Packet Inspection Capacity Calculator
Size deep packet inspection in packets per second: per-packet CPU cycle budget, cores required and nanoseconds per packet.
About Packet Inspection Capacity Calculator
Inspection cost is per packet, not per bit, so convert bandwidth into a packet rate first. Multiplying by the cycle cost of your pipeline gives the cycles per second you need, and dividing by the core clock gives the core count — a 2.5 GHz core delivers 2.5 billion cycles per second and nothing more. The nanosecond budget per packet is the number that kills designs: at 10 million pps you have about 100 ns per packet, which is roughly 250 cycles, and a single cache miss costs 100 of them.
Formula
Packet Inspection Capacity
pps = bits per second ÷ (packet size × 8); cores = ceil(pps × cycles per packet ÷ core clock in Hz).
- cycles per packet
- CPU cycles the inspection pipeline spends on one packet
- time budget
- Nanoseconds available per packet before the queue backs up
Worked example
With the default values below, Packet Inspection Capacity Calculator returns Packet Rate to Inspect of 9,765,625. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Throughput to inspectaccepts 0.01–10,000 Gbps
- 40 Gbps
- Average packet sizeaccepts 64–9,000 bytes
- 512 bytes
- CPU cycles per packet for inspectionaccepts 50–200,000 cycles
- 2,500 cycles
- Core clockaccepts 0.5–6 GHz
- 2.5 GHz
- Cores allocated to the data planeaccepts 1–512 cores
- 16 cores
Results
- Packet Rate to Inspect
- 9,765,625 pps
- Cores Required
- 10
- Data Plane Utilisation
- 61.0%
- Packet Rate per Core
- 1,000,000 pps
- Time Budget per Packet
- 102.40 ns
- Cycles Required per Second
- 24,414,062,500
Step by step
- 1Values used
- 2Packet Inspection Capacity
- 3Packet Rate to Inspect= 9,765,625 pps
- 4Cores Required= 10
- 5Data Plane Utilisation= 61.0
- 6Packet Rate per Core= 1,000,000 pps
- 7Time Budget per Packet= 102.40 ns
- 8Cycles Required per Second= 24,414,062,500
Assumptions and limits
- The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Packet Inspection Capacity calculated?
pps = bits per second ÷ (packet size × 8); cores = ceil(pps × cycles per packet ÷ core clock in Hz). Inspection cost is per packet, not per bit, so convert bandwidth into a packet rate first. Multiplying by the cycle cost of your pipeline gives the cycles per second you need, and dividing by the core clock gives the core count — a 2.5 GHz core delivers 2.5 billion cycles per second and nothing more.
Why does Packet Inspection Capacity matter?
The nanosecond budget per packet is the number that kills designs: at 10 million pps you have about 100 ns per packet, which is roughly 250 cycles, and a single cache miss costs 100 of them.
What values do I need to enter?
This calculator takes 5 inputs: Throughput to inspect, Average packet size, CPU cycles per packet for inspection, Core clock, Cores allocated to the data plane. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Why is 64-byte traffic the number that matters?
Because it is the worst case and attackers choose it deliberately. Dropping from 512-byte to 64-byte packets takes 40 Gbps from about 9.8 million pps to 78 million pps — an eight-fold increase in inspection work at identical bandwidth. Any device sized on an internet mix is trivially overwhelmed by a small-packet flood.