 wireless and core networks, to deliver low latency and high reliability, the IP core network had to also undergo a major transformation. The data traffic from the radio network is transferred to the 5G core network by a large network of switches and routers. There have been 5G SA network design fundamentals enhancements in the routing domain that have reduced the latency of such carrier backhaul networks immensely. Two such examples are the emergence of segment routing and the SD-WAN networks. These highly intelligent and programmable networks can transport large volumes of data with minimum delay and high accuracy. Essential precursors In this section, we will go over the most important considerations to keep in mind when designing a network. As the 5G technology provides unprecedented levels of flexibility in design, it also brings in the chance to overbuild or underbuild the network, or to build a network that is not suitable for its intended purpose. For example, if a network does not need support for edge use cases, there is no point in investing in an edge data center. To begin with, the following are some of the fundamental questions that should be answered to build a network that would be built-to-purpose, robust, and resilient. These questions are usually answered in a requirements-gathering workshop between the mobile network operator architecture teams and sometimes include the various vendors supplying the necessary components: What use cases are expected to be supported? This is key to designing a network to purpose. 5G supports use cases spanning IoT, mission- critical applications, and enhanced broadband scenarios, each of which has very different requirements in terms of network design. Mission-critical applications need a highly resilient, low-latency network, whereas enhanced broadband needs a higher capacity network and IoT would need neither low latency nor high capacities. Building a network that supports all of these at the same time at scale would be very expensive and most likely a futile