I was reading about digital transmission, there are many steps namely:

  1. Analog to Digital conversion

  2. Source coding

  3. Channel coding

  4. Line coding

  5. Pulse shaping

  6. Modulation

  7. Multiple access techniques

Out of curiosity, I tried to find information about these in context with ethernet (standard Gigabit). I have two questions:

  1. Which OSI layers are responsible for these responsibilities?
  2. What are the standards used for these techniques in Gigabit ethernet?

Can someone help me with it?


1 Answer 1


The physical layer is responsible for all physical encoding, interfacing, cabling. More specifically, Ethernet uses the PCS and PMA sublayers for encoding.

Gigabit Ethernet is generally defined in IEEE 802.3, mainly in clauses 34-40.

1000BASE-X variants for fiber and (obsolete) twinax use 8b/10b with NRZ encoding.

1000BASE-T over twisted-pair copper is more complex. The PCS sublayer splits the transmitted stream into four lanes for all four wire pairs, using hybrids and cancellers for full-duplex transmission (simultaneous transmitting and receiving). Each lane is encoded using symbols selected from four-dimensional, five-level (PAM5) symbols transmitted at 125 MBd. The PMA sublayer adds a polynomial scrambler to remove DC bias.

You can download IEEE 802.3 for free after registration at https://ieeexplore.ieee.org/browse/standards/get-program/page/series?id=68.

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