< draft-ietf-pana-requirements-07.txt   draft-ietf-pana-requirements-08.txt >
IETF PANA Working Group Alper E. Yegin, Editor Network Working Group A. Yegin, Ed.
INTERNET-DRAFT Yoshihiro Ohba Internet-Draft Samsung AIT
Expires: December 2003 Reinaldo Penno Expires: December 9, 2004 Y. Ohba
George Tsirtsis Toshiba
Cliff Wang R. Penno
June 2003 Nortel Networks
G. Tsirtsis
Flarion
C. Wang
ARO/NCSU
June 10, 2004
Protocol for Carrying Authentication for Protocol for Carrying Authentication for Network Access (PANA)
Network Access (PANA) Requirements Requirements
draft-ietf-pana-requirements-07.txt draft-ietf-pana-requirements-08.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance By submitting this Internet-Draft, I certify that any applicable
with all provisions of Section 10 of RFC2026. patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance with
RFC 3668.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as other groups may also distribute working documents as
Internet-Drafts. Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six Internet-Drafts are draft documents valid for a maximum of six months
months and may be updated, replaced, or obsoleted by other documents and may be updated, replaced, or obsoleted by other documents at any
at any time. It is inappropriate to use Internet-Drafts as time. It is inappropriate to use Internet-Drafts as reference
reference material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on December 9, 2004.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract Abstract
It is expected that future IP devices will have a variety of access It is expected that future IP devices will have a variety of access
technologies to gain network connectivity. Currently there are technologies to gain network connectivity. Currently there are
access-specific mechanisms for providing client information to the access-specific mechanisms for providing client information to the
network for authentication and authorization purposes. In addition network for authentication and authorization purposes. In addition
to being limited to specific access media (e.g., 802.1X for IEEE 802 to being limited to specific access media (e.g., 802.1X for IEEE 802
links), some of these protocols are limited to specific network links), some of these protocols are limited to specific network
topologies (e.g., PPP for point-to-point links). The goal of this topologies (e.g., PPP for point-to-point links). The goal of this
document is to identify the requirements for a link-layer agnostic document is to identify the requirements for a link-layer agnostic
protocol that allows a host and a network to authenticate each other protocol that allows a host and a network to authenticate each other
for network access. This protocol will run between a client's device for network access. This protocol will run between a client's device
and an agent in the network where the agent might be a client of the and an agent in the network where the agent might be a client of the
AAA infrastructure. AAA infrastructure.
Table of Contents Table of Contents
Abstract..........................................................1 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
Table of Contents.................................................2 2. Requirements notation . . . . . . . . . . . . . . . . . . . . 4
1. Introduction...................................................3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Key Words......................................................4 4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Terminology....................................................4 4.1 Authentication . . . . . . . . . . . . . . . . . . . . . . 6
4. Requirements...................................................5 4.1.1 Authentication of Client . . . . . . . . . . . . . . . 6
4.1. Authentication...............................................5 4.1.2 Authorization, Accounting and Access Control . . . . . 7
4.1.1. Authentication of Client...................................5 4.1.3 Authentication Backend . . . . . . . . . . . . . . . . 8
4.1.2. Authorization, Accounting and Access Control...............6 4.1.4 Identifiers . . . . . . . . . . . . . . . . . . . . . 8
4.1.3. Authentication Backend.....................................7 4.2 IP Address Assignment . . . . . . . . . . . . . . . . . . 9
4.1.4. Identifiers................................................7 4.3 EAP Lower Layer Requirements . . . . . . . . . . . . . . . 9
4.2. IP Address Assignment........................................7 4.4 PAA-to-EP Protocol . . . . . . . . . . . . . . . . . . . . 9
4.3. EAP Lower Layer Requirements.................................8 4.5 Network . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.4. PAA-to-EP Protocol...........................................8 4.5.1 Multi-access . . . . . . . . . . . . . . . . . . . . . 10
4.5. Network......................................................9 4.5.2 Disconnect Indication . . . . . . . . . . . . . . . . 10
4.5.1. Multi-access...............................................9 4.5.3 Location of PAA . . . . . . . . . . . . . . . . . . . 10
4.5.2. Disconnect Indication......................................9 4.5.4 Secure Channel . . . . . . . . . . . . . . . . . . . . 11
4.5.3. Location of PAA............................................9 4.6 Interaction with Other Protocols . . . . . . . . . . . . . 11
4.5.4. Secure Channel............................................10 4.7 Performance . . . . . . . . . . . . . . . . . . . . . . . 11
4.6. Interaction with Other Protocols............................10 4.8 Congestion Control . . . . . . . . . . . . . . . . . . . . 11
4.7. Performance.................................................10 4.9 IP Version Independence . . . . . . . . . . . . . . . . . 12
4.8. Congestion Control..........................................11 4.10 Denial of Service Attacks . . . . . . . . . . . . . . . . 12
4.9. IP Version Independence.....................................11 4.11 Client Identity Privacy . . . . . . . . . . . . . . . . . 12
4.10. Denial of Service Attacks..................................11 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
4.11. Client Identity Privacy....................................11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 14
5. Security Considerations.......................................11 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15
6. Acknowledgements..............................................11 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7. References....................................................12 8.1 Normative References . . . . . . . . . . . . . . . . . . . . 16
7.1. Normative References........................................12 8.2 Informative References . . . . . . . . . . . . . . . . . . . 16
7.2. Informative References......................................12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 17
8. Authors' Addresses............................................13 A. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 19
9. Appendix......................................................14 B. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 21
10. Full Copyright Statement.....................................16 Intellectual Property and Copyright Statements . . . . . . . . 24
1. Introduction
Providing secure network access service requires access control 1. Introduction
based on the authentication and authorization of the clients and the
access networks. Initial and subsequent client-to-network
authentication provides parameters that are needed to police the
traffic flow through the enforcement points. A protocol is needed to
carry authentication parameters between the client and the access
network.
Link-layer authentication mechanisms are used as enablers of secure Secure network access service requires access control based on the
network access. A higher-layer authentication protocol is deemed authentication and authorization of the clients and the access
necessary when link-layer authentication mechanisms either do not networks. Initial and subsequent client-to-network authentication
exist in terms of specifications/standards for a specific technology provides parameters that are needed to police the traffic flow
or present deployment difficulties; when link-layer mechanisms are through the enforcement points. A protocol is needed to carry
not able to meet the overall authentication and security authentication parameters between the client and the access network.
requirements; or when multi-layer (e.g., link-layer and See Appendix for the associated problem statement.
network-layer) authentication is needed. Currently there is no
standard network-layer solution for authenticating clients for
network access. In the absence of such a solution, some inadequate
standards-based solutions are deployed or non-standard ad-hoc
solutions are invented. The usage scenarios Internet-Draft [USAGE]
describes the problem statement in detail.
