connection and exchange data between a network
administrator and a device, it does not define the actual
format of the data. This is the role of the YANG (Yet
Another Next Generation) data modeling language,
which was defined by the IETF in 2010 in RFC 6020
specifically to be used with NETCONF.
YANG proved to be so successful and powerful that it has
evolved to be used as a general-purpose data modeling
language in different programming environments. A data
model is simply a well-understood and agreed upon
method to describe something. As an example, let’s
consider a simple data model for a person. A person can
be classified based on gender (male, female, other),
height (feet/inches, meters/centimeters), weight
(pounds, kilograms), hair color (brown, blond, black,
bald, other), and eye color (brown, blue, green, other)—
to name just a few characteristics. Using this generic data
model for a person, you can describe an individual in a
way that is easy for others to understand. If I tell you
Amy is a woman who is 5'8'' and 160 pounds with blond
hair and blue eyes, you can very easily interpret and
understand this data model information for a person.
The NETCONF protocol defines transport over SSH and
includes operations and configuration data stores that
allow for the management of network devices.
NETCONF authentication options are the same as for
any SSH communication. Username and password as
well as SSL certificates can be used, just as SSH is used
with CLI commands.
NETCONF uses a client/server communication model.
The server side is implemented on the network device
through a NETCONF agent that acts as a northbound
API. Clients connecting to the agent send partial or
complete configuration data and receive state and
operational data from the device. Any system that