PANA Working Group Alper E. Yegin, Editor
INTERNET-DRAFT Yoshihiro Ohba
Date: April 2003 Reinaldo Penno
Expires: October 2003 George Tsirtsis
Cliff Wang
Protocol for Carrying Authentication for
Network Access (PANA)
Requirements and Terminology
<draft-ietf-pana-requirements-05.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance
with all provisions of Section 10 of RFC2026.
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.
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 is to provide a link-layer agnostic and IPv4/IPv6 compatible
client-server protocol that allows a host to be authenticated for
network access. 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. 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...................................................3
2. Key Words......................................................4
3. Terminology....................................................4
4. Requirements...................................................5
4.1. Authentication...............................................5
4.1.1. Authentication of Client...................................5
4.1.2. Authorization, Accounting and Access Control...............6
4.1.3. Authentication Backend.....................................6
4.1.4. Identifiers................................................7
4.2. IP Address Assignment........................................7
4.3. EAP Lower Layer Requirements.................................7
4.4. PAA-EP Protocol..............................................8
4.5. Network......................................................8
4.5.1. Multi-access...............................................8
4.5.2. Disconnect Indication......................................8
4.5.3. Location of PAA............................................9
4.5.4. Secure Channel.............................................9
4.6. Interaction with Other Protocols............................10
4.7. Performance.................................................10
4.8. Ordered-delivery, Congestion Control........................10
4.9. Miscellaneous...............................................10
4.9.1. IP Version Independence...................................10
4.9.2. Denial of Service Attacks.................................10
4.9.3. Location Privacy..........................................10
5. Change Log....................................................11
Acknowledgements.................................................11
References.......................................................11
Authors' Addresses...............................................13
Appendix.........................................................14
Full Copyright Statement.........................................16
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1. Introduction
Providing secure network access service requires access control
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 methods between the client and the access
network. IETF PANA Working Group has been chartered with the goal of
designing a network-layer access authentication protocol.
Link-layer authentication mechanisms are used as enablers of secure
network access. A higher-layer authentication is deemed necessary
when link-layer authentication mechanisms are either not available
for lack of technology or deployment difficulties, or not able to
meet the overall requirements, or when multi-layer (e.g., link-layer
and 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. [USAGE] Internet-Draft describes the problem
statement in detail.
The protocol design will be limited to defining a client-server
messaging protocol (i.e., a carrier) that will allow authentication
payload to be carried between the host/client and an agent/server in
the access network for authentication and authorization purposes
regardless of the AAA infrastructure that may (or may not) reside on
the network. As a network-layer protocol, it will be independent of
the underlying access technologies. It will also be applicable to
any network topology.
The Working Group will not invent new security protocols and
mechanisms but instead it 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
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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].
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 connected 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 for network access authorization.
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.
Enforcement Point (EP)
A node on the access network where per-packet
enforcement policies (i.e., filters) are applied on the inbound
and outbound traffic of client devices. Information such as DI
and (optionally) cryptographic keys are provided by PAA per
client for constructing filters on the EP.
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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 (e.g., 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"). The current thinking is that a sufficient
solution would be for PANA to carry EAP [EAP]. If PANA WG decides
that extensions to EAP are needed, it will define requirements for
the EAP WG instead of designing such extensions.
Providing authentication, integrity and replay protection for data
traffic after a successful PANA exchange is outside the scope of
this protocol. In networks where physical layer security is not
present, link-layer or network-layer (e.g., IPsec) ciphering can be
used to provide such security. These mechanisms require presence of
cryptographic keying material at PaC and EP, which can be generated
by various EAP methods. Although PANA does not deal with key
derivation or distribution, it indirectly enables this by the virtue
of carrying EAP. The keying material produced by EAP methods cannot
be directly used with IPsec. In that case these initial keys can be
used with an IPsec key management protocol like IKE to generate the
required security associations. Key distribution from PAA to EP
SHOULD be handled by a separate protocol that takes care of
provisioning in the network (see section 4.3). Providing a complete
secure network access solution by also securing router discovery
[RDISC], neighbor discovery [NDISC], and address resolution
protocols [ARP] is outside the scope as well. Securing IPv6 router
discovery and neighbor discovery protocols are within the scope of
IETF SEND Working Group.
