In brief
Concurrent users and unique daily visitors are not the same thing. A formula with worked examples for a café, a hotel and an event, and when a second box is needed.
The box licence covers 250 concurrent users. The first question from a business owner who hears that number: "I get 400 guests a day, is that not enough?" Usually it is, because concurrent users and daily guests are different things. This post explains the difference, how to calculate it, and when you will need a second box.
Two different numbers
Concurrent users: the number of devices with an open session at a given moment. A guest counts while connected and while the session has not closed through its time limit or idle timeout. The licence limit looks at this number.
Unique daily guests: the number of different people who passed through the portal over the day. A guest leaves, the seat frees up, a new guest arrives. By the end of the day hundreds may have passed through while the concurrent count never reached 100.
The multiplier between them is how long guests stay and how quickly sessions close.
The formula
You can estimate peak concurrent sessions like this:
Concurrent (peak) = guests present at that moment × connection rate × devices per person
And unique daily guests:
Daily unique = capacity × occupancy × daily turnover × connection rate
Where:
- Connection rate: the share of guests who join the Wi-Fi (not everyone in a café, most people in a hotel).
- Devices per person: phone + laptop + tablet; close to 1 in a café, around 1.5 in a hotel.
- Daily turnover: how many times a seat fills in a day.
All of these are assumptions; replace them with your own.
Example 1: café
Assumptions: 60 seats, 90% occupancy at peak, 70% connect, 1.2 devices per person, 4 turns per day, 60% average occupancy across the day.
- Peak concurrent: 60 × 0.9 × 0.7 × 1.2 ≈ 45 sessions
- Daily unique: 60 × 0.6 × 4 × 0.7 ≈ 100 guests
Far below the 250 limit. With a 15-minute idle timeout a departing guest's device drops quickly and the peak shrinks further. The standard template (2-hour session, 15-minute idle) fits this profile.
Example 2: hotel
Assumptions: 120 rooms, 1.8 people per room, 80% occupancy, 85% connect, 1.5 devices per person.
- Guests present: 120 × 1.8 × 0.8 ≈ 173
- Peak concurrent: 173 × 0.85 × 1.5 ≈ 220 sessions
Here things change. Hotel sessions run 24 hours and device remembering is on; devices stay connected while guests are in their rooms. In the evening the concurrent count approaches 250. Countermeasures:
- Lowering the device limit per plan from 3 to 2 reduces the peak.
- A sensible idle timeout (30 minutes) drops the devices of guests who have left the room.
- If you plan for full occupancy in high season, consider a second box or a virtual appliance above 150 rooms.
Unique daily guests are 173 × 0.85 ≈ 147 people plus that day's arrivals; nothing to do with the limit.
Example 3: event
Assumptions: 600 attendees in one hall, 60% connect during the keynote, 1 device per person.
- Peak concurrent: 600 × 0.6 × 1 ≈ 360 sessions
One box is not enough. At an event everyone is present at once; there is no turnover. Options:
- Split halls or floors into separate guest networks with a box each. Each box keeps its own records and takes its own time stamps.
- Use the conference template (5/2 Mbps, 4-hour session, 10-minute idle, 1 device, 500 MB per day) to protect bandwidth; this manages speed sharing, not the concurrent count.
- Under 250 attendees one box is enough; above that, plan the number of boxes as attendees / 200 to leave headroom.
Comparison
| Scenario | Peak concurrent (estimate) | Daily unique (estimate) | One box? |
|---|---|---|---|
| Café, 60 seats | ~45 | ~100 | Yes, comfortably |
| Hotel, 120 rooms | ~220 | ~150-200 | Yes, near the limit |
| Event, 600 people | ~360 | ~360 | No, two boxes |
How session settings move the number
The setting with the biggest effect on the concurrent count is the idle timeout. When a guest leaves, the session does not close immediately; it closes when the idle timeout runs out. The difference between 15 and 60 minutes can double the peak in a fast-turnover venue.
Session length matters too, but less: when the session expires the guest re-verifies, the count dips briefly and comes back.
The device limit is a direct multiplier: going from 3 devices to 2 can cut a hotel's peak by a third. In a café the effect is small because guests arrive with one device anyway.
When to add a second box
Plan a second box or a virtual appliance if any of these applies:
- Your peak estimate exceeds 200 (use 200 as the threshold rather than 250, to leave headroom).
- You have physically separate buildings or floors and want each to keep its own records.
- Occupancy and connection rate rise together in high season (a summer hotel, a trade fair period).
With a second box the guest network is split by VLAN or SSID; each box keeps the internal IP assignment records for its own segment, chains them and takes time stamps. In the panel you see the two boxes separately and verify their archives separately.
If you have a virtualisation platform, the virtual appliance runs the same software as a VM. For hardware, see the box page. Send us your own figures and we will work it out together; during the 7-day trial the hourly load report in the panel shows your real peak.