SGMII Termination - Not understanding recommendation
Transmission lines can be terminated at both ends. In this case, the source termination also provides DC load bias, as the transmission line is AC coupled.

The 50 ohm resistors to ground are the 100 ohm differential termination of the transmission line with 0V bias.


Note that this diagram is only an example, and the actual circuit may be different depending on what DC bias the other device wants, and if it includes built-in termination.