g more optimized memory management solutions. In normal processing, CPU pinning is not used, as the processing moves between the CPU cores. The processing of moving a workload from one CPU to another is costly, as CPU cache will have to be populated with data when processing moves from one CPU to another, which leads to reduced efficiency. It also mitigates the default settings for interrupt processing-in this case, CPU0 handles all interrupts in Linux before to kernel 2.6. After 2.6, the interrupts are randomly assigned, which can cause contention between shared resources, as Building the Network of the Future Flavor Series Description General purpose General Purpose Host supporting Kernel vRouter Network-optimized hosts supporting Kernel vRouter Network Optimized Network-optimized supporting SRIOV Data traffic for Guest VMs Network-optimized host supporting DPDK vRouter FIGURE 4.6 Example flavor series. well as drive up the cache miss rate. The primary benefit of CPU pinning is increased processing efficiency since the traffic is being handled by the same CPU, and resolves these issues. Service providers can categorize general purpose VNFs along with the optimization methods mentioned above, in the VNF performance profiles (named, Flavor Series). This is depicted in Figure 4.6. The flavor series classification is based on the specific parameter (ram, disk, ephemeral disk, swap disk) and optional parameter (bandwidth, processor) requirements of the VNF. 4.5.2 SCALABILITY For scaling VNFs, there are two main scenarios-horizontal or vertical (also referred to as out or up). Scaling out generally refers to adding more zones to the network to distribute the processing and thus being able to handle a larger load. Scaling up refers to each zone having more power to process a larger load. Both scaling out and scaling up are difficult to do efficiently and effectively, but typically scaling up is the more cost-effective approach. Arriving at a balance between horizontal and vertical scal- ing is a key component of cost 