Question Mesh Network Smarts?

Crag_Hack

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Hi I've heard the general consensus that Wifi roaming is purely done by the client devices instead of the mesh satellites / WAPs. However here under "The problem with non-mesh access points" and "The advantages of mesh networking" PCWorld claims that mesh networks have smarts built into them to facilitate better roaming on the wireless network. Is this true/untrue? Maybe half-true? Thanks!
 
First why would you need so called seamless roaming. I will laugh when router manufactured start getting sued because someone fell down the stairs in their house staring at netflix on their phone. They already walk out into traffic on cell phones.

So many many years ago cisco tried this and most the information about the 802.11 roaming protocols you will find on cisco sites. This was back in the day when you paid by the minute for cell calls and coverage in buildings was horrible. Cisco tried to do what is now called wifi calling but it had a different name back then. It kinda worked but not well. In the end the cell company killed it off with unlimited voice plans and the use of micro cell tower placed in large buildings.

As stated the client is in full control and it does not pick the correct AP. Now the part they try to pretend are the roaming extensions to the 802.11 protocols. Most end devices do not support this so it really doesn't matter if the mesh units do. Again the client is still in control. Even when is has the roaming protocols it is just a bit more information to the end device. The huge problem is the signal level the AP detect from the end device do not mean the end device gets the same signal levels from the AP. The mesh network has no way to determine how well the end device can receive signals from any AP. It makes the assumption it is symmetrical which many times is correct but also why you still get random disconnects and drops as you move around.

Something like a cell phone the tower is in full control of the radio in your cell phone. It can adjust the transmit power on the fly and tell the radio to change towers.

BUT we are again back to why do you really need this feature. In most cases if you walk down the hall by the time you get to the other room the device will detect it and switch even using just dumb AP with no mesh. Nobody in a home environment is going to try to dynamically balance devices. The example cisco used was a bunch of employees move to a conference room and all want to use wifi. The system would force other users who were not on the conference room to move to other AP to allow the extra capacity. Again it kinda worked and kinda didn't
 

Crag_Hack

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K thanks for the excellent answer. Sounds like the PCWorld article claims including "Disruptive interruptions to connection quality, especially with real-time applications like streaming and video conferencing." resulting from non-mesh networks shortcomings are for the most part bogus.
 
If you were talking about online games where even adding a extra 200ms will cause a lag spike maybe. I want to see someone actually walking around there house carrying their pc and trying to play a shooter type game.

Most stuff like streaming and video conferencing have buffers that add delays of multiple full seconds in many cases. This tends to hide most this type of issue. You can sometime detect the delays kinda like when you watch nasa talk to astronaughts

I can see very little real world use case. In most cases if you are using internet based stuff you might as well just used a cell network that is designed from the ground up for seamless roaming.....you can still hear the static as it switches cell tower when you are driving so even that is not truly seamless. In your house you would never change towers as you walk around.

The only application I can see that needs very high bandwidth and needs some mobility is VR. There are already enough video of people hurting themselves falling over furniture in the same room. Are they really dumb enough to try to walk down the stairs with a vr headset on.

This is mostly marketing hype. People have learned the scam that all brands of routers pretty much have the same coverage. It isn't really the coverage that is the problem it is that the coverage is actually too large and all your neighbors signals are coming into your house. So you must sit closer to the router to get the same amount of usable bandwidth from your router. To increase coverage they now use multiple radio units in everyone's house which just makes the problem worse and worse.
There is so much mesh stuff being sold that some vendors now want people to think they actually "need?" seamless roaming.
 

Crag_Hack

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@bill001g OK I see with the roaming thing now. Are you saying though that most routers would be able to cover a whole house if there weren't interference from the neighbors? Isn't it true that most house's networks minimize overlap through using different channels to eliminate interference?
 

kanewolf

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@bill001g OK I see with the roaming thing now. Are you saying though that most routers would be able to cover a whole house if there weren't interference from the neighbors? Isn't it true that most house's networks minimize overlap through using different channels to eliminate interference?
There is almost no way to predict. Besides interference, there are walls. The construction materials make a big difference. A lot of European homes have cement or concrete block interior walls. WIFI doesn't penetrate concrete.
 
"minimize overlap through using different channels" :) :)

They are talking out both sides of their mouth when they talk about channels.

The so called channels are 5mhz wide on 2.4g radio. In theory there are 11 or 13 depending on country. So 60mhz total.
The minimum actual channel width used by wifi is 20mhz. It is much more common to use 40mhz to get higher speed. This means it is impossible to fit 2 signals without overlap.

On the 5ghz band the channel numbers do represent 20mhz bands but they now use 40,80 and even 160mhz of bandwidth. The 160mhz ones will not fit without overlapping things like weather radar.

We then get the 6ghz band which should solve this problem there is massive amounts of bandwidth but the bandwidth pigs are back.

Wifi7 now is going to use 320mhz channels. To make things even worse it will attempt to use the maximum radio bandwidth it can get on 2.4, 5 & 6 all at the same time, attempting to bond it all into 1 big pipe. This just 1 router not even discussing mesh or multiple units. Even if you were to play nice one of your neighbors is going to try the new bonded wifi7 routers and devices when they finally get onto the market.