A typical internetworking architecture will use a collection of managed hardware/software components that are single-purposed and contain embedded software/solutions. Often, these use no-commodity hardware and dedicated ASIC designs. Typical functions include routing, managed switches, firewalls, deep packet inspection and intrusion detection, load balancers, and data analyzers. Often, such dedicated appliances need to be managed by the customer and staffed with trained network IT personnel to maintain and administer them. These components may come from multiple vendors and require significantly different methods of management.

In this configuration, the data plane and control plane are unified. When the system needs to add or remove another node or set up a new data path, many of the dedicated systems need to be updated with new VLAN settings, QoS parameters, access control lists, static routes, and firewall pass-throughs. This may be manageable when dealing with several thousand endpoints. However, when we scale to millions of nodes that are remote, moving and connecting/disconnecting such traditional technology regularly becomes untenable: