ZyXEL Communications USG 2000 User Manual

 Chapter 32 Application Patrol

ZyWALL USG 2000 User’s Guide

• The ZyWALL gives bandwidth to higher-priority traffic first, until it reaches its 

configured bandwidth rate.

• Then lower-priority traffic gets bandwidth. 
• The ZyWALL uses a fairness-based (round-robin) scheduler to divide bandwidth 

among traffic flows with the same priority.

• The ZyWALL automatically treats traffic with bandwidth management disabled 

as priority 7 (the lowest priority). 

Maximize bandwidth usage allows applications with maximize bandwidth usage 
enabled to “borrow” any unused bandwidth on the out-going interface.

After each application gets its configured bandwidth rate, the ZyWALL uses the 
fairness- based scheduler to divide any unused bandwidth on the out-going 
interface amongst applications that need more bandwidth and have maximize 
bandwidth usage enabled.

Unused bandwidth is divided equally. Higher priority traffic does not get a larger 
portion of the unused bandwidth.

The following sections show how bandwidth management behaves with various 
settings. For example, you configure DMZ to WAN policies for FTP servers A and 
B. Each server tries to send 1000 kbps, but the WAN is set to a maximum 
outgoing speed of 1000 kbps. You configure policy A for server A’s traffic and 
policy B for server B’s traffic.

Figure 384   Bandwidth Management Behavior