The protocol design will be limited to defining a messaging protocol The protocol design will be limited to defining a messaging protocol
(i.e., a carrier) that will allow authentication payload to be (i.e., a carrier) that will allow authentication payload to be
carried between the host/client and an agent/server in the access carried between the host/client and an agent/server in the access
network for authentication and authorization purposes regardless of network for authentication and authorization purposes regardless of
the AAA infrastructure that may (or may not) reside on the network. the AAA infrastructure that may (or may not) reside on the network.
As a network-layer protocol, it will be independent of the As a network-layer protocol, it will be independent of the underlying
underlying access technologies. It will also be applicable to any access technologies. It will also be applicable to any network
network topology. topology.
The intent is not to invent new security protocols and mechanisms The intent is not to invent new security protocols and mechanisms but
but to reuse existing mechanisms such as EAP [EAP]. In particular, to reuse existing mechanisms such as EAP [RFC2284]
the requirements do not mandate the need to define new [I-D.ietf-eap-rfc2284bis]. In particular, the requirements do not
authentication protocols (e.g., EAP-TLS [EAPTLS]), key distribution mandate the need to define new authentication protocols (e.g.,
or key agreement protocols, or key derivation methods. The desired EAP-TLS [RFC2716]), key distribution or key agreement protocols, or
protocol can be viewed as the front-end of the AAA protocol or any key derivation methods. The desired protocol can be viewed as the
other protocol/mechanisms the network is running at the background front-end of the AAA protocol or any other protocol/mechanisms the
to authenticate its clients. It will act as a carrier for an already network is running at the background to authenticate its clients. It
defined security protocol or mechanism. will act as a carrier for an already defined security protocol or
mechanism.
As an example, the Mobile IP Working Group has already defined such As an example, the Mobile IP Working Group has already defined such a
a carrier for Mobile IPv4 [MIPV4]. A Mobile IPv4 registration carrier for Mobile IPv4 [RFC3344]. A Mobile IPv4 registration
request message is used as a carrier for authentication extensions request message is used as a carrier for authentication extensions
(MN-FA [MIPv4] or MN-AAA [MNAAA]) that allow a foreign agent to (MN-FA [RFC3344] or MN-AAA [RFC3012]) that allow a foreign agent to
authenticate mobile nodes before providing forwarding service. The authenticate mobile nodes before providing forwarding service. The
goal of PANA is similar in that it aims to define a network-layer goal of PANA is similar in that it aims to define a network-layer
transport for authentication information; however, PANA will be transport for authentication information; however, PANA will be
decoupled from mobility management and it will rely on other decoupled from mobility management and it will rely on other
specifications for the definition of authentication payloads. specifications for the definition of authentication payloads.
This document defines the common terminology and identifies the This document defines the common terminology and identifies the
requirements of a protocol for PANA. These terminology and requirements of a protocol for PANA. These terminology and
requirements will be used to define and limit the scope of the work requirements will be used to define and limit the scope of the work
to be done in this group. to be done in this group.
2. Key Words 2. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [KEYWORDS]. document are to be interpreted as described in [RFC2119].
3. Terminology 3. Terminology
PANA Client (PaC) PANA Client (PaC)
The client side of the protocol that resides in the host device The client side of the protocol that resides in the host device
which is responsible for providing the credentials to prove its which is responsible for providing the credentials to prove its
identity for network access authorization. identity for network access authorization.
PANA Client Identifier (PaCI) PANA Client Identifier (PaCI)
The identifier that is presented by the PaC to the PAA for The identifier that is presented by the PaC to the PAA for network
network access authentication. A simple username and NAI [NAI] access authentication. A simple username and NAI [RFC2794] are
are examples of PANA client identifiers. examples of PANA client identifiers.
Device Identifier (DI) Device Identifier (DI)
The identifier used by the network as a handle to control and The identifier used by the network as a handle to control and
police the network access of a client. Depending on the access police the network access of a client. Depending on the access
technology, this identifier might contain any of IP address, technology, this identifier might contain any of IP address,
link-layer address, switch port number, etc. of a connected link-layer address, switch port number, etc. of a connected
device. device.
PANA Authentication Agent (PAA) PANA Authentication Agent (PAA)
The access network side entity of the protocol whose The access network side entity of the protocol whose
responsibility is to verify the credentials provided by a PANA responsibility is to verify the credentials provided by a PANA
client and grant network access service to the device client and grant network access service to the device associated
associated with the client and identified by a DI. with the client and identified by a DI.
Enforcement Point (EP) Enforcement Point (EP)
A node on the access network where per-packet enforcement A node on the access network where per-packet enforcement policies
policies (i.e., filters) are applied on the inbound (i.e., filters) are applied on the inbound and outbound traffic of
and outbound traffic of client devices. Information such as DI client devices. Information such as DI and (optionally)
and (optionally) cryptographic keys are provided by PAA per cryptographic keys are provided by PAA per client for constructing
client for constructing filters on the EP. filters on the EP.
4. Requirements 4. Requirements
4.1. Authentication 4.1 Authentication
4.1.1. Authentication of Client 4.1.1 Authentication of Client
PANA MUST enable authentication of PaCs for network access. A PaC's PANA MUST enable authentication of PaCs for network access. A PaC's
identity can be authenticated by verifying the credentials (e.g., identity can be authenticated by verifying the credentials (e.g.,
identifier, authenticator) supplied by one of the users of the identifier, authenticator) supplied by one of the users of the device
device or the device itself. PANA MUST only grant network access or the device itself. PANA MUST only grant network access service to
service to the device identified by the DI, rather than granting the device identified by the DI, rather than granting separate access
separate access to multiple simultaneous users of the device. Once to multiple simultaneous users of the device. Once the network
the network access is granted to the device, the methods used by the access is granted to the device, the methods used by the device on
device on arbitrating which one of its users can access the network arbitrating which one of its users can access the network is outside
is outside the scope of PANA. the scope of PANA.
PANA MUST NOT define new security protocols or mechanisms. Instead, PANA MUST NOT define new security protocols or mechanisms. Instead,
it MUST be defined as a "carrier" for such protocols. PANA MUST it MUST be defined as a "carrier" for such protocols. PANA MUST
identify which specific security protocol(s) or mechanism(s) it can identify which specific security protocol(s) or mechanism(s) it can
carry (the "payload"). EAP [EAP] is a candidate protocol that carry (the "payload"). EAP is a candidate protocol that satisfies
satisfies many of the requirements for authentication. PANA would be many of the requirements for authentication. PANA would be a carrier
a carrier protocol for EAP. If the PANA Working Group decides that protocol for EAP. If the PANA Working Group decides that extensions
extensions to EAP are needed, it will define requirements for the to EAP are needed, it will define requirements for the EAP WG instead
EAP WG instead of designing such extensions. of designing such extensions.
