Congestion Management Schemes
Due to tremendous increase in the number of users and applications using the
Internet, congestion has become a major problem in today's Internet which has
resulted in excessive packet drops and delays in the network. As a result, there
has been a surge of interest in designing low-loss and low-delay networks by
encouraging users to adapt to changing networks conditions using minimal information
from the network. Explicit Congestion Notification (ECN) has been recently proposed
 to provide early indication to sources about imminent congestion in the network.
Current versions of TCP rely on loss as indicators of congestion. Clearly, this is
undesirable if one wants to operate the network at low-levels of loss. On the other
hand, losses are good indicators of congestion and one needs other signals from the
network to make congestion-control decisions with very little or no loss. ECN marking
is a mechanism to provide such information about the network to the users.