Next-generation Interconnect Technology Maintains Cost and Power Benefits of Copper at Higher Speeds
DAC has always had a tenuous relationship in the data center. Customers love the low cost, but it has always been the least reliable option and limited on distance. Quality manufacturing can have a big impact on the actual distance a cable can support. Reliability is one of the reasons why enterprises love 10G-Base-T so much compared to using splitter cables as hyperscalers do.
Today, 25 companies founded the HiWire™ Consortium to help accelerate and drive the industry migration towards 400 Gbps and address the need for high-speed server access with copper. Some of the largest suppliers of networking to the Cloud joined together to fill a gap in data center networking. Today the distances that DAC can support reliably continue to shrink as servers move towards higher speeds, and the size of the DAC cable continues to get larger. In some fully loaded scenarios, the cables on a switch can take up more faceplate size making for complicated Top-of-Rack installation and blocking airflow.
HiWire Active Electrical Cables (AEC) helps push out the life of copper for server access technology. AECs are a new type of copper cable that competes against DAC and Active Optical Cables (AOCs). With integrated gearbox, retimer and FEC functionality, AEC also allows for speed shifting, PAM4 to NRZ mode conversion and high integrity, lossless connectivity with in the cable which can enable the industry to look at more efficient network topologies. For example, the cable can covert from 400G PAM4 to 4X100G NRZ or a 100G SFP DD port can be split to 50 Gbps ports on the server NIC, the later is especially interesting with new 7.2-8.0 Tbps switches coming to market with SFP DD ports.
The HiWire Consortium is dedicated to providing data center ethernet customers something that consumers already enjoy – plug and play functionality. In the consumer world, if you pick up a cable with a USB-C mark or an HDMI mark, it just works – no evaluation, no tinkering. The USB community accomplishes this through two groups – the USB Promoters Group that does the technical heavy lift of developing electrical and mechanical standards and the USB Implementers Forum (USB-IF) which manages a 3rd party test infrastructure and licenses the USB mark to those cables that meet the requirement.
In the Ethernet work, the work in IEEE and the many MSAs are analogous to the USB Promoters Group, but we have nothing like the USB-IF – this is the gap the HiWire Consortium has been developed to fill. To assemble the building blocks from IEEE and the many MSAs into a specific set implementations that meet user needs; then to enable a 3rd party to test AECs to this specification and license a trusted mark. The goal is to push much of the qualification burden of integrators, OEMs and ODMs upstream to AEC manufacturers and ensure a consistent, high quality plug & play product experience.
HiWire is interesting for the market as it can be used today in several use cases ahead of 400G optics availability. It can provide a path forward, with similar capabilities to 800 Gbps and the 25.6 Tbps switches which are about to come out to market. Cloud Providers have the opportunity to remain with the copper technologies and splitter cables used for nearly a decade and not having to move to fiber also helps the industry concentrate on Onboard optics and silicon photonics, without the need of an interim technology, because DAC distances shrink too much as servers become more efficient.
Given the rapid adoption of new servers for Artificial Intelligence (AI) and Machine Learning (ML) as well as the use of PCI Gen 4 and delay in 400 Gbps optics availability, we expect a lot of interest in AEC cables.
