Random Early Detection is a fancy word for randomly dropping packets in a queue so we can avoid congestions and not perform Tail Drop. RED takes advantage of the congestion mechanism of TCP, therefor it is only suitable for this kind of traffic. When RED drops a packet, the source will not receive a confirmation for it and will reduce the window size, therefore slowing down the transmission rate. Another advantage of RED is that it avoids Global Synchronization. If all traffic that is over the limit is dropped, then all sources slow down, and then they all begin to send, overwhelming again the link. By randomly dropping traffic, not all sources are affected of a drop at the same time.