[SIPForum-discussion] No Ring Back Tone Issue
Anthony Orlando
avorlando at yahoo.com
Thu Sep 4 18:23:02 UTC 2008
no problem. I've seen this issue more than once. My feeling is the 183 and 180 should both contain the same sdp but it is not covered anywhere. Luckily our appserver (Broadsoft) was smart enough to put a flag to prevent what happens when you first send 183 w sdp then 180 without sdp.
A
--- On Thu, 9/4/08, Herve Jourdain <herve.jourdain at mstarsemi.com> wrote:
> From: Herve Jourdain <herve.jourdain at mstarsemi.com>
> Subject: RE: [SIPForum-discussion] No Ring Back Tone Issue
> To: avorlando at yahoo.com, "'SIP Forum'" <discussion at sipforum.org>, "'ramon nolasco'" <rpnolasco at yahoo.com>
> Date: Thursday, September 4, 2008, 5:08 AM
> Hi,
>
>
>
> I was not familiar with this RFC, so I had a quick look at
> it.
>
> But it seems it doesn't entirely "leave out the
> SDP", even if it's "foggily
> addressed" some times.
>
>
>
> In 7.1.1 (En-bloc call setup), you can see some audio going
> on after a 18x
> response. The comment says "This response may
> contain SDP to establish an early media stream (as
> shown in the
> diagram). If no SDP is present, the audio will be
> established in
> both directions after step 8 >
>
> This makes sense, and is already what has been discussed.
> Note the 18x. Step
> 8 is "200 OK".
>
>
>
> The only place where 183 is explicitly used is when the
> call is rejected
> with a reason, then 183 with SDP is specified (7.1.6 Cause
> present in ACM
> message).
>
>
>
> So basically, that sets Ramon back to the place where both
> solutions are
> "legal" and SIP standard compliant, as 18x can be
> either 180 or 183.
>
> And he'll have to work it out with his partner since
> both solutions seem SIP
> compliant.
>
>
>
> Thanks Anthony for pointing to this RFC I had overlooked, I
> must confess :-)
>
>
>
> Regards,
>
>
>
> Herve
>
>
>
> _____
>
> From: Anthony Orlando [mailto:avorlando at yahoo.com]
> Sent: jeudi 4 septembre 2008 10:38
> To: Herve Jourdain; SIP Forum
> Subject: Re: [SIPForum-discussion] No Ring Back Tone Issue
>
>
>
>
> RFC3398 describes the inter-working yet it leaves out the
> sdp. My
> experience is that we first receive 183sdp from early ACM
> then CPG which
> maps to 180 w/o sdp. This casued our app server to provide
> ring tone as
> well as the inband tone from the pstn.
>
> Our appserver has a flag for this behaviour which the
> 180w/o sdp will not
> trigger the ringtone to be provided by the media server.
>
> Unfortunatley I have found that while RFC3398 and Q1912.5
> describe the call
> flows well they don't include sdp. This is an area
> that needs addressing.
>
> --- On Thu, 9/4/08, Herve Jourdain
> <herve.jourdain at mstarsemi.com> wrote:
>
> From: Herve Jourdain <herve.jourdain at mstarsemi.com>
> Subject: Re: [SIPForum-discussion] No Ring Back Tone Issue
> To: "'ramon nolasco'"
> <rpnolasco at yahoo.com>, discussion at sipforum.org
> Date: Thursday, September 4, 2008, 1:56 AM
>
> Hi,
>
>
>
> I can't remember a < normative > RFC that would
> state just that.
>
> As far as I know, SDP and 18x handling is implementation
> dependant, though a
> common use - that seems widely accepted - would be to have
> the SDP in 183
> for ring back tone, when PSTN gateway is involved.
>
> But again, this doesn't seem to me to be
> "normative".
>
>
>
> And interoperability tests show that SDP can be sent both
> in 183 - most
> common case - but also in 180 - happened with some
> switches. I even saw 183
> responses without SDP.
>
> In the end, for the playing of ring back tone, I decided to
> do it on both
> 180 and 183 messages, provided they had SDP inside, and
> generate local tone
> if no SDP is provided. The background for this being that
> if anyone cares
> enough to send some SDP, then it should be worth
> "listening" to it. But
> again, this is an implementation choice.
>
>
>
> So I'm not sure there is a "definite
> normative" answer to your problem, it
> sounds like one - of many - SIP interoperability issue.
>
> One of you or your partner will have to take some steps
> there. Your current
> way is "legal" regarding SIP and your partner
> could handle it and still be
> SIP compliant, and if you modify your behaviour to conform
> to what your
> partner requires, you will also still be SIP compliant.
