• Table of contents
• The Gb proxy
  • Documentation
  • Configuring and using osmo-gbproxy
  • Advanced use cases
    • Cascading proxies
  • Design documentation

The Gb proxy¶

The purpose of the Gb proxy is to aggregate the Gb links of multiple BSS's and present them in one Gb link to the SGSN.

More specifically, the Gb proxy terminates the NS-VCs of each BSS locally. Furthermore, it establishes one NS-VC with the SGSN.

It also contains support for converting form a NS/UDP/IP (Gb over IP) stacking to a frame-relay based NS/FR/GRE/IP stacking.

Source code available as part of OpenBSC repository:

git clone git://git.osmocom.org/openbsc.git

The proxy then forwards NS-DUs (BSSGP PDUs) between the SGSN and the
respective BSS (and vice versa).

Documentation¶

• User manual
• VTY reference manual

Documentation is somewhat minimalistic at this point, as this is not a general-purpose network element but something highly specialized for some niche use cases. Feel free to contact sales@sysmocom.de in case you would want to hear more about its capabilities.

• Osmo-gbproxy design
• Osmo-gbproxy VTY
• Redundancy between GbProxy

Configuring and using osmo-gbproxy¶

Like other programs in this project, osmo-gbproxy accepts a number of command line arguments
but is generally configured by a configuration file (which can be interactively created/edited
from the VTY).

The command line arguments are:

  -h --help this text
  -d option --debug=DNS:DGPRS,0:0 enable debugging
  -c --config-file filename The config file to use.
  -s --disable-color
  -T --timestamp Prefix every log line with a timestamp
  -V --version. Print the version of [[OpenBSC]].
  -e --log-level number. Set a global loglevel.

There is a wiki page osmo-gbproxy_VTY with a reference for all VTY commands

Advanced use cases¶

Cascading proxies¶

You can also cascade multiple Gb proxies behind each other, where a number
of BSS connect to one Gb proxy, which in turn connects to another Gb proxy,
which then finally connects to the SGSN.

The reason for this type of use can be broken or limited Gb implementations
in proprietary BSS equipment, which fails to re-connect the Gb link after some
intermittent network outage.

Design documentation¶

There's a more detailed design description outlining
details of the proxy.