The :ietf-netconf-monitoring capability is advertised in the SR OS NETCONF server <hello> using the following syntax.
<capability>urn:ietf:params:xml:ns:yang:ietf-netconf-monitoring</capability>
The advertised capability provides information about the schemas supported by SR OS which allows a NETCONF client to query and retrieve schema information from the SR OS NETCONF server.
SR OS supports all subtrees from the YANG model that is used to monitor the NETCONF protocol as described in RFC 6022 (that is, “:ietf-netconf-monitoring” capability).
A <get-schema> operation is supported for explicit schema retrieval using NETCONF (YANG data models' discovery and download as described in RFC 6022). The following parameters are supported:
identifier
This parameter is a mandatory string. It specifies an identifier for the schema list entry (YANG file). It can be the name of a module or a submodule.
version
This parameter is an optional string. It specifies a version of the schema requested (for example, YANG file). It represents the most recent YANG revision statement in a module or submodule. There is an empty string if no revision statement is present. Because multiple versions may be supported by the NETCONF server, each version must be reported individually in the schema list (it can have same identifier but different versions).
format
This parameter is an optional string. It specifies the data modeling language in which the schema is written. The default value is yang when not specified. If specified, yang is the only value supported.
Unless the user intentionally specifies a schema path destination to acquire the YANG schema files, the software upgrade process manages the YANG schema files to ensure the schema files are synchronized with the software image on both the primary and standby CPM.
When an SR OS image boots (from bof primary-image), the associated YANG files match the image. If the primary SR OS image fails to boot and the secondary (or tertiary) SR OS image (from bof secondary-image or bof tertiary-image) loads, the YANG schema files associated with the loaded image are installed and available to the <get-schema> NETCONF RPC. Nokia recommends that each of the primary-image, secondary-image, and tertiary-image strings do not exceed 120 characters for the <get-schema> request to work properly with all schema files.
Use the configure system management-interface schema-path CLI command to configure the schema path. See the schema-path command description in the 7450 ESS, 7750 SR, 7950 XRS, and VSR Classic CLI Command Reference Guide for more information. If a schema-path command is configured, all the YANG schema files must be manually copied to the specified schema-path before using the <get-schema> RPC successfully.
When the requested schema does not exist, the <error-tag> returned is "invalid-value". The maximum length of a schema-path is 180 characters, however, Nokia recommends that a specified schema path be less than or equal to 135 characters, to guarantee that a <get-schema> works properly with the longest YANG module name in SR OS.
When more than one schema matches the requested parameters, the <error-tag> returned is "operation-failed".
<?xml version="1.0" encoding="UTF-8"?>
<rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-schema xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-monitoring">
<identifier>nokia-conf</identifier>
</get-schema>
</rpc>
]]>]]><?xml version="1.0" encoding="UTF-8"?>
<rpc-reply message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-
monitoring"><![CDATA[module nokia-conf {
yang-version "1.1";
namespace "urn:nokia.com:sros:ns:yang:sr:conf";
..
}
]]></data>
</rpc-reply>