Don't worry, I'm here to help you.
First thing first, you will need to know the requirement of your office needs.
Do you plan to let anyone use wifi or some will use cable?
How many users will need to connect to it?
How's the nature of the users that will connect to it? (Roam across APs or just stay)
Because we need to decide how many AP will be used, we have to know first the estimation number of how many users will be connect to it.
Wifi has a shared radio frequency (RF) medium. So when someone's using the medium, the other person must wait to get their turn and so on so forth for the next user.
The througput of wifi will be lower than using cables due to Wifi overhead packets to around 80-90%. So expect to have slightly lower internet speed than when you're using cable.
The througput will also drop for each user connected to an Access Point.
Here are the things you might need to consider when implement a wireless network.
1. How many clients will be served?
As I mentioned earlier, Wifi is a shared medium. The radio frequency will, in turn, serve every client with air-time for the internet connection.
So this one will be crucial to decide how much access point will you need to provide every user simultaneuously.
2. Access Point Capacity
Every access point has limitting the maximum number of clients which will be connected to it. So you'd better find an access point which suits your need.
An access point with 4:4 MIMO will be able to serve more clients and have more throughput than the one with 1:1 clients. So be careful when decides of what to use.
3. The nature of the clients (2.4 GHz or 5 GHz)
We need to know which one our users will be using first. In my country, Indonesia, most laptops are equipped with 2.4 GHz only Wifi adapter, then you will need access point which able to support 2.4 and 5 GHz band at the same time because some user will have the 5GHz band wifi support.
It is well known as dual-band access point.
Okay so, erm, how many access points do I need for my office then?
Let's get into the calculation.
Assuming I connected my laptop to the access point, which have this specification, 3x3:3 laptop MIMO, it will have the 40-60% TCP/IP througput than the actual bandwith.
Let's say I have actual througput of 450 Mbps for the Wifi adapter, I will have like around 225 Mbps actual througput for the TCP/IP connection.
That's when my laptop is connected while the other device isn't.
So what will happen when I connect another laptop which has the same spec?
The access point will share the air time to both devices, so the actual throughput will be like 50% of my actual throughput which is around 112 Mbps (225 Mbps divided by 2 devices).
The same thing will keep happen as I connect more device, like I have 3 laptops with the same specification connected to the AP, it will share the air time equally like 33% for each device then my actual throughput will be like 75 Mbps (225 Mbps divided by 3 devices).
Case 1:
So let's say, we will need to have our access points to serve 100 laptops which having raw throughput of 300 Mbps for normally web browsing and have the minimum of 2 Mbps speed of each for better user experience.
How many access point do we need to use?
Total laptop : 100
Laptop Raw Throughput: 300 Mbps
Actual Throughput: 150 Mbps
Minimum Bandwidth : 2 Mbps
2 / 150 = 1.3% to desired throughput
100 * 1.3% = 130% --> Rounded up it will be 200%, we will need to have at least two AP to be able to provide the requirement
Case 2:
There we have another situation which require us to serve different kind of devices.
45 Laptops with 300 Mbps raw throughput, 40 smartphones with 60 Mbps raw throughput, minimum bandwidth for each device of 4 Mbps.
Total Laptop : 45
Laptop Raw Throughput : 300 Mbps
Actual Throughput : 150 Mbps
Total Smartphone : 40
Smartphone Raw Throughput : 60 Mbps
Actual Throughput : 30 Mbps
Minimum Bandwidth for Application of 4 Mbps
For Laptop:
4/150 = 2.7%
45 * 2.7%= 121.5%
For Smartphone:
4/30 = 13.33%
40 * 13.33% = 533.3%
Total Laptop + Smartphone = 121.5% + 533.3% = 654.8% --> So we will need to have at least 7 APs to provide good connection (4 Mbps) for each user device
And that's it for part one.
You should be able to decide of how many access points will you need for your office by now.
Will share you another thing about Wifi designing later on.
Thanks for reading this.
APZ
