Cisco Application Centric Infrastructure (ACI) technology provides the capability to insert Layer 4 through Layer 7 functions using an approach called a service graph. The industry normally refers to the capability to add Layer 4 through Layer 7 devices in the path between endpoints as service insertion. The Cisco ACI service graph technology is considered a superset of service insertion. The goal of this chapter is to describe the service graph concept and how to design service insertion with the service graph.
As Figure 8-1 shows, Layer 4 through Layer 7 services can be physically located anywhere in the fabric, and the services can be running as physical or virtual appliances.