Argh! Trying to understand: AP’s adding “bandwidth” to one’s WiFi

[lifereinspired]

Hello,

Someone posted a reply to a question I had posed re: the Linksys MX5/MX10 series on another site. I’ve been trying to understand what they said for sometime - and I’ve had people agree with this type of idea and others say that it’s just not true. I’m including the text below but they are saying that adding multiple access points in my apt will give more bandwidth for dealing with more connected devices. I generally get tech stuff quite quickly but I cannot quite seem to wrap my brain about why this would be the case - and I really do want to understand it. Any info (either way - explaining whether it’s true or not - would be really appreciated. Thanks so much in advance!
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>quote: AC chipsets seem as though they aren’t setup to handle as many devices as I need. Maybe that’s not real. I don’t know.<

Since you seem worried about how many devices a system can handle let me tell you about one of the dirty secrets of home mesh systems. They DON'T handle more clients then a normal router regardless of how many nodes you have. In fact your existing R8500 can already handle more clients and has more bandwidth then most home mesh systems, even AX ones.

The reason is that home mesh nodes all run on the same channels. Even if they have a dedicated wireless backhaul, even if they have a wired backhaul. So all nodes interfere with each other and thus can't supply any more bandwidth or handle a higher client load.

A few cheap APs will vastly outperform any mesh system when you have many clients because they can run on independent channels. It doesn't have to be Ubiquiti, a few TP-LINK EAP225s around your house will give you far more real world bandwidth then that overpriced beta quality AX system. No single device gets max speed but in total you get far more by sharing the load.

Also performance issues aside, nothing from ~~Linksys~~ Belkin is anything close to quality.
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[coxhaus]

My thoughts are more APs more clients supported. I also think small business APs handle more clients than consumer gear and enterprise APs handle more clients than small business.

 

[thiggins]

WiFi is a shared medium with a channel (a group of frequencies) having a capacity (bandwidth) determined by the protocols and modulation methods used. A shared medium means only one device (STA) can use the channel (transmit) at a time. (I'm setting aside the effect of MU-MIMO and OFDMA, which are designed to allow multiple devices to use the channel simultaneously.)

Adding another AP tuned to the same channel and close to the first AP doesn't increase capacity because when the STA checks for a clear channel both APs respond and it can only use one. Since the second AP must stay off the channel, no additional capacity (bandwidth) is provided.

If the second AP is moved far enough away from the first or tuned to a non-overlapping channel, then when the STA checks the channel, only one AP will respond. Another STA can simultaneously check the channel on the first AP and also find it clear and simultaneously use the same channel. So bandwidth/capacity is increased. Setting the APs to different non-overlapping channels has the same effect of increasing available bandwidth.

Mesh systems that do not have a dedicated radio for backhaul (AP to AP connection) contend for the same channel, so share bandwidth with STAs. Mesh systems (or multiple APs) with Ethernet backhaul can provide higher bandwidth IF each AP uses a different channel or is placed far enough away from other APs so that they don't contend for the same airtime. The Ethernet connection provides an alternate source of bandwidth that doesn't interfere with WiFi.

 

[ColinTaylor]

Thanks for the explanation Tim.

Can I ask, do "home" mesh systems like Asus' AiMesh use the same channel for all their nodes? I'm slightly familiar with Aruba setups where you can assign different channels for each node.

 

[thiggins]

Thanks for the explanation Tim.

Can I ask, do "home" mesh systems like Asus' AiMesh use the same channel for all their nodes? I'm slightly familiar with Aruba setups where you can assign different channels for each node.

Mesh systems only have the option of using different channels if they have a dedicated backhaul radio or use Ethernet backhaul. Otherwise, radios need to be on the same channel to communicate between nodes.

 

[Keith Gorham]

Thanks for the explanation Tim.

Can I ask, do "home" mesh systems like Asus' AiMesh use the same channel for all their nodes? I'm slightly familiar with Aruba setups where you can assign different channels for each node.

I have an main router and two nodes setup as an AiMesh. The two nodes are hardwired and all three routers are on the same channel I do not know if there is a way to change this. This is the main reason I go back and forth between thinking which is better(Mesh or APs). I tested using both the latest Asus firmware and the lastest Merlin and both are the same as for as channel usage.

 

[coxhaus]

I have 2 Cisco AP581 APs at my house and they are connected with POE+ and are on different channels so they can both operate at the same time. Roaming works great. They support around 200 users, maybe 250 each.