I worked for a big Mobile Network company for 8 years. I am fluent with AAA (Radius and Diameter), incl. various flavors of Diameter from different vendors.
I know Linux (RHCE), C programming (incl. IPC, multithreaded programming), networking, all the troubleshooting tools for packet sniffing and analysis, also debugging tools e.g. strace, gdb, valgrind. Also many directory and billing solutions (SunJES/SunONE, OpenLDAP, OpenRadius, OpenDiameter, E/// IN, AmDocs etc.)
Please give me a call if you want a real bid. I would need to clarify Statement of Work and Plan of Approach. I am happy to share my LinkedIn profile proving my track record per request.