2.6 KiB

osmo-sip-connector - Osmocom SIP connector

This implements an interface between the MNCC (Mobile Network Call Control) interface of OsmoMSC (and also previously OsmoNITB) and SIP.

Call identities can be either the MSISDN or the IMSI of the subscriber.

Requirements of Equipment

  • DTMF need to be sent using SIP INFO messages. DTMF in RTP is not supported.
  • BTS+PBX and SIP connector+PBX must be in the same network (UDP must be able to flow directly between these elements)
  • No handover support.
  • IP based BTS (e.g. Sysmocom sysmoBTS but no Siemens BS11)
  • No emergency calls


  • PT of RTP needs to match the one used by the BTS. E.g. AMR needs to use the same PT as the BTS. This is because rtp_payload2 is not yet supported by the osmo-bts software.

  • AMR SDP file doesn't include the mode-set params and allowed codec modes. This needs to be configured in some way.


You can find the osmo-sip-connector issue tracker and wiki online at https://osmocom.org/projects/osmo-sip-conector and https://osmocom.org/projects/osmo-sip-conector/wiki

GIT Repository

You can clone from the official osmo-msc.git repository using

    git clone https://gitea.osmocom.org/cellular-infrastructure/osmo-sip-connector

There is a web interface at https://gitea.osmocom.org/cellular-infrastructure/osmo-sip-connector


User Manuals and VTY reference manuals are [optionally] built in PDF form as part of the build process.

Pre-rendered PDF version of the current "master" can be found at User Manual as well as the VTY Reference Manual

Mailing List

Discussions related to osmo-sip-connector are happening on the openbsc@lists.osmocom.org mailing list, please see https://lists.osmocom.org/mailman/listinfo/openbsc for subscription options and the list archive.

Please observe the Osmocom Mailing List Rules when posting.


Our coding standards are described at https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards

We us a gerrit based patch submission/review process for managing contributions. Please see https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit for more details

The current patch queue for osmo-sip-connector can be seen at https://gerrit.osmocom.org/#/q/project:osmo-sip-connector+status:open