VoIP usage is growing at an astronomical rate, resulting in large infrastructures that are becoming increasingly challenging to manage. Call routing can be complex because of several contributing factors. First, each site may independently manage and implement their own call routing policies. Second, a wide range of policies, such as minimal cost or maximum performance, may be in use. Existing call routing tools help with configuring or installing the policies, but do not provide a means to understand or verify the policies that have been configured.

 

VoIP technology is gaining popularity as an alternative to traditional telephony in homes and enterprises. Deployment in homes is fueled by lower cost services provided by home broadband Internet services providers, VoIP providers and peer-to-peer networks. Similarly, enterprises are converting their private branch exchanges (PBXs) and contact centers to VoIP. The key motivation for this transition is not just the reduced cost, but the ease of integration of voice services with other network-based applications and across multiple sites, particularly in the enterprise environment.

 

Call routing determines how calls are routed inside a voice infrastructure. Compared to the plain switched telephone network (PSTN) which uses a straightforward hierarchical call routing policy, VoIP has more flexibility. For example, a large VoIP infrastructure that spans a country will often have multiple voice gateways located at different cities that act as transit points for calls between the VoIP infrastructure and the PSTN. Calls destined to the PSTN need to exit the VoIP network at one of these gateways. The choice of gateways depends on the call routing policies implemented in the system. For example, a call may exit at the nearest voice gateway.