1-2regional branches together with VPN technologies to carry out operational applications, forinstance, to access the database of the company or to monitor remote devices throughTelnet.These new applications have one thing in common, that is, they all have specialrequirements for bandwidth, delay, and jitter. For example, videoconference and VoDrequire high bandwidth, low delay and jitter. As for mission-critical applications, such astransactions and Telnet, they may not require high bandwidth but do require low delay andpreferential service during congestion.The emerging applications demand higher service performance of IP networks. Betternetwork services during packets forwarding are required, such as providing dedicatedbandwidth, reducing packet loss ratio, managing and avoiding congestion, regulatingnetwork traffic, and setting the precedence of packets. To meet these requirements,networks must provide more improved services.Major Traffic Control TechnologiesFigure 1-1 End-to-end QoS modelAs shown in Figure 1-1, traffic classification, traffic policing, traffic shaping, congestionmanagement, and congestion avoidance form the foundation for differentiated serviceprovisioning. They deal with different issues of QoS:z Traffic classification identifies traffic based on certain match criteria. It is thefoundation for providing differentiated services and is usually applied in the inbounddirection of a port.z Traffic policing confines traffic to a specific specification and is usually applied in theinbound direction of a port. You can configure restriction or penalty measures againstthe exceeding traffic to protect carrier benefits and network resources.z Traffic shaping adapts output traffic rate, usually to the input capability of the receivingdevice, to avoid packet drop and port congestion. Traffic shaping is usually applied inthe outbound direction of a port.
