[SIPForum-techwg] Media line Transparency
Richard Shockey
richard at shockey.us
Thu Feb 12 19:16:39 EST 2009
The general theory is that if the SIPconnect compliant SSP does not
understand the INVITE then it should "Do No Harm" in other words don't touch
it.
> -----Original Message-----
> From: techwg-bounces at sipforum.org [mailto:techwg-bounces at sipforum.org]
> On Behalf Of Gunnar Hellstrom
> Sent: Thursday, February 12, 2009 6:02 PM
> To: 'Cullen Jennings'
> Cc: 'Bernard Aboba'; techwg at sipforum.org
> Subject: Re: [SIPForum-techwg] Media line Transparency
>
> Yes, of course I expect PBXes to do real-time text. It should be a
> natural
> addition to any audio call.
> ( Asterisk does if you take the right latest version )
>
> We discussed a month ago or so if we could get the requirement into
> SIPconnect, to handle the real-time text medium. But the result of
> that
> discussion was that it was not the right time to include more
> features.
>
> Therefore my hope stands to this statement about pasthrough of unknown
> media
> lines and media.
>
> ( And Hadriel confirmed that it would work ).
>
> Gunnar
> -----Original Message-----
> From: Cullen Jennings [mailto:fluffy at cisco.com]
> Sent: Thursday, February 12, 2009 10:19 PM
> To: Gunnar Hellstrom
> Cc: 'Bernard Aboba'; mdolly at att.com; techwg at sipforum.org
> Subject: Re: [SIPForum-techwg] Media line Transparency
>
>
> Are you expecting the PBXs to do real time text? Did I miss that in
> the
> spec?
>
> On Feb 12, 2009, at 7:48 AM, Gunnar Hellstrom wrote:
>
> > The requirement to pass media lines and corresponding parameter
> lines
> > and media packets is the temporary rescue we have for real- time
> text
> > until you are prepared to take that into the spec. It is vital for
> > example for emergency service calling.
> > It will be a line like
> > m=text 444444 AVP/RTP 101 102
> > and a set of parameter lines.
> >
> > I am however not totally convinced that it works to be transparent
> for
> > one medium and intercepting others. Is it not a need to modify c-
> > fields etc along the route to make media take the right path?
> >
> > Gunnar
> >
> >
> > From: techwg-bounces at sipforum.org [mailto:techwg-
> > bounces at sipforum.org] On Behalf Of Bernard Aboba
> > Sent: Thursday, February 12, 2009 8:10 AM
> > To: fluffy at cisco.com; mdolly at att.com
> > Cc: techwg at sipforum.org
> > Subject: Re: [SIPForum-techwg] Media line Transparency
> >
> > Yeah, at a minimum the document needs to explain the scenarios to
> > which the requirement applies.
> >
> > > Me too.
> > >
> > > On Feb 11, 2009, at 8:27 AM, DOLLY, MARTIN C, ATTLABS wrote:
> > >
> > > > I agree with Shaun
> > > >
> > > > ----- Original Message -----
> > > > From: techwg-bounces at sipforum.org <techwg-bounces at sipforum.org>
> > > > To: Horvath, Ernst <ernst.horvath at siemens.com>; Theo
> > Zourzouvillys <theo at crazygreek.co.uk
> > > > >
> > > > Cc: techwg at sipforum.org <techwg at sipforum.org>
> > > > Sent: Wed Feb 11 10:25:38 2009
> > > > Subject: Re: [SIPForum-techwg] Media line Transparency
> > > >
> > > >
> > > >> Transparency is only intended for connections from one PBX user
> > > >> to another PBX user. Why should that be prohibited as long as
> > > >> bandwidth limits are obeyed and the PBX owner pays for the
> > > >> transport as such, if the media passes through the SP network
> at
> > > >> all - it may well go directly end-to-end, in which case only
> > > >> transparency for the SDP body would be required.
> > > >> Transparency can be settled by a service level agreement
> between
> > > >> enterprise and SP.
> > > >
> > > > This all argues that the SP MAY pass through unknown media lines
> > > > and/or codecs (based on service level agreements). The text as
> > > > written REQUIRES the SP to always allow through unknown media,
> > > > whether or not there is an agreement and not just for the direct
> > > > media case.
> > > >
> > > > I cannot imagine an SP agreeing to that.
