sult, the accelerators are often found underutilized. Latency. Especially for fronthaul traffic, the undeterministic nature of the Linux networking stack is enough to eliminate it from being used. As we mentioned, the Linux kernel is feature-rich in its networking support. This is both an advantage and a pain, the rich feature support is sometimes not needed and can cause performance limitations. A light-weight implementation of networking components that implement the full processing chain from Ethernet receive/transmit up to detection of GTP-U is, for example, all that is needed to implement the transport components associated with U-plane traffic. 200 Open Radio Access Network (O-RAN) Systems Architecture and Design We thus make the case for an optimized implementation for (components of) the trans- port stack, that is feature-lean (support only those components that are required for the product), integrates with provided hardware acceleration and eliminates data copying where not needed. Such stacks are available commercially from vendors such as 6Wind, 7 or in an open-source implementation such as Vector Packet processing (VPP)8 that aims to provide production quality packet processing stack on commodity CPUs. Alternatively, the System Integrator can build a fully customized version of the pieces of the networking stack that are performance critical. The chart below in Fig. 5-10 shows performance for an IPSec termination application between (on the right) a default Linux stack, in the middle a feature-rich commercial grade stack and on the left a low-level optimized implementation that is application-tuned. see how the latter two options are 5-8X more performance optimized compared to the Linux default. Keep in mind that choosing a performance-optimized implementation for a networking stack does not mean that Linux is eliminated from the networking product altogether. Modern Network Interface Cards and on-chip networking IO blocks include hardware classi- fication capabilities that can be used to separate in