We consider the problem of virtualization of telecommunication (telecom) services, which are session-oriented by nature and currently run on dedicated hardware. Such virtualization involves eliminating the dedicated hardware and moving the software to run in virtual machines within a standard cloud computing infrastructure. Existing mechanisms for running services in the cloud are typically targeted towards web services with short-lived sessions where the services are often resilient to intermittent failures of the network or endpoints. We claim that such mechanisms are inadequate for implementations of typical telecom services where sessions are often long-lived and service users are intolerant of service and network interruptions. We present a framework, which we refer to as Telecom as a Service (TaaS), and the associated TaaS primitives for realizing highly scalable and elastic session-oriented telecommunications services in the cloud while imposing minimal changes to existing services and no changes to client implementations. We show through empirical data that our mechanisms scale with network load. © 2012 Alcatel-Lucent.