[SIPForum-discussion] No Ring Back Tone Issue

[Torstein Knutsen]

Hi there

Beware that most operators do not allow early media as a
*default*configuration. Especially if you have an ISDN interconnect,
it's not usual
enabled from the operators side. Meaning that "you" cannot send early media
back to the operaor.
Meaning that if a call flows trough your net like this :
(A-sub->PSTN->SBC1->...internet...->SBC2->PSTN->B-sub) Then early
media(ringtones, announcements etc) from B-subs "PSTN" will not reach A-subs
PSTN if SBC1's interconnect stops early-media...

regards
Torstein




On Fri, Aug 29, 2008 at 12:39 AM, WIGNELL, CLIFFORD (CLIFFORD) <
cwignell at alcatel-lucent.com> wrote:

>  Hello Raghul,
>
>
>
> Look at RFC3666, it describes the SIP<->PSTN call flows, by contrast
> RFC3665 provides "normal" SIP flows; good places to start.
>
>
>
> Best regards
>
>
>
> Cliff Wignell
>   ------------------------------
>
> *From:* discussion-bounces at sipforum.org [mailto:
> discussion-bounces at sipforum.org] *On Behalf Of *Raghul Prasanna
> *Sent:* Friday, 29 August 2008 5:33 AM
> *To:* Vivek Batra
> *Cc:* discussion at sipforum.org
>
> *Subject:* Re: [SIPForum-discussion] No Ring Back Tone Issue
>
>
>
> HI Vivek,
>
>
>
>
>
>  From your explanation I can understand that 183 with SDP result in early
> media, but incase of 180 with or without SDP with no 183, will reult in UA
> playing local ringback tone..
>
>
>
> Just want to know is there any RFC that says the above point...
>
>
>
> Thanks,
>
> Raghul
>
> --- On *Wed, 27/8/08, Vivek Batra <vivek7683 at gmail.com>* wrote:
>
> From: Vivek Batra <vivek7683 at gmail.com>
> Subject: Re: [SIPForum-discussion] No Ring Back Tone Issue
> To: "ramon nolasco" <rpnolasco at yahoo.com>
> Cc: discussion at sipforum.org
> Date: Wednesday, 27 August, 2008, 4:09 PM
>
> Comments inline in RED.
>
> --VB
>
> On Wed, Aug 27, 2008 at 9:23 AM, ramon nolasco <rpnolasco at yahoo.com>
> wrote:
>
> Hi All,
>
>
>
> Greetings and a good day to all of you! I have this and quite a rare one
> to me of "no ring back tone" problem with one of our interconnecting
> partners. Partner claims that our system normally sends "183 Session
> Progress" and "180 Ringing". That we are sending "183 Session Progress"
> without the ringtone data though our "180 Ringing" has a ringtone data. That
> their system looks for the ringtone data to process from the first received
> message response, which is our "183 Session Progress" and afterward
> disregards our "180 Ringing" response that followed, wherein the ringtone
> data is indeed present,  thus resulting to a successfull call but without
> ringback tone.
>
>
>
> My questions are, per standard:
>
>    1. When and why does "183 Session Progress" is being sent as a
>    response?
>
>    '183 Session Progress' or referred as Early Media is generally sent
> when media (RTP) is required within early dialog.
> Media is required in the early dialog when the call is placed from IP to
> PSTN.
> When ITSP/ Gateway routes the call from IP to PSTN, it generally sends the
> 183 response with SDP body and all the tones/ message are played by gateway
> to UA. However in case of 180 Ringing, RBT is played by local UA itself.
>
>
>    1.
>    2. Should "183 Session Progress" sometimes also *can* replace "180
>    Ringing", thus have the ringtone data? or
>
>   Yes. It depends on the local policy of UA whether it wants to stop the
> media created with 183 Session Progress and start playing local RBT or
> discards the 180 Ringing (recieved after 183 Session Progress) and remains
> connect the media till the final response.
> You will found lot of UA in the marked having both type of implementations.
>
>
>
>
>    1.
>    2. or it's always "180 Ringing" that has the ringtone data?
>
>   I am not sure what you are referring as Ringtone data. I believe that
> you are referring whether 180 Ringing has SDP or not.
> If you are referring the same, my answer would be Yes. 180 Ringing can have
> SDP body but this is not used to connect early media. 180 Ringing with SDP
> refers the Offer-Answer model as per RFC 3262.
> Only 183 Session Progress is sent as response to connect early media.
>
>
>    1.
>    2. Our setup is SBC-to-SBC, Huawei Eudemon 2300-to-Mediaring
>    Voizbridge, is it us who really has the problem or who needs then to adjust?
>    Adjust what?
>
>   In the above statements, you are referring that 183 Session Progress has
> no ringtone data. What actually you are referrig? You want to say that 183
> Session Progress has no SDP?
> Can you provide us the complete call flow?
>
>
>    1.
>    2. Is my partner's claim of "the should be system flow and process"
>    standard?
>
>  Appreciate any of your solution advice and many thanks in advance :)
>
>
>
> Best regards,
>
>
>
> Mon
>
>
>
>
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