Providing authentication, integrity and replay protection for data Providing authentication, integrity and replay protection for data
traffic after a successful PANA exchange is outside the scope of traffic after a successful PANA exchange is outside the scope of this
this protocol. In networks where physical layer security is not protocol. In networks where physical layer security is not present,
present, link-layer or network-layer ciphering (e.g., IPsec) can be link-layer or network-layer ciphering (e.g., IPsec) can be used to
used to provide such security. These mechanisms require presence of provide such security. These mechanisms require presence of
cryptographic keying material at PaC and EP. Although PANA does not cryptographic keying material at PaC and EP. Although PANA does not
deal with key derivation or distribution, it enables this by the deal with key derivation or distribution, it enables this by the
virtue of carrying EAP and allowing appropriate EAP method virtue of carrying EAP and allowing appropriate EAP method selection.
selection. Various EAP methods are capable of generating basic Various EAP methods are capable of generating basic keying material.
keying material. The keying material produced by EAP methods cannot The keying material produced by EAP methods cannot be directly used
be directly used with IPsec as it lacks the properties of an IPsec with IPsec as it lacks the properties of an IPsec SA (security
SA (security association) which include secure cipher suite association) which include secure cipher suite negotiation, mutual
negotiation, mutual proof of possession of keying material, proof of possession of keying material, freshness of transient
freshness of transient session keys, key naming, etc. These basic session keys, key naming, etc. These basic (initial) EAP keys can be
(initial) EAP keys can be used with an IPsec key management protocol used with an IPsec key management protocol like IKE to generate the
like IKE to generate the required security associations. A separate required security associations. A separate protocol, called secure
protocol, called secure association protocol, is required to association protocol, is required to generate IPsec SAs based on the
generate IPsec SAs based on the basic EAP keys. This protocol MUST basic EAP keys. This protocol MUST be capable of enabling
be capable of enabling IPsec-based access control on the EPs. IPsec IPsec-based access control on the EPs. IPsec SAs MUST enable
SAs MUST enable authentication, integrity and replay protection of authentication, integrity and replay protection of data packets as
data packets as they are sent between the EP and PaC. they are sent between the EP and PaC.
Providing a complete secure network access solution by also securing Providing a complete secure network access solution by also securing
router discovery [RDISC], neighbor discovery [NDISC], and address router discovery [RFC1256], neighbor discovery [RFC2461], and
resolution protocols [ARP] is outside the scope as well. address resolution protocols [RFC1982] is outside the scope as well.
Some access networks might require or allow their clients to get Some access networks might require or allow their clients to get
authenticated and authorized by the NAP (network access provider) authenticated and authorized by the NAP (network access provider) and
and ISP before the clients gain network access. NAP is the owner of ISP before the clients gain network access. NAP is the owner of the
the access network who provides physical and link-layer connectivity access network who provides physical and link-layer connectivity to
to the clients. PANA MUST be capable of enabling two independent the clients. PANA MUST be capable of enabling two independent
authentication operations (i.e., execution of two separate EAP authentication operations (i.e., execution of two separate EAP
methods) for the same client. Determining the authorization methods) for the same client. Determining the authorization
parameters as a result of two separate authentications is an parameters as a result of two separate authentications is an
operational issue and therefore it is outside the scope of PANA. operational issue and therefore it is outside the scope of PANA.
Both the PaC and the PAA MUST be able to perform mutual Both the PaC and the PAA MUST be able to perform mutual
authentication for network access. Providing only the capability of authentication for network access. Providing only the capability of
a PAA authenticating the PaC is not sufficient. Mutual a PAA authenticating the PaC is not sufficient. Mutual
authentication capability is required in some environments but not authentication capability is required in some environments but not in
in all of them. For example, clients might not need to authenticate all of them. For example, clients might not need to authenticate the
the access network when physical security is available (e.g., access network when physical security is available (e.g., dial-up
dial-up networks). networks).
PANA MUST be capable of carrying out both periodic and on-demand PANA MUST be capable of carrying out both periodic and on-demand
re-authentication. Both the PaC and the PAA MUST be able to initiate re-authentication. Both the PaC and the PAA MUST be able to initiate
both the initial authentication and the re-authentication process. both the initial authentication and the re-authentication process.
Certain types of service theft are possible when the DI is not Certain types of service theft are possible when the DI is not
protected during or after the PANA exchange [SECTHREAT]. PANA MUST protected during or after the PANA exchange
have the capability to exchange DI securely between the PAC and PAA [I-D.ietf-pana-threats-eval]. PANA MUST have the capability to
where the network is vulnerable to man-in-the-middle attacks. While exchange DI securely between the PAC and PAA where the network is
PANA MUST provide such a capability, its utility relies on the use vulnerable to man-in-the-middle attacks. While PANA MUST provide
of an authentication method that can generate keys for cryptographic such a capability, its utility relies on the use of an authentication
computations on PaC and PAA. method that can generate keys for cryptographic computations on PaC
and PAA.
4.1.2. Authorization, Accounting and Access Control 4.1.2 Authorization, Accounting and Access Control
After a device is authenticated using PANA, it MUST be authorized After a device is authenticated by using PANA, it MUST be authorized
for "network access." That is, the core requirement of PANA is to for "network access." That is, the core requirement of PANA is to
verify the authorization of a PaC so that PaC's device may send and verify the authorization of a PaC so that PaC's device may send and
receive any IP packets. It may also be possible to provide finer receive any IP packets. It may also be possible to provide finer
granularity authorization, such as authorization for QoS or granularity authorization, such as authorization for QoS or
individual services (e.g., http vs. ssh). However, while a backend individual services (e.g., http vs. ssh). However, while a backend
authorization infrastructure (e.g., Diameter) might provide such authorization infrastructure (e.g., Diameter) might provide such
indications to the PAA, explicit support for them is outside the indications to the PAA, explicit support for them is outside the
scope of PANA. For instance, PANA is not required to carry any scope of PANA. For instance, PANA is not required to carry any
indication of which services are authorized for the authenticated indication of which services are authorized for the authenticated
device. device.
Providing access control functionality in the network is outside the Providing access control functionality in the network is outside the
scope of PANA. Client access authentication SHOULD be followed by scope of PANA. Client access authentication SHOULD be followed by
access control to make sure only authenticated and authorized access control to make sure only authenticated and authorized clients
clients can send and receive IP packets via access network. Access can send and receive IP packets via the access network. Access
control can involve setting access control lists on the EPs. control can involve setting access control lists on the EPs.
Identification of clients that are authorized to access the network Identification of clients that are authorized to access the network
is done by the PANA protocol exchange. If IPsec-based access control is done by the PANA protocol exchange. If IPsec-based access control
is deployed in an access network, PaC and EPs should have the is deployed in an access network, PaC and EPs should have the
required IPsec SA in place. Generating the IPsec SAs based on EAP required IPsec SA in place. Generating the IPsec SAs based on EAP
keys is outside the scope of PANA protocol. This transformation MUST keys is outside the scope of PANA protocol. This transformation MUST
be handled by a separate secure association protocol (see section be handled by a separate secure association protocol (see section
4.1.1). 4.1.1).
Carrying accounting data is outside the scope of PANA. Carrying accounting data is outside the scope of PANA.
