[SIPForum-techwg] Comment on section 16.3 (DTMF)

Francois Audet audet at nortel.com
Fri Apr 17 14:49:27 EDT 2009 

To clarify... I think I might have been not clear.

As per the email I just sent, I STRONGLY PREFER that we mandate 4733.
In other words, I'd rather we REMOVE this sentence entirely: 
"Otherwise, DTMF MAY be sent inband using a previously negotiated
codec."

If we don't, as a manufacturer, I do not want to be forced
to send in-band audible DTMD (thus the MAY instead of MUST) because 
it will result in random occasional failures. If some vendor or service
provider wants to have a product with Random occasional failures and
bear
the cost, that's fine with me, but myself (vendor hat on) don't
want to go that route.

> -----Original Message-----
> From: Lindsay, Brian (CAR:AR00) 
> Sent: Friday, April 17, 2009 11:03
> To: Spencer Dawkins; Bernard Aboba; 'DOLLY, MARTIN C, 
> ATTLABS'; Audet, Francois (SC100:3055); 
> john.elwell at siemens-enterprise.com; techwg at sipforum.org
> Subject: RE: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> 
>  Hi Spencer,
> 
>    That was why I was suggesting an additional statement at 
> the end of the 2nd paragraph: "Otherwise, DTMF MAY be sent 
> inband using a previously negotiated codec."
> 
>   I believe Francois had suggested in a previous email that 
> this should be optional and hence the MAY.
> 
>   Regards
>      Brian
> 
> -----Original Message-----
> From: Spencer Dawkins [mailto:spencer at wonderhamster.org]
> Sent: Friday, April 17, 2009 1:58 PM
> To: Bernard Aboba; 'DOLLY, MARTIN C, ATTLABS'; Lindsay, Brian 
> (CAR:AR00); Audet, Francois (SC100:3055); 
> john.elwell at siemens-enterprise.com; techwg at sipforum.org
> Subject: Re: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> 
> Just making sure that I'm in sync here.
> 
> Is the intention to require Media Endpoints to use RFC 4733? 
> If so, we can say this more clearly.
> 
> I'm guessing not (since peer Media Endpoints may not conform 
> to SIPconnect/1.1), and if not, I think we do need some words 
> that allow Media Endpoints to use "something else" if the 
> peer Media Endpoint doesn't advertise RFC 4733 support...
> 
> Thanks,
> 
> Spencer
> 
> ----- Original Message -----
> From: "Bernard Aboba" <Bernard_Aboba at hotmail.com>
> To: "'DOLLY, MARTIN C, ATTLABS'" <mdolly at att.com>; 
> <blindsay at nortel.com>; <audet at nortel.com>; 
> <john.elwell at siemens-enterprise.com>;
> <spencer at wonderhamster.org>; <techwg at sipforum.org>
> Sent: Thursday, April 16, 2009 6:40 PM
> Subject: RE: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> 
> 
> > I'd argue that we want to encourage Media Endpoints supporting the 
> > reception of DTMF digits to advertize support for RFC 4733. 
>  However, 
> > if they don't advertise support for RFC 4733, the logical 
> alternative 
> > would be to send it inband (this was Francois's suggestion).  This 
> > should rule out use of INFO for DTMF.
> >
> > -----Original Message-----
> > From: techwg-bounces at sipforum.org 
> [mailto:techwg-bounces at sipforum.org]
> > On Behalf Of DOLLY, MARTIN C, ATTLABS
> > Sent: Thursday, April 16, 2009 4:19 PM
> > To: blindsay at nortel.com; audet at nortel.com; 
> > john.elwell at siemens-enterprise.com; spencer at wonderhamster.org; 
> > techwg at sipforum.org
> > Subject: Re: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> >
> > 4733 should still be supported with G711
> >
> > ----- Original Message -----
> > From: techwg-bounces at sipforum.org <techwg-bounces at sipforum.org>
> > To: Francois Audet <audet at nortel.com>; Elwell, John 
> > <john.elwell at siemens-enterprise.com>; Spencer Dawkins 
> > <spencer at wonderhamster.org>; techwg at sipforum.org 
> <techwg at sipforum.org>
> > Sent: Thu Apr 16 19:07:42 2009
> > Subject: Re: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> >
> >
> > Hi,
> >
> >   Regarding the sentence:
> >
> > "A SIP-PBX or SP-SSE MUST advertize support for RFC 4733 in 
> it's SDP 
> > on behalf of any Media Endpoint that supports receiving DTMF digits"
> >
> >   As endpoint could support receiving DTMF inband over 
> G.711, so this 
> > can only apply if the endpoint supports RCC 4733.
