Large Network Scaling

Skupper can scale to networks with many sites, but architecture choices matter significantly at scale.

Scaling Guidelines

Network Size	Recommendation
≤ 16 sites	All interior routers, any topology works
17–100 sites	Use edge sites for leaf nodes, interior sites as backbone
100+ sites	Hub-and-spoke with multiple interior hubs, edges at leaves

Key Principles

Use Edge Sites Beyond 16 Sites

Edge routers maintain minimal routing state, reducing memory and CPU:

Aspect	Interior Router	Edge Router
Routing table	Full network view	Only knows connected interior
Transit traffic	✅ Routes for others	❌ Own traffic only
Memory at scale	High	Low
CPU at scale	Higher	Lower
HA support	✅	❌

Don’t Build One Big Network

From the official docs:

“You should not try to put a bunch of applications on one big network. It’s less secure and less performant.”

Separate applications should have separate Skupper networks.

Multiple Smaller Networks Are Better

Each application or bounded context should get its own network for:

• Better security isolation
• Better performance (smaller routing tables)
• Simpler troubleshooting

Topology Patterns

Small (≤16 sites) — All Interior

     Interior (linkAccess: default)  ← Hub
        ↑           ↑          ↑
     Interior    Interior    Interior

Medium (17-100) — Hub + Edges

     Interior Hub (linkAccess: default)
        ↑           ↑          ↑
      Edge         Edge        Edge
      Edge         Edge        Edge

Large (100+) — Multi-Hub Backbone

  Interior A ←→ Interior B ←→ Interior C
    ↑  ↑  ↑       ↑  ↑  ↑       ↑  ↑  ↑
   E  E  E       E  E  E       E  E  E
   E  E  E       E  E  E       E  E  E
   ...            ...            ...

Interior hubs maintain full routing tables and can transit traffic between edges. Edges are lightweight — they only maintain a connection to their hub.