topic Re: subtree-filter support with yang-push subscription in Controllers

subtree-filter support with yang-push subscription

aurelien.fasolo — Sun, 08 Jan 2023 20:26:29 GMT

Hello,

I have been trying to get the following rpc command to work without success:

<?xml version="1.0" encoding="UTF-8"?> <rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="101"> <establish-subscription xmlns="urn:ietf:params:xml:ns:yang:ietf-event-notifications"> <stream xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">yp:yang-push</stream> <subtree-filter xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push"> <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"> <interface> <name/> <description/> </interface> </interfaces> <interfaces-state xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"> <interface> <name/> <admin-status/> <oper-status/> <statistics> <in-octets/> <out-octets/> </statistics> </interface> </interfaces-state> </subtree-filter> <period xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push">1000</period> </establish-subscription> </rpc>

It seems subscription fails because of the subtree filter:

<rpc-error> <error-type>protocol</error-type> <error-tag>operation-failed</error-tag> <error-severity>error</error-severity> <error-path xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">/yp:subtree-filter</error-path> <error-message xml:lang="en">unknown element: interfaces in /notif-bis:establish-subscription/yp:subtree-filter/if:interfaces</error-message> <error-info> <bad-element>subtree-filter</bad-element> </error-info> </rpc-error>

I am running a C8000v (Cisco IOS XE Software, Version 17.09.01a).

To be noted that subscriptions with xpath-filter work just fine but xpath feels less natural as it does not match the netconf/yang configuration syntax.

Kindly help me understand how to perform ietf-subscriptions with subtree filters.

Regards,

Aurélien

Re: subtree-filter support with yang-push subscription

Marcel Zehnder — Mon, 09 Jan 2023 08:37:49 GMT

Hi Aurelien

As this results in MDT sessions, my best guess is, that subtree-filtering is just not supported.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/prog/configuration/173/b_173_programmability_cg/model_driven_telemetry.html

Restrictions for Model-Driven Telemetry

Automatic hierarchy in selections is not supported for on-change subscriptions when using the yang-push stream. This means that when selecting a list, child lists of the list are not automatically included. For example, the subscriber must manually create a subscription for each child list.
Checking the authorization of data access is not supported. All the data requested by a subscriber is sent.
Subtree filters are not supported. If subtree filters are specified, the subscription is marked as invalid.
Defining multiple receivers within subscription parameters is not supported; only the first receiver destination is attempted. Other defined receivers are ignored.

Marcel

Re: subtree-filter support with yang-push subscription

aurelien.fasolo — Mon, 09 Jan 2023 12:26:29 GMT

Thank you @Marcel Zehnder for the quick reply. It is actually kind of a shame that a major vendor such as Cisco does not fully implement RFC.