Game Guide: Terran: Ramp Defense

A typical terran ramp defense consists of two supply depots and a barracks. The depots act as doors that you can lower to allow your units to go through, or raise to prevent the enemy from moving into your base. Players sometimes lift-off their barracks instead, but this can be riskier as landing takes a bit longer than raising a supply depot. Later on you'll need a couple missile turrets to detect cloaked units and provide additional protection against aerial threats.

Terrans have a very solid ramp defense, especially with siege tank support.

Terran player has blocked off their ramp. The supply depot can be lowered to let units through.	An even bigger defense is set up with marines and siege tanks.
Siege tanks guard a ramp and an expansion from high ground.	Zerglings are blocked from going up the ramp.
Two siege tanks make anyone pay for going up the ramp. Add missile turrets and some more siege tanks for more firepower.	Attack repelled with a bunker, a marauder, and a few marines thanks to a solid ramp defense.
A Terran player uses siege tanks to protect their ramp. Larger ramps require more buildings to defend.