efficiency, as neither horizontal nor vertical scaling is linear. There is a sweet spot range for hardware cost, where the cost of adding additional general purpose hardware is preferable to acquiring more powerful hardware. When scaling horizontally, the more nodes in the network, the more control nodes that are required, SO finding the balance between power and quantity is a key cost-efficiency driver. Scaling up involves using more powerful hardware, additional hardware, and optimizing the hardware. Using more powerful hardware is fairly simple, adding more and faster memory, CPU cores, network interface cards, and storage. There are limitations on how far you can push adding addi- tional hardware-physical limitations of space in the machine, power requirements, heat handling, and other factors that limit how much one system can do. The cost benefit of using general purpose hardware also decreases if each systems is loaded with maximum CPU, memory, network interface cards, and storage. Scaling the hardware vertically can be done by simply adding more resources, or optimizing the resources already there. One way of optimizing the resources that are there is using "Accelerated Data Paths" for packet processing. Adding additional processing zones to the virtualized carrier network, to scale out, promises to have an almost unlimited scale, as adding additional compute nodes is technically all that is required. While that sounds simple, there are limitations to this, including the management of the nodes. Scaling out VNFs and providing resiliency can be done in a stateless or stateful manner. Stateful VNFs track and document the current traffic flows that they are processing. It then communicates Network Functions Virtualization Infrastructure these flows in the case of an additional VNF instantiation, either because of a failure, or because additional processing is required. On the other hand, the stateless VNF assumes that it is accept- able to initialize the service at the time that the additional processing or 