Protocol for carrying Authentication for Network Access
Protocol for carrying Authentication for Network Access WG
||Protocol for carrying Authentication for Network Access
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In some scenarios, an IP-based device is required to authenticate
itself to the network prior to being authorized to use it. This
authentication usually requires a protocol that can support various
authentication methods, dynamic service provider selection, and
roaming clients. In the absence of such an authentication protocol on
most of the link-layers, architectures have resorted to filling the gap
by using a number of inadequate methods. For example, inserting an
additional layer between link-layer and network-layer mostly for client
authentication purpose (e.g., PPPoE), overloading another network-layer
protocol to achieve this goal (e.g., Mobile IPv4 with Registration-
required flag), and even defining application-layer ad-hoc
authentication mechanisms (e.g., http redirects with web-based login).
In these and other cases, a network-layer authentication protocol may
provide a cleaner solution to the authentication problem.
The goal of PANA is to define a protocol that allows clients to
authenticate themselves to the access network using IP protocols. Such
a protocol would allow a client to interact with a site's back-end AAA
infrastructure to gain access without needing to understand the
particular AAA infrastructure protocols that are in use at the
site. It would also allow such interactions to take place without a
link-layer specific mechanism. PANA would be applicable to both
multi-access and point-to-point links. It would provide support for
various authentication methods, dynamic service provider selection,
and roaming clients.
Mobile IPv4 developed its own protocols for performing PANA-like
functions (e.g., MN-FA interaction). Mobile IPv6 does not have the
equivalent of a Foreign Agent (FA) that would allow the access/visited
network to authenticate the MN before allowing access. The PANA
authentication agent (PAA) can perform the authentication function
attributed to the FA in Mobile IPv4, in Mobile IPv6 networks.
The WG will work with the assumption that a PANA client (PaC) is
already configured with an IP address before using PANA. This IP
address will provide limited reachability to the PaC until it is
authenticated with the PAA. Upon successful authentication, PaC is
granted broader network access possibly by either a new IP address
assignment, or by enforcement points changing filtering rules for the
same IP address.
PANA will neither define any new authentication protocol nor define key
distribution, key agreement or key derivation protocols. It is believed
that PANA will be able to meet its goals if it is able to carry EAP
payloads. Note, however, that EAP may need to be extended in order for
PANA to meet the need for all of its intended usages. Such extensions
are outside the scope of the PANA WG.
PANA will develop an IP-based protocol that allows a device to
authenticate itself with the network (and to a PAA in particular) in
order to be granted network access. The PAA itself may interface with
other AAA backend infrastructures for authenticating and authorizing
the service being requested by the host, but such interactions are
transparent to the PaC.
Network access authentication enables the client to be authorized for
packet data service. However it is possible that the underlying link
itself is insecure, i.e the packets being transmitted between the
client (PaC) and the enforcement point (EP) in the network are not
protected by any physical or cryptographic means. In such cases,
PANA will enable the establishment of an IPsec SA between the PaC
and the EP (a router) to enable access control. In networks that
have physical security or ciphering as a link-layer feature, no
such SA is required. Hence the establishment of the IPsec SA is
optional. The WG will deliver a document that explains how such
an IPsec SA is established by using IKE after successful PANA
authentication. No enhancements to either IKE or IPsec are expected.
The PAA does not necessarily act as an enforcement point (EP) to
prevent unauthorized access or usage of the network. When a PaC
succesfully authenticates itself to the PAA, EP(s) (e.g., access
routers) will need to be suitably notified. SNMP will be used
by the PAA to deliver the authorization information to one or
more EPs when the PAA is separated from EPs. The WG will document
the solution based on SNMP for carrying the authorization information
between the PAA and the EP.
The WG will also propose a solution of how the PaC discovers
the IP address of PAA for sending the authentication request.
The PANA WG will deliver
- A mechanism for the PAC to discover the PAA on the link.
- The PANA protocol itself, capable of carrying multiple authentication
methods (e.g. using EAP)
- A document that describes how SNMP is used to deliver authorization
information from the PAA to the EP in the scenarios where the PAA
and EP are separated.
- A document that explains the establishment of an IPsec SA between
the client and a router (EP) subsequent to authentication for
securing the data packets.