Protecting First-Level Responder Resources in an IP-based Emergency Services Architecture

Recently, there has been increased interest, shown by the research community and by industry fora, to enable emergency services for voice-over-IP based architectures. In order to provide emergency services functionality over the Internet, several aspects like location determination, dial string configuration, location conveyance, routing to the appropriate public safety answering point (PSAP) and security aspects have to be considered. This paper discusses security threats for the IP-based emergency architecture concentrating on denial-of-service attacks against public safety answering points (PSAPs) by using faked calls that aim to exhaust limited PSAP resources, such as the emergency personnel. We illustrate a number of different approaches that have been mentioned in the past to tackle these threats, including location signing, location-by-reference and authenticated emergency calls.