Add Notification Message?

[dlemire60]

Currently the Arch Spec has no mention of the notification message type. Notifications don't appear in the published v1.0 LS, but are called out in sections 3.2 and 3.3.3 of the v1.1 working version. What, if anything, should the LS say about this message type?

[davaya]

OpenC2 is a command and control protocol - it's purpose is to tell consumers to do something. It is not intended to be either a data retrieval protocol (as with web and database servers) nor an event/notification/push protocol (as with logging and messaging systems). But where data retrieval or notification are tied to C2 use cases, OpenC2 supports the query action and the notification message type. Notifications can be used to support asynchronous C2 operations where an action is initiated with a request/response pair, but progress and completion are signaled back to the producer using notifications. Notifications may also be useful in process control applications.

[sparrell]

@davaya words look good to me but belong in a PR to go into somewhere in the ls and arch doc.

I think a real example would be good also.

[sparrell]

How notifications work in pub/sub may be different than http. If a device is a http oc2 cmd consumer, I see notification logic per @davaya text. If a device is a pub/sub oc2 cmd consumer, it is not as obvious to me and an notification example would help.