Fixed telephony evolution at CERN

<!--HTML-->The heart of CERN’s telephony infrastructure consists of the Alcatel IP-PBX that links CERN’s fixed line phones, Lync softphones and CERN’s GSM subscribers to low-cost local and international telephony services. The PABX infrastructure also supports the emergency “red telephones” in the LHC tunnel and provides vital services for the Fire and Rescue Service and the CERN Control Centre. Although still reliable, the Alcatel hardware is increasingly costly to maintain and looking increasingly outmoded in a market where open source solutions are increasingly dominant. After presenting an overview of the Alcatel PABX and the services it provides, including innovative solutions such as the Closed User Group for our mobile telephony services, we present a possible architecture for a software based system designed to meet tomorrow’s communication needs and describe how the introduction of open-source call routers based on the SIP protocol and Session Border Controllers (SBC) could foster the introduction of new services and increase the agility of our telephony network to adapt to new communication standards.