OverviewChapter 9: Using Traffic Shaper 181Chapter 9This chapter describes how to use Traffic Shaper to control the flow of communication to and from yournetwork.This chapter includes the following topics:Overview ..................................................................................................181Setting Up Traffic Shaper .........................................................................182Predefined QoS Classes ............................................................................182Adding and Editing Classes ......................................................................184Viewing and Deleting Classes ..................................................................187Restoring Traffic Shaper Defaults ............................................................187OverviewTraffic Shaper is a bandwidth management solution that allows you to set bandwidth policies to control theflow of communication. Traffic Shaper ensures that important traffic takes precedence over less importanttraffic, so that your business can continue to function with minimum disruption, despite networkcongestion.Traffic Shaper uses Stateful Inspection technology to access and analyze data derived from allcommunication layers. This data is used to classify traffic in up to eight user-defined Quality of Service(QoS) classes. Traffic Shaper divides available bandwidth among the classes according to weight. Forexample, suppose Web traffic is deemed three times as important as FTP traffic, and these services areassigned weights of 30 and 10 respectively. If the lines are congested, Traffic Shaper will maintain the ratioof bandwidth allocated to Web traffic and FTP traffic at 3:1.If a specific class is not using all of its bandwidth, the leftover bandwidth is divided among the remainingclasses, in accordance with their relative weights. In the example above, if only one Web and one FTPconnection are active and they are competing, the Web connection will receive 75% (30/40) of the leftoverbandwidth, and the FTP connection will receive 25% (10/40) of the leftover bandwidth. If the Webconnection closes, the FTP connection will receive 100% of the bandwidth.Traffic Shaper allows you to give a class a bandwidth limit. A class's bandwidth limit is the maximumamount of bandwidth that connections belonging to that class may use together. Once a class has reachedits bandwidth limit, connections belonging to that class will not be allocated further bandwidth, even ifthere is unused bandwidth available. For example, you can limit all traffic used by Peer-To-Peer file-sharing applications to a specific rate, such as 512 kilobit per second. Traffic Shaper also allows you toassign a ―Delay Sensitivity‖ value to a class, indicating whether connections belonging to the class shouldbe given precedence over connections belonging to other classes.Traffic Shaper supports DiffServ (Differentiated Services) Packet Marking. DiffServ marks packets asbelonging to a certain Quality of Service class. These packets are then granted priority on the publicnetwork according to their class.Using Traffic Shaper
