  Static
   configuration, DHCP [RFC2131], stateless address auto-configuration
   [RFC2461] are possible mechanisms to choose from.  If the client for
   PANA configures an IPsec tunnel for enabling per-packet security,
   configuring IP addresses inside the tunnel becomes relevant, for
   which there are additional choices such as IKE [RFC2409].

   This document defines a general framework for describing how these
   various deployment choices are handled by PANA and the access network
   architectures.  Additionally, two possible deployments are described
   in detail: PANA over DSL (Digital Subscriber Line) networks and WLANs
   (Wireless LANs).





Jayaraman, et al.       Expires September 4, 2006               [Page 3]


Internet-Draft               PANA Framework                   March 2006


1.1.  Specification of Requirements

   In this document, several words are used to signify the requirements
   of the specification.  These words are often capitalized.  The key
   words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
   "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document
   are to be interpreted as described in [RFC2119].












































Jayaraman, et al.       Expires September 4, 2006               [Page 4]


Internet-Draft               PANA Framework                   March 2006


2.  Terminology

   Pre-PANA address (PRPA)

      This is an IP address configured on a client for PANA before
      starting the PANA exchange with a server for PANA.  This address
      may be unconfigured after a post-PANA address is configured.

   Post-PANA address (POPA)

      This is an IP address that is optionally configured on a client
      for PANA after successful authentication.  This address may be
      used for communicating with a server of PANA or any node in the
      Internet.

   IPsec Tunnel Inner Address (IPsec-TIA)

      This is an IP address configured on a client for PANA as the inner
      address of an IPsec tunnel mode SA (Security Association)
      established between the client and a per-packet access control
      element for IPsec-based access control.

   IPsec Tunnel Outer Address (IPsec-TOA)

      This is the address configured on a client for PANA as the outer
      address of an IPsec tunnel mode SA between the client and a per-
      packet access control element for IPsec-based access control.

   Secure Association Protocol

      A protocol that runs between a client for PANA and a per-packet
      access control element to provide a cryptographic binding between
      the initial entity authentication (and authorization) exchange to
      the subsequent exchange of data packets.  Examples of secure
      association protocols include the 4-way handshake in IEEE 802.11i
      [802.11i], and IKE [RFC2409] in IPsec-based access control.















Jayaraman, et al.       Expires September 4, 2006               [Page 5]


Internet-Draft               PANA Framework                   March 2006


3.  General PANA Framework

   PANA is designed to facilitate authentication and authorization of
   clients in access networks.  PANA is an EAP [RFC3748] lower-layer
   that carries EAP authentication methods encapsulated inside EAP
   between a client node and an agent in the access network.  While PANA
   enables the authentication process between the two entities, it is
   only a part of an overall AAA (Authentication Authorization and
   Accounting) and access control framework.  A AAA and access control
   framework using PANA is comprised of four functional entities.

   Figure 1 illustrates these functional entities and the interfaces
   (protocols, APIs) among them.  Note that PANA will not define API.

                                                 RADIUS/
                                                 Diameter/
           +-----+       PANA        +-----+     LDAP/ API    +-----+
           | PaC |<----------------->| PAA |<---------------->| AS  |
           +-----+                   +-----+                  +-----+
              ^                         ^
              |                         |
              |         +-----+         |
         IKE/ +-------->| EP  |<--------+ SNMP/ API
      4-way handshake   +-----+

                      Figure 1: PANA Functional Model

   PANA Client (PaC):

      The PaC is the client implementation of PANA.  This entity resides
      on the node that is requesting network access.  PaCs can be end
      hosts, such as laptops, PDAs, cell phones, desktop PCs, or routers
      that are connected to a network via a wired or wireless interface.
      A PaC is responsible for requesting network access and engaging in
      the authentication process using PANA.

   PANA Authentication Agent (PAA):

      The PAA is the server implementation of PANA.  A PAA is in charge
      of interfacing with the PaCs for authenticating and authorizing
      them for the network access service.

      The PAA consults an authentication server in order to verify the
      credentials and rights of a PaC.  If the authentication server
      resides on the same node as the PAA, an API is sufficient for this
      interaction.  When they are separated (a much more common case in
      public access networks), a protocol needs to run between the two.
      AAA protocols like RADIUS [RFC2865] and Diameter [RFC3588] are



Jayaraman, et al.       Expires September 4, 2006               [Page 6]


Internet-Draft               PANA Framework                   March 2006


      commonly used for this purpose.

      The PAA is also responsible for updating the access control state
      (i.e., filters) depending on the creation and deletion of the
      authorization state.  The PAA communicates the updated state to
      the Enforcement Points in the network.  If the PAA and EP are
      residing on the same node, an API is sufficient for this
      communication.  Otherwise, a protocol is required to carry the
      authorized client attributes from the PAA to the EP.  While not
      prohibiting other protocols, currently SNMP [I-D.ietf-pana-snmp]
      is suggested for this task.

      The PAA resides on a node that is typically called a NAS (network
      access server) in the access network.  For example on a BRAS
      (Broadband Remote Access Server) [DSL] in DSL networks, or PDSN
      (Packet Data Serving Node) [3GPP2] in 3GPP2 networks.  The PAA may
      be one or more IP hops away from the PaCs.

   Authentication Server (AS):

      The server implementation that is in charge of verifying the
      credentials of a PaC that is requesting the network access
      service.  The AS receives requests from the PAA on behalf of the
      PaCs, and responds with the result of verification together with
      the authorization parameters (e.g., allowed bandwidth, IP
      configuration, etc).  This is the server that terminates the EAP
      and the EAP methods.  The AS might be hosted on the same node as
      the PAA, on a dedicated node on the access network, or on a
      central server somewhere in the Internet.

   Enforcement Point (EP):

      The access control implementation that is in charge of allowing
      access (data traffic) of authorized clients while preventing
      access by others.  An EP learns the attributes of the authorized
      clients from the PAA.

      The EP uses non-cryptographic or cryptographic filters to
      selectively allow and discard data packets.  These filters may be
      applied at the link-layer or the IP-layer [I-D.ietf-pana-ipsec].
      When cryptographic access control is used, a secure association
      protocol needs to run between the PaC and EP.  After completion of
      the secure association protocol, link or network layer per-packet
      security (for example TKIP, IPsec ESP) is enabled for integrity
      protection, data origin authentication, replay protection and
      optionally confidentiality protection.





Jayaraman, et al.       Expires September 4, 2006               [Page 7]


Internet-Draft               PANA Framework                   March 2006


      An EP must be located strategically in a local area network to
      minimize the access of unauthorized clients to the network.  For
      example, the EP can be hosted on the switch that is directly
      connected to the clients in a wired network.  That way the EP can
      drop unauthorized packets before they reach any other client node
      or beyond the local area network.

