Subject: RE: [AAA-WG]: Issue 51: EAP Roundtrips

From: [email-masked]
Date: Wed, 20 Jun 2001 14:07:48 +0300

> Could you please take a look at the text I just sent to the 
> list to fix Issue 88,
> and tell me what changes would be required to handle 51. The 
> fixes in 88 are a
> result of operational experience in 802/radius networks. The 
> change in 51 is a
> proposed optimization, as I understand it, may break 
> interoperability with 802
> and radius networks. Is this correct?

Pat, 

I included the changes below. 

It is true that the operation of the NAS and the Diameter 
server with this optimization would be different from the 
operation in Radius. But as Diameter is a new protocol, I don't 
see any problems in requiring Diameter nodes to implement
new things. The current 802 documents refer to Radius, and if
this optimization is adopted, then new Diameter-specific
operation will be required in 802 nodes and PPP servers that 
implement Diameter.

Interoperability with existing Radius networks may become an 
issue. It would be hard to do protocol translation from "optimized" 
Diameter to Radius, if the AAA server speaks Diameter
and the NAS Radius (we'd need stateful translation). 
But it would be easy to translate from "unoptimized" Diameter 
to Radius. And if the AAA server speaks Radius and the NAS Diameter,
then protocol translation to "unoptimized" Diameter would be 
easy to implement.

Regards,
Henry

Proposed addition:
   
A Diameter-EAP-Answer message with the Result-Code AVP
indicating success or failure MAY contain an EAP-Payload of
type EAP-Request. In this case the Diameter server does not 
expect any response to the EAP-Request. As usual, the NAS relies 
on the Result-Code AVP to determine whether service is to be 
provided. In any case, the NAS MUST relay the encapsulated EAP-Request 
to the peer. The NAS MUST retransmit the EAP Request to the peer until 
a Response packet with the same Identifier is received or an optional 
retry counter expires. The NAS MUST NOT send the received Response packet 
to the Diameter server but it MUST discard the Response packet. 
On receipt of the Response packet, the NAS MAY manufacture an 
EAP-Success or an EAP-Failure (depending on the Result-Code AVP 
in the Diameter-EAP-Anser message), and send it to the peer.

---

From: Pat Calhoun <[email-masked]>
Date: Thu, 21 Jun 2001 06:11:45 -0700

> then protocol translation to "unoptimized" Diameter would be 

but how would an 802.11 bridge talking optimized Diameter know
that protocol translation is being done? There isn't a way to
signal to an access device that this is happening, and
would require additional protocol design.

PatC