What is Cisco Application Policy Infrastructure Controller? is part one of SDxCentral’s series to explain the Cisco ACI (Application Centric Infrastructure) framework. Check out Part 1 and Part 2 that detail the Cisco Application Policy Infrastructure Controller or Cisco APIC.
The Cisco Application Policy Infrastructure Controller (APIC) is the single point of policy and management of a Cisco Application Centric Infrastructure (ACI) fabric. Cisco APIC re-defines how Cisco networks are managed and operated. In traditional Cisco networks, each node is managed independently, via the command-line interface (CLI), which is time-consuming, tedious, and error-prone. In ACI networks, network admins use the APIC to manage the network – they no longer need to access the CLI on every node to configure or provision network resources.
Cisco Application Policy Infrastructure Controller differs from more traditional software-defined networking (SDN) Controllers and designs, in that there is zero de-coupling of the control plane from the data plane. Cisco APIC is only used to configure the policy; the policy is then delivered and instantiated on each of the nodes in the network. This allows the Cisco APIC to implement higher orders of logic to better integrate with the consumers of the network – the systems and application teams.
A common example is deploying a 3-tier application. In order to have done this in the past, administrators needed to know the VLANs, IP ranges, FW policy, Load balancing policy, etc. They are all network-centric terms that the consumers of the network didn’t know. The value in Cisco ACI is changing this paradigm and becoming more application-centric, as opposed to network-centric. There will be low-level parameters that need to be configured by a network admin, but these will be hidden and abstracted away for the server and application administrators.
With Cisco ACI, endpoint groups (EPGs) are created that may be “web,” “app,” and “db.” Contracts are created between EPGs to implement the desired functionality once, i.e. QOS, FW, LB, etc. As the business demands and more hosts and VMs are required, all that has to happen is the new machine be placed in the proper EPG. Every other change happens dynamically. One of the values of EPGs here is that they are not, or do not have to be, based on traditional network constructs, like IP subnets or VLANs.