What are two functionalities of SDN Northbound APIs?

Northbound APIs are the link between the applications and the SDN controller. The applications can tell the network what they need (data, storage, bandwidth, and so on) and the network can deliver those resources, or communicate what it has. These APIs support a wide variety of applications, such as load balancers, firewalls, orchestration platforms, and automation stacks. Northbound APIs also enable the applications to use the controller’s capabilities to program flows into the network devices using the southbound interface. Northbound APIs are usually RESTful APIs that use HTTP methods to exchange data in JSON or XML formats12.

OpenFlow is not a northbound API protocol, but a southbound API protocol that defines the communication between the SDN controller and the network switches or routers. OpenFlow allows the controller to manipulate the forwarding behavior of the switches or routers by sending commands and receiving events3 .

NETCONF is not a northbound API protocol, but a network management protocol that can be used as a southbound API protocol to configure and monitor network devices. NETCONF uses XML to encode data and remote procedure calls (RPCs) to exchange messages between the controller and the network devices . References := 1: What are SDN Northbound APIs (and SDN Rest APIs)? - SDxCentral 2: SDN North-bound and South-bound APIs and Interfaces 3: OpenFlow - Wikipedia : OpenFlow - SDxCentral : NETCONF - Wikipedia : NETCONF Protocol - Cisco

1sdxcentral.com2computernetworkingnotes.com3examguides.com