[cisco-voip] Fwd: Cisco ATA Fax Confusion

[Rhodium]

In relation to Ryan's comments, it would be NSE based fax passthrough with the fax negotiating low speed, not something inherently differently to the passthrough protocol. So it is not a different type of FaxoIP method but uses an existing method which is NSE passthrough.

Am I right?

--- On Sun, 1/24/10, Nick Matthews <matthnick at gmail.com> wrote:

> From: Nick Matthews <matthnick at gmail.com>
> Subject: Re: [cisco-voip] Fwd: Cisco ATA Fax Confusion
> To: "Rhodium" <rhodium_uk at yahoo.co.uk>
> Cc: "Ryan Ratliff" <rratliff at cisco.com>, "cisco-voip at puck.nether.net Group" <cisco-voip at puck.nether.net>
> Date: Sunday, January 24, 2010, 5:50 PM
> both passthrough, pass-through, and
> relay can handle up to 14.4.  Some
> of the newer 15.0 code is supposed to allow 56k, but I
> haven't heard
> the results of the testing.
> 
> -nick
> 
> On Sun, Jan 24, 2010 at 9:41 AM, Rhodium <rhodium_uk at yahoo.co.uk>
> wrote:
> > Hi Nick,
> >
> > Thanks for replying.
> >
> > So low speed fax as mentioned by Ryan is just fax
> "passthrough" (NSE based) with the fax negotiating a speed
> of <=9600 bps.
> >
> > Regards,
> >
> > Jason
> >
> > --- On Sun, 1/24/10, Nick Matthews <matthnick at gmail.com>
> wrote:
> >
> >> From: Nick Matthews <matthnick at gmail.com>
> >> Subject: Re: [cisco-voip] Fwd: Cisco ATA Fax
> Confusion
> >> To: "Rhodium" <rhodium_uk at yahoo.co.uk>
> >> Cc: "Ryan Ratliff" <rratliff at cisco.com>,
> "cisco-voip at puck.nether.net
> Group" <cisco-voip at puck.nether.net>
> >> Date: Sunday, January 24, 2010, 5:50 AM
> >> To clarify:
> >>
> >> fax pass-through:  protocol based pass through.
> >> Supported in SIP/H323.
> >> fax passthrough: nse based passthrough.  Same
> thing as
> >> modem passthrough
> >> fax relay:  a method of turning g711 packets
> into
> >> specific fax
> >> packets.  Options are T38 and Cisco.
> >> Cisco fax relay:  The default method in IOS
> versions
> >> before 15.0, and
> >> uses Cisco NSEs for transport and negotiation. 
> This
> >> is not the
> >> suggested option, as it is legacy.
> >> T38 NSE switchover:  this is cisco proprietary,
> and is
> >> supported with
> >> SCCP, SIP, MGCP, and H323
> >> T38 protocol switchover:  This is standards based
> and
> >> what you will
> >> use with 3rd party devices.  Supported in SIP,
> H323,
> >> and MGCP.
> >> NSE:  A cisco proprietary packet value for RTP
> >> (normally 101) that is
> >> used between Cisco devices to signal certain fax
> events.
> >>
> >> modem passthrough: used for both fax and modem
> passthrough
> >> using G711.
> >>  Available in the 4 protocols.  Only thing that
> ATAs
> >> officially
> >> support.  It turns off the echo canceller, and
> changes
> >> the playout
> >> buffer (for jitter).  Cisco proprietary since it
> uses
> >> NSEs.
> >>
> >> Faxes can work on G711, but that is if the echo
> canceller
> >> and playout
> >> buffer work for that particular stream and
> associated fax
> >> machines.
> >> It's very likely that high speed faxes (speed >
> 14.4)
> >> will not work on
> >> normal G711.
> >>
> >>
> >> Faxing is confusing :)
> >>
> >> -nick
> >>
> >> On Fri, Jan 22, 2010 at 4:52 PM, Rhodium <rhodium_uk at yahoo.co.uk>
> >> wrote:
> >> > Can't find anything about that particular fax
> oIP
> >> method from googling or on CCO??
> >> >
> >> > All I can find are the relay types, and the
> >> pass-through/passthrough types.
> >> >
> >> > Regards,
> >> >
> >> > Jason
> >> >
> >> > --- On Fri, 1/22/10, Ryan Ratliff <rratliff at cisco.com>
> >> wrote:
> >> >
> >> >> From: Ryan Ratliff <rratliff at cisco.com>
> >> >> Subject: Re: [cisco-voip] Fwd:  Cisco
> ATA Fax
> >> Confusion
> >> >> To: "Rhodium" <rhodium_uk at yahoo.co.uk>
> >> >> Cc: "cisco-voip at puck.nether.net
> >> Group" <cisco-voip at puck..nether.net>
> >> >> Date: Friday, January 22, 2010, 9:40 PM
> >> >> It's basically the same as the
