Thanks to its flexibility in supporting the same software even when the hardware in the system has been replaced, Ethernet has become the networking technology of choice. The standard also features speed negotiation and the ability to use different kinds and classes of media (such as optical fiber, copper cables, and PCB backplane).
Industry standards for Ethernet currently cover up to 400G data rates. Last April, the Ethernet Technology Consortium announced the 800GBASE-R specification for 800G Ethernet, which introduces a new media access control (MAC) and physical coding sublayer (PCS). And last fall, IEEE formed a group to consider the next transmission rate for Ethernet (800G is on the list along with 1.6T).
While some companies are starting to explore 1.6T Ethernet, we’re more likely to see prototypes emerging from early adopters in 2022. That said, now is a good time to evaluate your data connectivity infrastructure and determine how you will support 1.6T Ethernet. For starters, you’ll need to ensure that, once integrated, the MAC, PCS, and the physical medium attachment (PMA) will be able to deliver optimal performance and latency. Note that interoperability will be a difficult challenge if each of the sublayers comes from a different vendor. For 1.6T Ethernet, there are a range of configurations you can expect. Initial 16T designs will be based on a 100G SerDes and the PCS will have to support the 16 lanes needed to achieve 1.6T. As the 200G SerDes standards evolve, the PCS will need to support a PAM4 or PAM6 SerDes.
As the MAC gets designed for faster speeds, data paths have become wider. But, from a physical design standpoint, this may not be feasible for 1.6T. Something to consider. The other physical design challenge here involves the 56TB switch and its huge number of IOs, and the need to connect 50+ SerDes channels to the PCS and the MAC going into the switch. Even though the standard for 1.6T Ethernet is not yet set, it’s clear that supporting it will require some engineering creativity to manage the data volumes and optimize the connections.
With speeds increasing, there’s an opportunity to explore optical fiber connections, particularly for data centers. Copper cables are running out of steam, though engineers continue to make them work and they are more than suitable for small Ethernet installations. However, the next doubling of data rates will present opportunities to consider a transition to speedier, lighter, and thinner fiber optic Ethernet, particularly as the costs for such have come down quite a bit.