Most small business networks were not designed. They accumulated — a switch added when the office expanded, an access point where the signal was poor, a router somebody plugged in to solve a problem in 2019.
They work, mostly. Then something intermittent starts happening and there is no way to trace it, because nothing was written down and nothing follows a pattern.
Address planning
Unglamorous and the foundation of everything else.
Decide the address ranges before anything is deployed, with room to grow. Avoid the defaults that every consumer router uses, because they collide the moment somebody connects from home over a VPN and both ends are using the same range.
Reserve blocks by purpose: infrastructure at the bottom, servers and printers next, then the range handed out automatically to laptops and phones. Anything that other things connect to should have a fixed address, recorded.
Doing this makes every future problem easier to diagnose, because an address tells you what kind of device it is.
Separation
Not everything on your network should be able to reach everything else.
The separations worth making in almost any business:
Guest access, isolated. Visitors get internet and nothing else. This is straightforward and it is astonishing how often guest wi-fi sits on the same network as the accounts system.
Devices that are not computers. Cameras, door entry, building controls, printers, till systems. These are frequently the least maintained equipment you own, running software that will never be updated. They belong on their own segment where a compromise cannot spread.
Voice, if you use IP telephony. Separated and prioritised, so a large file transfer does not degrade a customer call.
This is done with VLANs, explained properly in VLANs explained for business. The important point is that separation limits how far a problem — a compromise, a broadcast storm, a misconfigured device — can travel.
The cabling is the part that lasts
Hardware is replaced every five to seven years. Cabling installed properly lasts fifteen or twenty.
Which is why it is the wrong place to economise, and the place businesses economise most often. Improvised runs, cables through doorways, connections made by whoever was available — these produce intermittent faults that are extremely difficult to diagnose and easy to prevent.
Get it installed properly, tested, labelled at both ends, and terminated into a patch panel in a cabinet. See network cabling done properly.
One clear route out
A network should have one obvious path to the internet, through one firewall.
What goes wrong: a second router installed for a specific purpose, a supplier's remote access device, a 4G backup that is always connected. Each is an additional way in and a source of confusing behaviour, and each is usually undocumented.
If you need a backup connection, design it as a failover rather than a permanent parallel path.
Resilience, proportionate to the business
Ask what an outage actually costs you per hour. That figure determines how much resilience is worth buying.
For most small offices: a second internet connection on a different technology that takes over automatically, an uninterruptible power supply for the network cabinet and anything critical, and a spare switch on the shelf. Beyond that, cost rises quickly for diminishing benefit.
The uninterruptible power supply is worth mentioning specifically. A brief power interruption that takes down the network cabinet takes down everything, including the phones you would use to report it.
Resilience is a business decision expressed in equipment. Work out the hourly cost of being down before deciding what to spend preventing it.
Wireless as a designed system
Access points placed where there is a power socket produce coverage nobody planned. A proper design considers where people actually work, what the building is made of, and how channels are allocated so access points do not interfere with each other.
More access points is not automatically better — badly placed ones interfere. This is covered in wi-fi that actually works in an office.
Documentation
The deliverable that separates a professional installation from a competent improvisation.
What you should hold, and be able to find in an emergency:
- A diagram showing what connects to what
- The address plan and what each range is for
- Fixed addresses and what they belong to
- Switch port allocations
- Access credentials, held securely and accessible to more than one person
- Internet service details and account references
- Where the cabinet is, and where the isolator is
If your current provider cannot supply this, that is worth knowing now rather than during an outage.
Practical order of work
- Understand what you actually have, including the things nobody mentions.
- Fix cabling faults first — they cause the problems hardest to diagnose.
- Plan addressing and apply it during a change window.
- Introduce separation, starting with guest and non-computer devices.
- Design wireless coverage rather than adding access points reactively.
- Add resilience proportionate to the cost of downtime.
- Document, and keep it current.
Our infrastructure team designs and installs business networks across Suffolk and Norfolk, with documentation as a deliverable. Start a conversation.
