By using SBCs in this configuration, media traverses directly from the peering SBCs to the access SBCs, reducing the workload on the Asterisk servers.
The result is a much more efficient use of resources, improving voice quality and allowing for many more subscribers on each of the Asterisk servers. By passing call traffic through ProSBC, metrics on voice quality are logged, allowing Gabriel and his staff to isolate other network or provider issues.
To ensure reliability, each ProSBC has a 1+1 redundant mate, ready to take traffic if the primary fails.
To address the call routing management issues, Gabriel worked with a developer to create a script that automates the process of updating the SBC route set tables based on the dial plan in each of the Asterisk servers. The script generates a revised route table for each SBC, periodically updating the SBCs using the ProSBC RESTful API. This has now fully automated the routing table update process as new subscribers are added, eliminating many of the manual and error-prone steps.
With the voice quality and route table issues resolved, Gabriel and his developer then turned to dealing with subscriber toll fraud issues and developing a proprietary fraud prevention application. Using the RADIUS call details output from ProSBC, the application monitors international toll call traffic, detecting unusual or fraudulent changes in behavior. If fraud is suspected, the application modifies the route table for that subscriber, preventing further abuse by redirecting potentially fraudulent calls to an announcement.