Vyatta Network OS Documentation

Learn how to install, configure and operate the Vyatta NOS, which helps drive our virtual networking & physical platforms portfolio.

Traffic management — shaping and policing

As traffic passes through your network it can be seen as bursts of data, with some of those bursts exceeding your maximum bandwidth capabilities. To prevent this there are two methods of traffic management: shaping and policing.

Traffic shaping is the preferred method. Traffic shaping only drops packets when are high levels of congestion, whilst policing drops packets as soon as the bandwidth threshold is exceeded.

Policing is usually done on input, before QoS classification occurs.

Traffic shaping

Traffic shaping, or smoothing, is the process of traffic and bandwidth management that we use to prevent overload of down-stream resources in your network.

Traffic shaping keeps excess packets in a queue and then schedules to transmit later, when the volume of incoming traffic is less. The result of traffic shaping is a smooth packet output rate.

Figure 1. Traffic shaping
Traffic policing
With policing, when the traffic rate reaches the configured maximum rate, excess traffic is dropped. The result of policing is an output rate that remains jagged, but with 'clipped' peaks.
Figure 2. Traffic policing