4.1.3. Authentication Backend 4.1.3 Authentication Backend
PANA protocol MUST NOT make any assumptions on the backend PANA protocol MUST NOT make any assumptions on the backend
authentication protocol or mechanisms. A PAA MAY interact with authentication protocol or mechanisms. A PAA MAY interact with
backend AAA infrastructures such as RADIUS or Diameter, but it is backend AAA infrastructures such as RADIUS or Diameter, but it is not
not a requirement. When the access network does not rely on an a requirement. When the access network does not rely on an
IETF-defined AAA protocol (e.g., RADIUS, Diameter), it can still use IETF-defined AAA protocol (e.g., RADIUS, Diameter), it can still use
a proprietary backend system, or rely on the information locally a proprietary backend system, or rely on the information locally
stored on the authentication agents. stored on the authentication agents.
The interaction between the PAA and the backend authentication The interaction between the PAA and the backend authentication
entities is outside the scope of PANA. entities is outside the scope of PANA.
4.1.4. Identifiers 4.1.4 Identifiers
PANA SHOULD allow various types of identifiers to be used as the PANA SHOULD allow various types of identifiers to be used as the PaCI
PaCI (e.g., username, NAI, FQDN, etc.). This requirement generally (e.g., username, NAI, FQDN, etc.). This requirement generally relies
relies on the client identifiers supported by various EAP methods. on the client identifiers supported by various EAP methods.
PANA SHOULD allow various types of identifiers to be used as the DI PANA SHOULD allow various types of identifiers to be used as the DI
(e.g., IP address, link-layer address, port number of a switch, (e.g., IP address, link-layer address, port number of a switch,
etc.). etc.).
A PAA MUST be able to create a binding between the PaCI and the A PAA MUST be able to create a binding between the PaCI and the
associated DI upon successful PANA exchange. This can be achieved by associated DI upon successful PANA exchange. This can be achieved by
PANA communicating the PaCI and DI to the PAA during the protocol PANA communicating the PaCI and DI to the PAA during the protocol
exchange. The DI can be carried either explicitly as part of the exchange. The DI can be carried either explicitly as part of the
PANA payload, or implicitly as the source of the PANA message, or PANA payload, or implicitly as the source of the PANA message, or
both. Multi-access networks also require use of a cryptographic both. Multi-access networks also require use of a cryptographic
protection along with DI filtering to prevent unauthorized access protection along with DI filtering to prevent unauthorized access
[SECTHREAT]. The keying material required by the cryptographic [I-D.ietf-pana-threats-eval]. The keying material required by the
methods needs to be indexed by the DI. The binding between DI and cryptographic methods needs to be indexed by the DI. The binding
PaCI is used for access control and accounting in the network as between DI and PaCI is used for access control and accounting in the
described in section 4.1.2. network as described in section 4.1.2.
4.2. IP Address Assignment 4.2 IP Address Assignment
Assigning an IP address to the client is outside the scope of PANA. Assigning an IP address to the client is outside the scope of PANA.
PANA protocol design MAY require the PaC to configure an IP address PaC MUST configure an IP address before running PANA.
before using this protocol. Allocating IP addresses to
unauthenticated PaCs may create security vulnerabilities, such as IP
address depletion attacks on the access network [SECTHREAT]. IPv4
networks with limited address space are the main targets of such
attacks. Launching a successful attack that can deplete the
addresses in an IPv6 network is relatively harder.
This threat can be mitigated by allowing the protocol to run without
an IP address configured on the PaC (i.e., using unspecified source
address). Such a design choice might limit the re-use of existing
security mechanisms, and impose additional implementation
complexity. This trade off should be taken into consideration in
designing PANA.
4.3. EAP Lower Layer Requirements 4.3 EAP Lower Layer Requirements
The EAP protocol itself imposes various requirements on its The EAP protocol itself imposes various requirements on its transport
transport protocols. These requirements are based on the nature of protocols. These requirements are based on the nature of the EAP
the EAP protocol, and they need to be satisfied for correct protocol, and they need to be satisfied for correct operation.
operation. Please see [EAP] for the generic transport requirements Please see [I-D.ietf-eap-rfc2284bis] for the generic transport
that MUST be satisfied by PANA as well. requirements that MUST be satisfied by PANA as well.
4.4. PAA-to-EP Protocol 4.4 PAA-to-EP Protocol
PANA does not assume that the PAA is always co-located with the PANA does not assume that the PAA is always co-located with the
EP(s). Network access enforcement can be provided by one or more EP(s). Network access enforcement can be provided by one or more
nodes on the same IP subnet as the client (e.g., multiple routers), nodes on the same IP subnet as the client (e.g., multiple routers),
or on another subnet in the access domain (e.g., gateway to the or on another subnet in the access domain (e.g., gateway to the
Internet, depending on the network architecture). When the PAA and Internet, depending on the network architecture). When the PAA and
the EP(s) are separated, there needs to be another transport for the EP(s) are separated, there needs to be another transport for
client provisioning. This transport is needed to create access client provisioning. This transport is needed to create access
control lists to allow authenticated and authorized clients' traffic control lists to allow authenticated and authorized clients' traffic
through the EPs. PANA Working Group will preferably identify an through the EPs. PANA Working Group will preferably identify an
existing protocol solution that allows the PAA to deliver the existing protocol solution that allows the PAA to deliver the
authorization information to one or more EPs when the PAA is authorization information to one or more EPs when the PAA is
separated from EPs. Possible candidates include but are not limited separated from EPs. Possible candidates include but are not limited
to COPS, SNMP, Diameter, etc. This task is similar to what the to COPS, SNMP, Diameter, etc. This task is similar to what the
MIDCOM Working Group is trying to achieve, therefore some of that MIDCOM Working Group is trying to achieve, therefore some of that
working group's output might be useful here. working group's output might be useful here.
It is assumed that the communication between PAA and EP(s) is It is assumed that the communication between PAA and EP(s) is secure.
secure. The objective of using a PAA-to-EP protocol is to provide The objective of using a PAA-to-EP protocol is to provide filtering
filtering rules to EP(s) for allowing network access of a recently rules to EP(s) for allowing network access of a recently
authenticated and authorized PaC. The chosen protocol MUST be authenticated and authorized PaC. The chosen protocol MUST be
capable of carrying DI and cryptographic keys for a given PaC from capable of carrying DI and cryptographic keys for a given PaC from
PAA to EP. Depending on the PANA protocol design, support for either PAA to EP. Depending on the PANA protocol design, support for either
of the pull model (i.e., EP initiating the PAA-to-EP protocol of the pull model (i.e., EP initiating the PAA-to-EP protocol
exchange per PaC) or the push model (i.e., PAA initiating the exchange per PaC) or the push model (i.e., PAA initiating the
PAA-to-EP protocol exchange per PaC), or both may be required. For PAA-to-EP protocol exchange per PaC), or both may be required. For
example, if the design is such that the EP allows the PANA traffic example, if the design is such that the EP allows the PANA traffic to
to pass through even for unauthenticated PaCs, the EP should also pass through even for unauthenticated PaCs, the EP should also allow
allow and expect the PAA to send the filtering information at the and expect the PAA to send the filtering information at the end of a
end of a successful PANA exchange without the EP ever sending a successful PANA exchange without the EP ever sending a request.
request.
