Abstract: A method and associated computer system. A processor queries a service catalog and a virtual service inventory to obtain network service instances including a virtual network function. The processor seamlessly replaces the virtual network function by a new version of the virtual network function without interruption of the network service in the production environment. The processor deploys the new version of the virtual network function unattached to the production environment, including: replacing a network address of the virtual network function in the load balancer with a network address of the new version of the virtual network function. In response to a determination by the processor that the virtual network function has a floating network address, the processor detaches the floating network address from the virtual network function and attaches the detached floating network address to the new version of the virtual network function.

Abstract: A method and associated computer system. A processor queries a service catalog and a virtual service inventory to obtain network service instances including a virtual network function. The processor deploys a new version of the virtual network function by performing at least one step of the following steps: replacing the network address of the virtual network function with the network address of the new version of the virtual network function; detaching a floating network address from the virtual network function and attaching the detached floating network address to the new version of the virtual network function (if one of the obtained network service instances is connected to a load balancer and/or the virtual network function is configured with an inherent load balancing); replacing the instance identifier of the virtual network function in a forwarding policy rule with the instance identifier of the new version of the virtual network function.

Abstract: A method and associated system for testing a virtual network function by a virtual network tester, wherein a predefined certification context specification specifies services based on the virtual network function in form of different usage patterns, and wherein a predefined test case selection matrix specifies applicable test cases for each usage pattern. In response to selecting a usage pattern from the different sage patterns, the applicable test cases are determined from the test case selection matrix and control parameters of the test case selection matrix based on the selected usage pattern.