Comparison of Placement Variants of Virtual Network Functions From Availability and Reliability Perspective

The virtual network function (VNF) is a virtual machine with specific software. A set of related VNFs can be represented as a network service (NS). The placement of all the VNFs of an NS can be in a single host node, and in multiple host nodes. Also, the placement of VNFs of an NS can be done using mixed-mode. In this work, we first analyze the NS availability considering the deployment of NS with the use of multiple host nodes, single host node, and mixed-mode. In the availability analysis, we consider the failure perspective of VNFs as well as the failure perspective of host node(s). Further, we analyze the NS reliability considering the placement of VNFs of NS based in different host nodes, single host node, and mixed-mode. Then we compare the availability as well as the reliability of NS considering these three placement strategies. Comparison results show that the availability, as well as the reliability, are better considering single host node based placement of VNFs of NS.