4.5. Network 4.5 Network
4.5.1. Multi-access 4.5.1 Multi-access
PANA MUST support PaCs with multiple interfaces, and networks with PANA MUST support PaCs with multiple interfaces, and networks with
multiple routers on multi-access links. In other words, PANA MUST multiple routers on multi-access links. In other words, PANA MUST
NOT assume the PaC has only one network interface, or the access NOT assume the PaC has only one network interface, or the access
network has only one first hop router, or the PaC is using a network has only one first hop router, or the PaC is using a
point-to-point link. point-to-point link.
4.5.2. Disconnect Indication 4.5.2 Disconnect Indication
PANA MUST NOT assume that the link is connection-oriented. Links may PANA MUST NOT assume that the link is connection-oriented. Links may
or may not provide disconnect indication. Such notification is or may not provide disconnect indication. Such notification is
desirable in order for the PAA to cleanup resources when a client desirable in order for the PAA to cleanup resources when a client
moves away from the network (e.g., inform the enforcement points moves away from the network (e.g., inform the enforcement points that
that the client is no longer connected). PANA SHOULD have a the client is no longer connected). PANA SHOULD have a mechanism to
mechanism to provide disconnect indication. PANA MUST be capable of provide disconnect indication. PANA MUST be capable of securing
securing disconnect messages in order to prevent malicious nodes disconnect messages in order to prevent malicious nodes from
from leveraging this extension for DoS attacks. leveraging this extension for DoS attacks.
This mechanism MUST allow the PAA to be notified about the departure This mechanism MUST allow the PAA to be notified about the departure
of a PaC from the network. This mechanism MUST also allow a PaC to of a PaC from the network. This mechanism MUST also allow a PaC to
be notified about the discontinuation of the network access service. be notified about the discontinuation of the network access service.
Access discontinuation can happen due to various reasons such as Access discontinuation can happen due to various reasons such as
network systems going down, or a change in access policy. network systems going down, or a change in the access policy.
In case the clients cannot send explicit disconnect messages to the In case the clients cannot send explicit disconnect messages to the
PAA, PAA can still detect their departure by relying on periodic PAA, PAA can still detect their departure by relying on periodic
authentication requests. authentication requests.
4.5.3. Location of PAA 4.5.3 Location of PAA
The PAA and PaC MUST be exactly one IP hop away from each other. The PAA and PaC MUST be exactly one IP hop away from each other.
That is, there must be no IP routers between the two. Note that this That is, there must be no IP routers between the two. Note that this
does not mean they are on the same physical link. Bridging does not mean they are on the same physical link. Bridging
techniques can place two nodes just exactly one IP hop away from techniques can place two nodes just exactly one IP hop away from each
each other although they might be connected to separate physical other although they might be connected to separate physical links. A
links. Furthermore, two nodes on the same IP subnet do not PAA can be on the NAS (network access server) or WLAN access point or
necessarily satisfy this requirement, as they can be more than one first hop router. The use of PANA when the PAA is multiple IP hops
hop away from each other [MULTILINK]. A PAA can be on the NAS away from the PaC is outside the scope of PANA.
(network access server) or WLAN access point or first hop router.
The use of PANA when the PAA is multiple IP hops away from the PaC
is outside the scope of PANA.
A PaC may or may not be pre-configured with the IP address of PAA. A PaC may or may not be pre-configured with the IP address of PAA.
Therefore the PANA protocol MUST define a dynamic discovery method. Therefore the PANA protocol MUST define a dynamic discovery method.
Given that the PAA is one hop away from the PaC, there are a number Given that the PAA is one hop away from the PaC, there are a number
of discovery techniques that could be used (e.g., multicast or of discovery techniques that could be used (e.g., multicast or
anycast) by the PaC to find out the address of the PAA. anycast) by the PaC to find out the address of the PAA.
4.5.4. Secure Channel 4.5.4 Secure Channel
PANA MUST NOT assume presence of a secure channel between the PaC PANA MUST NOT assume presence of a secure channel between the PaC and
and the PAA. PANA MUST be able to provide authentication especially the PAA. PANA MUST be able to provide authentication especially in
in networks which are not protected against eavesdropping and networks which are not protected against eavesdropping and spoofing.
spoofing. PANA MUST enable protection against replay attacks on both PANA MUST enable protection against replay attacks on both PaCs and
PaCs and PAAs. PAAs.
This requirement partially relies on the EAP protocol and the EAP This requirement partially relies on the EAP protocol and the EAP
methods carried over PANA. Use of EAP methods that provide mutual methods carried over PANA. Use of EAP methods that provide mutual
authentication and key derivation/distribution is essential for authentication and key derivation/distribution is essential for
satisfying this requirement. EAP does not make a secure channel satisfying this requirement. EAP does not make a secure channel
assumption, and supports various authentication methods that can be assumption, and supports various authentication methods that can be
used in such environments. Additionally, PANA MUST ensure its design used in such environments. Additionally, PANA MUST ensure its design
does not contain vulnerabilities that can be exploited when it is does not contain vulnerabilities that can be exploited when it is
used over insecure channels. PANA MAY provide a secure channel by used over insecure channels. PANA MAY provide a secure channel by
deploying a two-phase authentication. The first phase can be used deploying a two-phase authentication. The first phase can be used
for creation of the secure channel, and the second phase is for for creation of the secure channel, and the second phase is for
client and network authentication. client and network authentication.
4.6. Interaction with Other Protocols 4.6 Interaction with Other Protocols
Mobility management is outside the scope of PANA. However, PANA MUST Mobility management is outside the scope of PANA. However, PANA MUST
be able to co-exist and MUST NOT unintentionally interfere with be able to co-exist and MUST NOT unintentionally interfere with
various mobility management protocols, such as Mobile IPv4 [MIPV4], various mobility management protocols, such as Mobile IPv4 [RFC3344],
Mobile IPv6 [MIPV6], fast handover protocols [FMIPV4, FMIPV6], and Mobile IPv6 [I-D.ietf-mobileip-ipv6], fast handover protocols
other standard protocols like IPv6 stateless address [I-D.ietf-mipshop-fast-mipv6][I-D.ietf-mobileip-lowlatency-handoff],
auto-configuration [ADDRCONF] (including privacy extensions and other standard protocols like IPv6 stateless address
[PRIVACY]), and DHCP [DHCPV4, DHCPV6]. It MUST NOT make any auto-configuration [RFC2461] (including privacy extensions
[RFC3041]), and DHCP [RFC2131][RFC3315]. It MUST NOT make any
assumptions on the protocols or mechanisms used for IP address assumptions on the protocols or mechanisms used for IP address
configuration of the PaC. configuration of the PaC.
4.7. Performance 4.7 Performance
PANA design SHOULD give consideration to efficient handling of the PANA design SHOULD give consideration to efficient handling of the
authentication process. This is important for gaining network access authentication process. This is important for gaining network access
with minimum latency. As an example, a method like minimizing the with minimum latency. As an example, a method like minimizing the
protocol signaling by creating local security associations can be protocol signaling by creating local security associations can be
used for this purpose. used for this purpose.