Some access networks might require or allow their clients to get
authenticated and authorized by the NAP (network access provider)
and ISP before the clients gain network access. NAP is the owner of
the access network who provides physical and link-layer connectivity
to the clients. PANA MUST be capable of enabling two independent
authentication operations (i.e., execution of two separate EAP
methods) for the same client. Determining the authorization
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parameters as a result of two separate authentications is an
operational issue and therefore it is outside the scope of PANA.
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.
Certain type of service theft is possible when the DI is not
protected during or after the PANA exchange [SECTHREAT]. PANA MUST
have the capability to exchange DI securely between the PAC and PAA
where the network is vulnerable to man-in-the-middle attacks. While
PANA MUST provide such a capability, its utility relies on the use
of an authentication method that can generate keys for cryptographic
computations on PaC and PAA.
4.1.2. Authorization, Accounting and Access Control
In addition to carrying authentication information, PANA MUST also
provide only a binary authorization to indicate whether the PaC is
allowed to access full IP services on the network (i.e., able to
send and receive any IP packets). Providing finer granularity
authorization, such as negotiating QoS parameters, authorizing
individual services (e.g., http vs. ssh), individual users sharing
the same device, etc. are outside the scope of PANA.
Providing access control functionality in the network is outside the
scope of PANA. Client access authentication SHOULD be followed by
access control to make sure only authenticated and authorized
clients can send and receive IP packets via access network. Access
control can involve setting access control lists on the EPs.
Identification of clients that are authorized to access the network
is done by the PANA protocol exchange.
Carrying accounting data is outside the scope of PANA.
4.1.3. Authentication Backend
PANA protocol MUST NOT make any assumptions on the backend
authentication protocol or mechanisms. PAA MAY interact with backend
AAA infrastructures such as RADIUS or Diameter, but it is not a
requirement. When the access network does not rely on an IETF-
defined AAA protocol (e.g., RADIUS, Diameter), then it can still use
a proprietary backend system, or rely on the information locally
stored on the authentication agents.
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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.). This requirement generally
relies on the client identifiers supported by various EAP methods.
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,
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. Multi-access networks also
require use of a cryptographic protection along with DI filtering to
prevent unauthorized access [SECTHREAT]. The keying material
required by the cryptographic methods needs to be stored as an
attribute of DI. The binding between DI and PaC is used for access
control and accounting in the network as described in section 4.1.2.
4.2. IP Address Assignment
Providing address assignment functionality is outside the scope of
PANA. PANA protocol design MAY require the PaC to configure an IP
address before using this protocol. Allocating an IP address to
unauthenticated PaCs may create security vulnerabilities, such as IP
address depletion attacks on the access network [SECTHREAT]. This
threat may not be an issue for IPv6 because of the large address
space, but it can affect IPv4 networks. This threat can be mitigated
by allowing the protocol to run without an IP address 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
EAP protocol itself imposes various requirements on its transport
protocols. These requirements are based on the nature of the EAP
protocol, and needs to be satisfied for correct operation. Please
see [EAP] for the generic transport requirements that MUST be
satisfied by PANA as well.
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4.4. PAA-EP Protocol
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
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
Internet, depending on the network architecture). When the PAA and
the EP(s) are separated, there needs to be another transport for
client provisioning. This transport is needed to create access
control lists to allow authenticated and authorized clients traffic
through the EPs. This WG will preferably identify an existing
protocol solution that allows the PAA to deliver the authorization
information to one or more EPs when the PAA is separated from EPs.
Possible candidates include but not limited to COPS, SNMP, DIAMETER.
This task is similar to what MIDCOM Working Group is trying to
achieve, therefore some of that WGs output might be useful here.
It is assumed that the communication between PAA and EP(s) is
secure. The objective of using this protocol is to provide filtering
rules to EP(s) for allowing network access of a recently
authenticated and authorized PaC. The chosen protocol MUST be
capable of carrying DI and cryptographic keys for a given PaC from
PAA to EP. Depending on the PANA protocol design, support for either
of the pull model (i.e., EP initiating the PAA-EP protocol exchange
per PaC) or the push model (i.e., PAA initiating the PAA-EP protocol
exchange per PaC), or both MAY be required. For example, if the
design is such that the EP allows the PANA traffic to bypass even
for unauthenticated PaCs, it should also allow and expect the PAA to
send the filtering information at the end of successful PANA without
EP ever sending a request.
