What is the function of the OpFlex protocol policy repository?

it should be C.

B. Stores statistical information -> Observer
C. Captures and stores the user intent in policy -> Policy Repository
D. Learning and knowing every device in the network -> Endpoint Registry
E. Resolves Policy and configures hardware/software -> Policy Element

OpFlex Description

OpFlex is designed to allow a data exchange of a set of managed objects that is defined as part of an informational model. OpFlex itself does not dictate the information model and can be used with any tree-based abstract model in which each node in the tree has a universal resource identifier (URI) associated with it.

The protocol is designed to support XML and JSON (as well as the binary encoding used in some scenarios) and to use standard remote procedure call (RPC) mechanisms such as JSON-RPC over TCP. The use of a secure channel through Secure Sockets Layer (SSL) and Transport Security Layer (TSL) is also recommended.

The protocol defines a number of logical constructs required for its operation

Policy Repository

The policy repository (PR) is a logically centralized entity containing the definition of all policies governing the behavior of the system. In Cisco ACI, this function is performed by the Cisco APIC or by the leaf nodes of the network fabric. The policy authority handles policy resolution requests from each policy element.

Policy Element

A policy element (PE) is a logical abstraction for a physical or virtual device that implements and enforces policy. Policy elements are responsible for requesting portions of the policy from the policy authority as new endpoints connect, disconnect, or change. Additionally, policy elements are responsible for rendering that policy from an abstract form into a concrete form that maps to their internal capabilities. This process is a local operation and can function differently on each device as long as the semantics of the policy are honored.

Endpoint Registry

The endpoint registry (ER) stores the current operation state (identity, location, etc.) of each endpoint (EP) in the system. The endpoint registry receives information about each endpoint from the local policy element and then can share it with other policy elements in the system. The endpoint registry may be physically co-located with the policy authority, but it may also be distributed in the network fabric itself. In Cisco’s ACI solution, the endpoint registry actually lives in a distributed database within the network itself to provide additional performance and resiliency.

Observer

The observer collects statistics, faults, and events from each policy element in the system. In Cisco ACI, this function is performed by the Cisco APIC, but it could also be separated into a separate system.