  The goal of congestion control is to avoid congestion in network elements. A
network element is congested if it is being offered more traffic than it can
process. To detect such situations and to neutralize them we should monitor
traffic in the network. In this paper, we propose using Cisco's NetFlow
technology, which allows collecting statistics about traffic in the network by
generating special NetFlow packets. Cisco's routers can send NetFlow packets to
a special node, so we can collect these packets, analyze its content and detect
network congestion. We use Cisco's feature as example, some other vendors
(Juniper, 3COM, Alcatel, etc.) provide similar features for their routers. We
also consider a simple system, which collects statistical information about
network elements, determines overloaded elements and identifies flows, which
congest them.
