---
license: cc0-1.0
pretty_name: CIDR Set-Difference Reference Examples
tags:
  - networking
  - cidr
  - ipv4
  - ipv6
  - set-difference
---

# CIDR Set-Difference Reference Examples

Four small, synthetic JSON Lines examples for checking IPv4 and IPv6 CIDR-list normalization and mathematical set differences.

Each row contains:

- `before_cidrs` and `after_cidrs`: input lists;
- `normalized_before_cidrs` and `normalized_after_cidrs`: collapsed network coverage;
- exact minimal `removed_cidrs` and `added_cidrs`;
- before, after, removed and added address counts;
- the smallest removed and added address when nonempty;
- a short interpretation and limitation.

The examples cover equal totals with changed membership in both address families, a partial-overlap shift, and a normalization/aggregation no-change case. All addresses use IANA documentation prefixes. The expected values were calculated with Python's standard-library `ipaddress` module.

## Intended use

Use these rows as readable fixtures for parsers, tutorials, comparison UIs, or independent implementations of CIDR-list set difference. They are synthetic reference examples, not an exhaustive conformance suite or certification.

## Limits

These rows compare mathematical address sets only. They do not assess reachability, routing, firewall behavior, security policy, configuration validity, or whether a network change should be applied.

## Data and rights

The dataset text and expected results are original synthetic material dedicated under CC0-1.0. The IP ranges are reserved documentation prefixes; no user, production, private, credential, telemetry, or customer data is included.

## Optional implementation reference

[Yumi Network Set Evidence](https://noqt.no-qt.chatgpt.site/yumi/network-sets) is one public implementation of before/after CIDR-list comparison. The dataset is self-contained and does not require that implementation.