[asterisk-ss7] Incoming calls through SS7 for data modem transmissions - possible??

Marcelo Pacheco marcelo at m2j.com.br
Fri Nov 26 12:24:26 CST 2010


I had a quad E1 PCI setup with a PRI to the PSTN and a PRI to an AS5300,
the AS5300 was exactly handling analog modem calls.
Works ok, as long as the CPU is always lightly loaded.
Changing one E1 from PRI to SS7 should make no diference whatsoever if
you're using libss7, since libpri uses DAHDI and chan_dahdi for bridging
the call.
It was like 6 years ago, so I don't even have the scripts. Just saying
it should work, specially with faster (newer) CPUs.

José Pablo Méndez Soto wrote:
> Thank you Horacio and Cary.
>
> We will try receiving SS7, routing via SIP, answering on the AS5300,
> then looping back to itself (out PRI, in PRI ports) in order to invoke
> the modem termination. This way we may be able to spare the TDM cards
> in Asterisk and reuse the E1 ports installed in the gateway.
>
> Best regards,
>
> *José Pablo Méndez
>            *********
>
>
> 2010/11/24 Horacio J. Peña <horape at compendium.com.ar
> <mailto:horape at compendium.com.ar>>
>
>     Hola!
>
>     ZapRAS seems to work only with ISDN calls. "This command is not
>     for use with
>     analog lines; it does not provide a modem emulator."
>     (http://www.voip-info.org/wiki/view/Asterisk+cmd+ZapRAS)
>
>     You need something doing the modulation. It seems that iaxmodem is
>     your best
>     bet, and you'll have to make a good bunch of work on it to be able
>     to use as you
>     want to.
>
>     If your client has the cisco gateways, I'd suggest you to keep
>     them. They are
>     very reliable and tested, and with MICA cards they have not a high
>     resale value,
>     so you'll probably end with them as paperweights unless you happen
>     to have some
>     stack of C549 cards to repurpose them.
>
>     Saludos,
>     H
>
>     On Wed, Nov 24, 2010 at 07:58:37PM -0600, José Pablo Méndez Soto
>     wrote:
>     >    Hello,
>     >    We are working on implementing a solution for a medium service
>     >    provider. They were previously using a Cisco AS5300 gateway
>     with some
>     >    PRI trunks to receive modem calls, then route them out the
>     Internet.
>     >    The Telco they were buying the trunks from, discovered this
>     >    configuration and restricted them due to legal conventions,
>     and stated
>     >    that in order to continue doing this, they would have to talk SS7
>     >    directly.
>     >    We are planning on solving this by placing an Asterisk server
>     with some
>     >    TE410 cards talking SS7 to Telco, and another 4 ISDN ports
>     talking to
>     >    the AS5300 for the dial-up to complete after authenticating
>     against a
>     >    RADIUS server.
>     >    My questions is: can we use only Asterisk to
>     complete/terminate the
>     >    dial-up connection, removing the AS5300 out of the picture?
>     We would
>     >    probably need a PPP channel configuration to link the modem
>     connection
>     >    with the Internet.
>     >    Current topology to be set-up:
>     >    Telco --> SS7 --> TE410P-AsteriskServer --> ISDN --> AS5300 -->
>     >    Internet
>     >    Ideal topology:
>     >    Telco --> SS7 --> TE410P-AsteriskServer --> Internet
>     >    Some posts talk about zapRAS being able to accomplish this,
>     not quite
>     >    sure though
>     >    Sounds like possible:
>     >  
>      [1]http://lists.digium.com/pipermail/asterisk-users/2004-January/026956
>     >    .html
>     >  
>      [2]http://lists.digium.com/pipermail/asterisk-users/2009-November/24021
>     >    8.html
>     >    Sounds like not possible:
>     >  
>      [3]http://lists.digium.com/pipermail/asterisk-users/2009-November/24020
>     >    2.html
>     >    Thanks in advance,
>     >    José Pablo Méndez
>     >
>     > References
>     >
>     >    1. mailto:asterisk-users at lists.digium.com
>     <mailto:asterisk-users at lists.digium.com>
>     >    2.
>     http://lists.digium.com/pipermail/asterisk-users/2009-November/240218.html
>     >    3.
>     http://lists.digium.com/pipermail/asterisk-users/2009-November/240202.html
>
>     > --
>     >
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>
>     --
>     Horacio J. Peña
>     horape at compendium.com.ar <mailto:horape at compendium.com.ar>
>     horape at uninet.edu <mailto:horape at uninet.edu>
>
>

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