Patterns
🌐

Federated Orchestration(FO)

Coordinates AI processing across distributed edge devices while preserving data privacy

Complexity: highPattern

Core Mechanism

Federated Orchestration coordinates model training and/or inference across distributed clients (devices, sites, or organizations) without centralizing raw data. A coordinator distributes a model or plan, clients execute locally on their private data, and privacy-preserving aggregation combines updates. This preserves data sovereignty, reduces bandwidth for sensitive data, and enables cross-device (large, unreliable populations) and cross-silo (smaller, reliable institutions) collaboration. Enhancements include secure aggregation, differential privacy, robust aggregation, compression, and hierarchical federation for scale.

Workflow / Steps

  1. Enrollment & trust: register clients, attest software/TEE where applicable, provision credentials.
  2. Round planning: sample available clients; pick cross-device or cross-silo strategy and quotas.
  3. Distribute task: send global model/checkpoint, hyperparameters, and training/inference plan.
  4. Local execution: clients train or run inference on local data; compute model deltas or summaries.
  5. Privacy layer: apply secure aggregation and/or differential privacy before sharing updates.
  6. Aggregation: server or hierarchy aggregates updates (FedAvg/robust aggregators); validate quality.
  7. Evaluation: assess on held-out data/slices; check cohort fairness and drift; gate rollout.
  8. Personalization: optionally adapt global model to local domains (fine-tune, adapters, FedPer).
  9. Iteration & rollout: repeat rounds; version artifacts; stage and monitor deployments.
  10. Ops: handle stragglers/dropouts, heterogeneity (FedProx/SCAFFOLD), security, and audit.

Best Practices

Choose topology for context: cross-device (large, unreliable clients) vs cross-silo (fewer, reliable orgs).
Mitigate heterogeneity: use FedProx/SCAFFOLD; adapt local epochs, learning rates, and batch sizes.
Apply secure aggregation (Bonawitz et al.) so the server sees only encrypted/pooled updates.
Use differential privacy with moments/accountant to track and bound privacy budget (ε, δ).
Adopt robust aggregation (median/trimmed-mean/Krum) to resist outliers/Byzantine updates.
Compress updates: quantization, sparsification, sketching, and periodic full sync to cut bandwidth.
Sample clients fairly; balance participation to reduce cohort bias and starvation.
Validate each round on held-out and cohort-sliced data; monitor fairness and drift.
Version everything (model, data schema, optimizer, DP params); keep lineage and audit trails.
Encrypt in transit and at rest; prefer TEEs where feasible; harden against poisoning and inversion attacks.

When NOT to Use

  • Data can be centralized legally and cheaply, and central training meets requirements.
  • Ultra‑low latency single‑shot tasks where round‑based coordination breaks SLOs.
  • Very few participants with similar data—central or split learning may be simpler.
  • Models exceed client compute/memory/energy budgets; connectivity is highly unstable.
  • Use cases requiring raw cross‑party joins/feature engineering across silos.

Common Pitfalls

  • Non‑IID data causing divergence or slow convergence without heterogeneity controls.
  • Privacy leakage via updates (gradient inversion); missing secure aggregation/DP.
  • Poisoning/Byzantine clients degrading or backdooring the global model.
  • Client dropouts and stragglers stalling rounds; no partial aggregation or timeouts.
  • Bandwidth blowups from large dense updates; no compression or update sparsity.
  • Version/config drift; inadequate auditability and reproducibility of rounds.

Key Features

Privacy‑preserving aggregation (secure aggregation, differential privacy)
Decentralized local training/inference with data residency compliance
Robust aggregation against outliers/Byzantine behavior
Client heterogeneity tolerance (FedProx/SCAFFOLD)
Hierarchical federation for scale (edge → regional → central)
Bandwidth‑efficient updates (quantization, sparsity, sketches)
Personalization and domain adaptation options
End‑to‑end governance, lineage, and auditability

KPIs / Success Metrics

  • Global model quality (accuracy/AUC) and cohort fairness deltas.
  • Rounds to convergence; wall‑clock time per round; participation rate.
  • Communication cost per round (MB/client, total bytes) and compression ratio.
  • Client success rate, dropout/straggler rate, and energy usage on device.
  • Privacy budget consumed (ε, δ) and secure aggregation coverage.
  • Attack detection metrics (backdoor/poisoning flags) and rollback time.

Token / Resource Usage

  • Primary drivers: model size, update size/frequency, client count, and rounds. Prefer sparse/quantized updates.
  • Cap per‑round payloads; use sketching/top‑k gradients; schedule smaller local epochs for constrained clients.
  • If LLM steps exist, cap prompt/output tokens; send references/IDs not transcripts; cache static context.
  • Use hierarchical aggregation to localize traffic; compress over WAN; batch client uploads.

Best Use Cases

  • Healthcare networks: cross‑hospital learning without moving patient data.
  • Financial institutions: fraud/risk modeling across banks with data locality.
  • Mobile/edge: next‑word prediction, personalization, and on‑device vision.
  • Industrial IoT and smart cities: privacy‑sensitive analytics across sites.
  • Cross‑enterprise collaboration with strict data residency/compliance.

References & Further Reading

Patterns

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