Just want to theoretically check something regarding the wireless repeating through one example.
Let’s say I have two Mikrotik devices, each with one 2.4GHz 802.11 b/g/n MIMO radio and very good signal between them. First one is connected with wire to the Internet and wirelessly (with WDS) to second one. The second one is connected wirelessly (with WDS) to first one and at the same time AP for clients.
Two Mikrotiks should connect to each other on 802.11n standard as the signal is good.
Example 1
Let’s say now that client which has only 802.11n standard connects to second device. Let’s say if there was no wireless repeating the throughput for the client would be 150Mbit/s (2x2 MIMO = 300 Mbit/s in air).
Since there is wireless repeating the second device’s radio interface is shared between the client and the WDS connection to the first device, so theoretically max. throughput should be 75 Mbit/s. Is this correct?
Example 2
Let’s say now that client which has only 802.11g standard connects to second device instead of 802.11n client. Let’s say if there was no wireless repeating the throughput for the client would be 20Mbit/s (54Mbit/s in air).
What will be the speed with wireless repeating?
Since the second device’s radio is shared between WDS connection to first device and clients will the throughput be half - 10 Mbit/s?
Or it will be 20Mbit/s because the WDS link is on 802.11n and not on 802.11g?
So what in case that two clients connect to second Mikrotik, one with 802.11g and another 802.11n?
802.11g client(s) would have maximum (aggregate) throughput 10 Mbit/, 802.11n client(s) maximum (aggregate) throughput 75Mbit/s, while the WDS link to first Mikrotik would have maximum throughput 75Mbit/s as well?
I just made a “real world” test. Connected to RB2011-2hnd model by “a notebook” with intel mimo 2x2 bgn wifi card thru 1 brick wall (and furniture). Signal-to-noise distance 52db, ccq 100%. With having other devices connected to AP and running also other traffic from this notebook (not more than 1mbit/s) I measured this (on 120/12 Mbit/s link reachable over cable):
It means in ideal conditions the 80Mbit/s speeds are reachable. Maybe more? Anyway, now the WDS comes into this. As it roughly divides the link capacity to half, you can expect no more than 40Mbit/s reachable on clients connected to second AP.
Always expect worse, as there are so many circumstances that will make their job against your link… finally you will need to do your own test as there is no possibility to simulate your situation elsewhere.
WDS connection is something that should be avoided if you think connection seriously and you have a budget for it. In this case, use separate PtP link (preferably on 5G band) and use non overlapping frequencies on both APs in order to avoid interference. Then they will not be mutually influenced and would perform both the best.
