Fabric Sizer

Fabric Sizer is a lightweight web application that computes switch counts for common data-center topologies. The UI runs entirely in the browser and the sizing math lives in pure TypeScript modules so it can be reused outside of the app.

Supported topologies:

• 3-stage Clos
• 5-stage Clos
• Dragonfly+
• Multi-plane (dual-plane Clos)

Getting started

Fabric Sizer has no runtime dependencies beyond Node.js 20+ and pnpm.

pnpm install
pnpm dev

The dev script starts a tiny static server on http://localhost:4173. The app persists the last used inputs in localStorage, so you can refresh without losing your configuration.

To create a production bundle of the static assets:

pnpm build

The generated files land in dist/ and can be published directly to GitHub Pages or any static host.

Testing

The topology calculators are covered by focused unit tests. Run them with:

pnpm test

The tests exercise representative fixtures for each supported topology.

Project structure

public/
  app/
    calculators.js      # Browser-friendly implementations of the sizing functions
    main.js             # UI glue, validation, and rendering
    zod-lite.js         # Minimal validation helpers mirroring the zod API subset we need
  index.html            # Application shell
  styles.css            # Tailwind-inspired utility styles + shadcn-like cards
src/
  lib/fabric-calculators/
    types.ts            # Shared type declarations and SizingResult documentation
    common.ts           # Utility helpers shared by all calculators
    clos3.ts            # 3-stage Clos calculator (exports calculate)
    clos5.ts            # 5-stage Clos calculator (exports calculate)
    dragonflyPlus.ts    # Dragonfly+ calculator (exports calculate)
    multiPlane.ts       # Multi-plane calculator built on top of 3-stage Clos
scripts/
  dev-server.js         # Simple Node static file server used by pnpm dev
  build.js              # Copies public/ into dist/
tests/
  run-tests.js          # Node-based test harness for the calculators

Sizing result contract

All calculators return a SizingResult object shaped as follows (see src/lib/fabric-calculators/types.ts for inline documentation):

interface SizingResult {
  switchCounts: {
    leaves: number;
    spines: number;
    superSpines?: number;
    total: number;
  };
  assumptions: Array<{ label: string; description: string }>;
  metadata: Record<string, number | string>;
}

The assumptions array captures every ceil() or floor() operation that impacts the totals so that the UI can render a human-readable audit trail. The metadata bag holds secondary values (pods, leaves per pod, group counts, etc.) that populate the “Breakdown” panel in the UI.

Deployment

Because the app is a static site, deploying to GitHub Pages is just a matter of publishing the contents of dist/. For example, a GitHub Actions workflow could run pnpm build and push the resulting directory to your gh-pages branch.

License

Fabric Sizer is released under the MIT License. See LICENSE for details.