IP traffic has been growing at a rate many could not have imagined. Driven by expanding Internet users and devices that yield faster wireless and fixed broadband access, the expeditious ethernet data rate has now reached to 400G. From 1Gbps in 1997, to 10Gbps in 2004, 100 Gbps in 2010, it took a while for the next set up to 400 Gbps.
Steered by the ever-increasing internet traffic, there is always a need for more bandwidth.
Evolution of Ethernet
IEEE pulled the existing standards to frame a pathway to 400G. The 100 Gbps based on four parallel lanes of 25 Gbps was the starting point for 400G development.
However, a method to increase the serial rate was surely needed for 400G. The data rate of 400G with 16 x 25 Gbps parallel lanes would require 32 fibers per link for transmit and receive. Multiple parallel fibers solution was acceptable for short-distance links but not for longer cable lengths because of the following reasons:
- The number of transmission lines cannot be increased without a limit, because beyond a frequency, the signal transit time could not be equal for all signal lines.
- Another point to consider is the electromagnetic interference with other serial lines. The higher the frequency, the more the probability of interference.
- Lastly, the larger number of cables will drastically affect the cost for longer distances.
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