4.8. Congestion Control 4.8 Congestion Control
PANA MUST provide congestion control for the protocol messaging. PANA MUST provide congestion control for the protocol messaging.
Under certain conditions PaCs might unintentionally get synchronized Under certain conditions PaCs might unintentionally get synchronized
when sending their requests to the PAA (e.g., upon recovering from a when sending their requests to the PAA (e.g., upon recovering from a
power outage on the access network). The network congestion power outage on the access network). The network congestion
generated from such events can be avoided by using techniques like generated from such events can be avoided by using techniques like
delayed initialization and exponential back off. delayed initialization and exponential back off.
4.9. IP Version Independence 4.9 IP Version Independence
PANA MUST work with both IPv4 and IPv6. PANA MUST work with both IPv4 and IPv6.
4.10. Denial of Service Attacks 4.10 Denial of Service Attacks
PANA MUST be robust against a class of DoS attacks such as blind PANA MUST be robust against a class of DoS attacks such as blind
masquerade attacks through IP spoofing that would swamp the PAA, masquerade attacks through IP spoofing that would swamp the PAA,
causing it to spend resources and prevent network access by causing it to spend resources and prevent network access by
legitimate clients. legitimate clients.
4.11. Client Identity Privacy 4.11 Client Identity Privacy
Some clients might prefer hiding their identity from visited access Some clients might prefer hiding their identity from visited access
networks for privacy reasons. Providing identity protection for networks for privacy reasons. Providing identity protection for
clients is outside the scope of PANA. Note that some authentication clients is outside the scope of PANA. Note that some authentication
methods may already have this capability. Where necessary, identity methods may already have this capability. Where necessary, identity
protection can be achieved by letting PANA carry such authentication protection can be achieved by letting PANA carry such authentication
methods. methods.
5. Security Considerations 5. IANA Considerations
This document has no actions for IANA.
6. Security Considerations
This document identifies requirements for the PANA protocol design. This document identifies requirements for the PANA protocol design.
Due to the nature of this protocol most of the requirements are Due to the nature of this protocol most of the requirements are
security related. The actual protocol design is not specified in security related. The actual protocol design is not specified in
this document. A thorough discussion on PANA security threats can be this document. A thorough discussion on PANA security threats can be
found in PANA Threat Analysis and Security Requirements document found in PANA Threat Analysis and Security Requirements document
[SECTHREAT]. Security threats identified in that document are [I-D.ietf-pana-threats-eval]. Security threats identified in that
already included in this general PANA requirements document. document are already included in this general PANA requirements
document.
6. Acknowledgements 7. Acknowledgements
We would like to thank Subir Das, Lionel Morand, Mohan Authors would like to thank Bernard Aboba, Derek Atkins, Julien
Parthasarathy, Basavaraj Patil, Pete McCann, Derek Atkins, Dan Bournelle, Subir Das, Francis Dupont, Dan Forsberg, Pete McCann,
Forsberg, Francis Dupont, Bernard Aboba and the PANA Working Group Lionel Morand, Thomas Narten, Mohan Parthasarathy, Basavaraj Patil,
members for their valuable contributions to the discussions and Hesham Soliman, and the PANA Working Group members for their valuable
preparation of this document. contributions to the discussions and preparation of this document.
7. References 8. References
7.1. Normative References 8.1 Normative References
[KEYWORDS] S. Bradner, "Key words for use in RFCs to Indicate [I-D.ietf-pana-threats-eval]
Requirement Levels", RFC 2119, March 1997. Parthasarathy, M., "PANA Threat Analysis and security
requirements", draft-ietf-pana-threats-eval-04 (work in
progress), May 2003.
[USAGE] Y. Ohba, S. Das, B. Patil, H. Soliman, A. Yegin, "Problem [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Statement and Usage Scenarios for PANA", Requirement Levels", BCP 14, RFC 2119, March 1997.
draft-ietf-pana-usage-scenarios-06.txt, April 2003. Work in
progress.
[SECTHREAT] M. Parthasarathy, "PANA Threat Analysis and Security [RFC2284] Blunk, L. and J. Vollbrecht, "PPP Extensible
Requirements", draft-ietf-pana-threats-04.txt, May 2003. Work in Authentication Protocol (EAP)", RFC 2284, March 1998.
progress.
[EAP] L. Blunk, J. Vollbrecht, B. Aboba, J. Carlson, H. Levkowetz, 8.2 Informative References
"Extensible Authentication Protocol (EAP)",
draft-ietf-eap-rfc2284bis-04.txt, June 2003. Work in progress.
7.2. Informative References [I-D.ietf-eap-rfc2284bis]
Blunk, L., "Extensible Authentication Protocol (EAP)",
draft-ietf-eap-rfc2284bis-09 (work in progress), February
2004.
[8021X] "IEEE Standards for Local and Metropolitan Area Networks: [I-D.ietf-mipshop-fast-mipv6]
Port Based Network Access Control", IEEE Std 802.1X-2001. Koodli, R., "Fast Handovers for Mobile IPv6",
draft-ietf-mipshop-fast-mipv6-01 (work in progress),
February 2004.
[EAPTLS] B. Aboba, D. Simon, "PPP EAP TLS Authentication Protocol", [I-D.ietf-mobileip-ipv6]
RFC 2716, October 1999. Johnson, D., Perkins, C. and J. Arkko, "Mobility Support
in IPv6", draft-ietf-mobileip-ipv6-24 (work in progress),
July 2003.
[MULTILINK] D. Thaler, C. Huitema, "Multi-link Subnet Support in [I-D.ietf-mobileip-lowlatency-handoff]
IPv6", draft-ietf-ipv6-multilink-subnets-00.txt, December 2002. Work Malki, K., "Low latency Handoffs in Mobile IPv4",
in progress. draft-ietf-mobileip-lowlatency-handoffs-v4-09 (work in
progress), June 2004.
[PPP] W. Simpson (editor), "The Point-To-Point Protocol (PPP)", STD [IEEE-802.1X]
51, RFC 1661, July 1994. Institute of Electrical and Electronics Engineers, "Local
and Metropolitan Area Networks: Port-Based Network Access
Control", IEEE Standard 802.1X, September 2001.
[MIPV4] C. Perkins (editor), "IP Mobility Support for IPv4", RFC [RFC1256] Deering, S., "ICMP Router Discovery Messages", RFC 1256,
3344, August 2002. September 1991.
[MIPV6] D. Johnson and C. Perkins, "Mobility Support in IPv6", [RFC1661] Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51,
draft-ietf-mobileip-ipv6-21.txt, February 2003. Work in progress. RFC 1661, July 1994.
[MNAAA] C. Perkins, P. Calhoun, "Mobile IPv4 Challenge/Response [RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982,
Extensions", RFC3012, November 2000. August 1996.
[NDISC] T. Narten, E. Nordmark, and W. Simpson, "Neighbor Discovery [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
for IP Version 6 (IPv6)",RFC 2461, December 1998. 2131, March 1997.