   Some of the entities may be co-located depending on the deployment
   scenario.  For example, the PAA and EP would be on the same node
   (BRAS) in DSL networks.  In that case a simple API is sufficient
   between the PAA and EP.  In small enterprise deployments the PAA and
   AS may be hosted on the same node (access router) that eliminates the
   need for a protocol run between the two.  The decision to co-locate
   these entities or otherwise, and their precise location in the
   network topology are deployment decisions that are out of the scope
   of this document.

   Use of IKE or IEEE 802.11i 4-way handshake protocols for secure
   association is only required in the absence of any lower-layer
   security prior to running PANA.  Physically secured networks (e.g.,
   DSL) or the networks that are already cryptographically secured on
   the link-layer prior to PANA run (e.g., cdma2000) do not require
   additional secure association and per-packet security.  These
   networks can bind the PANA authentication and authorization to the
   lower-layer secure channel that is already available.

   Figure 2 illustrates the signaling flow for authorizing a client for
   network access.

                  PaC             EP               PAA              AS
                   |               |                |                |
      IP address ->|               |                |                |
      config.      |       PANA    |                |      AAA       |
                   |<------------------------------>|<-------------->|
                   |               |     SNMP       |                |
      (Optional)   |               |<-------------->|                |
      IP address ->|               |                |                |
      reconfig.    |   Sec.Assoc.  |                |                |
                   |<------------->|                |                |
                   |               |                |                |
                   |  Data traffic |                |                |
                   |<----------------->             |                |
                   |               |                |                |

                       Figure 2: PANA Signaling Flow

   The EP on the access network allows general data traffic from any
   authorized PaC, whereas it allows only limited type of traffic (e.g.,



Jayaraman, et al.       Expires September 4, 2006               [Page 8]


Internet-Draft               PANA Framework                   March 2006


   PANA, DHCP, router discovery, etc.) for the unauthorized PaCs.  This
   ensures that the newly attached clients have the minimum access
   service to engage in PANA and get authorized for the unlimited
   service.

   The PaC MUST dynamically or statically configure an IP address prior
   to running PANA.  After the successful PANA authentication, depending
   on the deployment scenario the PaC MAY need to re-configure its IP
   address or configure additional IP address(es).  The additional
   address configuration MAY be executed as part of the secure
   association protocol run (e.g., via IKE).  If this additional IP
   address configuration happens in the middle of an application
   protocol run, an appropriate procedure for changing an IP address
   will need to be taken so that the IP address change is transparent to
   the application protocol.

   An initially unauthorized PaC starts the PANA authentication by
   discovering the PAA, followed by the EAP exchange over PANA.  The PAA
   interacts with the AS during this process.  Upon receiving the
   authentication and authorization result from the AS, the PAA informs
   the PaC about the result of its network access request.

   If the PaC is authorized to gain the access to the network, the PAA
   also sends the PaC-specific attributes (e.g., IP address,
   cryptographic keys, etc.) to the EP by using another protocol (e.g.,
   SNMP).  The EP uses this information to alter its filters for
   allowing data traffic from and to the PaC to pass through.

   In case cryptographic access control needs to be enabled after the
   PANA authentication, a secure association protocol runs between the
   PaC and the EP.  The PaC should already have the input parameters to
   this process as a result of the successful PANA exchange.  Similarly,
   the EP should have obtained them from the PAA during the service
   provisioning.  The secure association protocol exchange produces the
   required security associations between the PaC and the EP to enable
   cryptographic data traffic protection.  Per-packet cryptographic data
   traffic protection introduces additional per-packet overhead but the
   overhead exists only between the PaC and EP and will not affect
   communications beyond the EP.

   Finally, filters that are installed at the EP allow general purpose
   data traffic to flow between the PaC and the intranet/Internet.









Jayaraman, et al.       Expires September 4, 2006               [Page 9]


Internet-Draft               PANA Framework                   March 2006


4.  Environments

   PANA can be used on any network environment whether there is a lower-
   layer secure channel prior to PANA, or one has to be enabled upon
   successful PANA authentication.

   With regard to network access authentication two types of networks
   need to be considered:

   a. Networks where a secure channel is already available prior to
   running PANA

      This type of network is characterized by the existence of
      protection against spoofing and eavesdropping.  Nevertheless, user
      authentication and authorization is required for network
      connectivity.

      One example is a DSL network where the lower-layer security is
      provided by physical means (a.1).  Physical protection of the
      network wiring ensures that practically there is only one client
      that can send and receive IP packets on the link.  Another example
      is a cdma2000 network where the lower-layer security is provided
      by means of cryptographic protection (a.2).  By the time the
      client requests access to the network-layer services, it is
      already authenticated and authorized for accessing the radio
      channel, and link-layer ciphering is enabled.

      The presence of a secure channel before PANA exchange eliminates
      the need for executing a secure association protocol after PANA.
      The PANA session can be bound to the communication channel it was
      carried over.  Also, the choice of EAP authentication method
      depends on the presence of this security during PANA run.  For
      example, weak authentication methods, such as EAP-MD5, may be used
      for such networks but not for the others.

   b. Networks where a secure channel is created after running PANA

      These are the networks where there is no lower-layer protection
      prior to running PANA.  A successful PANA authentication enables
      generation of cryptographic keys that are used with a secure
      association protocol to enable per-packet cryptographic
      protection.

      PANA authentication is run on an insecure channel that is
      vulnerable to eavesdropping and spoofing.  The choice of EAP
      method must be resilient to the possible attacks associated with
      such an environment.  Furthermore, the EAP method must be able to
      create cryptographic keys that will later be used by the secure



Jayaraman, et al.       Expires September 4, 2006              [Page 10]


Internet-Draft               PANA Framework                   March 2006


      association protocol.

      Whether to use a link-layer per-packet security (b.1) or a network
      layer security (b.2) is a deployment decision and outside the
      scope of this document.  This decision also dictates the choice of
      the secure association protocol.  If link-layer protection is
      used, the protocol would be link-layer specific.  If IP-layer
      protection is used, the secure association protocol would be IKE
      and the per-packet security would be provided by IPsec AH/ESP
      regardless of the underlying link-layer technology.









































Jayaraman, et al.       Expires September 4, 2006              [Page 11]


Internet-Draft               PANA Framework                   March 2006


5.  IP Address Configuration

   The PaC configures an IP address before the PANA exchange begins.
   This address is called a pre-PANA address (PRPA).  After a successful
   authentication, the client may have to configure a post-PANA address
   (POPA) for communication with other nodes, if the PRPA is a local-use
   (e.g., a link-local or private address) or a temporarily allocated IP
   address.  An operator might choose allocating a POPA only after
   successful PANA authorization either to prevent waste of premium
   (e.g., globally routable) IP resources until the client is
   authorized, or to enable client identity based address assignment.

   There are different methods by which a PRPA can be configured.

   1. In some deployments (e.g., DSL networks) the PaC may be statically
      configured with an IP address.  This address SHOULD be used as a
      PRPA.

