Are changes to Beacon Interval + DTIM useful in a multi-access point environment?

[Wolfschiesst]

Dear All,

I am not a fan of unreasonable "voodoo" router tuning.

However, I've often read that in more noisy Wifi-environments or in configurations with multiple access points, it would be useful to set the Wifi "beacon interval" from the default value of 100 (102.4 ms) to an nearby prime number (e.g. 97 ms / 101 ms) to reduce collisions with the APs and neighbors' routers. For larger deviations, you may also need to change the DTIM to match.

But I'm really interested in what you think about it? Do you have any experience with it? Would you recommend such an adjustment?

I have carried out a few tests with changing the beacon interval and possibly reducing the DTIM to 2, but so far I have not noticed any "really" big effects.

2 Examples for such a configuration:

* Variant 1:
- Router AC88U:
2.4Ghz -> beacon interval: 101
5Ghz -> Beacon Interval: 97
- Access Point AC88U:
2.4Ghz -> Beacon Interval: 101
5Ghz -> Beacon Interval: 97
- Access Point AC5300:
2.4Ghz -> Beacon Interval: 101
5-1Ghz -> beacon interval: 97
5-2Ghz -> Beacon Interval: 89

* Variant 2 (seems to me to be almost the most reasonable, since all nets have different intervals):
- Router AC88U:
2.4Ghz -> Beacon Interval: 193
5Ghz -> Beacon Interval: 97
- Access Point AC88U:
2.4Ghz -> Beacon Interval: 197
5Ghz -> Beacon Interval: 101
- Access Point AC5300:
2.4Ghz -> Beacon Interval: 199
5-1Ghz -> beacon interval: 103
5-2Ghz -> beacon interval: 107


Details:
Since our house is quite large and the neighbors also run many 2.4 Ghz and 5 Ghz wifi networks, I use an Asus AC-RT88U as the main router (network access on the 1st floor), an Asus AC-RT88U as an access point on the top floor and an Asus GT-AC5300 as an access point for the ground floor including supply of the terrace and garden.

To configuration:
- No mesh connection;
- uniform, same SSID across all devices / networks;
- the two APs are each connected to the main router via a powerline backbone line.
- Smart Connect active for all (for both RT88U: for 2.4 GHz and 5 GHz each with Merlin's Asuswrt firmware; for AC5300: for 2.4 GHz and 5-1/5-2 GHz).
- The settings for Wifi networks and band control (Smart Connect Rule), which are mostly recommended in the forum.

 

[heysoundude]

I suspect that you may get more pertinent and specific answers to your question if you post this to the "General Wireless Discussion" forum rather than this one.
I like the question, don't mistake me; this sort of discussion really gets my brain firing when people who know and understand the implications of making the changes you propose step in and help or explain why it might not be the best idea.

 

[L&LD]

I don't think this kind of 'tuning' makes sense.

WiFi is a shared medium and that means it must get along with all the other WiFi transmitters it can 'see' (and they with it).

Using non-standard beacon intervals may be useful if you have control of all the surrounding transmitters and put everything on the same 'standard'.

But I can't see how this would help though when using just your own network in an already crowded WiFi space though. If anything, it will add latency and possibly other gremlins to all WiFi networks that can 'see' yours, including yours too. Not to mention 'hardwired' products that may simply break outright. (Hardwired here isn't a LAN connection, rather, a device/driver or firmware setting that is set in stone).

 

[Wolfschiesst]

I suspect that you may get more pertinent and specific answers to your question if you post this to the "General Wireless Discussion" forum rather than this one.
I like the question, don't mistake me; this sort of discussion really gets my brain firing when people who know and understand the implications of making the changes you propose step in and help or explain why it might not be the best idea.

Ok, thanks for your reply. I will copy the threat to this section (as I can't move it).

 

[Wolfschiesst]

I don't think this kind of 'tuning' makes sense.

WiFi is a shared medium and that means it must get along with all the other WiFi transmitters it can 'see' (and they with it).

Using non-standard beacon intervals may be useful if you have control of all the surrounding transmitters and put everything on the same 'standard'.

But I can't see how this would help though when using just your own network in an already crowded WiFi space though. If anything, it will add latency and possibly other gremlins to all WiFi networks that can 'see' yours, including yours too. Not to mention 'hardwired' products that may simply break outright. (Hardwired here isn't a LAN connection, rather, a device/driver or firmware setting that is set in stone).

Thank you. Yes, that's convincing for me.

 

[Wolfschiesst]

What the speed on the power line backbone? If it’s what I think, this might be a bottleneck.

Seems to be no problem. Approx. 500Mbit/s. This is why I decided not to use a dedicated WLAN backbone from the triband AC5300.