That so much of the document is about how UltaEthernet maps to Libfabric rather confirms that premise! There's also a credit based flow system, and connection manager roles, which are also easily identifiable Infiniband concepts.

I'm interested to see what the optional hardware features are. And what their relationship is to the different UE profiles (AI Base, AI Full, and HPC).

> The Ultra Ethernet Transport (UET) layer is designed to handle the most challenging application scale, deliver packets reliably and securely, manage and avoid congestion within the network, and react to contention at the endpoints. Its goals are minimal tail latency and highest network utilization. At the same time, UET is designed to enable simple hardware and software implementations – such as what might be required for accelerator-integrated endpoints. UET can be programmed through the OFI libfabric standard interface. It sets out to address the shortcomings of RoCEv2, specifically its semantics, transport layer, wire operations, implementation complexities, and scale limits

Seems like it. Sorta how storage grade Ethernet took out fiber channel. Probably shares a lot with it in some of the lower layers.

UltraEthernet predates the AI boom. I don't blame them for adding the AI buzzwords, for this to succeed people need to think about it in the same vein as IB/RoCE/etc and a lot of the decision makers are unfortunately not technical enough to understand what this is or does.

Ultimately it's just a different (IMO slightly more refined) look at how to support RDMA on Ethernet vs RoCE which is a more ham fisted implementation.

RoCE took an encapsulation approach that has some drawbacks (namely it's reliance on PFC/ECN for congestion management).

This takes a different approach that attempts to actually do first-class re-implementations of Infiniband-ish congestion control with end-to-end credit based flow control similar to Infiniband virtual lanes.

Æthernet!

Ethernet + AI