 the traditional methods to cloud approach increases the requirements for flexible, programmable & scalable Infrastructure (Jain & Paul, 2013). ACI changes the way we use our datacenter/Infrastructure. Conventional approach was based upon the Imperative Model which means that we manage/support what our network devices do and we expect them to follow as per the configurations. ACI uses a declarative Model where we mention our expected result and the fabric does the work to provide that end expected result. ACI is a combination of Application Policy Infrastructure Controller (APIC) & 9K Platform. ACI is a centralized approach to the fabric (Leaf & Spine Fabric) including automation & Orchestration with application level visibility, policy driven approach and security. APIC is the centralized controller where the management has completely been abstracted from the fabric (Leaf & Spine 9K Switches) and gives the complete visibility with inbuilt tools. ACI is built around the white list Model which Figure 1. Application centric infrastructure ACI SPINE SWITCH ACI SPINE SWITCH ACI SPINE SWITCH ACI SPINE SWITCH ACI LEAF SWITCH ACI LEAF SWITCH LEAF SWITCH AC ILEAF SWITCH ACI LEAF SWITCH L4-L7 SERVICES EXTERNAL L3/L2 APIC CLUSTER OUT OF BAND MANAGEMENT-OOBM ACI FABRIC= APIC+NEXUS 9K SERIES Downloaded: 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 SDN Practical Orientation says that everything is denied by default and we have to have a contract between the two EPGs (End Point groups) to allow all traffic or specific port/protocols between two End Point Group (EPG). ACI provides a scalable, multi-tenant, programmable & policy driven Infrastructure where the end point connectivity is governed & controlled by the Application centric policies on a stateless hardware. ACI views the leaf & spine architecture from application's standpoint and connect various end point groups using contracts over non-blocking penalty free overlay network. Application centric Infrastructure Controller do not operate in t