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Data over VoIP

 
 
Ian
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      10-18-2003
"Peter" <(E-Mail Removed)> wrote in message news:<bmpg5l$pitu8$(E-Mail Removed)-berlin.de>...
> > > What are you on about?

> >
> > He wants to encapsulate data in VoIP traffic so he can establish a virtual
> > modem connection and run Net2Phone on top of that, thereby cheating the
> > system by getting a phone call for the price of a phone call.

>
> I like that... phone call for the price of a phone call What I want is
> modem (dialup) connection routed via VoIP to lower costs. Yes, there are
> still a couple of applications requiring direct dialup connection.
>
> Peter



Why not use serial to IP converters. if what you want is a serial link
over IP not VOIP. I have deployed many of these fo such things as
securty system. As to putting data over IP as per the cisco way its
very wastefull the ones I did meant we had to use a full 64K for a 33k
link.

Ian
 
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John R. Levine
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      10-18-2003
>OK, I guess I need to go into a bit more detail on this. I have a specific
>application that requires it's own proprietary dial-out modem connection


Makes sense. I still have an antique 2400 bps modem (configured to run
at 1200) because that's what bank credit card auth terminals use, and
it's much cheaper to pretend to be a terminal than to use something like
Cybercash.

> To complicate matters this is a mission-critical application, and
> reliability is key issue.


Oh. then the answer is easy. Get a real phone line from your ILEC or
a CLEC.

I like my VoIP setup, but it's much more fragile than my phone line,
even though my ILEC is my ISP and I have a T1, not consumer DSL. It's
more sensitive to power failures, network route flaps, all of the
stuff that makes net connections flaky. Also, the codecs in VoIP
systems aren't designed to handle modem signals other than faxes, so I
have my doubts about how well modem over VoIP would work even under
the best of circumstances.




 
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root
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      10-19-2003
Peter wrote:

>> "...connection routed via VoIP..." Are you trying to dial into an ISP,
>> then have your data take the same path that the ISP has set aside
>> for it's voice-over-IP traffic? If not please clarify because the
>> way your stating this request doesn't make sense.

>
> OK, I guess I need to go into a bit more detail on this. I have a specific
> application that requires it's own proprietary dial-out modem connection
> to work (don't tell me to dump it, this is not the issue here). To cut
> costs on the dial-out connection I'm looking to route it thru internet,
> i.e. the whole thing could look like this:
>
> client computer -> modem -> dialup into local gateway -> VoIP on public
> internet -> termination point into PSTN -> dialup into server computer
>
> OR
>
> client computer -> virtual modem connection over public internet ->
> termination point into PSTN -> dialup into server computer
>
> I'd be looking at either establishing termination point myself or
> utilizing services of existing VoIP provider.
>
> To complicate matters this is a mission-critical application, and
> reliability is key issue. There is software available that can do the
> second scheme, then it would require my own termination point (which is
> OK), but I'm not happy with the idea of using computer (especially
> Windows) for that. Too many things can go wrong.
>


If you tell us exact application, perhaps it will become more clear and
helpfull to help you. From your explanation, I assume you can setup a Linux
machine at the source/termination points. On both ends, equipped the Linux
machine with a modem each. If your application talks PPP, then setup the
source point to accept PPP connection and have this device connected
through PPP dial-in connection. Once connected, tell the device to remotely
login (telnet) into the destination Linux machine. Then, use minicom to do
the dial-out to a local server computer. This connection is much more
efficient/faster than riding on top of VoIP. AFAIK, VoIP uses only about
2KBps stream in each direction to send/receive compressed audio stream.
And, this may be a lossy compression.

> So far I haven't found any standalone hardware solutions that would do
> this, so VoIP boxes seem like the only alternative. Data transmission
> speed is not critical, and the added benefit of voice-over-IP could come
> in useful...
>
> Peter


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Ian
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      10-19-2003
"Peter" <(E-Mail Removed)> wrote in message news:<bmqpjo$mhbsi$(E-Mail Removed)-berlin.de>...
> > "...connection routed via VoIP..." Are you trying to dial into an ISP,
> > then have your data take the same path that the ISP has set aside
> > for it's voice-over-IP traffic? If not please clarify because the
> > way your stating this request doesn't make sense.

>
> OK, I guess I need to go into a bit more detail on this. I have a specific
> application that requires it's own proprietary dial-out modem connection to
> work (don't tell me to dump it, this is not the issue here). To cut costs on
> the dial-out connection I'm looking to route it thru internet, i.e. the
> whole thing could look like this:
>
> client computer -> modem -> dialup into local gateway -> VoIP on public
> internet -> termination point into PSTN -> dialup into server computer
>
> OR
>
> client computer -> virtual modem connection over public internet ->
> termination point into PSTN -> dialup into server computer
>
> I'd be looking at either establishing termination point myself or utilizing
> services of existing VoIP provider.
>
> To complicate matters this is a mission-critical application, and
> reliability is key issue. There is software available that can do the second
> scheme, then it would require my own termination point (which is OK), but
> I'm not happy with the idea of using computer (especially Windows) for that.
> Too many things can go wrong.
>
> So far I haven't found any standalone hardware solutions that would do this,
> so VoIP boxes seem like the only alternative. Data transmission speed is not
> critical, and the added benefit of voice-over-IP could come in useful...
>
> Peter


As I have said elsewhere why not use Ip to serial boxes

ClientPC->serial/IP--->IP
network-->ip/serial->Modem->dialup->modem->server

The ipnetwork must be in place as you say you want to do it over voip
which is only a type of protocol not a type of network, if you could
connect straight to the server without dialup you could connect the
serial to IP box direct to the server. I have used these on security
monitoring systems and they work fine.

