Network Oversubscription

Question

I am just joining my firm, and there is already an issue I am taking a look at. I am not part of the networking team but want to contribute as much as I am able.

Our firm is experiencing a drastic amount of new hires, and the increase seems to be taking a toll on the WAPs according to the networking team.

What would your troubleshooting steps be to rectify this?

• Check the AP's for any reporting?
• Bandwidth utilization? but that would capture all bandwidth right? hardwire and wireless
• Check the switch? not many issues on wired connection
• APs reboots weekly, firmware updated weekly.

Answer 1

You can roughly divide your troubleshooting into two areas: wired and wireless.

For wireless issues, the potential problems are:

1. Channel contention. Simply put, the more users that are vying for airtime on a given channel, the less throughput each of them will get. You also have to take into consideration interference from other sources. You'll need a WiFI analyzer to measure this.
2. AP performance. Many APs are limited in the number of clients they support. Don't forget that just because an AP has a 1G Ethernet connection, it doesn't mean that it can actually perform at that rate. You don't give any details in your question, so it's hard to say if this is an issue.

For the wired side, bandwidth constraints can be anywhere between the AP and the resource you're trying to reach.

We really can't say more since you've provided no details about your network. Note that consumer grade devices are off topic on this forum.

Answer 2

First recommendation: Leave it to the people getting paid to manage and improve it. If they need your help, they will ask for it.

If you really want to contribute, go to them directly and ask if you can help with anything. They'll appreciate your direct approach. Tell them you keep hearing complaints from people around the office regarding the WiFi usability and you wonder if you can do anything to help.

As for the actual technical answer to the technical problem of WiFi network capacity:

Each network differs according to its design and implementation. Most WiFi access points designed for business or enterprise use vary between 50 to 200 maximum connected devices so if you have an office of 100 people and assume they each have 2 to 3 devices, you need more than 1 access point for that office though how many you need depends on the model and manufacturer specifications.

Additionally, each access point will only carry so much traffic according to its design, features and connectivity. A 1 Gigabit uplink connection for the access point will never carry more than about 970 Megabit of actual throughput though depending on the radios in use, frequencies in use and other configuration specifics, the actual performance of all the traffic of the users on the access point may be much less. Some access points now have 2.5 Gigabit interfaces but that will require matching switch ports and appropriate cabling for them to perform at anywhere near that level.

Answer 3

The first troubleshooting step with Wi-Fi is to perform a wireless site survey. This should be performed by an expert, and it usually involves hiring an outside company with the requisite expertise.

The survey will determine various data, including the proper placement, quantity, channels, power levels, etc. for your WAPs, and it will identify any outside interference. You will get a heat map that you use to install and configure your WAPs. A big mistake that people often make is not understanding that Wi-Fi is three-dimensional, and signals will bleed between floors in a multi-story building. The site survey will identify that and take it into account.

It is also a good idea to get a follow up survey after everything is up and running, and you must realize that things change over time (neighbors move in and use Wi-Fi, interfering with your network, etc.), so you may want to get a new survey from time to time.