eap Mailing List: Re: Re: resolution to issue 161

[Alper Yegin (alper]

>> Add to state machine doc, section 2, before the last paragraph:
>> 
>>    Some environments where EAP is used, such as PPP, may support
>>    peer-to-peer operation. That is, both parties act as peers and
>>    authenticators at the same time, in two simultaneous and
>>    independent EAP conversations. In this case, the lower layer to at
>>    each node has to perform demultiplexing of incoming EAP packets.
>>    EAP packets with Code set to Response are delivered to the
>>    Authenticator state machine, and all other EAP packets are
>>    delivered to the Peer state machine.
> 
> What are the link layer requirements for support of EAP peer-to-peer
> operation?  I ask this because there is nothing in RFC 2248bis Section
> 2.4 or 3.1 that discusses these requirements.
> 
> For example, if there a requirement for the link layer to be able to
> demultiplex the EAP conversations in each direction, wouldn't that imply
> the need for a field in the link layer header with which to do this
> demultiplexing?  For example, IPv4/IPv6 packets are demultiplexed by
> different EtherType values, not really by the IP version number.
> 
> In Section 3.2.1 of RFC 2284bis the PPP Authentication Protocol format is
> defined.  EAP packets are encapsulated with an Authentication Protocol
> value of C227 (Hex).  Similarly, in IEEE 802.1X an Ethertype is assigned
> to 802.1X packets. Neither of these encapsulations can demultiplex EAP
> conversations occurring in different directions.  For example, there is no
> different Authentication Protocol value or Ethertype for this.
> 
> Since neither of these encapsulations demultiplexes EAP conversations in
> either direction, and the link layer does not look at frames deeper in the
> packet, such as the EAP Code or Type fields, I don't think that this
> explanation can be correct. If there is demultiplexing, then this would
> need to occur in the EAP layer, not in the link layer, no?

PANA message type (i.e., request vs. answer) can be used for demultiplexing
the payload (EAP message).

Alper