VOIP is the encapuslation of voice data into IP packets and depending
on the codecs used the sampling rates are very low. what you are
trying to do is pass serial data over IP, I believe Multitech do do
some boxes that as well as giving a VOIP link will also carry fax and
modem traffic but only at a slow speed. Serial to IP converters are
the recognised way to do it in situations that need reliablity and
security

Ian



Ian
 
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chris@nospam.com
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      10-19-2003
On Fri, 17 Oct 2003 17:57:02 -0400, SPD <(E-Mail Removed)> wrote:

>
>Aaron:
>
> Other than a Fax environment when would you use such
>functionality? I'm curious how it could be used given that
>anyone with access to the VoIP environment probably
>already has a working IP connection over which to pass
>data.



Examples for me include, fax machines, visitors with laptops that need
to dial home, security/alarm autodialers, etc.

Cisco still does not handle fax or modem relay very well on their low
end equipment. I've yet to find someone who got it working reliably
on the ATA-186 for example. When we went Cisco VOIP, I found out
Cisco was full of crap when they promised our setup would support
analog modems. It handled faxes ok, but didn't get modem connections
better than 14k until the recent IOS upgrades on our 3660. Now I can
get V.90 connections connecting from a VG248 (48port FXS) through Call
Manager to our 3660 gateway (out to pstn via T1).

-Chris
 
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John R. Levine
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      10-19-2003
>Cisco still does not handle fax or modem relay very well on their low
>end equipment. I've yet to find someone who got it working reliably
>on the ATA-186 for example.


My -186 works OK for sending faxes over Vonage. I get the impression
that they've upgraded the software in recent months.

>Cisco was full of crap when they promised our setup would support
>analog modems. It handled faxes ok, but didn't get modem connections
>better than 14k ...


I can believe that. The doc makes it clear that it recognizes faxes
and treats them specially.

 
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root
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      10-20-2003
John R. Levine wrote:

>>Cisco still does not handle fax or modem relay very well on their low
>>end equipment. I've yet to find someone who got it working reliably
>>on the ATA-186 for example.

>
> My -186 works OK for sending faxes over Vonage. I get the impression
> that they've upgraded the software in recent months.
>


Is your FAX machine connected to the second RJ-11 port or the same port your
phone is through a split line? I believe the 2nd RJ-11 port on an ATA-186
does not support Voice CoDec and it uses a CCITT Group 4 (2nd) FAX CoDec to
compress data from a FAX machine.

>>Cisco was full of crap when they promised our setup would support
>>analog modems. It handled faxes ok, but didn't get modem connections
>>better than 14k ...

>


What would you expect with a device that uses a CoDec for FAX that only runs
@14.4Kbps?

> I can believe that. The doc makes it clear that it recognizes faxes
> and treats them specially.


Sure. But, the doc did not specifically/clearly mention that it will connect
@14.4Kbps which a standard FAX is using.

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John R. Levine
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      10-20-2003
>> My -186 works OK for sending faxes over Vonage. I get the impression
>> that they've upgraded the software in recent months.

>
>Is your FAX machine connected to the second RJ-11 port or the same port your
>phone is through a split line?


The phone port.

> I believe the 2nd RJ-11 port on an ATA-186 does not support Voice
> CoDec and it uses a CCITT Group 4 (2nd) FAX CoDec to compress data
> from a FAX machine.


That apparently depends on how the ATA is configured. Some VoIP
providers will sell you voice on both ports. Also note that you can
dial a #99 prefix to turn off fax recognition, which I find makes
faxes work worse.


 
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root
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      10-20-2003
John R. Levine wrote:

>>> My -186 works OK for sending faxes over Vonage. I get the impression
>>> that they've upgraded the software in recent months.

>>
>>Is your FAX machine connected to the second RJ-11 port or the same port
>>your phone is through a split line?

>
> The phone port.
>


I believe the phone port is the one that does not use G.711 voice CoDec. Is
there a way for you to check how much of a bandwitdh does the ATA-186 use
when you are using the phone port and/or the voice port? I am using a
lowe-end VoIPBlaster (VB) sold by Creative Labs and notice it only uses a
total of about 4KBps (~32Kbps) for both up/down-streams.

>> I believe the 2nd RJ-11 port on an ATA-186 does not support Voice
>> CoDec and it uses a CCITT Group 4 (2nd) FAX CoDec to compress data
>> from a FAX machine.

>
> That apparently depends on how the ATA is configured. Some VoIP
> providers will sell you voice on both ports. Also note that you can
> dial a #99 prefix to turn off fax recognition, which I find makes
> faxes work worse.


I wouldn't have known that since I don't use ATA-186 device. All my
knowledge on this device is captured from posts in this NG as well as from
reading its specs off the Cisco website.

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Miguel Cruz
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      10-20-2003
John R. Levine <(E-Mail Removed)> wrote:
> That apparently depends on how the ATA is configured. Some VoIP
> providers will sell you voice on both ports.


My understanding is that the device doesn't have enough horsepower to do
aggressive compression simultaneously on both ports. So one of them uses a
less efficient (bandwidth-wise) codec. I am unfortunately away from any
useful references so I can't provide more detail.

miguel
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