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Network Fundamentals Visualizer

Route summarization & CIDR aggregation

Enter four subnets. The tool computes the shortest CIDR block that covers them all — with the bit-alignment walkthrough that shows exactly why the summary length is what it is.

Subnets to summarize
Summary route
Covers X hosts · advertised as one aggregate prefix
Bit-by-bit walkthrough
Why summarize?
  • Smaller routing table — one entry for a whole region instead of many.
  • Fewer routing updates — when a small subnet flaps, downstream neighbors don’t re-learn.
  • Faster lookups — routers spend less time on longest-prefix match with a lean table.
  • Contiguous + aligned required — non-contiguous or misaligned subnets can’t be summarized into one prefix (correctly).

Practice — quick check

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