A perimeter drain is something that all houses need, and it is designed to prevent water from seeping into your basement. It is also sometimes referred to as a French drain. It is intended to attract water in the soil that has either accumulated from heavy rains, melting snow, or from rising groundwater. It then carries the water away from your house, so it is less likely to seep in through your basement walls.
A sump pump is a small pump installed in the lowest part of a basement or crawlspace. Its job is to help keep the area under the building dry and to prevent it from flooding. Usually, sump pumps are installed in specially constructed sump pits. Water flows into the sump pit through drains or by natural water migration through the soil. The sump pump's job is to pump the water out of the pit and away from the building so the basement or crawlspace stays dry.