In the discontinuous buffer system, different buffer ions and pH are employed in the gel and in the electrode reservoirs. Protein samples are loaded onto the stacking gel, which is a large pore, non-restrictive gel that is layered on top of a smaller-pore gel, known as the resolving gel. 
A discontinuous buffer system offers two major benefits.

1. The first benefit is it enables researchers to apply relatively large volumes of dilute protein samples to the gel.
2. The second benefit is it provides a much greater resolution than that provided by a continuous buffer system.