PANA Working Group Alper E. Yegin, Editor
INTERNET-DRAFT Yoshihiro Ohba
Date: March 2002 Reinaldo Penno
Expires: September 2002 George Tsirtsis
Cliff Wang
Protocol for Carrying Authentication for
Network Access (PANA)
Requirements and Terminology
<draft-ietf-pana-requirements-01.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance
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Abstract
It is expected that future IP devices will have a variety of access
technologies to gain network connectivity. Currently there are
access-specific mechanisms for providing client information to the
network for authentication and authorization purposes. In addition
to being limited to specific access media (e.g., 802.1x for IEEE 802
links), some of these protocols are limited to specific network
topologies (e.g., PPP for point-to-point links). The goal of the
PANA Working Group is to design a general network-layer protocol to
authenticate clients to the networks. The protocol will run between
a client's device and an agent device in the network where the agent
might be a client of the AAA infrastructure. The protocol should be
independent of the underlying access-type and not be limited to
specific network topologies. This document defines the common
terminology and identifies the requirements for PANA.
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Table of Contents
Status of this Memo...............................................1
Abstract..........................................................1
Table of Contents.................................................2
1. Introduction...................................................2
2. Key Words......................................................3
3. Terminology....................................................4
4. Requirements...................................................4
4.1. Authentication...............................................4
4.1.1. Authentication of Client...................................4
4.1.2. Authorization, Accounting and Access Control...............5
4.1.3. Authentication Backend.....................................5
4.1.4. Identifiers................................................5
4.2. Network......................................................6
4.2.1. Multi-access...............................................6
4.2.2. Disconnect Indication......................................6
4.2.3. Location of PAA............................................6
4.2.4. Secure Channel.............................................6
4.3. Interaction with Other Protocols.............................6
4.4. Performance..................................................7
4.5. Reliability and Congestion Control...........................7
4.6. Miscellaneous................................................7
4.6.1. IP Version Independence....................................7
4.6.2. Denial of Service Attacks..................................7
4.6.3. Location Privacy...........................................7
Acknowledgements..................................................7
References........................................................8
AuthorsÆ Addresses................................................9
Full Copyright Statement.........................................10
1. Introduction
Currently there are a variety of access technologies available to
the network clients. While most of the clients currently have single
interface, it is expected that in the future they will have multiple
interfaces of different types to access the network.
An authentication mechanism is needed in order to provide secure
network access to the legitimate clients. Some of the current
authentication mechanisms are access technology specific. For
example 802.1x [8021X] works for only IEEE 802 link layers. If a
client can have more than one type of interface, using access-
specific authentication mechanisms leads to running a collection of
protocols on the client for the same purpose. It is clearly
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advantageous to use a general protocol to authenticate the client
for network access on any type of technology.
The most widely used protocol for authenticating clients is the PPP
[PPP]. This protocol can run on various access types, but it
provides an inherently point-to-point interface. While it can
efficiently be applied to such topologies, using PPP with a multi-
access network creates sub-optimal solutions. Such multi-access
networks require either a full mesh of PPP links among clients, or a
designated router as the end-point of PPP links.
There is currently no general protocol to be used by a client for
gaining network access, and the PANA Working Group will attempt to
fill that hole. The Working Group will design a protocol between a
client's device and an agent device in the network where the agent
might be a client of the AAA infrastructure. As a network-layer
protocol, it will be independent of the underlying access
technologies. It will also be applicable to any network topology.
The protocol design will be limited to defining a messaging protocol
(i.e., a carrier) for providing the clients' information to the
network for authentication and authorization purposes. The Working
Group will not invent new security protocols and mechanisms but
instead will use the existing mechanisms. In particular, the Working
Group will not define authentication protocols, key distribution or
key agreement protocols, or key derivation. The desired protocol can
be viewed as the front-end of the AAA protocol or any other
protocol/mechanisms the network is running at the background to
authenticate its clients. It will act as a carrier for an already
defined security protocol or mechanism.
As an example, Mobile IP Working Group has already defined such a
carrier for Mobile IPv4 [MIPV4]. Mobile IPv4 registration request
message is used as the carrier for authentication extensions (MN-FA
[MIPV4], or MN-AAA [MNAAA]) to receive forwarding service from the
foreign agents. In that sense, designing the equivalent of Mobile
IPv4 registration request messages for general network access is the
goal of this work, but not defining the equivalent of MN-FA or MN-
AAA extensions.
