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A basic overview of Wi-Fi for the home.
Recommended Tools
Wi-Fi Analyzer
Android Phone: Wi-Fi Anaylzer app or iPhone: Airport Utility
MacBook:
Wi-Fi Explorer Lite
Speedtest App: Ookla SpeedSmart, AT&T Speedtest
Checklist for connecting to an AT&T public Wi-Fi hotspot - similar steps can be used to check your home Wi-Fi connection
Overview
802.11 is the standard defining a family of wireless LAN protocols (Wi-Fi). A protocol is simply an agreed upon way for two devices to communicate. Two devices start communicating by doing a handshake, which allows the devices to agree on how to communicate.
Wi-Fi uses a type of protocol that listens to a channel to see if any other device is using it before sending data. So, only one device can be transmitting on a channel at a time. If there are many devices on a channel, then each must wait its turn to send data. This will make the Wi-Fi appear to be slow. Moving to another less used channel will improve throughput.
Throughput is the amount of data that can be sent. Throughput is determined by the channel, the protocol and the bandwidth of the channel. Throughput is also impacted by Attenuation, Signal Strength and Signal to Noise Ratio.
Common 802.11 protocols are a, b, g, n and ac. ax is the newest standard. The protocols are listed from slowest, b, to fastest, ax. In general, if a device is using a slower protocol, then this impacts other devices on that channel. As an example, say a 2.4GHz wireless access point (AP) is capable of supporting b, g and n, then if b/g/n are all enabled b devices will slow down the the throughput of the n devices. For best throughput, only enable one protocol on one radio. I only use n on 2.4GHz, and ac on 5GHz.
For best throughput, enable broadest channels (e.g., 40MHz instead of 20MHz on 802.11n)
Wi-Fi Neighborhood
Most ISPs set up a home's gateway radio channels to default values. Since the availability of ISPs isn't always that competitive, this means most of neighbors are broadcasting on the same channel. Spectrum and AT&T both use channel 1 as their default values.
Use Wi-Fi Analyzer, Wi-Fi Explorer Lite, or Airport Utility to examine the channels being used. Select one that is least used.
For 2.4GHz channels, only use channels 1, 6 or 11.
If the AP or Gateway has the ability to automatically scan and select the best channel then enable that feature.
When I first moved into the neighborhood, everyone was on channel 1. I moved my channel to 11. At a block party, I told a neighbor he could improve his throughput by moving to channel 11. Within a few weeks, all my neighbors were on channel 11. I moved back to channel 1. Now, I have it set to auto-scan.
Wi-Fi AP Limits
APs have built-in limits due to the CPU used or amount of memory. Usually, the AP publishes its limits.
An example is the number of devices that can associate. Association means the AP and another device (like a cell phone or laptop) are connected. The AP stores among other things the MAC address and IP of the associated device. Once the limit is reached, no additional devices can associate. My AT&T gateway's AP has an advanced setting for the number of associations. Its default value is 80.
Please note the number of associations to an AP is usually far less than the DHCP or IP address space.
The number of active users (i.e., those passing traffic at high rates) is much lower than the number of associations, usually about 50 to 75. A number of factors influence this, such as, the CPU, bus bandwidth and ethernet connection.
In Home Gateways, the CPU is so under-powered that shutting off unused services will improve throughput.
Low Throughput
Since 802.11 is a collision detection/collision avoidance protocol, too many devices can lower the bandwidth for all. And, might possibly prevent some devices from working properly. On earlier 802.11 protocols, the number of broadcast SSIDs could lower the throughput (but this isn't much an issue on n or ac).
Disable lower protocols (e.g., on n, disable a/b/g)
See me/See you
Devices decide when to connect to an AP or switch to another one. For example, when I go to the office my phone auto-connects to my company's Wi-Fi without me doing anything and when I come home it auto-connects, again without me doing anything.
If I am in a large venue like a stadium, airport or big box store, then there are multiple APs and my device decides when to handoff between the APs. The handoff decision is made based on the received signal strength (RSS or RSSI, where I = indicator) from the AP.
However, there is another potential problem with Wi-Fi, which is called the see me/see you problem. An AP and a smart device each broadcast a Wi-Fi signal. I can look at my cell phone and see the RSS of the AP using a Wi-Fi Anaylzer tool, but it is much harder to look at an AP and see the RSS of a smart device. I need to setup the device, put the device into setup mode, then go to my AP and see what the RSS from device is.
In the see me/see you problem, a device gets a strong signal from the AP, but the AP gets a weak signal from the device. The device thinks it is connected, but the AP hears every other device better than the one with the weak signal. And so, the AP ignores that smart device.
I am lazy, so I cheat and connect my smart home devices to n-only APs based on distance, and not on RSS. This makes setup of a smart device a bit more difficult. Normally, I have my phone set to connect to only ac Wi-Fi at home. When setting up a smart home device, I must switch my SmartPhone to the right n-only SSID, then setup the device then switch my phone back to ac and forget the n-only Wi-Fi network.
SSIDs
The SSID is the name of your Wi-Fi.
I have 3 APs with 6 radios: the ac radio on my gateway is disabled to improve the throughput of my ISP's gateway, two APs are set to AC only, and three APs are n-only. All my radios use a unique SSID and broadcast on a unique channel.
Smart Home Devices
All my Smart Home devices connect to one of three 802.11n APs.
Determining MacBook Wi-Fi Settings
Security
Be sure to use WPA2 (PSK) or better encryption with a password.
From a Wi-Fi professional's point-of-view, a home Wi-Fi network is called an open network even though it is secured by encryption and a password. This is because parts of the association and authentication sequences are passed unencrypted.
PASSPOINT is the next step in security, and all steps in the Wi-Fi connection process are encrypted.
Notes:
NetGear AC1000 R6080 Router and AP is a piece of junk. Do not buy!. The AC1000 model R6080 has very misleading branding and specs. I bought the R6080 a while ago. I think I got it at Best Buy. I am not sure if I missed it there or when I read the specs. Either way, I would expect an AC AP and router to operate at Gbps speeds.
I have a gigabit ISP connection, and run a 1Gbps network in my house. So, when I did my home's heatmap, I was surprised the upstairs AP (R6080) was maxing out at 100Mbps regardless of distance and barriers. While the AC1000 R6080 says it can handle 300-700Mbps, all of the ethernet ports are only 100Mbps. Really?
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