What are the similarities between gel electrophoresis and SDS-PAGE?

Gel electrophoresis and SDS-PAGE are two types of laboratory methods that are used to separate macromolecules according to their size and charge. In both techniques, a gel stab with small pores is used, which allows the charged macromolecules to migrate towards the end with the opposite charge. The potential difference between the two electrodes acts as the driving force of the movement of molecules through the gel.