Q. Example on audio transmission?

• admission policy

- QoS mechanism; switches (routers) first check resource requirements of a flow before admitting it to the network

Closed-loop congestion control

- back pressure

• Congested router inform preceding upstream router to reduce the outgoing traffic

- Choke point

• A packet sent by a router to the source (similar to ICMP source quench) to inform it of congestion

- implicit signaling

• The impediment in receiving an ACK can be a signal that a network is congested

- explicit signaling

• A router can explicitly send a special bit (flag) in the packet to the source or the destination