Using iperf is very nice. Only - usually when you test the WiFi performance, kids are at school and you don’t have them Streaming Youtube stupid videos ;}
To understand the issue with WiFi - note that WiFi is like using a hub.
A Hub will show degraded network performance the more “active” hosts are on the network.
On WiFi it is the same. The more devices are on it, the more “collisions” will occur (As we are on the same collision domain), and the lower the net data transfers speeds.
As general rule on a AP (HUB), the number of connected hosts to the AP will determine the max available bandwidth of a host.
So - on a Hub we have the following that applies
- Physical topology = Star
- Logical topology = Bus
- Single Collision domain
- We assume the max possible utilization of the shared network is divided by the number of communication paths.
So - for 4 devices, we have 3 using-devices connected to the AP, each building a communication channel to the AP. So 33%. Remove ~3% for protocol overhead and we round up to 30% max available bandwidth per host.
54Mbps is shared = 54Mbps/4*22% ~= 2.97Mbps net sustained throughput to be expected per device if all are active talkers and we are using a regular AP with 1 physical antenna.
Note that I applied this to a Ethernet Hub - using the speed of a regular WiFi without MiMo for simple estimate. To the WiFi, we need to add the WiFi overhead. So the end result will be a little lower.
This - to explain that if you use WiFi, take a AP that has MiMo but never connect more than available Antennas in the MiMo layout. If it has 2 Antennas, connect only 2 devices to have full WiFi bandwidth per antenna! If not, the rule as described before applies very fast per physical antenna.
1 device connected to AP: 54Mbps/1*97% ~= 52.38 Mbps (assuming the overhead is 3%)
2 devices connected to AP: 54Mbps/2*47% ~= 12.69 Mbps per device
3 devices connected to AP: 54Mbps/3*30% ~= 5.40 Mbps per device
4 devices connected to AP: 54Mbps/4*22% ~= 2.97 Mbps per device
I know there are faster devices out there bundling channels to go to 108Mbps. But the same rule applies. And the worst is if there are other devices streaming! The more active talkers, the lower the performance.
So - if possible, use a SWITCH and connect the Vero to a NAS using a SWITCH through Ethernet! because a switch dispatches the traffic only between the communication partners, same as connecting only ONE device to the HUB/AP.