Subnetting and VLANs (Virtual Local Area Networks) are two concepts that go hand-in-hand in a modern business Wi-Fi network. It's virtually impossible to have a large network that functions as a single entity - breaking up the network into smaller subnetworks helps maintain security, as well as making the network easier to manage.
A subnet, or subnetwork, is simply a chunk of your internal IP addresses that have been "carved out" for separate use. For example, if you have a traditional IPv4 network using 192.168.x.x addresses, a subnet might start with 192.168.5.x, and then the final number (0-255) identifies the particular device on that subnet.
Subnets are, then, a virtual necessity when implementing a VLAN, since (unless you're using high-end Level-3 routers) the VLAN needs to be on its own subnet to be able to interface with the rest of the network.
So, let's talk a bit about changes you can make to your network structure, and how these can ultimately increase your average WiFi speed.
Boosting The Speed Of Your Subnets And VLANs
1 - Know What You Have
A full and complete audit of all the hardware attached to a network is a necessity when trying to optimize your WiFi performance. In a virtualized network, every Internet appliance will have an effect on how the network behaves.
One key thing to keep in mind here is that, when you audit all the devices attached to the network, you're likely to find some surprises. Especially in a large business, devices and hardware tend to "appear" without anyone (admitting to) knowing where exactly they came from.
Sometimes you can improve your network's performance simply by kicking off various unauthorized devices your workers have brought in.
2 - Look For Bottlenecks
Older hardware can be an especial burden on WiFi networks, since ultimately, a network is only as efficient as its weakest link. Modern VLANs attempt to compensate by routing around older hardware when possible, but there's only so much that can be done.
As a rule of thumb, a piece of networking or Internet hardware has an effective lifespan of about 3-5 years. Due to the rapid pace of technology changes, anything more than five years old is likely to cause compatibility issues and bottlenecks in your network, especially when new equipment is introduced.
If you buy a new piece of equipment, like a server, and you're not getting the expected speed boosts, bottlenecks elsewhere in the system are the likely cause.
3 - Use 5ghz Wi-Fi Equipment
If you're still using WiFi hardware that works in the 2.4ghz range, you're probably going to see interference from other sources, including radios, cordless phones, microwaves, and of course other wireless access points.
Besides offering higher speeds, WiFi appliances utilizing the 5ghz bandwidth range are less likely to suffer from interference simply because there are few other devices using that portion of the radio spectrum.
4 - Add More Subnets
It's difficult to give specific advice in a blog about whether it's better to add subnets, VLANs, or hardware. These are the sorts of decisions best made through in-depth expert consultation and usage studies.
However, as a general rule, adding subnets will often reduce network congestion. If you have 200 terminals, they can all fit onto a single subnet... but that leaves very little room for growth, and often causes them to compete for bandwidth. Segregating users into separate subnets usually reduces local congestion, although it does ultimately offload the work onto your routers.
In our experience, many companies do well assigning a separate subnet to every department. Besides ensuring every area has plenty of room to grow, this aids Wi-Fi security as well. There's no reason for your accounting data to be accessible to R&D workers, for example.
Either way, if you're not getting the performance you want from your network, please don't hesitate to contact us for a free consultation on your available options!