One or more aspects of the disclosure relate to various functions and processes related to routing of calls originating from other service providers. For example, a method includes receiving a request to route a call or a call session, such as a session initiation request, from a second service provider and proceeding to route the requested call or session through a call routing facility of the first service provider to a requested destination of the call. Routing the call through the call routing facility may include determining a service provider type and/or an origination number type for the call, determining routing information for the call using the type information, and causing routing of the call to a destination of the call based on the routing information. Further aspects of the disclosure relate to various functions and processes related to accessing routing data and/or information from a routing database.