   2. In IPv4, some clients attempt to configure an address dynamically
      using DHCP [RFC2131].  If they are unable to configure an address
      using DHCP, they can configure a link-local address using
      [RFC3927].

      When the network access provider is able to run a DHCP server on
      the access link, the client would configure the PRPA using DHCP.
      This address may be from a private address pool [RFC1918].  Also,
      the lease time on the address may vary.  For example, a PRPA
      configured solely for running PANA can have a short lease time.
      The PRPA may be used for local-use only (i.e., only for on-link
      communication, such as for PANA and IPsec tunneling with EP), or
      also for ultimate end-to-end data communication.

      In case there is no running DHCP server on the link, the client
      would fall back to configuring a PRPA via zeroconfiguration
      technique [RFC3927].  This yields a long-term address that can
      only be used for on-link communication.  (Note: At time of this
      writing, the zeroconfiguration technique is not widely implemented
      in routers.)

   3. In IPv6, clients automatically configure a link-local address
      [RFC2462] when they initialize an interface.  Additionally, they
      may also configure global address(es) when DHCP or router
      advertisements with global prefixes are made available to the
      them.

   In case PAA is not on the same IP subnet as the PaCs are, the
   deployment must ensure that a non-link-local PRPA is configurable by
   the clients.



Jayaraman, et al.       Expires September 4, 2006              [Page 12]


Internet-Draft               PANA Framework                   March 2006


   When a PRPA is configured, the client starts the PANA exchange.  By
   that time, a dual stacked client might have configured both an IPv4
   address and an IPv6 address as PRPAs.  Regardless of whether the PaC
   has both IPv4 and IPv6 PRPAs or only one of those, only one PANA run
   is required.  A dual-stack device that implements PaC or PAA MUST be
   able to run PANA over both IPv4 and IPv6.  When a dual-stack PaC or
   PAA initiates PANA authentication, it chooses either IPv4 or IPv6
   where the choice is made depending on the deployment.  A dual-stack
   PaC or PAA that is initiated PANA authentication by its peer MUST use
   the same IP version that the peer is using.

   When the client successfully authenticates to the network, it may be
   required to configure POPAs for its subsequent data communication
   with the other nodes.

   If the client is already configured with an address that can be used
   with data communication, it is not required to configure a POPA.
   Otherwise, the PANA-Bind-Request message allows the PAA to indicate
   the available configuration methods to the PaC.  The PaC can choose
   one of the methods and act accordingly.

   1. If the network relies on physical or link layer security, the PaC
      can configure a POPA using DHCP [RFC2131] [RFC3315] or using IPv6
      stateless auto-configuration [RFC2461].  An IPv4 PRPA SHOULD be
      unconfigured when the POPA is configured to prevent IPv4 address
      selection problem [RFC3927].  If IPv6 is used, the link-local PRPA
      SHOULD NOT be unconfigured [RFC3484].

      If the PaC is a dual-stacked node, it can configure both IPv4 and
      IPv6 type POPAs.  The available POPA configuration methods are
      indicated within PANA.

   2. If the network uses IPsec for protecting the traffic on the link
      subsequent to PANA authentication [I-D.ietf-pana-ipsec], the PaC
      would use the PRPA as the outer address of IPsec tunnel mode SA
      (IPsec-TOA).  The PaC also needs to configure an inner address
      (IPsec-TIA).  There are different ways to configure an IPsec-TIA
      which are indicated in a PANA-Bind-Request message.

      When an IPv4 PRPA is configured, the same address may be used as
      both IPsec-TOA and IPsec-TIA.  In this case, a POPA is not
      configured.  Alternatively, an IPsec-TIA can be obtained via the
      configuration method available within [RFC3456] for IPv4,
      [RFC4307] for both IPv4 and IPv6.  This newly configured address
      constitutes a POPA.  Please refer to [I-D.ietf-pana-ipsec] for
      more details.





Jayaraman, et al.       Expires September 4, 2006              [Page 13]


Internet-Draft               PANA Framework                   March 2006


      IKEv2 [RFC4307] can enable configuration of one IPv4 IPsec-TIA and
      one IPv6 IPsec-TIA for the same IPsec tunnel mode SA.  Therefore,
      IKEv2 is recommended for handling dual-stacked PaCs where single
      execution of PANA and IKE is desired.  In this case, the same IP
      version that has been used for PANA is used for IKE, and the IKE
      entity on the dual-stack PaC will request one or both of IPv4 and
      IPv6 IPsec-TIAs from the IKE entity on the EP and obtain the
      one(s) that is(are) available on the EP.

   Although there are potentially a number of different ways to
   configure a PRPA, and POPA when necessary, it should be noted that
   the ultimate decision to use one or more of these in a deployment
   depends on the operator.  The decision is dictated by the operator's
   choice of per-packet protection capability (physical and link-layer
   vs network-layer), PRPA type (local and temporary vs global and long-
   term), and POPA configuration mechanisms available in the network.



































Jayaraman, et al.       Expires September 4, 2006              [Page 14]


Internet-Draft               PANA Framework                   March 2006


6.  Data Traffic Protection

   Protecting data traffic of authenticated and authorized client from
   others is another component of providing a complete secure network
   access solution.  Authentication, integrity and replay protection of
   data packets is needed to prevent spoofing when the underlying
   network is not physically secured.  Encryption is needed when
   eavesdropping is a concern in the network.

   When the network is physically secured, or the link-layer ciphering
   is already enabled prior to PANA, data traffic protection is already
   in place.  In other cases, enabling link-layer ciphering or network-
   layer ciphering might rely on PANA authentication.  The user and
   network have to make sure that an appropriate EAP method which
   generates keying materials is used.  Once the keying material is
   available, it needs to be provided to the EP(s) for use with data
   traffic protection.

   Network-layer protection, i.e., IPsec, can be used when data traffic
   protection is required but link-layer protection is not available.
   Note that the keying material generated by an EAP method is
   insufficient to be used alone by IPsec AH/ESP or most link layer
   mechanisms.  In addition to the fresh and unique session key derived
   from the EAP method, IPsec also needs both traffic selectors and
   other IPsec SA parameters are missing.  The shared secret can be used
   in conjunction with a key management protocol like IKE [RFC2409] to
   turn a session key into the required IPsec SA.  The details of such a
   mechanism is outside the scope of PANA and is specified in [I-D.ietf-
   pana-ipsec].  PANA provides bootstrapping functionality for such a
   mechanism by carrying EAP methods that can generate initial keying
   material.

   Using network-layer ciphers should be regarded as a substitute for
   link-layer ciphers when the latter is not available.  Network-layer
   ciphering can also be used in addition to link-layer ciphering if the
   added benefits outweigh its cost to the user and the network.  In
   this case, PANA bootstraps only the network-layer ciphering; link-
   layer ciphering is enabled using any of the existing link-layer
   specific methods.












