Define the "right level" of interoperability

[jernst]

From https://matrix.to/#/!uHqAjmOtrLtidOiczC:matrix.org/$D31omcSRjOOXYtSpivZesVtE_P5fV4tDJS84lgjjKCc?via=matrix.org&via=mozilla.org&via=one.ems.host

Helge says:

I think the stuff is with interoperability is also problematic because statements are either "trivial" or "overreach" with probably no middle ground in between. I'm talking here in the context of defining a protocol. This protocol is called hypothetical Fediverse core protocol (HFCP)

"Trivial interoperability": If Alice and Bob both implement HFCP and Alice sends a HFCP message to Bob, then Bob correctly receives the message.

"Overreach interoperability": If Alice and Bob both implement HFCP and Alice sends a HFCP message to Bob, then Bob's app correctly displays the message.

[aschrijver]

I think this boils down to ActivityPub being a layered protocol. Also in my latest comment I defined ActivityPub as a "pluggable protocol". How we define and name the layers should bring clarity here.

• Lower layer: How basic secure communication between peers (Actors) takes place.

• Upper layer: Where I define the pluggable integration that allows my solution to be part of the Fediverse social network.

With that you get for the scope:

• Lower layer: Precise specification, MUST-implement for compliance.
• Upper layer: Prescription for interoperable integration, MUST-follow guidelines for compliance.
• Overreach: Describe a particular integration (e.g. Mastodon Compliance Profile)
  • This exercise is left for decentralized community hubs and individual projects.