4.5. Network
4.5.1. Multi-access
Protocol MUST support PaCs with multiple interfaces, and networks
with multiple routers on multi-access links. In other words, PANA
MUST not assume PaC has only one network interface, or the access
network has only one first hop router, or the PaC is using a point-
to-point link.
4.5.2. Disconnect Indication
PANA MUST NOT assume that the link is connection-oriented. Links MAY
or MAY NOT provide disconnect indication. Such notification is
desirable in order for the PAA to cleanup resources when a client
moves away from the network (e.g., inform the enforcement points
that the client is no longer connected). PANA SHOULD have a
mechanism to provide disconnect indication. When such indications
are not protected by means of physical or link-layer mechanisms,
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PANA MUST ensure this protection to prevent attackers from
leveraging this extension for DoS attacks.
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
be notified about the discontinuation of the network access service.
Access discontinuation can happen due to various reasons such as
network systems going down, or a change in access policy.
In case the clients cannot send explicit disconnect messages to the
PAA, PAA can still detect their departure by relying on periodic
authentication requests.
4.5.3. Location of PAA
The PAA and PaC MUST be exactly one IP hop away from each other.
That means, there must be no IP routers between two. Note that, this
does not mean they are on the same physical link. Bridging
techniques can place two nodes just exactly one IP hop away from
each other although they might be connected to separate physical
links. Furthermore, two nodes on the same IP subnet does not
necessarily satisfy this requirement, as they can be more than one
hop away from each other [MULTILINK]. PAA can be on the NAS (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 not be pre-configured with the IP address of PAA.
Therefore PANA protocol MUST define a dynamic discovery method.
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
anycast) by the PaC to find out the address of the PAA.
4.5.4. Secure Channel
PANA MUST not assume presence of 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 enable protection against replay attacks on both
PaCs and PAAs.
This requirement partially relies on the EAP protocol and the EAP
methods carried over PANA. Use of EAP methods that provide mutual
authentication and key derivation/distribution is essential for
satisfying this requirement. EAP does not make a secure channel
assumption, and supports various authentication methods that can be
used in such environments. Additionally, PANA MUST ensure its design
does not contain vulnerabilities that can be exploited when it is
used over insecure channels. PANA MAY provide a secure channel by
deploying a two-phase authentication. First phase can be used for
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creation of the secure channel, and the second phase is for client
and network authentication.
4.6. 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
[DHCP]. It MUST NOT make any assumptions on the protocols or
mechanisms used for IP address configuration of the PaC.
4.7. 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.
4.8. Ordered-delivery, Congestion Control
PANA MUST provide ordered-delivery for messages that carry EAP PDUs
as described in [EAP]. PANA MUST provide congestion control for all
messages. It can do so by using techniques like delayed
initialization and exponential back off.
4.9. Miscellaneous
4.9.1. IP Version Independence
PANA MUST work with both IPv4 and IPv6.
4.9.2. 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/or prevent legitimate clients' attempts
of network access.
4.9.3. Location Privacy
Location privacy is outside the scope of PANA.
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5. Change Log
Version 05
* Definition of EP added.
* Text is clarified to indicate some of the requirements are
satisfied by EAP and EAP methods.
* IP address pre-configuration requirement changed.
* EAP lower layer requirements section added.
* Location of PAA further clarified (link vs. subnet vs. IP hops).
* PAA-EP protocol section added.
Version 04
* Minor Editorial corrections.
* Inserted the PANA model appendix.
Version 03
* In section 4.2.2 the requirement for a heartbeat mechanism to
provide disconnect indication was removed. Rewording of the
section was done.
* In section 4.2.3 and 4.1.2 rewording was done to account for the
separation of PAA and EP and the protocol between them.
* In section 4.2.4 new text was added to account for the possibility
to rely on the high layer protocol (EAP) to meet the requirements
stated.
* In section 4.5 new text was added to allow reliability and
congestion control to be provided by the payload protocol, e.g.,
EAP.
Acknowledgements
We would like to thank Subir Das, Lionel Morand, Mohan
Parthasarathy, Basavaraj Patil and the PANA Working Group members
for their valuable contributions to the discussions and preparation
of this document.
References
[KEYWORDS] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[USAGE] Y. Ohba, S. Das, B. Patil, H. Soliman, A. Yegin, "Problem
Statement and Usage Scenarios for PANA", draft-ietf-pana-usage-
scenarios-05.txt, April 2003. Work in progress.
