An allocation component allocates its received calls among a plurality of telephony systems including a first telephony system and a second telephony system. A first routing protocol (RP) component distributes those of the calls allocated to the first telephony system among a first plurality of call center sites. A second RP component distributes those of the calls allocated to the second telephony system among a second plurality of call center sites. A load-balancing Interactive Voice Response (IVR) system dynamically distributes its received calls between the plurality of telephony systems based on agent availability data associated with the first and second plurality of call center sites and the second plurality of call center sites. A primary IVR receives a plurality of calls and routes a first percentage thereof to the allocation component and a second percentage thereof to the load-balancing IVR system.