Transient Behaviour of an Adaptive Traffic Control Scheme

The support for low latency high throughput IP networks for multimedia streaming is today very limited. This paper shows that in high-capacity Gbps IP networks, RTP/UDP/IP packets of 1500 bytes/packet will achieve extremely low queuing latency (<10ms) and still utilise the network capacity almost 100%. A router must implement a low-complexity algorithm that monitors the queue length and the rate of change of queue length. By sending this information to neighbouring routers and hosts, the traffic can be dynamically controlled to achieve the desired balanced throughput and latency. This paper investigates the transient effects, i.e. how fast this algorithm reacts, by simulations. It shows that during the first measure period, a packet dropping mechanism prevents flooding the queue. A scaling message is sent to the source, which adaptively scales its content. Thus, during a 5 ms interval, a traffic overload event is under full control. 1