ZyXEL Communications 200 Series 用户手册

Chapter 11 Trunks

ZyWALL USG 100/200 Series User’s Guide

Figure 189   Weighted Round Robin Algorithm Example

The spillover load balancing algorithm sends network traffic to the first interface in the trunk 
member list until the interface’s maximum allowable load is reached, then sends the excess 
network traffic of new sessions to the next interface in the trunk member list. This continues as 
long as there are more member interfaces and traffic to be sent through them.

Suppose the first trunk member interface uses an unlimited access Internet connection and the 
second is billed by usage. Spillover load balancing only uses the second interface when the 
traffic load exceeds the threshold on the first interface. This fully utilizes the bandwidth of the 
first interface to reduce Internet usage fees and avoid overloading the interface.

In this example figure, the upper threshold of the first interface is set to 800K. The ZyWALL 
sends network traffic of new sessions that exceed this limit to the secondary WAN interface.

Figure 190   Spillover Algorithm Example

• See 

 for related information on the Trunk screens.

• See 

 for more background information on trunks.

• See 

 for an example of how to configure load balancing.

Click Network > Interface > Trunk to open the Trunk screen. This screen lists the 
configured trunks and the load balancing algorithm that each is configured to use.