self-optimizing network [SON] functions-dynamically tuning cell site parameters, for example, to improve customer experience as network conditions change [e.g., OUTAGE_MITIGATION] (see Chapter 8 for more details regarding SON). As previously discussed, customer traffic will typically traverse both physical and virtual net- work elements, managed by legacy OSSs and ONAP. Thus, operators will need to be able to support both the physical and virtual worlds in parallel, using legacy OSSs and ONAP-enabled intelligence. These domains cannot be considered in isolation; traffic will be routed back and forth between the physical and virtual elements as network conditions change, change management activities will need to be coordinated across domains, and troubleshooting complex network and service issues will regularly necessitate debugging complex interactions between the two domains. 15.5 TOPICS FOR FURTHER STUDY In this section, we identify and describe some topics for further discussion. 1. VNF decomposition to enhance operability: Early virtualization activities across the industry have often focused on taking software from physical network elements and essen- tially migrating that software to the cloud with minimal changes for it to run in the cloud. Virtualization provides us with an opportunity to rethink how we structure network soft- ware, and decompose functionality. However, these VNFs are often not being designed from the ground up to operate in the cloud. How can we decompose VNFs while keep- ing operational complexity in check? How can we go a step further and even simplify the operability of VNFs by redesigning them as we virtualize? An example of this is the Edgeplex architecture, which decomposes edge router functionality to maximize the flex- ibility with which customers can be managed in a bid to improve reliability and manage- ability [EDGEPLEX]. There are significant research opportunities to explore how to most effectively design VNFs to improve operability. 2. Network automation intelligence: SDN a