Signaling System 7 (SS7) data contains network usage information that is not available from any other source. SS7 data is standalone source data. Because it is not dependent on a support system or on switch translations, it can be used to accurately trace and time all calls entering or leaving any class 4 or class 5 switch. An unparalleled level of call detail can be derived from it. This letter describes the call-routing analysis service, a Lucent Worldwide Services (LWS) tool suite that uses SS7 data and can be run on any vendor's wireline, tandem, or wireless switch.