Call-by-call routing is a process of routing each call to the optimum destination according to real-time conditions within the call center. It is procedure wherein a call is forwarded to an appropriate agent after telephony system. Call can be routed due to numerous reasons which include, rise in call volume, language preferred, department requested, location, time and many other reasons. Depending on the proximity and availability of the call center outsourcing company, call gets routed to another place or city. The advantage of routing calls is round-the-clock availability of customers from multiple locations and time zones.

In call-by-call environment, each call is routed with the help of a routing processor at customers’ site analyzing both the instant call center data as well as information provided by the network to determine how that call should be handled.