This document defines the common terminology and identifies the
requirements of a protocol for PANA. These terminology and
requirements will be used to define and limit the scope of the work
to be done in this group.
2. Key Words
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [KEYWORDS].
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3. Terminology
Device Identifier (DI)
The identifier used by the network as a handle to control and
police the network access of a client. Depending on the access
technology, identifier might contain any of IP address, link-
layer address, switch port number, etc. of a device. PANA
authentication agent keeps a table for binding device
identifiers to the PANA clients. At most one PANA client
should be associated with a DI on a PANA authentication agent.
PANA Client (PaC)
The entity wishing to obtain network access from a PANA
authentication agent within a network. A PANA client is
associated with a network device and a set of credentials to
prove its identity within the scope of PANA.
PANA Authentication Agent (PAA)
The entity whose responsibility is to authenticate the
credentials provided by a PANA client and grant network
access service to the device associated with the client
and identified by a DI.
4. Requirements
4.1. Authentication
4.1.1. Authentication of Client
PANA MUST authenticate a PaC for network access. A PaC can be
identified by the credentials (identifier, authenticator) supplied
by one of the users of the device or the device itself. PANA MUST
only grant network access service to the device identified by the
DI, rather than granting separate access to multiple simultaneous
users of the device. Once the network access is granted to the
device, the methods used by the device on arbitrating which one of
its users can access the network is outside the scope of PANA.
PANA MUST NOT define new security protocols or mechanisms. Instead
it must be defined as a "carrier" for such protocols. PANA MUST
identify which specific security protocol(s) or mechanism(s) it can
carry (the "payload"). An example of a carrier would be the
registration request message of Mobile IPv4 [MIPV4] that carries MN-
FA authentication extension.
Authentication and encryption of data traffic sent to and from an
authenticated PaC is outside the scope of PANA. Providing a complete
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secure network access solution by also securing router discovery
[RDISC], neighbor discovery [NDISC], and address resolution
protocols [ARP] is outside the scope as well.
Both the PaC and the PAA MUST be able to authenticate each other for
network access. Providing capability of only PAA authenticating the
PaC is not sufficient.
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
both the initial authentication and the re-authentication process.
When the DI is carried explicitly as part of the PANA payload, the
authentication computation MUST also include this field to provide
integrity protection for the DI. When the DI is carried implicitly
as the source of the PANA message, the protocol has to make sure
that the DI's integrity is protected by some other means (e.g.,
physical verification of incoming port number of the PANA message in
the case of switch port number as a DI and PAA co-located with the
link-layer access device). Protecting PaCs against DI theft is
outside the scope of PANA.
4.1.2. Authorization, Accounting and Access Control
In addition to carrying authentication information, PANA MUST also
carry a binary result (i.e., success or failure) of authorization
for network access to the PaC. Providing finer granularity
authorization is outside the scope of PANA.
Providing access control functionality in the network is outside the
scope of PANA. PAA MAY communicate the DI associated with a PaC to
other entities in the network to setup access control and accounting
state. This interaction is outside the scope of PANA as well.
Carrying accounting data is outside the scope of PANA.
4.1.3. Authentication Backend
PAA MAY use either a AAA backend, some other mechanism or a local
database to authenticate the PaC. PANA protocol MUST NOT make any
assumptions on the backend authentication protocol or mechanisms.
The interaction between the PAA and the backend authentication
entities is outside the scope of PANA.
4.1.4. Identifiers
PANA SHOULD allow various types of identifiers to be used for the
PaC (e.g., NAI, IP address, FQDN, etc.)
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PANA SHOULD allow various types of identifiers to be used as the DI
(IP address, link-layer address, port number of a switch, etc.)
PAA MUST be able to create a binding between the PaC and the
associated DI upon successful PANA exchange. The DI MUST be carried
either explicitly as part of the PANA payload, or implicitly as the
source of the PANA message, or both. This binding is used for access
control and accounting in the network as described in section 4.1.2.
4.2. Network
4.2.1. Multi-access
Protocol MUST support PaCs with multiple interfaces, and networks
with multiple routers on multi-access links.
4.2.2. Disconnect Indication
PANA MUST NOT assume connection-oriented links. Links may or may not
provide disconnect indication. PANA SHOULD define a "disconnect"
indication to allow PaCs to notify the PAA of their departure from
the network. A similar indication SHOULD also be used to let PAA
notify a PaC about the discontinuation of the network access. Access
discontinuation can happen due to various reasons such as network
systems going down, or a change in access policy.
