Comparison Table
Capacity Planning Models Comparison
Side-by-side comparison of capacity planning models to support infrastructure sizing and headroom decisions for enterprise network deployments.
Reference Notice
Articles published on this website summarize publicly available information, industry research and educational materials.
Capacity Planning Model Comparison
| Criterion | Average Utilization Model | Peak Demand Model | N+1 Headroom Model |
|---|---|---|---|
| Basis for sizing | Mean traffic over time period | 95th or 99th percentile traffic | Full demand + one redundant unit |
| Risk profile | Higher — misses burst periods | Moderate — captures high demand | Lower — absorbs failure & bursts |
| Cost profile | Lower initial cost | Moderate cost | Higher cost |
| Best for | Non-critical, predictable workloads | Business-critical applications | Mission-critical, regulated environments |
| Operational complexity | Low | Medium | Medium–High |
| Failure handling | Performance degradation on failure | Potential degradation on failure | Transparent failover within headroom |
| Growth accommodation | Requires frequent reassessment | Limited headroom for growth | Explicit growth buffer included |
| Suitable environments | Dev/test, internal tools | Most production environments | Data centre, critical business systems |
Hybrid Planning Approach
Most enterprise environments apply different planning models to different infrastructure tiers. Access layer ports are typically provisioned at full count required (no spare), while distribution and core uplinks are provisioned with sufficient headroom to absorb both growth and failure scenarios. WAN circuits are sized at peak demand with a capacity review trigger at 70–80% utilization. The appropriate model for each layer depends on the criticality of the services it supports, the cost of capacity at that layer, and the lead time for capacity additions if demand exceeds expectations.