[8021X] "IEEE Standards for Local and Metropolitan Area Networks:
Port Based Network Access Control", IEEE Draft 802.1X/D11, March
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2001.
[SECTHREAT] M. Parthasarathy, "PANA Threat Analysis and Security
Requirements", draft-ietf-pana-threats-03.txt, April 2003. Work in
progress.
[EAP] L. Blunk, J. Vollbrecht, B. Aboba, J. Carlson, "Extensible
Authentication Protocol (EAP)", draft-ietf-eap-rfc2284bis-01.txt,
January 2003. Work in progress.
[MULTILINK] D. Thaler, C. Huitema, "Multi-link Subnet Support in
IPv6", draft-ietf-ipv6-multilink-subnets-00.txt, December 2002. Work
in progress.
[PPP] W. Simpson (editor), "The Point-To-Point Protocol (PPP)", STD
51, RFC 1661, July 1994.
[MIPV4] C. Perkins (editor), "IP Mobility Support for IPv4", RFC
3344, August 2002.
[MIPV6] D. Johnson and C. Perkins, "Mobility Support in IPv6",
draft-ietf-mobileip-ipv6-21.txt, February 2003. Work in progress.
[MNAAA] C. Perkins, P. Calhoun, "Mobile IPv4 Challenge/Response
Extensions", RFC3012, November 2000.
[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] R. Koodli (editor), et. al., "Fast Handovers for Mobile
IPv6", March 2003. Work in progress.
[DHCP] R. Droms (editor), et. al., "Dynamic Host Configuration
Protocol for IPv6", November 2002. 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
600 Technology Park
Billerica, MA, 01821
USA
Phone: +1 978 288 8011
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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Appendix
A. PANA Model
Following sub-sections capture the PANA usage model in different
network architectures with reference to its placement of logical
elements such as PANA Client (PaC) and PANA Authentication Agent
(PAA) w.r.t Enforcement Point (EP) and Access Router (AR). Four
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.
A.1. PAA Co-located with EP but separated from AR
In this scenario (Figure 1), PAA is co-located with the enforcement
point on which access control is performed. PaCs communicate with
the PAA for network access on behalf of a device (D1, D2, etc.).
PANA in this case provides a means to transport the authentication
parameters from the PaC to PAA. PAA understands 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-+
[D1] |
+- ----- AR ----- (AAA)
|
PaC -----EP/PAA-+
[D2]
Figure 1: PAA co-located with EP but separated from AR.
A.2. PAA Co-located with AR but separated from EP
Figure 2 describes this model. In this scenario, PAA is not co-
located with EPs but it is placed on the AR. Although we have shown
only one AR here there could be multiple ARs one of which is co-
located with the PAA. PaC exchanges the same messages with PAA as
discussed earlier. The difference here is when the initial
authentication for the PaC succeeds, access control parameters are
to be distributed to respective enforcement points so that the
corresponding device on which PaC is authenticated must be able to
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
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protocol is needed between PAA and EP to carry access control
parameters.
PaC -------- EP --+
[D1] |
+--- AR/PAA --- (AAA)
|
PaC -------- EP --+
[D2]
Figure 2: PAA co-located with AR but separated from EP.
A.3. PAA Co-located with EP and AR
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
same messages with PAA and PAA performs similar functionalities as
above. 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--+
[D1] |
+ -------(AAA)
|
PaC ---------- EP/PAA/AR--+
[D2]
Figure 3: PAA co-located with EP and AR.
A.4. PAA Separated from EP and AR
Figure 4 represents this model. In this scenario, PAA is neither co-
located with EPs nor with Ars. It still resides on the same IP link
as ARs. PaC does similar exchanges with PAA as discussed earlier.
Similar to model in A.2, after successful authentication, access
control parameters will be distributed to respective enforcement
points via a separate protocol and PANA does not play any explicit
role in this.
Yegin (Editor), et.al. Expires Oct 2003 [Page 15]
Internet Draft PANA Requirements and Terminology Apr 2003
PaC ----- EP -----+- AR -----+
| |
PaC ----- EP --- -+ |
| |
PaC ----- EP -----+- AR ---- + ----(AAA)
|
+- PAA
Figure 4: PAA separated from EP and AR.
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Yegin (Editor), et.al. Expires Oct 2003 [Page 16]