4.2.3. Location of PAA
PAA MAY be one or more hop away from the PaC. PANA MUST define a
method used by PaCs for locating the PAAs in a network.
4.2.4. Secure Channel
PANA MUST not assume a secure channel between the PaC and the PAA.
PANA MUST be able to provide authentication especially in networks
which are not protected against eavesdropping and spoofing. PANA
MUST provide protection against replay attacks on both PaCs and
PAAs.
4.3. Interaction with Other Protocols
Mobility management is outside the scope of PANA. Though, PANA MUST
be able to co-exist and not interfere with various mobility
management protocols, such as Mobile IPv4 [MIPV4], Mobile IPv6
[MIPV6], fast handover protocols [FMIPV4, FMIPV6], and other
standard protocols like IPv6 stateless address auto-configuration
[ADDRCONF] (including privacy extensions [PRIVACY]), and DHCP
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[DHCP]. It MUST NOT make any assumptions on the protocols or
mechanisms used for IP address configuration of the PaC.
4.4. Performance
PANA design SHOULD give consideration to efficient handling of
authentication process. This is important for gaining network access
with minimum latency. As an example, a method like minimizing the
protocol signaling by creating local security associations can be
used for this purpose.
4.5. Reliability and Congestion Control
PANA MUST provide reliability and congestion control. It can do so
by using techniques like re-transmissions, cyclic redundancy check,
delayed initialization and exponential back-off.
4.6. Miscellaneous
4.6.1. IP Version Independence
PANA MUST work for both IPv4 and IPv6.
4.6.2. Denial of Service Attacks
PANA MUST be robust against a class of DoS attacks such as blind
masquerade attacks through IP spoofing that swamp the PAA in
spending much resources and prevent legitimate clientsÆ attempts of
network access. The required robustness is no worse than that for
TCP SYN attack.
4.6.3. Location Privacy
Location privacy is outside the scope of PANA.
Acknowledgements
We would like to thank Basavaraj Patil, Subir Das, and the PANA
Working Group members for their valuable contributions to the
discussions and preparation of this document.
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References
[KEYWORDS] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[8021X] "IEEE Standards for Local and Metropolitan Area Networks:
Port Based Network Access Control", IEEE Draft 802.1X/D11, March
2001.
[PPP] W. Simpson (editor), "The Point-To-Point Protocol (PPP)", STD
51, RFC 1661, July 1994.
[MIPV4] C. Perkins (editor), "IP Mobility Support", RFC 2002,
October 1996.
[MIPV6] D. Johnson and C. Perkins, "Mobility Support in IPv6",
draft-ietf-mobileip-ipv6-15.txt, July 2001. Work in progress.
[MNAAA] C. Perkins, P. Calhoun, "Mobile IPv4 Challenge/Response
Extensions", RFC3012, November 2000.
[RDISC] S. Deering, "ICMP Router Discovery Messages", RFC 1256,
September 1991.
[NDISC] T. Narten, E. Nordmark, and W. Simpson, "Neighbor Discovery
for IP Version 6 (IPv6)",RFC 2461, December 1998.
[ARP] D. Plummer, "An Ethernet Address Resolution Protocol", STD 37,
RFC 826, November 1982.
[FMIPV4] K. ElMalki (editor), et. al., "Low latency Handoffs in
Mobile IPv4", November 2001. Work in progress.
[FMIPV6] G. Dommety (editor), et. al., "Fast Handovers for Mobile
IPv6", July 2001. Work in progress.
[DHCP] R. Droms (editor), et. al., "Dynamic Host Configuration
Protocol for IPv6", December 2001. Work in progress.
[PRIVACY] T. Narten, R. Draves, "Privacy Extensions for Stateless
Address Autoconfiguration in IPv6", RFC 3041, January 2001.
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Authors' Addresses
Alper E. Yegin
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
Toshiba America Research, Inc.
P.O. Box 136
Convent Station, NJ, 07961-0136
USA
Phone: +1 973 829 5174
Email: yohba@tari.toshiba.com
Reinaldo Penno
Nortel Networks
2305 Mission College Boulevard
Santa Clara, CA, 95054
USA
Phone: +1 408 565 3023
Email: rpenno@nortelnetworks.com
George Tsirtsis
Flarion Technologies
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
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