osmo-mgw - Osmocom MGW (Media GateWay) Implementation

This repository contains a C-language implementation of an MGW (Media GateWay) for use [not only] within the 2G (GSM) and/or 3G (UMTS) Cellular Network built using Osmocom CNI (Cellular Network Infrastructure) software.

The OsmoMGW program provides an MGCP interface towards an MGCP call agent (client) like OsmoMSC and OsmoBSC, and receives and sends RTP streams as configured via the MGCP control plane.

This Media Gateway implementation is capable of

streaming RTP for 2G (3GPP AoIP and Abis-over-IP)
streaming RTP for 3G (IuCS including the IuFP protocol)
TDM (E1/T1) based Abis interface with TRAU frames on 16k sub-slots
basic support for LCLS (Local Call, Local Switch) related features
various built-in translation capabilities
between Abis TRAU frames and RTP formats
between 2G AMR/RTP and 3G AMR/IuFP/RTP
between bandwidth-efficient and octet-aligned AMR
between different standards for encapsulating GSM HR codec frames in RTP

osmo-mgw is typically co-located with

osmo-bsc (GSM BSC)
osmo-msc (GSM/UMTS MSC)
osmo-hnbgw (UMTS HNBGW); osmo-mgw implements RTP relay between Iuh and IuCS interfaces

The libosmo-mgcp-client library exposes utilities used by e.g. OsmoMSC (found in osmo-msc.git) to instruct OsmoMGW via its MGCP service.

Homepage

You can find the OsmoMGW issue tracker and wiki online at https://osmocom.org/projects/osmo-mgw and https://osmocom.org/projects/osmo-mgw/wiki.

GIT Repository

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

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

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

Documentation

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-mgw 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.

Contributing

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

We use 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-mgw can be seen at https://gerrit.osmocom.org/#/q/project:osmo-mgw+status:open

History

OsmoMGW originated from the OpenBSC project, which started as a minimalistic all-in-one implementation of the GSM Network. In 2017, OpenBSC had reached maturity and diversity (including M3UA SIGTRAN and 3G support in the form of IuCS and IuPS interfaces) that naturally lead to a separation of the all-in-one approach to fully independent separate programs as in typical GSM networks.

OsmoMGW was one of the parts split off from the old openbsc.git. It originated as a solution to merely navigate RTP streams through a NAT, but has since matured.