> >
> >   How about clarifying as:
> >
> > "A SIP-PBX or SP-SSE MUST advertize support for RFC 4733 in 
> it's SDP 
> > on behalf of any Media Endpoint that supports receiving DTMF digits 
> > using RFC 4733 procedures"
> >
> >   For the following:
> >
> > "Any Media Endpoint that supports sending DTMF MUST use the 
> RFC 4733 
> > procedures, provided that the other side has advertized support for 
> > receiving RFC 4733 in the offer/answer exchange."
> >
> >  How about adding:
> >
> > "Otherwise, DTMF MAY be sent inband using a previously negotiated 
> > codec."
> >
> >  Regards
> >     Brian
> >
> > -----Original Message-----
> > From: techwg-bounces at sipforum.org 
> [mailto:techwg-bounces at sipforum.org]
> > On Behalf Of Audet, Francois (SC100:3055)
> > Sent: Thursday, April 16, 2009 11:02 AM
> > To: Elwell, John; Spencer Dawkins; techwg at sipforum.org
> > Subject: Re: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> >
> > That works for me.
> >
> >> -----Original Message-----
> >> From: Elwell, John [mailto:john.elwell at siemens-enterprise.com]
> >> Sent: Thursday, April 16, 2009 01:18
> >> To: Audet, Francois (SC100:3055); Spencer Dawkins; 
> >> techwg at sipforum.org
> >> Subject: RE: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> >>
> >> We run up against the architectural problem again when we 
> talk about 
> >> the Media Endpoint doing SDP offer/answer.
> >>
> >> I previously proposed the following text and I though Francois 
> >> agreed,
> >
> >> so why can't we adopt this?
> >>
> >> "A SIP-PBX or SP-SSE MUST advertize support for RFC 4733 
> in it's SDP 
> >> on behalf of any Media Endpoint that supports receiving 
> DTMF digits.
> >>
> >> Any Media Endpoint that supports sending DTMF MUST use the 
> RFC 4733 
> >> procedures, provided that the other side has advertized 
> support for 
> >> receiving RFC 4733 in the offer/answer exchange."
> >>
> >> John
> >>
> >>
> >> > -----Original Message-----
> >> > From: Francois Audet [mailto:audet at nortel.com]
> >> > Sent: 14 April 2009 23:19
> >> > To: Spencer Dawkins; Elwell, John; techwg at sipforum.org
> >> > Subject: RE: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> >> >
> >> > I don't think the phrase "supports the transport of DTMF
> >> tones" makes
> >> > any sense.  That whole second paragraph is unclear on 
> who is sender 
> >> > who is receiver. I would reword the second paragraph as follows:
> >> >
> >> > "Any Media Endpoint that supports the reception of DTMF 
> tones MUST 
> >> > support the negotiation via an SDP offer/answer of the supported 
> >> > method used to transmit the tones. The Media Endpoint
> >> transmiting the
> >> > RTP payload MUST use the dynamic RTP payload type 
> advertized in the 
> >> > SDP by the Media Endpoint advertizing support for receiving
> >> RFC 4733
> >> > packets."
> >> >
> >> > And the third paragraph:
> >> >
> >> > "Any Media Endpoint that supports sending DTMF MUST use the
> >> RFC 4733
> >> > procedures to transmit DTMF tones using the RTP telephone-event 
> >> > payload format, provided that the other side has 
> advertized support 
> >> > for receiving RFC 4733 in the offer/answer exchange."
