Question about ON_CHANGE subscriptions

[ianbarrere]

I am testing ON_CHANGE subscriptions with IOS-XR and I am wondering how they are meant to work, as I couldn't determine it from the documentation. I would think that counter values, and things that change on their own, would trigger an update to be sent in an ON_CHANGE subscription, but that does not seem to be the case from my testing.

If I manually change the status of an interface, for example, then it predictably generates an update, but I am not seeing updates for the organically changing counters. Is this an issue with IOS-XR's implementation or is it by design?