Jayaraman, et al.       Expires September 4, 2006              [Page 15]


Internet-Draft               PANA Framework                   March 2006


7.  PAA-EP Protocol

   PANA provides client authentication and authorization functionality
   for securing network access.  The other component of a complete
   solution is the access control which ensures that only authenticated
   and authorized clients can gain access to the network.  PANA enables
   access control by distinguishing authenticated and authorized clients
   from others and generating filtering information for access control
   mechanisms.

   Access control can be achieved by placing EPs (Enforcement Points) in
   the network for policing the traffic flow.  EPs should prevent data
   traffic from and to any unauthorized client unless it's either PANA
   or one of the other allowed traffic types (e.g., ARP, IPv6 neighbor
   discovery, DHCP, etc.).

   When a PaC is authenticated and authorized, the PAA should notify
   EP(s) and ask for installing filtering rules to allow the PaC to send
   and receive data traffic.  When the PAA and EP(s) are not co-located,
   they MUST implement SNMP [I-D.ietf-pana-snmp] for the PAA-EP
   communication.  They MAY optionally implement and use other standard
   or proprietary protocols as well.

   This section describes the possible models on the location of PAA and
   EP, as well as the basic authorization information that needs to be
   exchanged between PAA and EP.  When PAA and EP are not co-located in
   a single device, there are other issues such as dead or rebooted peer
   detection and consideration for specific authorization and accounting
   models.  However, these issues are closely related to the PAA-EP
   protocol solution and thus not discussed in this document.  See
   [I-D.ietf-pana-snmp] for further discussion.

7.1.  PAA and EP Locations

   EPs' location in the network topology should be appropriate for
   performing access control functionality.  When the access control is
   performed at link-layer, an IP-capable access device on the same link
   as the client devices is the logical choice.  When IPsec-based or
   non-cryptographic access control mechanisms are used, the EPs'
   location can range from the first-hop router to other routers within
   the access network.  The first-hop router may be preferred in order
   to limit the access of unauthorized IP traffic.

   PAA and EPs should be aware of each other as this is necessary for
   access control.  Generally this can be achieved by manual
   configuration.  Dynamic discovery is another possibility, but this is
   left to implementations and outside the scope of this document.




Jayaraman, et al.       Expires September 4, 2006              [Page 16]


Internet-Draft               PANA Framework                   March 2006


   Since PANA allows the separation of EP and PAA, there are several
   models depending on the number of EPs and PAAs and their locations.

   In the simplest model, the PAA and EP are co-located on the same
   device.  In this model, the PAA-EP communication is implemented
   locally by using an API.  When there are multiple such co-located
   devices in the same IP subnet, only the PAA co-locating with the EP
   that is closest to the PaC among all EPs in the same subnet needs to
   be discovered by the PaC in order to perform per-packet access
   control appropriately.  To achieve this, each PAA/EP device on an
   link-layer switch or access point MUST NOT forward multicast PANA
   discovery message sent by PaCs attached to it to other devices.  This
   model is suitable for an access network with a small number of EPs.

   In the other model, the PAA and EP are separated into multiple
   devices and they communicate using a PAA-EP protocol such as SNMP.  A
   typical scenario is that a single PAA controls multiple EPs
   (Figure 3).  While this model is complex compared to the first model,
   it is particularly useful in an access network with a large number of
   EPs because it eliminates EAP messaging when the PaC switches from
   one EP to another in the same access network without inter-PAA
   communications.  In a more complex scenario, the single PAA may be
   replaced with multiple PAAs to avoid a single point of failure.
   Those PAAs may or may not be co-located with EPs.

                                   +---+
                                   |EP |--+
                                   +---+   \
                                            \
                          +---+    +---+    +---+
                          |PaC|    |EP |----|PAA|
                          +---+    +---+    +---+
                                            /
                                   +---+   /
                                   |EP |--+
                                   +---+

       Figure 3: An example model for a single PAA and multiple EPs

7.2.  Notification of PaC Presence

   When PAA and EP are separated and PAA is configured to be the
   initiator of the discovery and initial handshake phase of PANA, EP
   has the responsibility to detect presence of a new PaC and notifies
   the PAA(s) of the presence [RFC4058].  Such a presence notification
   is carried in a PAA-EP protocol message [I-D.ietf-pana-snmp].





Jayaraman, et al.       Expires September 4, 2006              [Page 17]


Internet-Draft               PANA Framework                   March 2006


7.3.  Filter Rule Installation

   Filtering rules to be installed on EP generally include a device
   identifier of PaC, and also cryptographic keying material (e.g., IKE
   pre-shared key [RFC2409]) when cryptographic data traffic protection
   is needed (See Section 6).  Each keying material is uniquely
   identified with a keying material name (e.g., ID_KEY_ID in IKE
   [RFC2409]) and has a lifetime for key management, accounting, access
   control and security reasons in general.  In addition to the device
   identifier and keying material, other filter rules, such as the IP
   filter rules specified in NAS-Filter-Rule AVPs carried in Diameter
   EAP application [RFC4072] may be installed on EP.  When IPsec is used
   the filter rules are applied to IP packets carried inside the IPsec
   tunnel, otherwise, the filter rules are applied to IP packets that
   are not protected with IPsec.




































Jayaraman, et al.       Expires September 4, 2006              [Page 18]


Internet-Draft               PANA Framework                   March 2006


8.  Network Selection

   The network selection problem statement is made in [I-D.ietf-eap-
   netsel-problem].  PANA [I-D.ietf-pana-pana] provides a way for
   networks to advertise which ISPs are available and for a PaC to
   choose one ISP from the advertised information.  When the PaC chooses
   an ISP in the PANA exchange, the ultimate destination of the AAA
   exchange is determined based on the identity of the chosen service
   provider.  It is also possible that the PaC does not choose a
   specific ISP in the PANA exchange.  In this case, both the ISP choice
   and the AAA destination are determined based on the PaC's identity,
   where the identifier may be an NAI [RFC2486] or the physical port
   number or link-layer address of the subscriber.

   As described in [I-D.ietf-eap-netsel-problem], network selection is
   not only related to AAA routing but also related to payload routing.
   Once an ISP is chosen and the PaC is successfully authenticated and
   authorized, the PaC is assigned an address by the ISP.

   Consider a typical DSL network where the AR (access router), EP, and
   PAA are co-located on a BRAS in the access network operated by a NAP
   (Network Access Provider).  Figure 4 shows a typical model for ISP
   selection.

