Agentic AI & Cloud AI Infrastructure

AI Cluster Networking

At scale, the network between accelerators limits training speed as much as the chips do. Every cloud builds special fabrics for AI clusters.

Multicloud AI & ERP / Agentic AI & Cloud AI Infrastructure

AI Cluster Networking: diagram comparing AWS, Azure and Google Cloud
How chips talk during training, and how AWS, Azure and Google Cloud each implement it.

Why it matters

In distributed training, every step ends with chips exchanging results. If the network is slow, thousands of expensive accelerators wait for the slowest link. Network design directly sets training time and cost.

How it works

How chips talk

Inside a server or pod, chips use fast chip-to-chip links. Between servers, a dedicated cluster fabric carries traffic. After each step, an all-reduce shares gradients across every chip, and the next step starts only when the slowest exchange completes.

AWS, Azure and Google Cloud compared

AWSAzureGoogle Cloud
Cluster fabricElastic Fabric Adapter, UltraClustersInfiniBandJupiter fabric
Inside a node or podNVLink, NeuronLink, UltraServersNVLinkTPU inter-chip interconnect, NVLink
PlacementCluster placement groupsProximity placement groupsCompact placement, topology-aware scheduling
Collectives libraryNCCL with EFANCCL, RCCLNCCL, XLA collectives
Reconfigurable linksNot applicableNot applicableOptical circuit switching for TPUs

What makes each cloud different

AWS

AWS's Elastic Fabric Adapter bypasses the operating system for low-latency communication, UltraClusters provide non-blocking networks at very large scale, and UltraServers link many chips as one large node.

Azure

Azure's ND-series VMs include InfiniBand in a non-blocking fat-tree topology, the same approach used in traditional supercomputers, with NCCL and RCCL for NVIDIA and AMD GPUs.

Google Cloud

Google links TPUs through inter-chip interconnect within pods and uses optical circuit switching to reconfigure links between them, on top of the Jupiter data center fabric.

Design decisions that matter

  1. 01Keep jobs inside one placement group

    Short, uniform network paths.

  2. 02Use the cloud's fabric

    EFA, InfiniBand or ICI, never ordinary networking.

  3. 03Tune collectives

    NCCL settings matter at scale.

  4. 04Watch for slow links

    One degraded link slows everything.

Common mistakes we see

  • Spreading jobs across zones. Latency kills step time.
  • Default network settings. Leaving bandwidth unused.
  • Ignoring topology. Schedulers placing ranks far apart.

A practical 30-day plan

  1. Week 1

    Measure step time and communication share.

  2. Week 2

    Enable the cloud fabric and placement groups.

  3. Week 3

    Tune collective settings and topology-aware scheduling.

  4. Week 4

    Add link health monitoring.

How NTS helps

NTS tunes AI cluster networking on AWS, Azure and Google Cloud, covering fabric setup, placement, collective tuning and health monitoring, to cut step time on large training jobs.

What you get

  • High-bandwidth network design for GPU clusters
  • EFA, InfiniBand or RDMA configuration
  • Placement and topology planning
  • Network performance testing

Typical outcomes

  • Higher GPU utilization
  • Shorter training times
  • Predictable cluster performance

How we work with you

  1. 1Assess

    A focused review of your AI cluster networking across AWS, Azure and Google Cloud. We look for the gaps we find most often: spreading jobs across zones, default network settings and ignoring topology.

  2. 2Design

    A target architecture and roadmap built on the decisions that matter most: keep jobs inside one placement group, use the cloud's fabric, tune collectives and watch for slow links.

  3. 3Build

    Hands-on delivery alongside your team. We measure step time and communication share, enable the cloud fabric and placement groups, tune collective settings and topology-aware scheduling, and finally add link health monitoring.

  4. 4Run and improve

    We monitor network performance and tune configuration as clusters grow.

Why teams choose NTS for AI cluster networking

  • Networking that keeps GPUs busy

    We remove the bottlenecks that slow distributed training.

  • Specialist knowledge

    We understand EFA, InfiniBand and RDMA in depth.

  • Measured performance

    We benchmark before and after every change.

Book a free 30-minute review

Talk to an NTS architect about your AI cluster networking on AWS, Azure and Google Cloud.