4 ms·

[edit: re-read your post; you're well aware what handoff is, so sorry for the overly vivid explanation] That's 'cell planning'. Roaming is different: Let's sa

[edit: re-read your post; you're well aware what handoff is, so sorry for the overly vivid explanation] That's 'cell planning'. Roaming is different: Let's say you're moving from your bedroom to the kitchen. The bedroom AP's signal suddenly drops. Your smartphone needs to find the kitchen AP, re-connect, and re-transmit all the packets that might have been lost. Mobile networks assist the smartphone: it tells the smartphone that the kitchen AP will soon be in range. It already allocates and configures resources at the target AP. Then the handover is more seamless. In theory, WiFi can do this too. But last time I checked, it seemed a vendor-specific mess.

RulerOf 6y ago
>In theory, WiFi can do this too. WiFi actually can't do this. It's a shame, but fully network-directed roaming is not a thing in 802.11 yet, and I don't know when it's going to bother to show up. The major protocol extensions you can use are 802.11k, 802.11r, and 802.11v. They have a compounding increase in roaming performance in roughly that level of significance. 802.11k is a pure win. It should always be used. 802.11r is hit or miss. When it works, roaming can take under 10ms. When it doesn't, you disassociate entirely and reconnect. I have an SSID with it enabled but never use it. 802.11v is a pure win, but not very well supported. I use Cisco hardware specifically for this feature set, but I can't really say I recommend it. I kinda hate the controller software, and it's licensed separately. Cheap hardware on eBay though.
- goihoiholi 6y ago
  Thanks! Do those extensions require client support, and if so, is it supported by consumer devices?
  - RulerOf 6y ago
    Yes. iOS supports them all: https://support.apple.com/en-us/HT202628 https://support.apple.com/en-us/HT202628 Mac OS doesn't support any of them (much to my chagrin). On Windows, it has to be implemented by the driver. I suggest using Intel: https://www.intel.com/content/www/us/en/support/articles/000021562/network-and-i-o/wireless-networking.html https://www.intel.com/content/www/us/en/support/articles/000... With Android, it's hit or miss. All modern flagships support them AFAIK. Going back in time, it's limited to premium vendors. I'd expect the majority of devices to support 802.11k, although they're quiet about it. You'd have to check logs on your AP (if available) to determine if it's in use.

RulerOf 6y ago

>In theory, WiFi can do this too. WiFi actually can't do this. It's a shame, but fully network-directed roaming is not a thing in 802.11 yet, and I don't know when it's going to bother to show up. The major protocol extensions you can use are 802.11k, 802.11r, and 802.11v. They have a compounding increase in roaming performance in roughly that level of significance. 802.11k is a pure win. It should always be used. 802.11r is hit or miss. When it works, roaming can take under 10ms. When it doesn't, you disassociate entirely and reconnect. I have an SSID with it enabled but never use it. 802.11v is a pure win, but not very well supported. I use Cisco hardware specifically for this feature set, but I can't really say I recommend it. I kinda hate the controller software, and it's licensed separately. Cheap hardware on eBay though.

goihoiholi 6y ago
Thanks! Do those extensions require client support, and if so, is it supported by consumer devices?
- RulerOf 6y ago
  Yes. iOS supports them all: https://support.apple.com/en-us/HT202628 https://support.apple.com/en-us/HT202628 Mac OS doesn't support any of them (much to my chagrin). On Windows, it has to be implemented by the driver. I suggest using Intel: https://www.intel.com/content/www/us/en/support/articles/000021562/network-and-i-o/wireless-networking.html https://www.intel.com/content/www/us/en/support/articles/000... With Android, it's hit or miss. All modern flagships support them AFAIK. Going back in time, it's limited to premium vendors. I'd expect the majority of devices to support 802.11k, although they're quiet about it. You'd have to check logs on your AP (if available) to determine if it's in use.