Evolution towards Telco-Cloud: Reflections on Dimensioning, Availability and Operability : (Invited Paper).

There are multiple drivers of moving away from physical implementation of telecommunication network elements towards software (SW) only deployments in all IP networks. One of the major motivations is the possibility to use commercial IT hardware as platform, due to cost efficiency and the common required experience for hardware (HW) operation and maintenance. The growing demand for decoupling HW and application SW requires an increasing utilization of virtualization. On top of IT-grade HW, the virtualized network functions can be deployed to the cloud. However, to fulfill the strict requirements of telecommunication networks on cloud, there are special configurations and best practices that shall be followed. These led to the notion of ‘Telco-Cloud’. The rapidly increasing amount of cloud-based Virtual Network Functions introduced new concepts for dimensioning, deployment, operation, management, licensing, and monitoring. Several established availability and operability requirements and expectations are inherited also from the legacy world of Physical Network Functions, meanwhile the telecommunication world itself undergoes a continuous change towards the new worlds of Telco-Cloud and 5G. This paper gives an overview of the transition to Telco-Cloud, basic dimensioning and availability design concepts and some operability challenges are discussed. Finally, a few examples are shown from research and development, as well as feedback from real operator networks.