Agutu, GordonDjouani, KarimBiermann, ElmarieNoel, Guillaume2016-02-232016-02-232011-02-15Agutu, G., Djouani, K., Biermann, E., & Noel, G. (2011). Context-aware VoIP congestion control service. The African Journal of Information and Communication (AJIC), 11, 55-76. https://doi.org/10.23962/10539/19721ISSN 2077-7213 (online version)ISSN 2077-7205 (print version)http://hdl.handle.net/10539/19721https://doi.org/10.23962/10539/19721IP networks can have difficulty coping with delay-sensitive VoIP traffics during emergency situations caused by fires and related disasters. During emergencies there is a huge increase in voice and video traffic, causing a huge strain on the network. The strain on the network is as a result of both essential and non-essential traffic. In such crisis situations, calls originating from or destined for rescue personnel, such as doctors and police, are considered essential. Any other calls from eyewitnesses and the public are considered non-essential, since they degrade the quality of service for the emergency response teams by consuming the scarce network resources. Providing the rescue team with the quality of service that they require necessitates network access restriction for non-essential traffic. In this paper, the authors present a voice and video service that uses Context-Awareness and Semantic Web technologies to restrict network access to privileged users during crisis situations. The service monitors the network for crisis conditions, enables the network to respond appropriately when a crisis occurs, detects the end of the crisis and reverts to its default state.encall admission control, context-awareness, ontology, semantic web, web ontology languageArticle