LoST: A Protocol for Mapping Geographic Locations to Public Safety Answering Points

Abstract

Public safety answering points (PSAPs) serve limited geographic areas, so emergency callers must be directed to the most appropriate PSAP. As part of the overall Internet Engineering Task Force (IETF) emergency services architecture, we have developed a new protocol, LoST (location-to-service translation), that allows end systems and voice-over-IP (VoIP) proxies to map location data into URLs representing either PSAPs or other session initiation protocol (SIP) proxies that perform a more fine-grained mapping. LoST is designed to operate globally, with a highly-distributed authority.