> >> >> straight g.711 fax pass-through.  I
> think the
> >> only
> >> >> difference with this and modem
> passthrough is that
> >> when we
> >> >> detect the fax tones we'll turn off some
> of the
> >> DSP features
> >> >> (ecan, etc) that are useful for voice but
> not for
> >> fax.
> >> >>
> >> >> -Ryan
> >> >>
> >> >> On Jan 22, 2010, at 4:34 PM, Rhodium
> wrote:
> >> >>
> >> >> Thanks for following it up internally.
> :)
> >> >>
> >> >> What is this by the way in terms of fax
> >> protocols:
> >> >>
> >> >> > The other option is that it has
> fallen back
> >> to g.711
> >> >> low
> >> >> > speed fax and you are getting
> lucky.
> >> >>
> >> >>
> >> >> --- On Fri, 1/22/10, Ryan Ratliff <rratliff at cisco.com>
> >> >> wrote:
> >> >>
> >> >> > From: Ryan Ratliff <rratliff at cisco.com>
> >> >> > Subject: Re: [cisco-voip] Fwd: 
> Cisco ATA
> >> Fax
> >> >> Confusion
> >> >> > To: "Rhodium" <rhodium_uk at yahoo.co.uk>
> >> >> > Cc: "cisco-voip at puck.nether.net
> >> >> Group" <cisco-voip at puck.nether.net>
> >> >> > Date: Friday, January 22, 2010, 9:26
> PM
> >> >> > I ran this by somebody that
> actually
> >> >> > works fax issues every day and there
> are two
> >> ways your
> >> >> call
> >> >> > can be working.
> >> >> >
> >> >> > The first is that modem passthrough
> is
> >> actually being
> >> >> > used.  This can be confirmed by
> waiting 10
> >> >> seconds
> >> >> > after the call is answered and
> looking at the
> >> output
> >> >> of
> >> >> > 'show call active voice brief'.  If
> you see
> >> >> modem-pass
> >> >> > here then it's switched to modem
> >> passthrough.
> >> >> >
> >> >> > The other option is that it has
> fallen back
> >> to g.711
> >> >> low
> >> >> > speed fax and you are getting
> lucky.
> >> >> >
> >> >> > -Ryan
> >> >> >
> >> >> > On Jan 22, 2010, at 4:15 PM, Ryan
> Ratliff
> >> wrote:
> >> >> >
> >> >> > Are your calls working in one
> direction only
> >> or both
> >> >> > ways?  We are all in agreement that
> the ATA
> >> only
> >> >> > supports NSE based passthrough and I
> do know
> >> that the
> >> >> > default fax protocol on cisco
> routers is
> >> modem
> >> >> passthrough
> >> >> > so maybe there's another bit of your
> config
> >> that's
> >> >> allowing
> >> >> > the call to proceed.
> >> >> >
> >> >> > In the doc you referenced it
> mentions that
> >> no
> >> >> fall-back
> >> >> > will still allow for the fax to
> proceed if
> >> modem
> >> >> passthrough
> >> >> > is configured..  Maybe this also
> applies if
> >> fax
> >> >> > pass-through fallback isn't
> successful.
> >> >> >
> >> >> > -Ryan
> >> >> >
> >> >> > On Jan 22, 2010, at 3:50 PM, Rhodium
> wrote:
> >> >> >
> >> >> > Yep, I am aware of the hyphenations.
> Been
> >> trying to
> >> >> use
> >> >> > them in the right context if you
> look at my
> >> emails.
> >> >> ;o)
> >> >> >
> >> >> > I don't think the fall back command
> applies
> >> to NSE
> >> >> > passthrough but protocol based
> pass-through:
> >> >> >
> >> >> > http://www.cisco..biz/en/US/docs/ios/12_3/vvf_c/cisco_ios_fax_services_over_ip_application_guide/t38.html#wp1156682
> >> >> >
> >> >> > Also, the written documentation I
> have shows
> >> it under
> >> >> > protocol based pass-through.
> >> >> >
> >> >> > Which led me to ask the question,
> why is it
> >> working?
> >> >> Are
> >> >> > you sure that it refers to protocol
> based
> >> pass-through
> >> >> and
> >> >> > not NSE?
> >> >> >
> >> >> > Regards,
> >> >> >
> >> >> > Jason
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> _______________________________________________
> >> >> > cisco-voip mailing list
> >> >> > cisco-voip at puck.nether.net
> >> >> > https://puck.nether.net/mailman/listinfo/cisco-voip
> >> >> >
> >> >> >
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >
> >> >
> >> >
> >> >
> >> >
> _______________________________________________
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> >> >
> >>
> >
> >
> >
> >
> >
>