Information About the gNMI Protocol About GNMI gNMI is gRPC Network Management Interface developed by Google. gNMI provides the mechanism to install, manipulate, and delete the configuration of network devices, and also to view operational data. The content provided through gNMI can be modeled using YANG. gRPC is a remote procedure call developed by Google for low-latency, scalable distributions with mobile clients communicating to a cloud server. gRPC carries gNMI, and provides the means to formulate and transmit data and operation requests.
When a gNMI service failure occurs, the gNMI broker (GNMIB) will indicate an operational change of state from up to down, and all RPCs will return a service unavailable message until the database is up and running. Upon recovery, the GNMIB will indicate a change of operation state from down to up, and resume normal handling of RPCs. gNMI supports RPC services. For more information, see the Model-Driven Telemetry chapter. JSON IETF Encoding for YANG Data Trees RFC 7951 defines JavaScript Object Notation (JSON) encoding for YANG data trees and their subtrees. gNMI uses JSON for encoding data in its content layer. The JSON type indicates that the value is encoded as a JSON string.
JSON_IETF-encoded data must conform to the rules for JSON serialisation described in RFC 7951. Both the client and target must support JSON encoding. Instances of YANG data nodes (leafs, containers, leaf-lists, lists, anydata nodes, and anyxml nodes) are encoded as members of a JSON object or name/value pairs. Encoding rules are identical for all types of data trees, such as configuration data, state data, parameters of RPC operations, actions, and notifications. Every data node instance is encoded as a name/value pair where the name is formed from the data node identifier. The value depends on the category of the data node.
The leaf Data Node A leaf node has a value, but no children, in a data tree. A leaf instance is encoded as a name/value pair. This value can be a string, number, literal true or false, or the special array [null], depending on the type of the leaf. In the case that the data item at the specified path is a leaf node (which means it has no children, and an associated value) the value of that leaf is encoded directly. (A bare JSON value is included; it does not require a JSON object.) The following example shows a leaf node definition: leaf foo { type uint8; } The following is a valid JSON-encoded instance: "foo": 123 gNMI Protocol Information About the gNMI Protocol gNMI Protocol 2