> > > >
> > > > Cheers,
> > > > Shaun
> > > >
> > > >> -----Original Message-----
> > > >> From: Horvath, Ernst [mailto:ernst.horvath at siemens.com]
> > > >> Sent: Wednesday, February 11, 2009 9:48 AM
> > > >> To: Bharrat, Shaun; Theo Zourzouvillys
> > > >> Cc: techwg at sipforum.org
> > > >> Subject: RE: [SIPForum-techwg] Media line Transparency
> > > >>
> > > >> Shaun,
> > > >>
> > > >>
> > > >>> -----Original Message-----
> > > >>> From: techwg-bounces at sipforum.org
> > > >>> [mailto:techwg-bounces at sipforum.org] On Behalf Of Bharrat,
> Shaun
> > > >>> Sent: Wednesday, February 11, 2009 2:56 PM
> > > >>> To: Theo Zourzouvillys
> > > >>> Cc: techwg at sipforum.org
> > > >>> Subject: Re: [SIPForum-techwg] Media line Transparency
> > > >>>
> > > >>> Theo:
> > > >>>
> > > >>>
> > > >>>> In which case, the call would be terminating on an UA inside
> > the
> > > >>>> SP-SSEs network (i.e, a PSTN gateway) - the above text,
> > > >> *end to end*
> > > >>>> transparency, is relevant to SP-SSE SIP elements between
> > > >> the UAC and
> > > >>>> the UAS.
> > > >>>
> > > >>> I'm not sure what you are getting at. I would think that if
> > > >> phone A on
> > > >>> a PBX in enterprise A calls phone B on a PBX in enterprise
> > > >> B, then the
> > > >>> media would (or certainly could) traverse the SP-SSE network.
> > The
> > > >>> SP-SSE cannot be obliged to allow an unqualified media path
> > through
> > > >>> its network.
> > > >>
> > > >> Transparency is only intended for connections from one PBX user
> > > >> to another PBX user. Why should that be prohibited as long as
> > > >> bandwidth limits are obeyed and the PBX owner pays for the
> > > >> transport as such, if the media passes through the SP network
> at
> > > >> all - it may well go directly end-to-end, in which case only
> > > >> transparency for the SDP body would be required.
> > > >> Transparency can be settled by a service level agreement
> between
> > > >> enterprise and SP.
> > > >>
> > > >> Regards,
> > > >> Ernst Horvath
> > > >>
> > > >>>
> > > >>> I'm probably just completely misunderstanding your point.
> > > >>>
> > > >>> Cheers,
> > > >>> Shaun
> > > >>>
> > > >>>> -----Original Message-----
> > > >>>> From: Theo Zourzouvillys [mailto:theo at crazygreek.co.uk]
> > > >>>> Sent: Wednesday, February 11, 2009 6:54 AM
> > > >>>> To: Bharrat, Shaun
> > > >>>> Cc: techwg at sipforum.org
> > > >>>> Subject: Re: [SIPForum-techwg] Media line Transparency
> > > >>>>
> > > >>>> On Wed, Feb 11, 2009 at 3:40 AM, Bharrat, Shaun
> > > >>>> <SBharrat at sonusnet.com> wrote:
> > > >>>>> I missed this in Section 6.1 before...
> > > >>>>>
> > > >>>>> SP-SSEs
> > > >>>>> 1. MUST accommodate unsupported (and unrecognized)
> > > >> media types by
> > > >>>>> passing SDP media lines and attributes unchanged, and
> > > >>>>>
> > > >>>>> Am I misreading this or is this saying that an SP-SSE
> > > >>>> effectively is
> > > >>>>> barred from mediating or policing the media should the
> > > >>>> SIP-PBX provide
> > > >>>>> an unknown codec? I cannot understand how this can be a
> > > >>> MUST. If an
> > > >>>>> enterprise pays for G711, the SP-SSE should not be
> > > >>>> obligated to accept
> > > >>>>> anything else, whether or not it understands the other
> > > >>> media lines
> > > >>>>> and/or codecs.
> > > >>>>>
> > > >>>>> Can someone elaborate.
> > > >>>>
> > > >>>> In which case, the call would be terminating on an UA inside
> > the
> > > >>>> SP-SSEs network (i.e, a PSTN gateway) - the above text,
> > > >> *end to end*
> > > >>>> transparency, is relevant to SP-SSE SIP elements between
> > > >> the UAC and
> > > >>>> the UAS.
> > > >>>>
> > > >>>>
> > > >>>> ~ Theo
> > > >>>>
> > > >>>> --
> > > >>>> Theo Zourzouvillys
> > > >>>> Chief Technical Officer
> > > >>>> VoIP.co.uk - Commerce House, Telford Road, Bicester, OX26 4LD
> > > >>>> Tel: +44 1908 764 196
> > > >>>>
> > > >>>
> > > >>> _______________________________________________
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> > > >>>
> > > >>
> > > >
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