9 YANG Data Modeling Explained
1. YANG Overview
YANG (Yet Another Next Generation) is a data modeling language used to model configuration data, state data, remote procedure calls, and notifications for network management protocols. It provides a standardized way to define the structure and content of data that can be managed over the network.
Example: Think of YANG as a blueprint for a house. Just as a blueprint defines the structure and layout of a house, YANG defines the structure and content of data in network management.
2. Modules and Submodules
YANG models are organized into modules and submodules. A module is a top-level container that defines a complete data model, while a submodule is a part of a module that can be reused across different modules. This modular approach allows for flexibility and reusability in data modeling.
Example: Consider a module as a book and a submodule as a chapter. Just as a book contains multiple chapters, a YANG module can contain multiple submodules, each contributing to the overall data model.
3. Data Nodes
Data nodes are the building blocks of a YANG model. They represent individual pieces of data, such as configuration parameters, operational state, and notifications. Data nodes can be containers, lists, leafs, and leaf-lists, each with specific roles in the data model.
Example: Think of data nodes as ingredients in a recipe. Just as a recipe contains various ingredients, a YANG model contains various data nodes that define the data structure.
4. Containers
Containers are data nodes that group related data nodes together. They provide a hierarchical structure to the data model, making it easier to organize and manage complex data. Containers can contain other containers, lists, leafs, and leaf-lists.
Example: Consider a container as a folder on your computer. Just as a folder contains files and subfolders, a YANG container contains related data nodes, organizing them in a structured manner.
5. Lists
Lists are data nodes that represent collections of similar data entries. Each entry in a list is identified by a unique key, allowing for efficient retrieval and manipulation of list entries. Lists are useful for modeling data that can have multiple instances.
Example: Think of a list as a shopping list. Just as a shopping list contains multiple items, a YANG list contains multiple entries, each identified by a unique key.
6. Leafs and Leaf-Lists
Leafs are data nodes that represent simple data values, such as strings, integers, and booleans. Leaf-lists are similar to leafs but allow for multiple values. Leafs and leaf-lists are the terminal nodes in a YANG model, meaning they cannot contain other data nodes.
Example: Consider a leaf as a single piece of fruit and a leaf-list as a collection of fruits. Just as a fruit represents a simple value, a YANG leaf represents a simple data value, while a leaf-list represents multiple values.
7. RPCs (Remote Procedure Calls)
RPCs in YANG define operations that can be performed on the network device. These operations can be invoked by network management applications to execute specific tasks, such as configuring a device or retrieving operational data.
Example: Think of RPCs as remote control commands. Just as a remote control allows you to perform actions on a device, YANG RPCs allow you to perform operations on a network device.
8. Notifications
Notifications in YANG define events that can be sent by the network device to inform network management applications about significant changes or occurrences. Notifications are useful for monitoring and reacting to real-time events in the network.
Example: Consider notifications as alert messages. Just as an alert message informs you about an important event, YANG notifications inform network management applications about significant events in the network.
9. YANG Tree Representation
The YANG tree representation provides a visual representation of the data model, showing the hierarchical structure of data nodes. This representation helps in understanding the relationships between different data nodes and the overall structure of the data model.
Example: Think of the YANG tree representation as a family tree. Just as a family tree shows the relationships between family members, the YANG tree representation shows the relationships between data nodes in the data model.