NETCONF Framework

Similar to the International Organization for Standardization (ISO) or OSI model, the NETCONF framework uses a hierarchical structure. A lower layer provides services for the upper layer. The hierarchical structure enables each layer to focus only on a single aspect of NETCONF and reduces the dependencies on different layers.

NETCONF is partitioned into four layers, as illustrated in the following table.

Table 4.3 describes the NETCONF framework.

NETCONF Capabilities

A NETCONF capability is a set of functionality that supplements basic NETCONF functionality. A network device can add protocol operations through the capability set to extend the operation scope of existing configuration objects.

Each capability is identified by a unique Uniform Resource Identifier (URI). The URI format is as follows:

urn:ietf:params:xml:ns:netconf:capability:{name}:{version}

In the preceding URI, the name refers to the capability name, and the version refers to the capability version.

The capability definition may name on one or more dependent capabilities. The NETCONF server must support any capabilities upon which it depends. In addition, NETCONF provides semantic specifications for defining capabilities. Device vendors can define proprietary capabilities as required.

TABLE 4.3 NETCONF Framework

(i) Layer

Example

(j) Description

(к) Transport layer

BEEP, SSH, SSL, console

The transport layer provides a communication path for interaction between the NETCONF client and server NETCONF can be carried on any transport protocol that meets all of the following requirements:

  • • The transport protocol is connection-oriented. A permanent link is established between the NETCONF client and server, and then, data is transmitted reliably and sequentially
  • • NETCONF user authentication, data integrity, and security depend on the transport layer
  • • The transport protocol provides a mechanism to distinguish whether the session type is client or server for NETCONF

RPC layer

,

The RPC layer provides a simple RPC request and response mechanism independent of transport protocols. The client uses the element to encapsulate RPC request information and sends the RPC request information to the server. The server uses the element to encapsulate RPC response information (content at the operation and content layers) and sends the RPC response information to the client

Operations

layer

,

The operations layer defines a series of basic operations used in RPC, which constitute the basic capabilities of NETCONF

Content layer

Configuration

The content layer consists of configuration data involved in network management. The configuration data depends on vendors’ devices All the layers except the content layer have been standardized for NETCONF. The content layer has no standard NETCONF data modeling language or data model. Common NETCONF data modeling languages include Schema and YANG. YANG is a widely used data modeling language designed for NETCONF

The NETCONF client and server exchange capabilities to notify each other of their supported capabilities. The client can send operation requests only within the capabilities supported by the server.

 
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