Telscale SS7 card

Scope of technology


Isup to SIP GW

BSC for low-cost 2.5G BTS



Some background

For the last 15 years I was accustomed to use my own hardware and SS7 stack for various telecoms projects. My old-fashioned boards can be found in SMSCs (both GSM and IS-41), IVRs and call centers (ISUP and ISDN), GSM A-interface gateways etc. As an example, here you can find a picture of a strange mobile solution with ISUP and 204 E1. Mtp2 for both 64k and 2M signaling links was implemented on ADSP-2181, all other ss7 stuff on CPU under linux. SIP, MGCP, MEGACO, RTP were also of my own.

In 2006 a blackfin-based board with uClinux was done. For some reasons it was never deployed.

Recently I was involved into building 2 MVNO networks and came across a nice Mobicents SS7 stack in Java.. and decided to restore my former activities and publish them.

So, let me introduce OpenSigtran project.

The core of it is a single-thread stack, optimized for embedded systems with limited resources.

The project started in the end of 2011. Prototype was build with old cards, Mobisents USSD solution used to generate traffic. Tdm traces are available.

Now pilot boards are deployed, and commercial Telscale SS7 cards can be ordered from Telestax. SS7 to M3UA is tested in commercial environment, with Mobicents USSD server. M3UA/SCTP is a legacy option, while M3UA/TCP can be useful, if application-level software is running under MS Windows.

What it looks like

The board has a couple of E1/T1 line interfaces, two 100M Ethernet jacks and runs uClinux inside.

Depending on the configuration, it should operate as

  • Sigtran gateway (M3UA/SCTP and M3UA/TCP now)
  • SS7 probe, capable of monitoring 4 E1 or T1 data streams (ea two duplex PCM lines), providing signaling data in libpacp-compatible format (ea Wireshark)
  • SS7 MTP to Sigtran M3UA signalling gateway + MGCP/MEGACO media gateway
  • ISDN/ISUP to SIP gateway
  • SIP to BSSAP, plus interfacing rtp to the legacy TDM TRAU modules (or GSM FR onboard)

    For a media gateway, initially G.711 + dtmf + echo cancellation will be done.

    The board is currently implemented in PCI form-factor to reduce costs, while it is a 100% stand-alone system.
    All interfacing is done via Ethernet: no drivers, no host OS requirements.
    Aother form-factors can be ordered

    The roadmap, and the present state of affairs (to be corrected) can be found here. It will be hopefully updated regularly.

    You are welcomed with wishes, comments and any sort of cooperation.

    November' 2012

    The project is not dead ;) There is no time to update a site..
    There are several deployments with Mobicents USSD and SMSC (M3UA over SCTP and TCP).
    Configuration with 32 heavily loaded links, 2 M3UA instances is tested.
    First batch with cards is finally got.
    I'm trying to put production on the rails. I hope the website will be redesigned soon, and the following features are expected:
  • Media (MGCP+rtp)
  • M2UA
  • IUA (ea ISDN User Adaptation)

    May' 2013

    Another factory is chosen, who offers excellent quality
    GIT is updated. Here M3UA sources, as well as Wireshark plugin to decode messages on the fly
    As a SIGTRAN Gateway, Card can be configured from GUI

  • Card supports RTP and MGCP now
  • ISUP - SIP conversion will be announced soon

    July' 2013

    Telscale SS7 Card acts as A-Interface gateway, interconnecting MSC and OpenBSC. A pilot is running.

    August' 2013

    Working on two activities with Telscale SS7 card:
  • Pilot with OpebBSC and low-cost 2.5G hardware connected to a legacy MSC (Alcatel S-12)
  • SS7 ISUP to SIP gateway on JSLEE technology