Computers use modems to communicate and receive data over existing communication infrastructures, such as telephone networks and cable networks. A typical analog modem receives digital data from a computer and converts the digital data into a series of analog signals for transmission over a twisted-pair telephone line. An analog modem also receives analog signals from the telephone line and converts the analog signals into digital data for use by the computer. Similarly, digital subscriber line (DSL) technologies allow existing twisted-pair telephone lines to simultaneously communicate both voice and data signals at higher rates than traditional analog modems. In addition, other modems, such as cable modems and wireless modems, communicate and receive data using other communication media.
To communicate with one or more client computers, service providers typically use an access server that includes a pool of modems. When the access server receives an initial communication from a client computer, the server allocates the communication to one of the available modems from the modem pool. As service providers continue to demand higher performance from access servers, existing allocation methods have become increasingly unsatisfactory.