OsmoMSC is the Osmocom implementation of a Mobile Switching Center (MSC).

It implements the following interfaces:
  • 3GPP AoIP over M3UA or SUA towards BSCs, for example OsmoBSC, possibly via a STP like OsmoSTP
  • 3GPP IuCS over M3UA or SUA towards RNCs or HNBGWs, for example OsmoHNBGW, possibly via a STP like OsmoSTP
  • Osmocom GSUP (alternative to SS7/TACP/MAP) towards an HLR such as OsmoHLR
    • Subscriber management
    • Supplementary Services (SS/USSD)
    • Short Message Service (SMS)
    • inter-MSC handover
  • SMPP v3.4 for external SMS entities (minimal SMSC is built-in)
  • MGCP for controlling an external Media Gateway like OsmoMGW
  • MNCC for external call-control handlers, such as osmo-sip-connector for SIP trunks
  • Osmocom VTY interface for configuration + introspection
  • Osmocom CTRL interface for programmatic access to internal state/configuration

Position in a typical network


OsmoMSC was the result of splitting OsmoNITB into three parts during the 2017 NITB-split. Parts of OsmoNITB became OsmoBSC, other parts became OsmoHLR, while the mobility management, call control and SMS handling became OsmoMSC. At the time of the rewrite, the entire MSC and VLR state machines have been properly re-implemented using osmo-fsm

Binary Packages

Osmocom provides binary packages for several flavors of Debian and Ubuntu GNU/Linux on a variety of architectures (i586, x86_64, armhf, armv7l). Unless you are a software developer interested in developing on Osmocom, it is recommended you use those packages instead of building from source.

For more details see Binary_Packages


Source code

The source code is available from (module osmo-msc).

Public read-only access is available via

git clone

You can browse it via gitea:

Contributions are welcome via Gerrit.

Test Suite

We have a TTCN-3 test suite as part of our Titan_TTCN3_Testsuites


Commercial Support

Commercial support as well as development, system integration and training services for this project are available from sysmocom

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Updated by laforge over 1 year ago ยท 19 revisions

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