I have two items of that router, a Archer C7 router, a freebox revolution.
My Main Target Architecture would be the following (if possible )
ISP (Freebox Revolution) <-- wifi - X > <---> Archer C7 ( Openwrt)
- WA850RE as dump AP ( which is already with OpenWrt)
- WA850RE as dump AP ( in DDWRT but could be firmwared to Openwrt )
Is there a possibility to add Fast Roaming ( 802.11r) to those WA850E devices ?
Is there a problem with short memory size ?
What is the compatibility with current supported openwrt release ? with last release?
is it possible to configure WA850RE as Dump AP SSID=X inside my network using another TpLink ARCHER C7 as main router ( original firmware today - already connected to me ISP router)
Hope that explanation is enough for a good comprehension
IEEE 802.11r is standardized, if all (AP-) devices involved implement it properly and give you access to the relevant settings to harmonize them (wireless encryption/ credentials and 802.11r specific settings) as needed, it 'should' work across platforms.
…but it's certainly going to be easier to run the same firmware on all devices involved, as that clears out many pitfalls with that.
but i was told that old devices as it is the case for wa850RE could not support new release of firmware for openwrt and I wander if the target i described is possible. ( must install extra code that could not be supported on that devices)
I am refering to the tuto https://www.youtube.com/watch?v=kMgs2XFClaM
The TP-Link TL-WA850RE (at least the known hardware revisions I can find easily) are below minimum system requirements (4/32) and are no longer supported by OpenWrt. If you want to stick with OpenWrt, the only real option would be to replace them with more capable (modern) hardware that meets current (and future-) requirements, sticking to EOLed releases with known security issues (remote, local and/ or wireless specific) should not be considered an option.
Evaluating the security status of other firmwares (be it OEM or other third party ones) would be something to evaluate in their respective venues. But there is a reason why OpenWrt's system requirements are rising over time, keeping on track with current upstream versions takes its toll (software grows, slowly, but steadily).
The only real increase in flash/ RAM requirements you can blame OpenWrt itself for, is the addition of ssl/ tls support as required for WPA3 support (and -as a 'free' by-product- https access to luci itself), the rest are mostly direct consequences of updating core software components (kernel- and userland).