{
  "schema_version": "1.0.0",
  "rubric_version": "1.0",
  "license": "CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)",
  "record": {
    "id": "K-0021",
    "slug": "interconnect-bandwidth",
    "title": "Interconnect bandwidth",
    "aliases": [
      "chip-to-chip bandwidth",
      "network bandwidth"
    ],
    "status": "draft",
    "last_reviewed": "2026-09-23",
    "review_interval_days": 90,
    "steward": null,
    "provenance": {
      "drafted_by": "ai",
      "reviewed_by": []
    },
    "risk_flags": [],
    "flags": [],
    "one_liner": "The data rate of links between accelerators or groups of them; large-scale training needs far more of it than inference, so limiting it constrains workloads.",
    "sources": [
      {
        "source": "S-0053",
        "supports": "communication bandwidth as a chip specification alongside operations per second and memory; EO cluster definition using network connections over 100 Gbit/s; decentralized training risk",
        "locator": "§ on quantifiability and detectability; limitations"
      },
      {
        "source": "S-0005",
        "supports": "large-scale training links thousands of chips with high-bandwidth interconnect, efficient inference dozens to low hundreds; between pods inference needs tokens while training transfers gradients or activations; this gap is the target of bandwidth limits",
        "locator": "Interconnect bandwidth limits"
      },
      {
        "source": "S-0018",
        "supports": "front-end token-level traffic vs high-bandwidth, latency-sensitive back-end fabric that is harder to tap",
        "locator": "inference vs training"
      }
    ],
    "related": [
      "K-0017",
      "K-0025",
      "K-0014"
    ],
    "type": "concept",
    "url": "https://trustbutveri.fyi/concepts/interconnect-bandwidth/",
    "source_file": "content/concepts/interconnect-bandwidth.md",
    "flags_all": [
      "ai-drafted"
    ],
    "body_markdown": "Interconnect bandwidth is the rate at which accelerators, servers or clusters can exchange data over the links between them; it is one of the measurable specifications of AI accelerators, alongside operations per second and memory capacity [[S-0053]].\n\nLarge-scale training links thousands of accelerators with high-bandwidth interconnect, while efficient inference can run on dozens to low hundreds of closely connected accelerators [[S-0005]]. Between such pods, inference needs to pass only tokens, whereas training exchanges gradients or activations; Scher and Thiergart identify this gap as the target of bandwidth limits, as in [[M-0014|bandwidth limits and compartmentalization]] [[S-0005]]. Inside a data centre, front-end links carry token-level inputs and outputs, while the back-end fabric between accelerators carries tensors and collective operations at much higher bandwidth, is latency-sensitive, and is harder to [[K-0014|tap]] [[S-0018]]. A US executive order defined reportable computing clusters partly by network connections faster than 100 Gbit/s [[S-0053]]. The distinction between workloads could weaken if decentralized training over lower-quality compute and links becomes more viable [[S-0053]].",
    "body_text": "Interconnect bandwidth is the rate at which accelerators, servers or clusters can exchange data over the links between them; it is one of the measurable specifications of AI accelerators, alongside operations per second and memory capacity [S-0053]. Large-scale training links thousands of accelerators with high-bandwidth interconnect, while efficient inference can run on dozens to low hundreds of closely connected accelerators [S-0005]. Between such pods, inference needs to pass only tokens, whereas training exchanges gradients or activations; Scher and Thiergart identify this gap as the target of bandwidth limits, as in bandwidth limits and compartmentalization [S-0005]. Inside a data centre, front-end links carry token-level inputs and outputs, while the back-end fabric between accelerators carries tensors and collective operations at much higher bandwidth, is latency-sensitive, and is harder to tap [S-0018]. A US executive order defined reportable computing clusters partly by network connections faster than 100 Gbit/s [S-0053]. The distinction between workloads could weaken if decentralized training over lower-quality compute and links becomes more viable [S-0053].",
    "referenced_by": [
      {
        "id": "M-0014",
        "title": "Bandwidth limits and compartmentalization",
        "url": "https://trustbutveri.fyi/mechanisms/bandwidth-limits-and-compartmentalization/"
      },
      {
        "id": "M-0009",
        "title": "Hardware-enabled guarantees (flexHEG) and guarantee processors",
        "url": "https://trustbutveri.fyi/mechanisms/flexheg-guarantee-processors/"
      },
      {
        "id": "M-0022",
        "title": "Side-channel suppression for isolated facilities",
        "url": "https://trustbutveri.fyi/mechanisms/side-channel-suppression/"
      },
      {
        "id": "I-0011",
        "title": "AI 2040 inference-only verification stack",
        "url": "https://trustbutveri.fyi/implementations/ai-2040-inference-only-verification-plan/"
      },
      {
        "id": "C-0008",
        "title": "Communication between compute groups is bounded",
        "url": "https://trustbutveri.fyi/claims/bandwidth-is-bounded/"
      },
      {
        "id": "C-0004",
        "title": "This compute runs inference, not training",
        "url": "https://trustbutveri.fyi/claims/inference-not-training/"
      },
      {
        "id": "C-0009",
        "title": "Model weights or data have not left the facility",
        "url": "https://trustbutveri.fyi/claims/weights-have-not-left/"
      },
      {
        "id": "K-0017",
        "title": "Compartmentalization",
        "url": "https://trustbutveri.fyi/concepts/compartmentalization/"
      },
      {
        "id": "K-0025",
        "title": "Inference and training workloads",
        "url": "https://trustbutveri.fyi/concepts/inference-and-training-workloads/"
      },
      {
        "id": "K-0014",
        "title": "Network tap",
        "url": "https://trustbutveri.fyi/concepts/network-tap/"
      },
      {
        "id": "K-0022",
        "title": "Weight exfiltration",
        "url": "https://trustbutveri.fyi/concepts/weight-exfiltration/"
      }
    ]
  }
}