Re: [Serusers] Access control on PSTN gateways

At 01:03 AM 1/11/2003, Michael Graff wrote: [...] Don't worry, that's mostly me where confusion comes from. I understand now -- you wish that requests From: sip:graff@isc.org will appear to the destination as From: sip:65077970xx@isc.org so that a gateway can propagate the number down to PSTN and use it for accounting. I think the right way to do this thing is to have a proxy server attaching a "network asserted identity" (NAI) to the request. The NAI piece of data includes then the desired number. This has been recently discussed on the IETF/SIPPING mailing list, thread "URIs for Gateways". The major drawback of this method is it is still under discussion, it will take quite long to complete (if ever, you never know in IETF). Changing content of From header field by proxy is imho too risky and could result in interoperability problems. Pre-3261 implementations use from to identify transactions and dialogs. 3261 implementations only use from-tag, but it is hard to tell which currently available implementations really do that. Some people might be concerned too about a possible damage to transparency, which -- similarly to how NAT's rewrite packets and cause confusion -- might result in confusion. So I may be too pesimistic or ignorant, but I unfortunately only see these imperfect options: - account from a proxy server and use some local translation (graff->65077970xx) during the accounting process; ignore the issue of displaying 65077970xx down in PSTN - use 65077970xx as SIP user id and 'graff' as an alias for incoming request - wait until NAI is standardized in IETF and deployed in SIP products - rewriting From at a quite high risk of interoperability problems What do you think? -Jiri