As we closed #1930 and #1684 today with a reference to an IRC discussion that was ongoing I want to present the conclusion of that discussion.

We think that having all nodes ping into the world in regular intervals is not something we would like to see in a first implementation of this feature. Instead we would like to focus on information that we can cheaply derive from the local node and offer a multitude of flags to various packages, that they can easily test for to see if the node is or isn't in a required state.

For that we define a directory /var/gluon/online/ that carries empty marker files. With our initial proposal we think of two simple markers that we would like to see in the first version:

• neighbors or mesh to reflect that the node has neighbors that it meshes with
• route_default4/6 or default_gw4/6, to reflect that the respective network stack has a default route

In later versions these can be extended by a multitude of things, I could imagine exposing whether we have an active NTP sync for example. This would also be open to contributions of markers through community packages.

A script should run in a regular fashion, that calls the canonical checks for the mesh protocols provider and based on these touches certain files, should they not exist, or deletes them should they no longer be valid. I think it would be helpful not to touch already existing markers so that we can look at the mtime of these markers to know when they entered a certain state.

For batman-adv we think batctl n and batctl gwl are strong contenders, and for babeld something can be grepped from the dump command of its control socket.

N.B: I'm not sure what state the babel setup is in, and I wouldn't want to make it a mandatory part of the implementation if, as I have recently heard, it doesn't build for multiple releases now and nobody noticed.

@NeoRaider @blocktrron @AiyionPrime @T-X I hope this summarises what we talked about, if not feel free to add your larification below.