  During overload, most networks drop packets due to buffer unavailability. The
resulting timeouts at the source provide an implicit mechanism to convey
congestion signals from the network to the source. On a timeout, a source
should not only retransmit the lost packet, but it should also reduce its load
on the network. Based on this realization, we have developed a simple
congestion control scheme using the acknowledgment timeouts as indications of
packet loss and congestion. This scheme does not require any new message
formats, therefore, it can be used in any network with window flow control,
e.g., ARPAnet or ISO.
