Discovery "Zero Hop" contacts.

[Dainisss]

When MeshCore companion moves or arrives at a new location, it is difficult to get information about whether there are any repeaters and companions nearby, because advertisements are sent quite rarely.
One idea that could make it easier to find out which nodes are nearby, would be to send your own "Advert - Zero Hop" in response to receiving "Advert - Zero Hop" from other node.
This would not create a large additional load on the network, but would allow you to find out the nearest neighbors in a fairly simple way.

[recrof]

this is fairly common request, and It has one simple pain point which make this a bad idea: you have a big city that has hill which top sees every repeater in the city.. you use this new feature on the top of the hill and all 80 repeaters want to advert all at once. adverts are big packets and take about second to tx on default 250kHz / sf=11. if you do the math, it doesn't look good.

[Dainisss]

But the real problem is already in the countryside and sparsely populated areas because there is no means of finding out if there is any node nearby.
There is no solution to that.
The companion node does not send "Advert - Zero Hop", without the need to check for possible contacts.
You can respond to a request, if the request is sent by a companion client.

[TBNRregs]

You could also have a limit how frequently you can do it. Probably one time every 5 minutes. And if the repeaters hear the advert request from the same node more than 3 times in 24h span than ignore it.

[liquidraver]

You can write to public chat, you will know how many repeaters are heard your message.
You can ask for adverts in public so the nodes that do want you to know they are there, will advert.

[recrof]

@TBNRregs just once is enough to cause pretty bad time. no cooldown will help with that.

[hofmand]

Public chat is a flood message & reply, it would be good to have a lighter weight solution. See also #804.

[Michael-Frank]

I agree that mesh "onbarding" is quite slow in the absence of advert/telemetry spam.
Fundamentally: meshcore is

• more a "planned" mesh and not/less ad-hoc
• active "push" (messages/adverts) and pull (telemetry) based requiring end user interaction
  So naturally a "mobile" node is not first class citizen.
  What you wont get: "impression of a working mesh by passively recieving spam"

What exaclty is the usecase you are missing?

• chat with pepole in the new area via public chat: works without changes
• write to allready knwon people over the mesh - works. Flood routing will find a route, even when repeaters are still unknown to you.
• private chat with new people in the area: granted, they need to send adverts first - ask them for adverts in public
• knowing routers: only helpful if you need to manually stich a path together. But that requires knowledge about local topology you dont have. You can import routers from the internet map.

Whats missing (for me) is an easy way to check from a new location: can i potentially reach people/the mesh and how well and what are my available routers, without activly annoying people. I currently can do this manually, zero-hop pinging nearby routers one by one.
But i really whish there would be some quality of life feature like one of the three options:

• option 1: on receiving "zero hop client adverts" zero hop neighbors send a acknowledgement (ACK) + snr/rssi - ui displays it
• option 2: a zero hop flood ping (smaller packet then advert) - with responses like option 1)
• option 3: like option 2 but with a trace like list of routers i want to simultaniously zero-hop ping. Could be combined with option 2) Blank = all 0-hop neighbours, set=only the devices that find themself in the list respond.

Justification:

• pong ACK is smaller than full advert
• This would simplify scouting/optimizing router locations.
• Such a feature could actually reduce mesh load as people dont need to spam "test can you hear me" in public or trying to flood route "test 1..n" to your home node just to see if you get "repeats heard x".