OpenURMA: a clean-room open implementation of Huawei's Unified Bus protocol OpenURMA:华为UB协议的洁净室开源实现 preprintinterconnectopen hardware
academic team
arXiv:2605.28717 · 2026-05-27
Huawei published the Unified Bus (UB) spec in 2025 as an RDMA alternative that decouples per-application endpoint state from per-host transport state — directly attacking the PCIe four-traversal latency penalty that RoCE inherits from InfiniBand. This paper is the first publicly-documented clean-room implementation of UB outside Huawei, and reports comparable wire-rate latency on a generic NIC. Even if UB never becomes a US-vendor product, the existence of an open implementation matters: it makes UB a real competitive option that hyperscalers can prototype against, rather than a Huawei-only specification. 华为在2025年发布Unified Bus(UB)规范,作为RDMA的替代方案——通过将「应用级端点状态」与「主机级传输状态」解耦,直接攻击RoCE从InfiniBand继承的PCIe四次穿越延迟惩罚。本论文是华为之外首个公开文档化的UB洁净室实现,并在通用网卡上报告了可比的线速延迟。即使UB最终未成为美国厂商的产品,开源实现的存在仍有意义:它把UB从「华为专属规范」变成了超大规模客户可以原型验证的真实竞争选项。