[ARP] D. Plummer, "An Ethernet Address Resolution Protocol", STD 37, [RFC2461] Narten, T., Nordmark, E. and W. Simpson, "Neighbor
RFC 826, November 1982. Discovery for IP Version 6 (IPv6)", RFC 2461, December
1998.
[FMIPV4] K. ElMalki (editor), et. al., "Low latency Handoffs in [RFC2716] Aboba, B. and D. Simon, "PPP EAP TLS Authentication
Mobile IPv4", November 2001. Work in progress. Protocol", RFC 2716, October 1999.
[FMIPV6] R. Koodli (editor), et. al., "Fast Handovers for Mobile [RFC2794] Calhoun, P. and C. Perkins, "Mobile IP Network Access
IPv6", March 2003. Work in progress. Identifier Extension for IPv4", RFC 2794, March 2000.
[DHCPV4] R. Droms, "Dynamic Host Configuration Protocol", RFC 2131, [RFC3012] Perkins, C. and P. Calhoun, "Mobile IPv4 Challenge/
March 1997. Response Extensions", RFC 3012, November 2000.
[DHCPV6] R. Droms (editor), et. al., "Dynamic Host Configuration [RFC3041] Narten, T. and R. Draves, "Privacy Extensions for
Protocol for IPv6 (DHCPv6)", November 2002. Work in progress. Stateless Address Autoconfiguration in IPv6", RFC 3041,
January 2001.
[PRIVACY] T. Narten, R. Draves, "Privacy Extensions for Stateless [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and
Address Autoconfiguration in IPv6", RFC 3041, January 2001. M. Carney, "Dynamic Host Configuration Protocol for IPv6
(DHCPv6)", RFC 3315, July 2003.
8. Authors' Addresses [RFC3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344,
August 2002.
Alper E. Yegin Authors' Addresses
DoCoMo USA Labs
181 Metro Drive, Suite 300
San Jose, CA, 95110
USA
Phone: +1 408 451 4743
Email: alper@docomolabs-usa.com
Yoshihiro Ohba Alper E. Yegin (editor)
Toshiba America Research, Inc. Samsung Advanced Institute of Technology
P.O. Box 136 75 West Plumeria Drive
Convent Station, NJ, 07961-0136 San Jose, CA 95134
USA USA
Phone: +1 973 829 5174
Email: yohba@tari.toshiba.com
Reinaldo Penno Phone: +1 408 544 5656
Nortel Networks EMail: alper.yegin@samsung.com
600 Technology Park Yoshihiro Ohba
Billerica, MA, 01821 Toshiba America Research, Inc.
USA 1 Telcordia Drive
Phone: +1 978 288 8011 Piscataway, NJ 08854
Email: rpenno@nortelnetworks.com USA
George Tsirtsis Phone: +1 732 699 5305
Flarion Technologies EMail: yohba@tari.toshiba.com
Bedminster One
135 Route 202/206 South
Bedminster, NJ, 07921
USA
Phone : +44 20 88260073
E-mail: G.Tsirtsis@Flarion.com, gtsirt@hotmail.com
Cliff Wang
Smart Pipes
565 Metro Place South
Dublin, OH, 43017
USA
Phone: +1 614 923 6241
Email: cwang@smartpipes.com
9. Appendix Reinaldo Penno
Nortel Networks
600 Technology Park
Billerica, MA 01821
USA
A. PANA Model Phone: +1 978 288 8011
EMail: rpenno@nortelnetworks.com
Following sub-sections capture the PANA usage model in different George Tsirtsis
network architectures with reference to its placement of logical Flarion
elements such as the PANA Client (PaC) and the PANA Authentication Bedminster One
Agent (PAA) with respect to the Enforcement Point (EP) and the 135 Route 202/206 South
Access Router (AR). Four different scenarios are described in Bedminster, NJ 07921
following sub-sections. Note that PAA may or may not use AAA USA
infrastructure to verify the credentials of PaC to authorize network
access.
A.1. PAA Co-located with EP but Separated from AR Phone: +44 20 88260073
EMail: G.Tsirtsis@Flarion.com, gtsirt@hotmail.com
Cliff Wang
ARO/NCSU
316 Riggsbee Farm
Morrisville, NC 27560
USA
Phone: +1 919 548 4207
EMail: cliffwangmail@yahoo.com
Appendix A. Problem Statement
Access networks in most cases require some form of authentication in
order to prevent unauthorized usage. In the absence of physical
security (and sometimes in addition to it) a higher layer (L2+)
access authentication mechanism is needed. Depending on the
deployment scenarios, a number of features are expected from the
authentication mechanism. For example, support for various
authentication methods (e.g., MD5, TLS, SIM, etc.), network roaming,
network service provider discovery and selection, separate
authentication for access (L1+L2) service provider and ISP (L3), etc.
In the absence of a link-layer authentication mechanism that can
satisfy these needs, operators are forced to either use non-standard
ad-hoc solutions at layers above the link, insert additional shim
layers for authentication, or misuse some of the existing protocols
in ways that were not intended by design. PANA will be developed to
fill this gap by defining a standard network-layer access
authentication protocol. As a network-layer access authentication
protocol, PANA can be used over any link-layer that supports IP.
DSL networks are a specific example where PANA has the potential for
addressing some of the deployment scenarios therein. Some DSL
deployments do not use PPP as the access link-layer (IP is carried
over ATM and the subscriber device is either statically- or
DHCP-configured). The operators of these networks are either left
with using an application-layer web-based login (captive portal)
scheme for subscriber authentication, or providing a best-effort
service only as they cannot perform subscriber authentication
required for the differentiated services. The captive portal scheme
is a non-standard solution that has various limitations and security
flaws.
PPP-based authentication can provide some of the required
functionality. But using PPP only for authentication is not a good
choice, as it incurs additional messaging during the connection setup
and extra per-packet processing, and it forces the network topology
to a point-to-point model. Aside from resistance to incorporating
PPP into an architecture unless it is absolutely necessary, there is
even interest in the community to remove PPP from some of the
existing architectures and deployments (e.g., 3GPP2, DSL).
Using Mobile IPv4 authentication with a foreign agent instead of
proper network access authentication is an example of protocol
misuse. Registration Required flag allows a foreign agent to force
authentication even when the agent is not involved in any Mobile IPv4
signalling (co-located care-of address case), hence enabling the use
of a mobility-specific protocol for an unrelated functionality.
PANA will carry EAP above IP in order to enable any authentication
method on any link-layer. EAP can already be carried by IEEE 802.1X
and PPP. IEEE 802.1X can only be used on unbridged IEEE 802 links,
hence it only applies to limited link types. Inserting PPP between
IP and a link-layer can be perceived as a way to enable EAP over that
particular link-layer, but using PPP for this reason has the
aforementioned drawbacks, hence not a good choice. While IEEE 802.1X
and PPP can continue to be used in their own domains, they do not
take away the need to have a protocol like PANA.