                   <---- NAP ----><--------- ISP --------->

                                        +---ISP1
                                       /
                  +---+    +---------+/
                  |PaC|----|AR/EP/PAA|
                  +---+    +---------+\
                               BRAS    \
                                        +---ISP2

                    Figure 4: A Network Selection Model

   When network selection is made at network-layer with the use of PANA
   instead of link-layer specific authentication mechanisms, the IP link
   between the PaC and PAA needs to exist prior to doing PANA (and prior
   to network selection).  In this model, the PRPA is either given by
   the NAP or a link-local address is auto-configured.  After the
   successful authentication with the ISP, the PaC may acquire an
   address (POPA) from the ISP.  It also learns the address of the
   access router (AR), e.g., through DHCP, to be used as its default
   router.  The address of the AR may or may not be in the same IP
   subnet as that of the PaC's POPA.  Note that the physically secured
   DSL networks do not require IPsec-based access control.  Therefore
   the PaC uses one IP address at a time where the POPA replaces the



Jayaraman, et al.       Expires September 4, 2006              [Page 19]


Internet-Draft               PANA Framework                   March 2006


   PRPA upon configuration.


















































Jayaraman, et al.       Expires September 4, 2006              [Page 20]


Internet-Draft               PANA Framework                   March 2006


9.  Authentication Method Choice

   Authentication methods' capabilities and therefore applicability to
   various environments differ among them.  Not all methods provide
   support for mutual authentication, key derivation or distribution,
   and DoS attack resiliency that are necessary for operating in
   insecure networks.  Such networks might be susceptible to
   eavesdropping and spoofing, therefore a stronger authentication
   method needs to be used to prevent attacks on the client and the
   network.

   The authentication method choice is a function of the underlying
   security of the network (e.g., physically secured, shared link,
   etc.).  It is the responsibility of the user and the network operator
   to pick the right method for authentication.  PANA carries EAP
   regardless of the EAP method used.  It is outside the scope of PANA
   to mandate, recommend, or limit use of any authentication methods.
   PANA cannot increase the strength of a weak authentication method to
   make it suitable for an insecure environment.  PANA can carry these
   EAP encapsulating methods but it does not concern itself with how
   they achieve protection for the weak methods (i.e., their EAP method
   payloads).





























Jayaraman, et al.       Expires September 4, 2006              [Page 21]


Internet-Draft               PANA Framework                   March 2006


10.  Example Cases

10.1.  DSL Access Network

   In a DSL access network, PANA is seen applicable in the following
   scenarios.

   A typical DSL access consists of an access router (BRAS -- Broadband
   Remote Access Server) [DSL] in the DSL access provider network, and a
   bridge/router (DSL Modem/Routing Gateway) in the customer premises
   network (CPN) that is in charge of connecting the CPN to the DSL
   network.  The DSL Modem/RG supports multiple modes of operation and
   PANA is applicable in each of these modes.

   In the current DSL deployment, a DSLAM (DSL Access Multiplexor) which
   is placed between the DSL Modem/RG and the BRAS is a transparent
   device from PANA perspective.  In a future DSL model, the PAA may
   reside in the DSLAM which may directly connect ISP routers through
   VLANs.

            Host--+                                     +-- ISP1
                  |                  DSL link           |
                  +-- DSL Modem/RG --- DSLAM --- BRAS --+-- ISP2
                  |                                     |
            Host--+                                     +-- ISP3

          <-------- CPN --------> <------ NAP ------> <-- ISP -->

                            Figure 5: DSL Model

   The devices at the customer premises have been shown as "hosts" in
   the above network.

   DSL networks are protected by physical means.  Eavesdropping and
   spoofing attacks are prevented by keeping the unintended users
   physically away from the network media.  Therefore, generally
   cryptographic protection of data traffic is not common.
   Nevertheless, if enhanced security is deemed necessary for any
   reason, IPsec-based access control can be enabled on DSL networks as
   well by using the method described in [I-D.ietf-pana-ipsec].

10.1.1.  Bridging Mode

   In the bridging mode, the DSL Modem/RG acts as a simple link-layer
   bridge.  The hosts in the CPN will function as clients to obtain
   addresses from the BRAS by using DHCP or PPPoE.

   If PPPoE is used, authentication is typically performed using CHAP or



Jayaraman, et al.       Expires September 4, 2006              [Page 22]


Internet-Draft               PANA Framework                   March 2006


   MS-CHAP.

   PANA will be applicable when the hosts use DHCP to obtain an IP
   address.  DHCP does not support authentication of the devices on
   either side of the DSL access line.  In the simplest method of
   address assignment, the BRAS will allocate the IP address to a host
   with a lease time reasonably sufficient to complete a full PANA based
   authentication which will be triggered immediately after the address
   assignment.  The hosts will perform the PaC function and the BRAS
   will perform the PAA, EP and AR functions.

            Host--+
            (PaC) |
                  +-- DSL Modem/RG --- DSLAM --- BRAS ----- ISP
                  |     (Bridge)             (PAA,EP,AR)
            Host--+
            (PaC)

                           Figure 6: Bridge Mode

   The DSL service provider's trunk network should not be accessible to
   any host that has not successfully completed the PANA authentication
   phase.

10.1.2.  Router Mode

   In this mode, the DSL Modem/RG acts as a router for the CPN.  The DSL
   Modem/RG itself may obtain the IP address using DHCP or be configured
   with a static IP address.  Once the DSL Modem/RG is authenticated
   using PANA and is provided access to the service provider's network,
   the BRAS should begin exchanging routing updates with the DSL
   Modem/RG.  All devices at the customer premises will then have access
   to the service provider's network.

            Host--+
                  |
                  +-- DSL Modem/RG --- DSLAM --- BRAS ----- ISP
                  |   (Router, PaC)          (PAA,EP,AR)
            Host--+

                           Figure 7: Router Mode

   It is possible that both ends of the DSL link are configured with
   static IP addresses.  PANA-based mutual authentication of PaC and PAA
   is desirable before data traffic is exchanged between the CPN and the
   service provider network.  The DSL Modem/RG may also use NAPT
   (Network Address Port Translation).




Jayaraman, et al.       Expires September 4, 2006              [Page 23]


Internet-Draft               PANA Framework                   March 2006


10.1.3.  PANA and Dynamic ISP Selection

   In some installations, a BRAS is shared by multiple service
   providers.  Each service provider configures the BRAS with a certain
   IP address space.

   The devices at the customer premises network indicate their choice of
   service provider and the BRAS chooses the IP address from the
   appropriate service provider's pool.  In many cases, the address is
   assigned not by the BRAS but by the AAA server that is managed fully
   by the service provider.

   This simplifies the management of the DSL access network as it is not
   always necessary to configure each DSL access line with the service
   provider's identity.  The service provider is chosen dynamically by
   the DSL Modem/RG.  This is typically known as "dynamic Internet
   Service Provider selection".  The AAA function is usually overloaded
   to perform dynamic ISP selection.

10.1.3.1.  Selection as Part of the DHCP protocol or an Attribute of DSL
           Access Line

   The ISP selection, therefore the IP address pool, can be conveyed
   based on the DHCP protocol exchange using, e.g., the 'client-id'
   field of a DHCP packet, or by associating the DSL access line to the
   service provider before the PANA authentication begins.  When any of
   these schemes is used, the IP address used during PANA authentication
   (PRPA) is the ultimate IP address and it does not have to be changed
   upon successful authorization.

