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What is the difference between 1.25 Gbps vs 1 Gbps SGMII signal data rate?

My understanding is that 1.25 Gbps is the raw data rate and 1 Gbps is the actual data rate (After removing the headers and all other information attached to the data) Below screenshot is form this document

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student7
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1 Answers1

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A few pages before the paragraph you asked about is this diagram:

enter image description here

In the transmit path, every 8 bits of data entering from the left is converted to a 10 bit line code by the 8B/10B encoder before it exits on the right to be serialized by the SERDES and sent on to the line (optical fiber or twisted pair) by the PMD (physical medium dependent) block.

So if you have 1 gigabit per second of data, you will produce 1.25 gigabits per second of serialized code symbols on the line.

The input to this block isn't strictly raw data since the data has added framing overhead added by the MAC layer before it reaches this point.

The Photon
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