TL;DR;
To offer new game "styles" like Galactic War, or a new lobby system, we need to remove all features from the lobby-server, that would be redundant. By removing the "Candidate Exchange" and replacing it with a service that could be reused by other lobby-systems, we kinda should go that route.

as an option Xirsys is offering Signaling servers.
How this could work:

1. lobby-server sending a signal to icebreaker that a game is created (full?)
2. icebreaker open a channel for a game with the api
3. icebreaker create a token for every user (public user-id) with this api
4. icebreaker get the latest signaling host with this
5. ice-adapter gets the config via some GET call to icebreaker (retry if channels is not created)
6. ice-adapter doing ice things with the signaling server

# simplified version
LobbyServer will dispatch these events to the client/connector
HostGame
  game-id: uuid/int
  public-user-id: uuid (every time a new one)
  ice-config-host: (icebreaker url with user identification)
  players: [list of public uuids]

JoinGame
  game-id: uuid/int
  public-user-id: uuid (every time a new one)
  ice-config-host: (icebreaker url with user identification )
  players: [list of public uuids]


LobbyServer will dispatch these events to the icebreaker
CreateChannel
  game-id: uuid/int
  players: [list of public uuids]

IceBreaker GET /config/{token}/{public user uuid}
Response:
{
  signaling-websocket-host: {{URL from xirsys with token}}
}

There are some questions about security, garbage collection (delete channels after some time) and how long a token should be valid, but nothing that is impossible to implement.

Downside is the complexity shift to the ice breaker (needs to know all game + users) needs persistence (redis?) to store tokens and games, and also needs to make some more requests to xirsys.

The ICE Adapter also has to make adjustments on how to talk to the signaling server, but also nothing to complicated.

PS: don't really know what is better, own server vs xirsys, both having pros/cons