10.1.3.2.  Selection as Part of the PANA Authentication

   The ISP selection of the client can be explicitly conveyed during the
   PANA authentication (see "Network Selection" in [I-D.ietf-pana-
   pana]).  In that case, the client can be assigned a temporary IP
   address (PRPA) prior to PANA authentication.  This IP address might
   be obtained via DHCP with a lease reasonably long to complete PANA
   authentication, or via the zeroconf technique [RFC3927].  In either
   case, successful PANA authentication signalling prompts the client to
   obtain a new (long term) IP address via DHCP.  This new IP address
   (POPA) replaces the previously allocated temporary IP address.

   The devices at the customer premises have been shown as "hosts" in
   the above network.

   The document specifically describes the use of PANA in non-PPP-based
   DSL deployments.  These are the deployments that lack a standard
   network access authentication protocol between the customer premise



Jayaraman, et al.       Expires September 4, 2006              [Page 24]


Internet-Draft               PANA Framework                   March 2006


   and the NAP.

10.2.  Wireless LAN Example

   This section describes how PANA can be used on WLANs.  PANA may
   bootstrap either link-layer or IP-layer security.  IP-layer security
   uses IPsec-based data traffic protection, bootstrapped by PANA.  When
   IP-layer security is used, link-layer security is not necessary.  The
   PAA indicates to the PaC whether IP-layer or link-layer protection is
   necessary via the Protection-Capability AVP in a PANA-Bind-Request
   message.  The most common deployment cases are expected to be (1) a
   co-located EP and Access Point (AP) bootstrapping link-layer
   security, or (2) an Access Router (AR) co-located with a PAA (and
   perhaps an EP) bootstrapping IP-layer security.  These cases are
   depicted together in Figure 8.

                        +-----+
                        |AP/EP|----+
                        +-----+    |
                                   |
           +---+        +-----+    |    +---------+
           |PaC|        |AP/EP|----+----|AR/PAA/EP|----- Internet
           +---+        +-----+    |    +---------+
                                   |
                        +-----+    |
                        |AP/EP|----+
                        +-----+

                     Figure 8: PANA Wireless LAN Model

10.2.1.  PANA with Bootstrapping IPsec

   In this model, data traffic is protected by using IPsec tunnel mode
   SA and an IP address is used as the device identifier of the PaC (see
   Section 5 for details).  Some or all of AP, DHCPv4 Server (including
   PRPA DHCPv4 Server and IPsec-TIA DHCPv4 Server), DHCPv6 Server, PAA
   and EP may be co-located in a single device.  EP is always co-located
   with AR and may be co-located with PAA.  When EP and PAA are not co-
   located, PAA-EP protocol is used for communication between PAA and
   EP.

   Note that for all of the cases described in this section, a PBR
   (PANA-Bind-Request) and PBA (PANA-Bind-Answer) exchange in PANA
   [I-D.ietf-pana-pana] should occur after installing the authorization
   parameter to the AR, so that IKE can be performed immediately after
   the PANA authentication is successfully completed.  The PAA can
   obtain the required device identifier (i.e., the IPsec-TOA in this
   case) to be installed on the AR from the IP header of a PANA message



Jayaraman, et al.       Expires September 4, 2006              [Page 25]


Internet-Draft               PANA Framework                   March 2006


   sent by the PaC before sending the PBR.  However, when the PBR/PBA
   exchange fails, the authorization parameters already installed on the
   AR must be immediately revoked to avoid unauthorized access.

10.2.1.1.  IPv4

   Case A: IPsec-TIA obtained by using DHCPv4

      In this case, the IPsec-TIA and IPsec-TOA are the same as the
      PRPA, and all configuration information including the IP address
      is obtained by using DHCPv4 [RFC2131].  No POPA is configured.
      Case A is the simplest compared to other ones and might be used in
      a network where IP address depletion attack on DHCP is not a
      significant concern.  The PRPA needs to be a routable address
      unless NAT is performed on AR.

        PaC           AP      DHCPv4 Server      PAA          EP(AR)
         | Link-layer |             |             |             |
         | association|             |             |             |
         |<---------->|             |             |             |
         |            |             |             |             |
         |           DHCPv4         |             |             |
         |<-----------+------------>|             |             |
         |            |                           |             |
         |PANA(Discovery and handshake phase      |             |
         |     & PAR/PAN exchange in authentication             |
         |       and authorization phase)         |             |
         |<-----------+-------------------------->|             |
         |            |                           |             |
         |            |                           |Authorization|
         |            |                           |[IKE-PSK,    |
         |            |                           | PaC-DI,     |
         |            |                           | Session-Id] |
         |            |                           |------------>|
         |            |                           |             |
         |PANA(PBR/PBA exchange in                |             |
         |     authentication and authorization phase)          |
         |<-----------+-------------------------->|             |
         |            |                           |             |
         |            |            IKE            |             |
         |<-----------+---------------------------------------->|
         |            |                           |             |

         Figure 9: An example case for configuring IPsec-TIA by using
                                    DHCPv4






Jayaraman, et al.       Expires September 4, 2006              [Page 26]


Internet-Draft               PANA Framework                   March 2006


   Case B: IPsec-TIA obtained by using IKE

      Like Case A, the PRPA is obtained by using DHCPv4 and used as the
      IPsec-TOA.  The difference is that the POPA is obtained by using
      IKE (via a Configuration Payload exchange or equivalent) and used
      as the IPsec-TIA.

   Case C: IPsec-TIA obtained by using RFC3456

      Like Case B, the PRPA is obtained by using DHCPv4.  The difference
      is that the POPA (eventually used as IPsec-TIA) and other
      configuration parameter are configured by running DHCPv4 over a
      special IPsec tunnel mode SA [RFC3456].  Note that the PRPA DHCPv4
      Server and IPsec-TIA DHCPv4 Server may be co-located on the same
      node.

      Note: this case may be used only when IKEv1 is used as the IPsec
      key management protocol (IKEv2 [RFC4307] does not seem to support
      [RFC3456] equivalent case).
































Jayaraman, et al.       Expires September 4, 2006              [Page 27]


Internet-Draft               PANA Framework                   March 2006


   PaC           AP   DHCPv4 Server         PAA
    | Link-layer |         |                 |
    | association|         |                 |
    |<---------->|         |                 |
    |            |         |                 |
    |         DHCPv4       |                 |
    |<-----------+-------->|                 |
    |            |                           |
    |PANA(Discovery and handshake phase      |
    |     & PAR/PAN exchange in              |
    |       authentication and authorization phase)
    |<-----------+-------------------------->|
    |            |                           |
    |            |                           |          EP(AR)
    |            |                           |            |Authorization
    |            |                           |            |[IKE-PSK,
    |            |                           |            | PaC-DI,
    |            |                           |            | Session-Id]
    |            |                           |----------->|
    |            |                           |            |
    |PANA(PBR/PBA exchange in authentication |            |
    |     and authorization phase)           |            |
    |<-----------+-------------------------->|            |
    |            |                           |            |
    |  IKEv1 phase I & II                                 |
    |  (to create DHCP SA)                                |
    |<-----------+--------------------------------------->|
    |            |                                        |
    |      DHCP over DHCP SA                              |
    |<-----------+--------------------------------------->|
    |            |                                        |
    |  IKEv1 phase II                                     |
    | (to create IPsec SA for data traffic)               |
    |<-----------+--------------------------------------->|

        Figure 10: An example case for configuring IPsec-TIA by using
                                   RFC3456

10.2.1.2.  IPv6

   IPsec-TIA (POPA) is obtained by using IKE (via a Configuration
   Payload exchange or equivalent).  Other configuration information may
   be obtained in the same Configuration Payload exchange or may be
   obtained by running an additional DHCPv6.







