In a telephone network, an intelligent peripheral (IP) provides a variety of auxiliary call processing functions, such as announcement playback and digit collection. In response to each call, the IP queries a service control point (SCP) over a data network, for instructions as to processing of the call. The IP runs software to select one SCP for control of each call, from a number of SCPs on the data network, and obtain the requisite instructions for the call from the identified SCP. For each call, the IP software identifies the telephone number of the subscriber and uses the NPA-NXX and D digits from that number to access a first mapping table and obtain a CLLI code identifying an SCP. Using the CLLI code from the first table, the IP software accesses a second mapping table to obtain the CLLI code for the mate to the identified SCP. Using the two CLLI codes, the IP also goes through the second table to obtain all of the Internet Protocol addresses for the two SCPs. For each call, the IP selects one of the identified addresses for a mated pair and queries an SCP using that address. The IP software runs an algorithm to select different ones of the addresses for processing of different calls and thereby balance the load that the IP places on the various SCP data ports.