Re: [MMUSIC] T.38 (Re: M-line philosophy (Re: Wisdom sought: Prioritization of codecs))

Stefan,

I agree with you that usecase does not exists.

I think that T.38 shall be considered as part of PSTN interop as DTMF
usecase is already considered for PSTN interop. In fact, DTMF interop with
PSTN gateway shall be easily achieved using non-media (RTP) mechanism but it
is tough achieve real-time fax interop without media (T.38) support.

Thanks
Partha

-----Original Message-----
From: mmusic-bounces@ietf.org [mailto:mmusic-bounces@ietf.org] On Behalf Of
Stefan Hakansson LK
Sent: Friday, November 23, 2012 4:39 PM
To: mmusic@ietf.org
Subject: Re: [MMUSIC] T.38 (Re: M-line philosophy (Re: Wisdom sought:
Prioritization of codecs))

Thanks for the clarifications, and I agree to what rtcweb/webrtc should
decide.

What I was implying in my original mail is that I think T.38 support
should not be added to browsers (at least not as part of the
rtcweb/webrtc effort), and there are at least two reasons:

* It is not in any of the use-cases
* You can support store-and-forward FoIP in browsers already

But this discussion should happen in the rtcweb/webrtc space.

Stefan

On 11/22/2012 02:59 PM, Schwarz, Albrecht (Albrecht) wrote:
> Looks like that your are describing T.37 FoIP behaviour, whereas Adam
> did point on T.38 FoIP.
>
> WebRTC should firstly agree
> a) whether fax is part of this conversational realtime multimedia
> service at all,
> and if,
> b) which transport mode via IP.
>
> To a): support of F.185 (Internet fax) Yes/No
> To b):
>      b.1) T.37 FoIP store-and-forward already sufficient Yes/No
>      b.2) T.38 FoIP realtime required Yes/No ((perhaps T.38 over RTP/UDP
> or UDPTL/UDP))
>      b.3) or any alternative to T.38 FoIP realtime Yes/No
>
> NOTE: T.38 would specify the behaviour of the
> 1) PSTN gateway (as "T.38 gateway", which is always a PSTN-to-IP
> gateway) and
> 2) Browser (as "T.38 IAD" (Internet aware fax device))
> in below illustration.
>
> -Albrecht
>
> -----Original Message-----
> From: mmusic-bounces at ietf.org [mailto:mmusic-bounces at ietf.org] On
> Behalf Of Stefan Hakansson LK
> Sent: Donnerstag, 22. November 2012 14:39
> To: mmusic at ietf.org
> Subject: Re: [MMUSIC] T.38 (Re: M-line philosophy (Re: Wisdom sought:
> Prioritization of codecs))
>
> On 11/20/2012 15:56, Adam Roach wrote:
>  >
>  >
>  >    +---------+   +------------+   +---------+
>  >    | Web App |---| SIP Server |---|         |
>  >    +---------+   +------------+   |         | +-------------+
>  >         |                         | PSTN GW |--| Fax Machine |
>  >    +---------+      media         |         | +-------------+
>  >    | Browser |--------------------|         |
>  >    +---------+                    +---------+
>
> For cases when one client is not a proper fax machine, is not the usual
> thing that is done that the facsimile is converted to/from TIFF, JPEG,
> PDF or similar somewhere between that client and the fax machine? (And
> often sent as a mail attachment)
>
> If so, all tools are already available (e.g. File API if you want to
> store/access on the local file system, XHR or WebSockets - or even the
> rtcweb data channel for transport) to build a client that can handle
> fax. (I am probably missing something)
>
> Stefan
>
> _______________________________________________
> mmusic mailing list
> mmusic at ietf.org
> https://www.ietf.org/mailman/listinfo/mmusic

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