Jayaraman, et al.       Expires September 4, 2006              [Page 28]


Internet-Draft               PANA Framework                   March 2006


              PaC           AP           PAA          EP(AR)
               | Link-layer |             |             |
               | association|             |             |
               |<---------->|             |             |
               |            |             |             |
               |            |             |             |
               |PANA(Discovery and handshake phase      |
               |     & PAR/PAN exchange in              |
               |       authentication and authorization phase)
               |<-----------+------------>|             |
               |            |             |             |
               |            |             |             |
               |            |             |Authorization|
               |            |             |[IKE-PSK,    |
               |            |             | PaC-DI,     |
               |            |             | Session-Id] |
               |            |             |------------>|
               |            |             |             |
               |PANA(PBR/PBA exchange in  |             |
               |     authentication and authorization phase)
               |<-----------+------------>|             |
               |            |                           |
               |                   IKEv2                |
               |  (with Configuration Payload exchange) |
               |<-----------+-------------------------->|
               |            |             |             |

     Figure 11: An example sequence for configuring IPsec-TIA in IPv6

10.2.2.  PANA with Bootstrapping WPA/IEEE 802.11i

   In this model, PANA is used for authentication and authorization, and
   link-layer ciphering is used for access control.  Successful PANA
   authentication enables link-layer ciphering which is based on PSK
   (Pre-Shared Key) mode of WPA (Wi-Fi Protected Access) [WPA] or IEEE
   802.11i [802.11i].  The PSK is derived from the EAP AAA-Key as a
   result of successful PANA authentication.  In this model, MAC
   addresses are used as the device identifiers in PANA.

   This model allows the separation of PAA from EPs(APs).  A typical
   purpose of using this model is to reduce AP management cost by
   allowing physical separation of RADIUS/Diameter client from access
   points, where AP management can be a significant issue when deploying
   a large number of access points.  Additionally, this centralized AAA
   framework enhances mobility-related performance (inter-AP but intra-
   PAA mobility does not require additional PANA executions).

   By bootstrapping PSK mode of WPA and IEEE 802.11i from PANA it is



Jayaraman, et al.       Expires September 4, 2006              [Page 29]


Internet-Draft               PANA Framework                   March 2006


   also possible to improve wireless LAN security by providing protected
   disconnection procedure at L3.

   This model does not require any change in the current WPA and IEEE
   802.11i specifications.  This also means that PANA doesn't provide
   any link-layer security features beyond those already provided for in
   WPA and IEEE 802.11i.

   The IEEE 802.11 specification [802.11] allows Class 1 data frames to
   be received in any state.  Also, IEEE 802.11i [802.11i] optionally
   allows higher-layer data traffic to be received and processed on the
   IEEE 802.1X Uncontrolled Ports.  This feature allows processing IP-
   based traffic (such as ARP, IPv6 neighbor discovery, DHCP, and PANA)
   on IEEE 802.1X Uncontrolled Port prior to client authentication.

   Until the PaC is successfully authenticated, only a selected type of
   IP traffic is allowed over the IEEE 802.1X Uncontrolled Port.  Any
   other IP traffic is dropped at the AP without being forwarded to the
   DS (Distribution System).  Upon successful PANA authentication, the
   traffic switches to the controlled port.  Host configuration,
   including obtaining an (potentially new) IP address, takes place on
   this port.  Usual DHCP-based, and also in the case of IPv6 stateless
   autoconfiguration, mechanism is available to the PaC.  After this
   point, the rest of the IP traffic, including PANA exchanges, are
   processed on the controlled port.

   When a PaC does not have a PSK for the AP, the following procedure is
   taken:

   1.  The PaC associates with the AP.

   2.  The PaC configures a PRPA by using a method defined in Section 5
       and then runs PANA.

   3.  Upon successful authentication, the PaC obtains a separate PSK
       for each AP controlled by the PAA as well as the information on
       the available POPA configuration methods.

   4.  The AP initiates IEEE 802.11i 4-way handshake to establish a PTK
       (Pair-wise Transient Key) with the PaC, by using the PMK.

   5.  The PaC obtains a POPA when necessary using one of the available
       POPA configuration methods.

   An alternative to running PANA over IEEE 802.1X Uncontrolled Port is
   to dedicate a virtual open-access AP for the authentication.  Upon
   successful PANA authentication over this AP, the PaC will switch over
   to another virtual AP to utilize the PANA-derived PSK.



Jayaraman, et al.       Expires September 4, 2006              [Page 30]


Internet-Draft               PANA Framework                   March 2006


10.2.3.  Capability Discovery

   When a PaC is a mobile, there may be multiple APs available in its
   vicinity.  Each AP can be one of the following types:

   a) AP without IEEE 802.11i

      There is no IEEE 802.11i link-layer security on this AP.

   b) AP with IEEE 802.11i using PSK mode bootstrapped from PANA

      The clients are required to perform PANA authentication which
      allows the PaC to bootstrap a dynamic PSK to access this AP.

   c) AP with IEEE 802.11i using native PSK mode

      AP and PaC must share a statically configured PSK to access this
      AP.

   d) AP with IEEE 802.11i using 802.1X/EAP mode

      The clients are required to perform IEEE 802.1X/EAP authentication
      for this AP.

   Checking the capability information advertised in IEEE 802.11 Beacon/
   Probe Response frames (IEEE 802.11i defines RSN Information Element
   (IE) for this purpose), PaC can extract certain information about the
   different types of APs.

   Specifically, if no RSN IE is contained in Beacon/Probe Response
   frames then the AP is Type (a).  Additionally, Type (d) can be
   recognized because IEEE 802.1X-EAP mode is advertised in the RSN IE.

   However Types (b) and (c) are not distinguishable by a PaC that does
   not have a PSK bootstrapped from PANA for the AP, because in both
   cases PSK mode is advertised in the RSN IE.  Thus, the PaC will need
   to take an additional action of trying to associate to the AP.

   If either the PaC receives a disassociation frame from the AP as the
   AP does not hold a PSK for the PaC, or AP immediately starts 4-way
   handshake after association, PaC can consider AP as Type (c).
   Otherwise it is Type (b).

   The PaC behavior after identifying an Type (b) AP is described in
   Section 10.2.2.