> >> >
> >> > > -----Original Message-----
> >> > > From: Spencer Dawkins [mailto:spencer at wonderhamster.org]
> >> > > Sent: Tuesday, April 14, 2009 15:09
> >> > > To: Audet, Francois (SC100:3055); Elwell, John;
> >> techwg at sipforum.org
> >> > > Subject: Re: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> >> > >
> >> > > I think the final text you guys are talking about looks
> >> roughly like
> >> > > this:
> >> > >
> >> > > "A SIP-PBX or SP-SSE MUST advertize support for RFC 4733
> >> in its SDP
> >> > > on behalf of any Media Endpoint that supports receiving
> >> DTMF digits.
> >> > >
> >> > > "Any Media Endpoint that supports the transport of DTMF
> >> tones MUST
> >> > > support the negotiation via an SDP offer/answer of the 
> supported 
> >> > > method used to transport the tones. The Media Endpoint
> >> MUST support
> >> > > the ability to use any dynamic RTP payload type when
> >> negotiating the
> >> > > use of RFC 4733.
> >> > >
> >> > >
> >> > > "Any Media Endpoint that supports sending DTMF MUST use
> >> the RFC 4733
> >> > > procedures to transport DTMF tones using the RTP 
> telephone-event 
> >> > > payload format, provided that the other side has
> >> advertized support
> >> > > for receiving RFC 4733 in the offer/answer exchange."
> >> > >
> >> > >
> >> > >
> >> > > Does this work for  people?
> >> > >
> >> > >
> >> > >
> >> > > Thanks,
> >> > >
> >> > >
> >> > >
> >> > > Spencer
> >> > >
> >> > >
> >> > >
> >> > > ----- Original Message -----
> >> > > From: "Francois Audet" <audet at nortel.com>
> >> > > To: "Elwell, John" <john.elwell at siemens-enterprise.com>;
> >> > > <techwg at sipforum.org>
> >> > > Sent: Thursday, April 09, 2009 3:47 PM
> >> > > Subject: Re: [SIPForum-techwg] Comment on section 16.3 (DTMF)
> >> > >
> >> > >
> >> > > > Yep.
> >> > > >
> >> > > >> -----Original Message-----
> >> > > >> From: Elwell, John 
> [mailto:john.elwell at siemens-enterprise.com]
> >> > > >> Sent: Thursday, April 09, 2009 13:22
> >> > > >> To: Audet, Francois (SC100:3055); techwg at sipforum.org
> >> > > >> Subject: RE: [SIPForum-techwg] Comment on section 
> 16.3 (DTMF)
> >> > > >>
> >> > > >>
> >> > > >>
> >> > > >> > -----Original Message-----
> >> > > >> > From: Francois Audet [mailto:audet at nortel.com]
> >> > > >> > Sent: 09 April 2009 19:33
> >> > > >> > To: Elwell, John; techwg at sipforum.org
> >> > > >> > Subject: RE: [SIPForum-techwg] Comment on section 16.3
> >> > > >> > (DTMF)
> >> > > >> >
> >> > > >> > I think the wording is kind of awkward.
> >> > > >> >
> >> > > >> > The real point is that IF you need to either send or
> >> > > >> receive (or both)
> >> > > >> > DTMF, it must be done using RFC 4733. Typically, phones
> >> > > for example
> >> > > >> > don't need to be able to receive DTMF. Some specialized
> >> > > devices may
> >> > > >> > not have to send them either (e.g., a hot-line phone with
> >> > > >> no keypad,
> >> > > >> > etc.).
> >> > > >> >
> >> > > >> > What about:
> >> > > >> >
> >> > > >> > Any Media Endpoint in the Enterprise network or Service
> >> > > Provider's
> >> > > >> > network that support receiving DTMF digits MUST advertize
> >> > > >> its support
> >> > > >> > for RFC 4733 in it's SDP in an Offer or Answer as
> >> appropriate.
> >> > > >> >
> >> > > >> > Any Media Endpoint that supports sending DTMF MUST use
> >> > > the RFC 4733
> >> > > >> > procedures, provided that the other side has advertize
> >> > > support for
> >> > > >> > receiving RFC 4733 in the Offer/Answer exchange.
> >> > > >> >
> >> > > >> > Note that there is no advertizing of the ability to send
> >> > > RFC 4733;
> >> > > >> > only the ability to receive RFC 4733.
