Marco Meinardi wrote:

Dear Guys,

I still need help designing my SER architecture. I have to implement prepaid system with customized billing methods and I have been advised to use Asterisk B2BUA.

SER and Asterisk will handle signalling, Mediaproxy will handle ALL RTP streams.

UAc ---> SER: Auth, Loc ---> Asterisk B2BUA ---> UAs |_____________________________| Mediaproxy

I want to keep SER as my central SIP proxy performing user registration, authentication and location, using Asterisk only for terminating ongoigng calls after the credit is over. An external perl application will calculate the time that the call should last, according to remaning credit, Asterisk will decrement this time counter and terminate the call when it reaches to 0. Subtracting credit will be done in post-processing reading SER acc table.

Please advise me, by telling me if this is the correct approach and if it possible to implement.

Yes, you can. But first think about if it is really necessary to use (open)ser at all? How many acitive users you will have? Also Asterisk can act as Registrar.

Further, as Asterisk is capable of NAT traversal, I think there is no need for mediaproxy. Make SIP NAT traversal on the proxy, and Asterisk will do the RTP NAT traversal (nat=yes, canreinvite=no)

regards Klaus