WiFi roaming question
Hi All,
I have setup a WiFi infrastructure with several APs connected by ethernet, with only one AP acting as the gateway/dhcp server. It is a "mixed band" infrastructure (2.4/5GHz).
My goal was to see how, as a WiFi client, I would have to manage which access point to connect to.
My environment is a custom embedded Linux system with connman and wpa_supplicant.
It turned out that, as a client, I don't have to bother with roaming stuff, it simply works out of the box.
Though, I have a couple of questions regarding this OOBX (new buzz word seen here and there for "out of the box experience" :) ).
- At which level the roaming is done? Is it at the WiFi kernel stack (cfg/mac 80211), at driver level, or at chipset/firmware level or a mix of them?
- Can I change my setup, so that I have control over the roaming?
- Is it a good idea to try to manage that myself from userspace?
My usecase is a set of industrial devices that needs to connect to a WiFi network (either a unique AP or a set of APs).
On top of that I have to manage a special case where, for whatever reason, the user would have forgotten to switch off somes APs, these APs shouldn't be on might then interferes with the running system.
I know my questions are a bit broad, but I would appreciate if some one could give me some hints or even better point me to some Linux centric papers/articles.
Regards,
Chris
PS: I've found some documentation about IAPP, 802.11i, 802.11F, L2 vs L3 roaming (FWIU wifi vs IP), ... But nothing really clear to me and none of them speaks about Linux compatibility/implementation.
Quoted 1 line
It turned out that, as a client, I don't have to bother with roaming stuff, it simply works out of the box.
Roaming has 2 types:
1) based on the disconnection (beacon loss)
2) based on the RSSI
Is it really roaming doing background scanning and preauth #2 (or) a connect and disconnect (assuming same ssid and security) #1?
Quoted 4 lines
Though, I have a couple of questions regarding this OOBX (new buzz word seen here and there for "out of the box experience" :) ).
- At which level the roaming is done? Is it at the WiFi kernel stack (cfg/mac 80211), at driver level, or at chipset/firmware level or a mix of them?
- Can I change my setup, so that I have control over the roaming?
- Is it a good idea to try to manage that myself from userspace?
wpa_supplicant (userspace) takes care of the roaming for you, i belive it has support for both types #1 and #2 (along with background scan)
Some proprietary version which implement at driver/fw level, this reduces the roam delay as it need not involve any context switches.
Quoted 15 lines · Krishna Chaitanya
Quoted 1 line
It turned out that, as a client, I don't have to bother with roaming stuff, it simply works out of the box.
Roaming has 2 types:
1) based on the disconnection (beacon loss)
2) based on the RSSIIs it really roaming doing background scanning and preauth #2 (or) a connect and disconnect (assuming same ssid and security) #1?
Quoted 4 lines
Though, I have a couple of questions regarding this OOBX (new buzz word seen here and there for "out of the box experience" :) ).
- At which level the roaming is done? Is it at the WiFi kernel stack (cfg/mac 80211), at driver level, or at chipset/firmware level or a mix of them?
- Can I change my setup, so that I have control over the roaming?
- Is it a good idea to try to manage that myself from userspace?
Quoted 6 lines
wpa_supplicant(userspace) takes care of the roaming for you, i belive it has support for both types #1 and #2 (along with background scan)Some proprietary version which implement at driver/fw level, this reduces the roam delay as it need not involve any context switches.
Thanks Krishna for your answer.
Regards,
Chris