Appendix B. Usage Scenarios
PANA will be applicable to various types of networks. Based on the
presence of lower-layer security prior to running PANA, the following
types cover all possibilities:
a) Physically secured networks (e.g., DSL networks). Although data
traffic is always carried over a physically secured link, the client
might need to be authenticated and authorized when accessing the IP
services.
b) Networks where L1-L2 is already cryptographically secured before
enabling IP (e.g., cdma2000 networks). Although the client is
authenticated on the radio link before enabling ciphering, it
additionally needs to get authenticated and authorized for accessing
the IP services.
c) No lower-layer security present before enabling IP. PANA is run
in an insecure network. PANA-based access authentication is used to
bootstrap cryptographic per-packet authentication and integrity
protection.
PANA is applicable to not only large-scale operator deployments with
full AAA infrastructure, but also to small disconnected deployments
like home networks and personal area networks.
Since PANA enables decoupling AAA from the link-layer procedures,
network access authentication does not have to take place during the
link establishment. This allows deferring client authentication
until the client attempts to access differentiated services (e.g.,
high bandwidth, unlimited access, etc.) in some deployments.
Additionally multiple simultaneous network access sessions over the
same link-layer connection can be realized as well.
Following scenarios capture the PANA usage model in different network
architectures with reference to its placement of logical elements
such as the PANA Client (PaC) and the PANA Authentication Agent (PAA)
with respect to the Enforcement Point (EP) and the Access Router
(AR). Five different scenarios are described in following
sub-sections. Note that PAA may or may not use AAA infrastructure to
verify the credentials of PaC to authorize network access.
Scenario 1: PAA co-located with EP but separated from AR
In this scenario (Figure 1), PAA is co-located with the enforcement In this scenario (Figure 1), PAA is co-located with the enforcement
point on which access control is performed. PaCs communicate with point on which access control is performed. This might be the case
the PAA for network access on behalf of a device (D1, D2, etc.). where PAA is co-located with the L2 access device (e.g., an
PANA in this case provides a means to transport the authentication IP-capable switch).
parameters from the PaC to PAA. PAA knows how to verify the
credentials. After verification, PAA sends back the success or
failure response to PaC. However, PANA does not play any explicit
role in performing access control except that it provides a hook to
access control mechanisms. This might be the case where PAA is
co-located with the access point (an IP-capable L2 access device).
PaC -----EP/PAA--+ PaC -----EP/PAA--+
[D1] | |
+------ AR ----- (AAA) +------ AR ----- (AAA)
| |
PaC -----EP/PAA--+ PaC -----EP/PAA--+
[D2]
Figure 1: PAA co-located with EP but separated from AR. Figure 1: PAA co-located with EP but separated from AR.
A.2. PAA Co-located with AR but Separated from EP Scenario 2: PAA co-located with AR but separated from EP
Figure 2 describes this model. In this scenario, PAA is not In this scenario, PAA is not co-located with EPs but it is placed on
co-located with EPs but it is placed on the AR. Although we have the AR. Although we have shown only one AR here there could be
shown only one AR here there could be multiple ARs, one of which is multiple ARs, one of which is co-located with the PAA. Access
co-located with the PAA. PaC exchanges the same messages with PAA as control parameters have to be distributed to the respective
discussed earlier. The difference here is when the initial enforcement points so that the corresponding device on which PaC is
authentication for the PaC succeeds, access control parameters have authenticated can access to the network. A separate protocol is
to be distributed to respective enforcement points so that the
corresponding device on which PaC is authenticated can access to the
network. Similar to the earlier case, PANA does not play any
explicit role in performing access control except that it provides a
hook to access control mechanisms. However, a separate protocol is
needed between PAA and EP to carry access control parameters. needed between PAA and EP to carry access control parameters.
PaC ----- EP --+ PaC ----- EP --+
[D1] | |
+------ AR/PAA --- (AAA) +------ AR/PAA --- (AAA)
| |
PaC ----- EP --+ PaC ----- EP --+
[D2]
Figure 2: PAA co-located with AR but separated from EP. Figure 2: PAA co-located with AR but separated from EP
A.3. PAA Co-located with EP and AR Scenario 3: PAA co-located with EP and AR
In this scenario (Figure 3), PAA is co-located with the EP and AR on In this scenario (Figure 3), PAA is co-located with the EP and AR on
which access control and routing are performed. PaC exchanges the which access control and routing are performed.
same messages with PAA and PAA performs similar functionalities as
before. PANA in this case also does not play any explicit role in
performing access control except that it provides a hook to access
control mechanisms.
PaC ----- EP/PAA/AR--+ PaC ----- EP/PAA/AR--+
[D1] | |
+-------(AAA) +-------(AAA)
| |
PaC ----- EP/PAA/AR--+ PaC ----- EP/PAA/AR--+
[D2]
Figure 3: PAA co-located with EP and AR. Figure 3: PAA co-located with EP and AR.
A.4. PAA Separated from EP and AR Scenario 4: Separated PAA, EP, and AR
Figure 4 represents this model. In this scenario, PAA is neither In this scenario, PAA is neither co-located with EPs nor with ARs.
co-located with EPs nor with ARs. It still resides on the same IP It still resides on the same IP link as ARs. After the successful
link as ARs. PaC does similar exchanges with PAA as discussed authentication, access control parameters will be distributed to
earlier. Similar to model in A.2, after successful authentication, respective enforcement points via a separate protocol and PANA does
access control parameters will be distributed to respective not play any explicit role in this.
enforcement points via a separate protocol and PANA does not play
any explicit role in this.
PaC ----- EP -----+--- AR ---+ PaC ----- EP -----+--- AR ---+
| | | |
PaC ----- EP --- -+ | PaC ----- EP --- -+ |
| | | |
PaC ----- EP -----+--- AR -- + ----(AAA) PaC ----- EP -----+--- AR -- + ----(AAA)
| |
+--- PAA +--- PAA
Figure 4: PAA separated from EP and AR. Figure 4: PAA, EP and AR separated.
10. Full Copyright Statement Scenario 5: PAA separated from co-located EP and AR
"Copyright (C) The Internet Society (2003). All Rights Reserved. In this scenario, EP and AR are co-located with each other bu
This document and translations of it may be copied and furnished to separated from PAA. PAA still resides on the same IP link as ARs.
others, and derivative works that comment on or otherwise explain it After the successful authentication, access control parameters will
or assist in its implementation may be prepared, copied, published be distributed to respective enforcement points via a separate
and distributed, in whole or in part, without restriction of any protocol and PANA does not play any explicit role in this.
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be PaC --------------+--- AR/EP ---+
revoked by the Internet Society or its successors or assigns. | |
PaC --------------+ |
| |
PaC --------------+--- AR/EP -- + ----(AAA)
|
+--- PAA
This document and the information contained herein is provided on an Figure 5: PAA separated from EP and AR.
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING Intellectual Property Statement
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF The IETF takes no position regarding the validity or scope of any
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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 (2004). 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.
 End of changes. 151 change blocks. 
473 lines changed or deleted 545 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/