Simply put, connectivity can be described as the ability to both link systems seamlessly and monitor how well information travels between system A to system B. It is a standardized metric and relates to the distance a signal communicates over a communications channel, attributing to the signal’s “reach.” The higher the signal’s reach, the more power that is consumed.
Until recently, copper had a majority presence in networks because of its high conductivity, malleability, thermal resistance, and low cost. However, as network speeds and complex functionalities increased, the overall system-on-chip (SoC) size also grew for artificial intelligence (AI), hyperscale data centers, and networking applications.
Long-reach (LR) connectivity may not deliver ideal results in some cases. With higher data rates per lane, the total distance that traditional long-reach interconnects can control is minuscule when compared to VSR. Additionally, to achieve longer distances, circuit components can become susceptible to complexity and turn out to be more costly to design and manufacture.
Imagine you need to connect a server to a switch in a data center. Traditionally, long-reach copper interconnects were used to make that connection. But if you need the switch to run at higher speeds, thicker and denser pipes are needed for more data to pass through.
As the industry moves from 100 to 200 Gbps in the next few years, this process of the electrical copper interconnect carrying the signal through a PCB interface to the switch becomes an arduous and impractical approach. While it can still be achieved with high-quality grade cables or with active cables, not only does the insertion and power loss become significant, but it also exacerbates mechanical problems such as cable rigidness, making it difficult to access and close the backs of server racks.