Telling a transmitter to slow down Reactive: react after the fact of congestion Could be proactive: respond before the fact of congestion.

Telling a transmitter to slow down Reactive: react after the fact of congestion Could be proactive: respond before the fact of congestion. Before sending packets, the transmitter tells the network how many packets it wants to send The network checks to see if it can handle those packets and if so, reserves resources for those packets. It not, the packets have to wait. How do you give them all access? Send when you have a packet to send. Why So Many Standards Organizations? Layer N uses service provided by layer N -1 n layer N-1 provides a service to layer N Why Layering?