NETCONF is a session-based network management protocol, which uses XML-encoded remote procedure calls (RPCs) and configuration data to manage network devices. It is a standard RFC 4741 which mandates the use of SSH as transport protocol other than variously defined mapping with transport protocols like SOAP, BEEP (Blocks Extensible Exchange Protocol), HTTPS over TLS. It is designed to be a replacement for Command Line Interface (CLI) based programmatic interfaces, such as Perl + Expect over Secure Shell (SSH).
YANG is data modeling language for Netconf. It is worked out due to various challenges proposed by SNMP/SMI framework today, like backup-and-restore of element configuration, SMI Label Length and lack of concepts like transactions.
Netconf Key Feature
- Distinction between configuration and state data
- Multiple configuration data stores (candidate, running, startup)
- Configuration changes validations
- Configuration change transactions, allow network-wide transaction
- Selective data retrieval with filtering and rollback
- Streaming and playback of event notifications
- Extensible RPC mechanism
All NETCONF operations are carried out within a session, which is tied to the transport layer connection. The NETCONF server is required to authenticate the entity requesting a session before processing any requests from the client. NETCONF messages are encoded in XML, using the UTF-8 character set or a special message “]]>]]>” is used to provide message framing for SSH connection.
Netconf Comparative Benefits
One of the big advantages of NETCONF over SNMP is how the protocol works when manipulating a group of semantically related configuration data. Whereas SNMP modifies the value of a single parameter at a time, NETCONF modifies all or selected parameters on a single primitive operation. Another advantage of NETCONF is that it allows configuration to occur in a transactional manner. NETCONF takes into account when some of the network devices successfully upload the configuration, but others fail to upload the configuration. In this case, NETCONF allows a managed device to rollback to a known state configuration. This is because NETCONF defines transactional models that synchronize, validate, and commit device configuration within an entire network deployment.
Key Industry Adopters
- Juniper Networks
- BATM/Telco System
A separate working group called NETMOD formed in May 2008. Its primary goal is to specify a standard data modeling language and standard content for the NETCONF protocol. The new data modeling language, YANG, is a conceptual schema for data configuration. It provides a concise description of data types, relationships between data configuration, and integrity constraints that ensure the correctness of uploaded values during the configuration process.