NetConf/YANG

Let's get started

What is NETCONF?

A network managing protocol to configure network elements.

It transports xml (json) via SSH.

<rpc-reply message-id="1" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
    <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
      <interface>
       <name>eth0</name>
       <type xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">ianaift:ethernetCsmacd</type>
       <enabled>true</enabled>
       <ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
         <address>
            <ip>2001:db8:c18:1::3</ip>
            <prefix-length>128</prefix-length>
          </address>
        </ipv6>
      </interface>
    </interfaces>
</data>
</rpc-reply>

What is YANG?

A data modeling language for the definition of data sent over the NETCONF network configuration protocol.
It is a schema to validate xml.

container interfaces {
description
    "Interface configuration parameters.";
list interface {
    key "name";
    leaf name {
      type string;
    }
    leaf type {
      type identityref {
        base interface-type;
      }
      mandatory true;
    }
    leaf enabled {
      type boolean;
      default "true";
    }
} // list interface
} // container interfaces

NetConf

NetConf was designed based on Operators Requirements, which are documented in RFC3535. It addresses security topics and operational and maintenance topics.

What is the difference?

Protocol:	SNMP	NETCONF	SOAP	REST	RESTCONF	gRPC	What comes next ...
Transport Stack	UDP (connectionless)	SSH TCP	SSL HTTP TCP	SSL HTTP TCP	SSL HTTP TCP	HTTP/2 TCP
Encoding	BER	XML (new JSON)	XML	XML, JSON	XML, JSON	binary
Resources (filter mechanism)	OIDs	Path (xPath on server)		URLs	URLs	URLs
Data models	MIBs	YANG modules	WSDL, XSD		YANG modules	Protocol Buffers
Data Modeling Language	SMI	YANG	WSDL, XSD	Undefined, (WSDL), WADL, text…	YANG	Protocol Buffers
Management Operations	SNMP operations	NETCONF operations	In the XML Schema, not standardized	HTTP operations	HTTP operations	HTTP/2 operations
SDO (like)	IETF	IETF	W3C	W3C	IETF	Google

NETCONF Datastore concept

configuration datastore:

The datastore holding the complete set of configuration data that is required to get a device from its initial default state into a desired operational state.

running configuration datastore:

A configuration datastore holding the complete configuration currently active on the device. The running configuration datastore always exists.

candidate configuration datastore:

A configuration datastore that can be manipulated without impacting the device's current configuration and that can be committed to the running configuration datastore. Not all devices support a candidate configuration datastore.

startup configuration datastore:

The configuration datastore holding the configuration loaded by the device when it boots. Only present on devices that separate the startup configuration datastore from the running configuration datastore.

NETCONF Operations

Operation	Description
get	Retrieve running configuration and device state information.
get-config	Retrieve all or part of a specified configuration datastore.
edit-config	Loads all or part of a specified configuration to the specified target (<running>, <candidate>) configuration datastore. operation-types: merge, replace, create, delete, remove
copy-config	Create or replace an entire configuration datastore with the contents of another complete configuration datastore.
delete-config	Delete a configuration datastore. The <running> configuration datastore cannot be deleted.
(partly-) lock	It allows the client to lock the entire configuration datastore system of a device.
(partly-) unlock	Releases a configuration lock, previously obtained with the <lock> operation.
commit	Sets the running configuration to the current contents of the candidate configuration.
validate	This protocol operation validates the contents of the specified configuration.
close-session	Request graceful termination of a NETCONF session.
kill-session	Force the termination of a NETCONF session.
(hello-message)	(exchange of yang capabilities (yang modules) between server and client)

How does it work?

(one of x possibilities)