How many access points are needed in the office?

There is no conversion factor from square metres to the number of access points, so the question of how many access points an office really needs is resolved differently. The result depends on the number of devices, the arrangement of partitions and what this network has to carry. This article shows which dimensions actually determine why adding equipment can make the situation worse and what to prepare to make the selection make sense.

Why won't anyone honest give the number per square metre

Simple conversions of the number of points per area are popular because they are convenient, although they mainly describe the range, which is the least important of the parameters determining the quality of a wireless network in the office.

Two offices with identical space may require one or five access points, as the result depends on the number of devices working simultaneously, their applications, room division and wall material.

An access point, a device that provides a wireless network, is not a router, although in small offices both functions are sometimes enclosed in one housing.

Four quantities that actually decide

Number of devices, not number of people

When estimating workload, it's easy to make the most common mistake, because ten people in the office rarely means ten devices. There is a laptop, a phone, and often a second phone per user, and the common pool is complemented by a conference set, a printer, sometimes a tablet, and equipment that no one initially thinks about: cameras, sensors, or a TV in the room.

You need to count devices active at the same time, not all devices ever registered in the network.

What do these devices do

Thirty laptops reading e-mail pose a completely different load than ten conducting video conferences, because video calls, working on files from the server and cloud synchronisation generate constant, not momentary, traffic.

Special cases include warehouse terminals, wireless telephony and data collectors, which require low latency and seamless switching between points, thus imposing a stronger design impact than the sheer number of users.

Partition system

Partition walls made of slabs dampen poorly, while reinforced concrete walls, elevator shafts, shafts and partitions with sheet metal do so much more strongly. Metallic-coated glass, popular in new office buildings, also dampens much more than its appearance suggests.

Therefore, a larger open space may require fewer points than a smaller office layout, even though it occupies a significantly larger usable space.

Neighborhood Radio

In an office building and in the city centre, the 2.4 GHz band may be occupied by neighbors' networks, which cannot be changed, but must be taken into account. The 5 GHz band has a much larger capacity, but it penetrates through partitions less easily, which may require a denser distribution of points.

Range is not the same as a useful connection

This distinction changes the entire conversation about design.

The device sees the network over a much longer distance than it can sensibly use it, so at the edge of the range there is a connection, but it operates at the lowest speeds. Then the most surprising mechanism is revealed: such a client takes up a disproportionate amount of airtime.

Wi-Fi networks operate on a common medium in which one device transmits on a given channel at a given time while the rest wait. A slow transmitting device blocks the medium longer than a fast device, as a result of which one laptop at the edge of the range can slow down everyone using the same channel.

When designing a network, the aim is not just to "cover everywhere", but to ensure the appropriate quality of connection wherever someone works, because both goals lead to different projects.

More points does not always mean better

The "let's add one more" reflex can be harmful, even though it sounds like the simplest answer to the lack of coverage.

Access points placed too close together on the same frequency begin to interfere with each other because instead of sharing traffic, they use the same medium and shorten each other's time in which they can transmit. A network with six points may then perform worse than with three well-placed ones.

The second effect occurs when, with an excess of points, devices switch more frequently, and each such change causes a short break in transmission, which is felt during video conferencing.

The practical conclusion is simple: if the current network is malfunctioning, adding equipment without determining the cause remains a bet, not a solution, so it is worth following the path from the article about what to do when your corporate network is slow.

How to connect access points

This question determines the result more than the device model that will ultimately be selected.

The access point must receive data from the wired network, and if there is no cable to it, it can receive it via radio from another point, using radio backhaul, commonly known as mesh.

The mesh limitation is structural: the same radio module simultaneously serves clients and a connection to a neighboring point, so the bandwidth available to users decreases and decreases again on the next hop. Additionally, the mesh inherits the quality of the radio connection between points, which means it remains sensitive to the same interference as the rest of the network.

Mesh makes sense when cable installation is impossible or disproportionately expensive, the solution is temporary, or the area is peripheral and has little traffic.

Backhaul wire is appropriate when the area is loaded, there are devices operating there that require stability, or the point is to serve more than a few people.

In practice, this means something simple: if you are even considering Wi-Fi in the office, plan a cable to each place where the access point will be placed, because installing cabling during renovation is many times cheaper than later.

The cable is also needed because access points are usually powered through the same cable, using the PoE standard, and the switch has a finite power budget that must be calculated before selecting specific models.

Zones that are planned separately

• conference rooms: few metres, many devices at once, high stability requirements,
• reception and guest area: often a separate network segment, variable number of devices,
• warehouse or back office: other compartments, other requirements, often terminals,
• outdoor spaces: terrace, parking lot, maneuvering area, other equipment and other fixings,
• corridors and staircases: If someone is going to walk on them with a connection, they require continuous coverage.

Typical mistakes when selecting yourself

• counting people instead of devices,
• installation of the point in a rack cabinet, in a corner or behind a sheet metal partition,
• model selection before determining how many devices it should support,
• switch power budget bypass,
• basing the whole thing on mesh because "we didn't want to forge",
• treating the declared coverage area from the catalogue card as a promise. This value is created in conditions that do not exist in the office.

When an estimate is enough and when a measurement is needed

An estimate is sufficient when the office is small, with a simple layout, light partitions, no critical equipment and no high density.

Measurement on an object is needed when the building has thick partitions or an unusual structure, there are high-density zones, there are terminals or wireless telephony in operation, the facility is a hall or warehouse, or the previous attempt has already failed.

In halls and warehouses, estimation from behind the desk practically does not work, because the damping depends on the changing arrangement of the goods, which we describe separately in the article about Wi-Fi in the hall and warehouse.

How many access points in the office: what to prepare for selection

• floor plan, even handwritten, with division into rooms,
• information about the material of walls and ceilings, if known,
• number of devices working simultaneously, divided into zones,
• list of applications requiring stability: videoconferencing, terminals, telephony,
• information where the cabinet is located and whether new cables can be connected to it,
• description of current problems if the network already exists.

The more of this information is available, the less time it takes to determine the facts, and therefore the more accurate the result becomes.

How we do it

We start with what the network needs to carry, not with a catalogue, choosing the number and arrangement of points, checking the switch's power budget and identifying places requiring cabling. If the property requires it, we measure it on site rather than basing the design solely on an estimate.

In corporate networks, we are a Zyxel Networks Partner and we also implement Ubiquiti UniFi, and we select the platform according to the facility and who will operate the network.

After implementation, the network can be under our constant care, including monitoring the status of access points, updates in agreed service windows and configuration adjustments in the event of changes in the company, the scope of which is written in the contract. It can also remain entirely with you, along with full documentation and administrative rights.

Scope: building and maintaining corporate networks.

Book a free IT review: in an hour online we will determine whether an estimate is sufficient, or if a measurement is needed before you buy anything.