Calculator Inputs
The page stays single-column overall, while the input area shifts to three, two, or one columns by screen width.
Example Data Table
These worked examples show how the same formulas behave across different networking environments.
| Scenario | Subscribers | Active % | Sessions | Duration | Payload | Final Capacity |
|---|---|---|---|---|---|---|
| Metro Fiber Edge | 8,000 | 16.00% | 3.80 | 9.00 min | 24.00 MB | 771.02 Mbps |
| Regional ISP Core | 22,000 | 21.00% | 4.70 | 13.00 min | 38.00 MB | 7,835.93 Mbps |
| Campus Aggregation Ring | 5,600 | 28.00% | 3.10 | 15.00 min | 44.00 MB | 1,271.02 Mbps |
Formula Used
This calculator follows a teletraffic style workflow. It starts with subscriber activity, converts busy-hour demand into Erlangs and traffic volume, then engineers final capacity through efficiency, utilization, burst, growth, redundancy, and safety assumptions.
Use higher burst factors when traffic arrives unevenly, lower efficiency when encapsulation is heavy, and lower target utilization when strict quality targets must be protected.
How to Use This Calculator
- Enter the subscriber base that shares the link or aggregation segment.
- Set the busy-hour active percentage based on measurements or realistic assumptions.
- Add session count, session duration, and average payload for each active user.
- Include overhead, retransmission, and packet size to reflect protocol behavior.
- Set efficiency and utilization goals to match operational policy.
- Add burst, growth, redundancy, and safety margins for design resilience.
- Press Calculate Traffic to view the result summary, table, graph, and export links above the form.
FAQs
1. What does peak hour traffic mean?
Peak hour traffic is the highest sustained network demand during the busiest hour. Engineers use it to size access links, uplinks, backbones, and capacity reserves without relying on daily averages alone.
2. Why does the calculator show Erlangs?
Erlangs express offered load based on session count and holding time. They help connect user behavior with capacity planning, especially when many simultaneous sessions share the same network resources.
3. Why include a burst factor?
Average busy-hour traffic can hide short spikes. A burst factor scales the average rate to reflect uneven arrivals, making the final design more realistic for latency-sensitive and congested environments.
4. What is link efficiency in this model?
Link efficiency represents the share of raw line rate available for useful traffic after framing, headers, control overhead, and operational losses. Lower efficiency means more purchased bandwidth for the same demand.
5. Why is target utilization lower than 100%?
Networks rarely run safely at full utilization. Lower targets leave room for jitter control, queue stability, failover, maintenance events, and unexpected surges that would otherwise degrade application performance.
6. When should I increase redundancy reserve?
Increase redundancy reserve when your design must survive link failure, maintenance windows, or N+1 protection scenarios. It is especially useful on core links, aggregation rings, and business-critical service paths.
7. Are packet rate estimates important?
Yes. Packet rate can stress routers, firewalls, and session-aware devices even when raw bandwidth looks acceptable. It is valuable for capacity checks involving smaller packets and heavy signaling traffic.
8. Can I use this for broadband and enterprise links?
Yes. The model works for broadband segments, campus uplinks, enterprise WAN links, and ISP aggregation if you provide realistic assumptions for activity, session behavior, burstiness, and engineering margins.