Re: Selection of media (m=) at MG

> well spotted, thus just a single media configuration ('Clearmode') would be already sufficient to emulate that ISDN bearer service
However, two comments:

(a) In the "call establishment phase": what must be created at the MG?: 
would it be necessary to create a context, or would it be enough to 
create only an ISDN termination in the null context (which would 
generate that tone/announcement, and then, MGC would apply a modify 
command to create the context for the information phase)?

(b) I believe, the announcement do not necessarily have to be recorded 
in AGW, but that may come from an announcement server (I guess this 
would also be possible for DTMF tones). Could this justify the creation 
of such IP termination with voice codec G.711 in the establishment 
phase, or that communication with the announcement server does not 
belong to the ISDN call and, therefore, it should not be involved in its 
Megaco context?

Regards,



> PS
> Your previous email was related to ISDN-to-SIP interworking at call control level, a subject which is out of scope of MEGACO.
> Thus, something for SIPPING, SIP-IMPLEMENTERS, ... (or TISPAN WG3 list) in my understanding.
>
>> -----Original Message-----
>> From: Javi Muñoz [mailto:[email protected]]
>> Sent: Mittwoch, 30. November 2011 18:13
>> To: [email protected]
>> Cc: Schwarz, Albrecht (Albrecht)
>> Subject: Re: [Megaco] Selection of media (m=) at MG
>>
>> A second comment,
>>
>> If:
>>>>      a) TGW: no impact, because tone/announcement inserted by ISDN
>>>> local exchange (terminating Q.931); TGW needs just
>> clearmode support
>>
>> (I agree)
>>
>> then, why?
>>>> E.g., MGC
>>>> ->   call establishment phase: IF tones/announcements THEN H.248
>>>> Command.req for tone/announcement control plus media configuration
>>>> with voice codec
>> That "media configuration with voice codec" (G.711) would be
>> done at the MeGaCo termination of the IP side of the MG, not
>> at the termination of the ISDN side. If tone/announcement is
>> inserted (in the UNI ISDN) by this MG, the termination of the
>> IP side of the MG would not be used, so that "voice codec"
>> would not be relevant (no media would be transported over the
>> IP network).
>>
>> am I wrong?
>>
>> Regards,
>>
>> Javi
>>