Subject: [Dime] First results on Diameter vs. RadSec patent research: EP1147635

From: Stefan Winter <[email-masked]>
Date: Wed, 1 Aug 2007 14:28:01 +0200

Hello all,

(sorry for cross-posting, this may also be of interest for dime)

when presenting the RadSec draft in IETF69 Chicago, I mentioned the patent 
claims of Nokia concerning Diameter. As a reaction, some participants claimed 
that RadSec itself implements a subset of the Diameter features and may very 
well itself be subject to these patents. So I started an investigation in 
this respect.

I started the research myself by grabbing a copy of patent EP1147635 by Nokia, 
which is claiming to affect Diameter. My focus of the patent's examination 
was whether this patent might also affect RadSec.

The content of this patent is, in short, that packets on a network get tagged 
as "possible duplicate" on retransmission in order to make the endpoint aware 
that the received content may be a duplicate of a previous packet. It also 
provides a mechanism to correlate the multiple copies even when the packets 
took different paths through the network.

Diameter does exactly that, described in section 5.5.4 "Failover and Failback 
Procedures" of RFC3588: a bit in the Diameter header, the "T" bit, is set 
whenever a Diameter packet needed to be retransmitted. Also, Diameter packets 
carry an end-to-end identifier that makes it possible to identify duplicates.

This means that at least from my point of view, Nokia's claim concerning 
Diameter is true. Every implementation of the Diameter base protocol will use 
the patented technology and needs to either license it or will violate it. 
(Note: I am not a lawyer. This is just my interpretation; consider my 
knowledge being "Slashdot-level").
From the wording in this section 5.5.4 and the explanation of the T bit in 
chapter 3, it seems that setting the T bit is mandatory on retransmissions, 
so adhering to the protocol specification leaves no room for circumventing 
the content of the patent (e.g., by keeping it 0 at all times).

Luckily, RadSec does not implement such a sophisticated duplicate packet 
detection algorithm. So, this particular patent appears not to be of any 
concern for implementors of RadSec.

I will continue investigating the bunch of other patents and patent 
applications relating to Diameter as soon as I get copies of them. For 
reference, here is Nokia's claim statement concerning Diameter (as submitted 
to the IETF IPR tracker):

----------

Title: Nokia's Statement About IPR Claimed in RFC 3588
Received: January 6, 2004
From: [email-masked]

This is to advise the IETF that Nokia believes the Nokia 
patents: EP1147635 and AU757984, and the related patent 
applications: BRPI0007603-1, CA2360093, CN00804050.8, FI990102, 
JP2000-595452 and US09/903863 may be relevant to Diameter Base 
Protocol RFC3588.

Nokia agrees not to assert those claims in Nokia above mentioned 
patents that apply to the RFC3588 and are technically necessary 
to implement this IETF standard specification against any other 
party in respect of its implementation of the specification, provided 
that the party relying on this commitment does not assert its patents 
against Nokia.

Regards,

Harri Honkasalo

Director of IPR, Standard Technology

Nokia Corporation

----------

Greetings,

Stefan Winter

-- 
Stefan WINTER

RESTENA Foundation - Réseau Téléinformatique de l'Education Nationale et de 
la Recherche
R&D Engineer

6, rue Richard Coudenhove-Kalergi
L-1359 Luxembourg
email: [email-masked]     Tel.:     +352 424409-1
http://www.restena.lu               Fax:      +352 422473
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