However, the introduction of a sudden burst of traffic may cause large numbers of established, steady streams to lose packets simultaneously.
TCP has automatic recovery from dropped packets, which it interprets as congestion on the network (which is usually correct).
When these delays expire at the same time, all the senders will send additional packets and the router queue will again overflow in a repeating feedback loop.
This pattern is referred to as "global synchronization" and leads to inefficient use of bandwidth, due to the large numbers of dropped packets, which must be retransmitted, and because the senders have a reduced sending rate, compared to the stable state, while they are backed off, following each loss.
The consensus appears to be that the tail drop algorithm is the leading cause of the problem, and other queue size management algorithms such as random early detection (RED) and Weighted RED will reduce the likelihood of global synchronization, as well as keeping queue sizes down in the face of heavy load and unexpected peak traffic.