Roaming questions
Alexander Ganslandt <[email protected]>
| Newsgroups | dev.linux.lists.iwd |
|---|---|
| Message-ID | <[email protected]> |
Hello, I'm looking into different roaming solutions and currently evaluating iwd, which seems promising so far! My use-case is a device live streaming video while moving around large areas, and the goal is to do so without hiccups in the live stream. I have a few questions: Looking at station_roam_failed(), it will schedule a full scan if the previous limited scan failed to find a better BSS to roam to. A full scan on our chip takes about 7 seconds, which is often enough time for the signal to get low enough to deauthenticate the station when you're moving. It seems to me that a better approach would be to schedule a scan for either the "known frequencies", or all non-DFS frequencies (since passive scanning takes extra time) or some other popular group of frequencies that won't take long to scan. If we're lucky there is a good BSS in that scan, otherwise we schedule a scan for the rest of the frequencies. In the worst case, this should be identical to a full scan with minor extra overhead. Do you have any thoughts about this from your side? Is it something that could be accepted into iwd or could it cause issues for other use-cases? Another question is about the "CriticalRoamThreshold". There seems to be a config for this and some functions for lowering and raising the roam threshold, but I can't see that they're called from anywhere? It seems to me that only "RoamThreshold" is used, or am I missing something? There's also a hardcoded delay of 5 seconds from the point where the roam threshold is passed before a scan is started, is that just a "hysteresis" to not immediately start a scan if the signal temporarily drops, or does it have some other function? Thanks in advance! Best regards, Alexander