OpenBSC is worth a close look.
OpenBSC is the current name for a software program that started with the name bs11-abis.
What is OpenBSC
It is a BSC (Base Station Controller) side implementation of the A-bis protocol, as implemented in the GSM Technical Specification 08.5x and 12.21. It implements a minimal subset of the BSC, MSC and HLR. It does not implement ant of the interfaces (like the A and B interfaces) between the higher-order GSM network components.
The goal of the project is to
- provide a basis for experimentation and security research with GSM from the network side
- document, publicized and point out any security related issues that we find as part of that
- learn more about GSM networks on a lower level, particularly the practical aspects with real-world equipment
We are not primarily interested in
- building a stable/reliable BSC/MSC for deployment in networks requiring high-9 (99.999….) availability
- building something that follows the GSM spec to the last detail
- disrupting actual commercial GSM network
Phi Beta Iota: We have learned that the OpenBTS pioneers are working with and admire OpenBSC–the latter has different goals and the architecture is traditional.