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

Francois Audet audet at nortel.com
Thu Apr 16 11:01:37 EDT 2009 

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
> > > >> > >
> > > >> >
> > > >>
> > > >
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> > > 
> > > 
> > > 
> > 
>

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