Subject: RE: [Sipping] SIP billing service, new draft-beck-sipping-billing -scen-00.txt

From: "Beck01, Wolfgang" <[email-masked]>
Date: Mon, 8 Apr 2002 09:47:37 +0200

James,
> -----Original Message-----
> From: James Undery [mailto:[email-masked]]
>
> [justified criticism about lacking requirements omitted]
> 
> The scenarios miss a large number of obvious
> attacks, using route to generate 200s to BYEs, both parties 
> colluding to
> defraud (by creating asymetry in timings of two BSPs; 
> assuming a global
> BSP is logistically infeasible)
The purpose of the billing service is not to generate call detail records
on behalf of the ITSP or ISP, but on behalf of the callee. If the two parties
don't want to use a billing service, they just call each other directly.

The draft assumes that the parties have an interest to use the BSP's proxies:
- the callee needs a proof that somebody has called
- the caller needs a proof that he didn't call.
The BSP is just a neutral third party.

> 
> However, it should be noted as I am biased and don't believe you can
> bill for any resource you don't directly control. A corollary of this
> belief is, in order to bill on the call duration you must be call
> stateful.
The SIP billing service is stateful in a back-end system that gathers
information (offline?) from its stateless proxies. Do you think call
stateful proxies would be better suited to provide a certain level of
non-repudiation?

--
Wolfgang Beck
T-Systems Nova GmbH 

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP