Deep Dive into the UnifiedBus (Lingqu) Network Protocol, Architecture, and Features

UnifiedBus (Lingqu) was announced at Huawei's 2025 Full‑Connection Conference as a full‑stack, self‑developed interconnect protocol for AI supernodes. It serves as a unified communication substrate for massive‑scale compute clusters, bridging chip‑level, board‑level, and cabinet‑level interconnects and eliminating the fragmented approaches of PCIe, NVLink, and Ethernet.

The protocol is not a single hardware transport layer but a complete stack comprising hardware specifications, firmware, system software, and upper‑layer services. The stack is organized into three layers within a comprehensive UB OS ecosystem:

Physical layer (PHY) : defines SerDes electrical specifications, full‑optical interfaces, and PCB passive backplane interconnect standards, distinguishing copper board‑internal interconnects from optical module cabinet‑interconnects.

Transaction layer (UB Transaction) : the core layer that implements unified memory addressing, peer‑to‑peer access, data sharding, and error‑correction, enabling direct cross‑device memory reads and writes.

Service layer (UB Service) : provides four major modules—cluster management, resource scheduling, fault management, and virtualization adaptation—that interface with the OS kernel and AI frameworks.

Key functional modules include:

Resource scheduling: global pooling and allocation of compute, memory, and storage.

Cluster control: device discovery, fault isolation, and hot‑plug support.

Virtualization adaptation: support for VMs, containers, and distributed training frameworks.

UBoE interconnect: seamless interoperability between UnifiedBus supernodes and traditional Ethernet or IDC clusters.

Atlas950/960 SuperPod machines are the reference implementation of UnifiedBus. Each SuperPod integrates 384 Ascend NPU chips interconnected via UnifiedBus, presenting the entire node as a single giant computer. These systems have been batch‑deployed in multiple Chinese AI computing centers for commercial use.