---
type: "Concept"
title: "Hub-and-spoke vs hierarchical coordination"
description: "Centralised aggregation vs hierarchical/asynchronous/enclave-backed designs."
tags: [fl, architecture, federated]
generated: { by: human:crpage, at: 2026-07-09T09:44:00Z }
status: stable
---

Federations can be centrally orchestrated (hub-and-spoke) or use hierarchical, partially asynchronous or enclave-backed aggregators for resilience and scale. Whether public-sector federations should remain hub-and-spoke is an open architectural question; systems research (e.g. Flotilla) shows newer designs can exceed Flower on very large, unstable federations.

Relates to: [Flower](../frameworks/flower.md), [Flotilla](../frameworks/flotilla.md).