VR2R-0293_r1

VR2R-0293

① SA Source

• Source: 開啟完整 SA 文章
• Section: Relocating ConnectX-9
• Line hint: 262

Context Before

For the GB200/GB300, the PCIe signal distance between the GPU/CPU and the CX-7/8 is shorter than the Ethernet/InfiniBand signal distance between the CX-7/8 and the OSFP cages.

Evidence

Previously—having to transmit a 200G Ethernet/InfiniBand signal from the NIC in the back half of the compute tray to the OSFP cage in the front of the compute tray necessitated the use of flyover cables as the signal loss over PCB at 200Gbit/s (uni-directional) per lane is too high.

Context After

But now that the NIC is closer to the OSFP cage, the lower speed PCIe Gen6 signal (64Gbit/s per lane uni-directional) travels the longer distance. By making the PCIe Gen6 signal longer, the signal can travel over PCB given that PCIe Gen6 has better signal integrity than the higher speed 200G Ethernet/InfiniBand signal.

② Atomic Claim

過去，從 compute tray 後半部的 NIC，把 200G Ethernet／InfiniBand signal 傳到前端 OSFP cage 時，必須使用 flyover cables，因為 PCB 上每 lane 200Gbit/s（uni-directional）的 signal loss 太高。

• Epistemic Mode: ASSERTED
• Mapping Status: PARTIAL

③ Semantic Frame

{
  "frame_type": "NARY_RELATION",
  "participants": [
    {
      "node": {
        "id": "04_knowledge_base/Compute Tray",
        "label": "compute tray"
      },
      "role": "system_context"
    },
    {
      "node": {
        "id": "04_knowledge_base/NIC",
        "label": "NIC"
      },
      "role": "network_device"
    },
    {
      "node": {
        "id": "04_knowledge_base/Ethernet",
        "label": "Ethernet"
      },
      "role": "network_protocol"
    },
    {
      "node": {
        "id": "04_knowledge_base/InfiniBand",
        "label": "InfiniBand"
      },
      "role": "network_protocol"
    },
    {
      "node": {
        "id": "04_knowledge_base/PCB",
        "label": "PCB"
      },
      "role": "pcb_medium"
    }
  ],
  "qualifiers": {
    "condition_text": "OSFP cage and flyover cable are plain text in source claim; per-lane rate is uni-directional",
    "numeric_mentions": [
      "200G",
      "200Gbit/s"
    ],
    "temporal_mentions": [
      "previously"
    ]
  },
  "relation_type": "HIGH_SPEED_NETWORK_SIGNAL_REQUIRES_FLYOVER_CABLE"
}

④ Canonical Entity Mapping

Role	Surface Label	Canonical Target
system_context	compute tray	04_knowledge_base/Compute Tray
network_device	NIC	NIC
network_protocol	Ethernet	Ethernet
network_protocol	InfiniBand	InfiniBand
pcb_medium	PCB	PCB

⑤ Human Review

請在 Properties 逐項確認：

• 原文 → Atomic Claim 是否忠實
• Atomic Claim → Semantic Frame 是否忠實
• Canonical Entity mapping 是否正確
• Epistemic mode 是否保留原文語氣
• 最後選擇 review_action

Review state

Markdown 內文不是正式 approval。只有 Apply bridge 寫入的 Decision Ledger event 才是正式決策。