>
>
>
> So to me, it sounds like you "just" need to make
> a decision about which way
> you want to go with your partner, and implement it:
> you'll still be SIP
> compliant either way.
>
> My 2 cents: SDP in 183, again, seems to stick more to
> "common practices" in
> SIP, in my opinion.
>
>
>
> Hope this helps.
>
>
>
> Regards,
>
>
>
> Herve
>
>
>
> _____
>
> From: discussion-bounces at sipforum.org
> [mailto:discussion-bounces at sipforum.org] On Behalf Of ramon
> nolasco
> Sent: mercredi 3 septembre 2008 03:21
> To: discussion at sipforum.org
> Subject: Re: [SIPForum-discussion] No Ring Back Tone Issue
>
>
>
>
>
> Dear VB, Raghul, Cliff, Torstein, Vijay, Shyw13,
> Raghavendra and All,
>
>
>
> Thanks and appreciate so much in sharing your know how,
> comments and tips,
> which all are based on the existing standards and solid
> experience and
> background.
>
>
>
> One most important thing I need to clarify....
>
>
>
> "As per standard, should our 183 response to the
> callee, SHOULD already have
> SDP? For them then to play the ring back tone locally?
> Though we have the
> SDP on our 180 response, but they can't consider
> processing it somehow"
>
>
>
>
>
> Below is the email explanation of our partner on how their
> SIP system
> handles our 183 and 180 responses. And with this, they
> wanted us to embed
> SDP in our 183 message. Is their request to us still
> standard for SIP?
>
>
>
> SIP Partner wrote:
>
>
>
> With regarding on mentioned packet data SDP(Session
> Description Protocol
> RFC2327) Yes, that should be the important keywords and
> necessary packet in
> the sip connection for figure out this case .
>
> We think following matter is the highlighted point which is
> complicating.
>
> ------------------------------------------------------------------------
>
> 1)
>
> Our source device can accept the alerting message
> "only one time". but your
> destination device didn't have SDP packet data when you
> advertise us the
> "FIRST"alerting message.
>
> That is why we couldn't realize the ring tone , even
> though your destination
> device prepared the SDP packet data on the second exchange
> of alerting.
>
> (Our source device cannot accept second contact for
> alerting from
> destination device.)
>
> 2)
>
> So ,we 'd like you to figure out the cause of missed
> SDP data on your first
> alerting message.
>
> We believe so that our source device can realize the ring
> tone sounds,
>
> if we receive your SDP on your first contact for Alerting
> message.
>
> ------------------------------------------------------------------------
>
> Point)
>
> "Alerting message & SDP which you have prepared
> are correct", but our source
> device need you to succeed it on the "the first
> time" of
>
> alerting negotiation.
>
>
>
> Sorry for my poor explanation , but i hope it can be your
> good help...
>
>
>
> Thank you
>
>
>
> I wish that you all say and comment, for it's in the
> standard, that SDP in
> 183 SHOULD NOT be the basis for playing the ring back tone
> for it's the SDP
> in the 180 that SHOULD be the basis.
>
>
>
> Regards,
>
> Mon
>
>
>
>
> ----- Original Message ----
> From: Torstein Knutsen <torstein.knutsen at gmail.com>
> To: "WIGNELL, CLIFFORD (CLIFFORD)"
> <cwignell at alcatel-lucent.com>
> Cc: discussion at sipforum.org
> Sent: Friday, August 29, 2008 2:46:59 PM
> Subject: Re: [SIPForum-discussion] No Ring Back Tone Issue
>
> 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) <
> <mailto:cwignell at alcatel-lucent.com>
> 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: <mailto:discussion-bounces at sipforum.org>
> discussion-bounces at sipforum.org [mailto:
> <mailto:discussion-bounces at sipforum.org>
> discussion-bounces at sipforum.org] On
> Behalf Of Raghul Prasanna
> Sent: Friday, 29 August 2008 5:33 AM
> To: Vivek Batra
> Cc: <mailto:discussion at sipforum.org>
> 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 <
> <mailto:vivek7683 at gmail.com>
> vivek7683 at gmail.com> wrote:
>
> From: Vivek Batra < <mailto:vivek7683 at gmail.com>
> vivek7683 at gmail.com>
> Subject: Re: [SIPForum-discussion] No Ring Back Tone Issue
> To: "ramon nolasco" <
> <mailto:rpnolasco at yahoo.com> rpnolasco at yahoo.com>
> Cc: <mailto:discussion at sipforum.org>
> 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 <
> <mailto:rpnolasco at yahoo.com> 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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