> >> > > >> [JRE] Fine, but this is not quite in accordance with the 
> >> > > >> architecture, where the SIP-PBX or SP-SSE does the
> >> > > signalling and the
> >> > > >> media endpoint does the RTP. To correct this I would say:
> >> > > >>
> >> > > >> "A SIP-PBX or SP-SSE MUST advertize support for RFC 4733
> >> > > in it's SDP
> >> > > >> on behalf of any Media Endpoint that supports receiving
> >> > > DTMF digits.
> >> > > >>
> >> > > >> Any Media Endpoint that supports sending DTMF MUST use the
> >> > > RFC 4733
> >> > > >> procedures, provided that the other side has advertized
> >> > > support for
> >> > > >> receiving RFC 4733 in the offer/answer exchange."
> >> > > >>
> >> > > >> John
> >> > > >>
> >> > > >> >
> >> > > >> >
> >> > > >> > > -----Original Message-----
> >> > > >> > > From: techwg-bounces at sipforum.org 
> >> > > >> > > [mailto:techwg-bounces at sipforum.org] On Behalf Of
> >> > Elwell, John
> >> > > >> > > Sent: Thursday, April 09, 2009 06:20
> >> > > >> > > To: techwg at sipforum.org
> >> > > >> > > Subject: [SIPForum-techwg] Comment on section 
> 16.3 (DTMF)
> >> > > >> > >
> >> > > >> > > 1. "Any Media Endpoint in the Service Provider's network
> >> > > >> MUST also
> >> > > >> > > support the ability to transport DTMF tones 
> using the RTP 
> >> > > >> > > telephone-event payload format as described in RFC 4733
> >> > > >> when using
> >> > > >> > > any codec.
> >> > > >> > > Any Media Endpoint in the Enterprise network that
> >> > > >> originates and/or
> >> > > >> > > terminates voice traffic MUST support RFC 4733."
> >> > > >> > >
> >> > > >> > > Why are requirements slightly different for the 
> two sides.
> >> > > >> > > Should we combine these statements:
> >> > > >> > > "Any Media Endpoint in the Enterprise network or Service
> >> > > >> Provider's
> >> > > >> > > network MUST also support the ability to transport DTMF
> >> > > >> tones using
> >> > > >> > > the RTP telephone-event payload format as described in
> >> > > >> RFC 4733 when
> >> > > >> > > using any codec."
> >> > > >> > >
> >> > > >> > > 2. Concerning this same text, this doesn't explicitly
> >> > > >> make provision
> >> > > >> > > for media endpoints that can transport DTMF but do
> >> > not need to
> >> > > >> > > receive it.
> >> > > >> > > So should we add the sentence:
> >> > > >> > > "This applies to transmission and, if applicable,
> >> > > >> reception of DTMF
> >> > > >> > > tones."?
> >> > > >> > >
> >> > > >> > > 3. "Any Media Endpoint in the Enterprise network that
> >> > > >> supports the
> >> > > >> > > transport of DTMF tones MUST support the negotiation
> >> > > via an SDP
> >> > > >> > > offer/answer of the supported method used to transport
> >> > > the tones."
> >> > > >> > > Shouldn't this apply to SP endpoints too? A 
> text proposal
> >> > > >> for this
> >> > > >> > > is in an earlier email dealing with architecture.
> >> > > >> > >
> >> > > >> > > John
> >> > > >> > >
> >> > > >> > > _______________________________________________
> >> > > >> > > techwg mailing list
> >> > > >> > > Send mail to: techwg at sipforum.org Unsubscribe or edit
> >> > > options at:
> >> > > >> > > http://sipforum.org/mailman/listinfo/techwg
> >> > > >> > >
> >> > > >> >
> >> > > >>
> >> > > >
> >> > > > _______________________________________________
> >> > > > techwg mailing list
> >> > > > Send mail to: techwg at sipforum.org Unsubscribe or edit options
> >> > > > at:
> >> > > > http://sipforum.org/mailman/listinfo/techwg
> >> > > >
> >> > >
> >> > >
> >> > >
> >> >
> >>
> >
> > _______________________________________________
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