multiple NFs and the grey line bypassing those NFs. In our design, the service paths are unidirectional, that is, different 5 SDN and NFV in 5G SFC controller Services can notify the controller with flow resolution events. The controller can act on these based on predefined policies and push updates rules to the OF switches The controller translates the policies into rules that are pushed to the OF Switches Cache Inner network forwards traffic between perimeter OF switches using efficient L2 switching OF switches on the perimeter classify incoming traffic and steer it towards the next service in the chain Internet Virus scan OpenFlow(OF) protocol Services and access node (BNG, router) are SFC service protocol located on the perimeter of the service network. Traffic bypass They connect to the network through OF switches Traffic steering Figure 5.5 OpenFlow-based SFC solution. service paths are specified for upstream and downstream traffic. The black solid line in this figure shows a service path for the upstream traffic through virus scan, DPI, and content cache. The grey solid line shows a service path that bypasses all the services. StEERING architecture uses two different types of switches. The Perimeter OF Switches are placed on the perimeter of the service delivery network. These switches will classify the incoming traffic and steer it toward the next service in the chain. These are the switches to which services or gateway nodes are connected. The inner switches will forward the traffic using efficient L2 switching. These switches are only connected to other switches. These switches may or may not be OF switches. Traffic steering is a two-step process. The first step classifies incom- ing packets and assigns them a service path based on predefined sub- scriber and application. The second step forwards packets to a next service based on its current position along its assigned service path. This two-step traffic steering process only needs to be performed once between any two border routers, regardless of the 