ZyXEL ZyWALL USG 20 User Guide - Page 453

CHAPTER 28 Bandwidth Management 28.1 Overview Bandwidth management provides a convenient way to manage the use of various services on the network. It manages general protocols (for example, HTTP and FTP) and applies traffic prioritization to enhance the performance of delaysensitive applications like voice and video. 28.1.1 What You Can Do in this Chapter Use the BWM screens (see Section 28.2 on page 461) to control bandwidth for services passing through the ZyWALL, and it identifies the conditions that refine this. 28.1.2 What You Need to Know When you allow a service, you can restrict the bandwidth it uses. It controls TCP and UDP traffic. Use policy routes to manage other types of traffic (like ICMP). Note: Bandwidth management in policy routes has priority over policy routes to manage the bandwidth of TCP and UDP traffic. If you want to use a service, make sure both the firewall allow the service's packets to go through the ZyWALL. Note: The ZyWALL checks firewall rules before it checks bandwidth managementl rules for traffic going through the ZyWALL. Bandwidth management examines every TCP and UDP connection passing through the ZyWALL. Then, you can specify, by port, whether or not the ZyWALL continues to route the connection. DiffServ and DSCP Marking QoS is used to prioritize source-to-destination traffic flows. All packets in the same flow are given the same priority. CoS (class of service) is a way of managing traffic ZyWALL USG 20/20W User's Guide 453