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What causes high CPU usage on routers performing deep packet inspection?

Asked on Nov 09, 2025

Answer

High CPU usage on routers performing deep packet inspection (DPI) is often caused by the resource-intensive nature of analyzing and processing each packet's payload to identify patterns, threats, or compliance issues. This process requires substantial processing power, especially on routers that lack specialized hardware for DPI tasks.

Example Concept: Deep packet inspection involves examining the data part (payload) of packets as they pass through a router. Unlike basic packet filtering, which only inspects headers, DPI analyzes the entire packet to detect and block malicious traffic, enforce policies, or prioritize certain types of data. This comprehensive analysis can significantly increase CPU load, especially in high-throughput environments or when the router lacks dedicated DPI hardware accelerators.

Additional Comment:

Consider using routers with dedicated DPI hardware to offload processing from the CPU.
Ensure that DPI rules and policies are optimized to reduce unnecessary processing.
Monitor traffic patterns and adjust DPI configurations to balance security needs and performance.
Evaluate whether all traffic requires DPI or if it can be selectively applied to specific flows.

✅ Answered with Networking best practices.

Ask any question about Networking here... and get an instant response.

What causes high CPU usage on routers performing deep packet inspection?

Asked on Nov 09, 2025

Answer

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