Jayaraman, et al.       Expires September 4, 2006              [Page 31]


Internet-Draft               PANA Framework                   March 2006


11.  Security Considerations

   Security is discussed throughout this document.  For protocol-
   specific security considerations, refer to [I-D.ietf-pana-pana].















































Jayaraman, et al.       Expires September 4, 2006              [Page 32]


Internet-Draft               PANA Framework                   March 2006


12.  IANA Considerations

   This document has no actions for IANA.
















































Jayaraman, et al.       Expires September 4, 2006              [Page 33]


Internet-Draft               PANA Framework                   March 2006


13.  Acknowledgments

   We would like to thank Bernard Aboba, Yacine El Mghazli, Randy
   Turner, Hannes Tschofenig, Lionel Morand, Mark Townsley and Jari
   Arkko for their valuable comments.














































Jayaraman, et al.       Expires September 4, 2006              [Page 34]


Internet-Draft               PANA Framework                   March 2006


14.  References

14.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

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

   [RFC3927]  Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
              Configuration of IPv4 Link-Local Addresses", RFC 3927,
              May 2005.

   [RFC2462]  Thomson, S. and T. Narten, "IPv6 Stateless Address
              Autoconfiguration", RFC 2462, December 1998.

   [RFC2461]  Narten, T., Nordmark, E., and W. Simpson, "Neighbor
              Discovery for IP Version 6 (IPv6)", RFC 2461,
              December 1998.

   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

   [RFC2409]  Harkins, D. and D. Carrel, "The Internet Key Exchange
              (IKE)", RFC 2409, November 1998.

   [RFC4307]  Schiller, J., "Cryptographic Algorithms for Use in the
              Internet Key Exchange Version 2 (IKEv2)", RFC 4307,
              December 2005.

   [I-D.ietf-pana-snmp]
              Mghazli, Y., "SNMP usage for PAA-EP interface",
              draft-ietf-pana-snmp-05 (work in progress), January 2006.

   [I-D.ietf-pana-pana]
              Forsberg, D., "Protocol for Carrying Authentication for
              Network Access (PANA)", draft-ietf-pana-pana-10 (work in
              progress), July 2005.

   [I-D.ietf-pana-ipsec]
              Parthasarathy, M., "PANA Enabling IPsec based Access
              Control", draft-ietf-pana-ipsec-07 (work in progress),
              July 2005.

   [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for



Jayaraman, et al.       Expires September 4, 2006              [Page 35]


Internet-Draft               PANA Framework                   March 2006


              IPv6 (DHCPv6)", RFC 3315, July 2003.

   [RFC2131]  Droms, R., "Dynamic Host Configuration Protocol",
              RFC 2131, March 1997.

   [RFC3456]  Patel, B., Aboba, B., Kelly, S., and V. Gupta, "Dynamic
              Host Configuration Protocol (DHCPv4) Configuration of
              IPsec Tunnel Mode", RFC 3456, January 2003.

   [DSL]      DSL Forum Architecture and Transport Working Group, "DSL
              Forum TR-059 DSL Evolution - Architecture Requirements for
              the Support of QoS-Enabled IP Services", September 2003.

14.2.  Informative References

   [RFC2865]  Rigney, C., Willens, S., Rubens, A., and W. Simpson,
              "Remote Authentication Dial In User Service (RADIUS)",
              RFC 2865, June 2000.

   [RFC3588]  Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
              Arkko, "Diameter Base Protocol", RFC 3588, September 2003.

   [RFC1918]  Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
              E. Lear, "Address Allocation for Private Internets",
              BCP 5, RFC 1918, February 1996.

   [I-D.ietf-eap-netsel-problem]
              Arkko, J. and B. Aboba, "Network Discovery and Selection
              Problem", draft-ietf-eap-netsel-problem-03 (work in
              progress), October 2005.

   [RFC2486]  Aboba, B. and M. Beadles, "The Network Access Identifier",
              RFC 2486, January 1999.

   [RFC4058]  Yegin, A., Ohba, Y., Penno, R., Tsirtsis, G., and C. Wang,
              "Protocol for Carrying Authentication for Network Access
              (PANA) Requirements", RFC 4058, May 2005.

   [RFC4072]  Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible
              Authentication Protocol (EAP) Application", RFC 4072,
              August 2005.

   [3GPP2]    3rd Generation Partnership Project 2, "cdma2000 Wireless
              IP Network Standard", 3GPP2 P.S0001-B/v2.0,
              September 2004.

   [802.11i]  Institute of Electrical and Electronics Engineers, "IEEE
              Standard for Information technology - Telecommunications



Jayaraman, et al.       Expires September 4, 2006              [Page 36]


Internet-Draft               PANA Framework                   March 2006


              and information exchange between systems - Local and
              metropolitan area networks - Specific requirements Part
              11: Wireless LAN Medium Access Control (MAC) and Physical
              Layer (PHY) specifications Amendment 6: Medium Access
              Control (MAC) Security Enhancements", IEEE Standard
              802.11i, 2004.

   [802.11]   Institute of Electrical and Electronics Engineers,
              "Information technology - telecommunications and
              information exchange between systems - local and
              metropolitan area networks - specific requirements part
              11: Wireless lan medium access control (mac) and physical
              layer (phy) specifications", IEEE Standard 802.11,
              1999(R2003).

   [WPA]      The Wi-Fi Alliance, "WPA (Wi-Fi Protected Access)", Wi-
              Fi WPA v3.1, 2004.


































Jayaraman, et al.       Expires September 4, 2006              [Page 37]


Internet-Draft               PANA Framework                   March 2006


Authors' Addresses

   Prakash Jayaraman
   Network Equipment Technologies, Inc.
   6900 Paseo Padre Parkway
   Fremont, CA  94555
   USA

   Phone: +1 510 574 2305
   Email: prakash_jayaraman@net.com


   Rafa Marin Lopez
   University of Murcia
   30071 Murcia
   Spain

   Email: rafa@dif.um.es


   Yoshihiro Ohba
   Toshiba America Research, Inc.
   1 Telcordia Drive
   Piscateway, NJ  08854
   USA

   Phone: +1 732 699 5365
   Email: yohba@tari.toshiba.com


   Mohan Parthasarathy
   Nokia
   313 Fairchild Drive
   Mountain View, CA  94043
   USA

   Phone: +1 408 734 8820
   Email: mohanp@sbcglobal.net


   Alper E. Yegin
   Samsung Advanced Institute of Technology
   Istanbul,
   Turkey

   Phone: +90 538 719 0181
   Email: alper01.yegin@partner.samsung.com




Jayaraman, et al.       Expires September 4, 2006              [Page 38]


Internet-Draft               PANA Framework                   March 2006


Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   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
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.


Disclaimer of Validity

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Copyright Statement

   Copyright (C) The Internet Society (2006).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78, and
   except as set forth therein, the authors retain all their rights.


Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.




Jayaraman, et al.       Expires September 4, 2006              [Page 39]