ZyXEL 2WG User Guide

Chapter 8 WAN and 3G Screens

ZyWALL 2WG User’s Guide

To load balance using the weighted round robin method, select Weighted Round Robin in the 
Load Balancing Algorithm field.

Figure 112   Load Balancing: Weighted Round Robin

The following table describes the related fields in this screen.

With the spillover load balancing algorithm, the ZyWALL sends network traffic to the primary 
interface until the maximum allowable load is reached, then the ZyWALL sends the excess 
network traffic of new sessions to the secondary WAN interface. Configure the Route 
Priority metrics in the WAN General screen to determine the primary and secondary WANs.
In cases where the primary WAN interface uses an unlimited access Internet connection and 
the secondary WAN uses a per-use timed access plan, the ZyWALL will only use the 
secondary WAN interface when the traffic load reaches the upper threshold on the primary 
WAN interface. This allows you to fully utilize the bandwidth of the primary WAN interface 
while avoiding overloading it and reducing Internet connection fees at the same time. 
In the following example figure, the upper threshold of the primary WAN interface is set to 
800K. The ZyWALL sends network traffic of a new session that exceeds this limit to the 
secondary WAN interface.

Table 35   Load Balancing: Weighted Round Robin

Active/Active 

Mode

Select Active/Active Mode and set the related fields to enable load balancing on the 

ZyWALL. 

Load Balancing 

Algorithm

Set the load balancing method to Weighted Round Robin.

WAN Interface 

to Local Host 

Mapping 

Timeout 

Select this option to have the ZyWALL send all of a local computer’s traffic through 

the same WAN interface for the period of time that you specify (1 to 600 seconds). 
This is useful when a redirect server forwards a local user’s request for a file and 

informs the file server that a particular WAN IP address is requesting the file. If the 

user’s subsequent sessions came from a different WAN IP address, the file server 

would deny the request. 

Interface

This field displays the name of the WAN interface (WAN 1 and WAN 2). 

Ratio

Specify the weight for the interface. Enter 0 to set the ZyWALL not to send traffic load 

to the interface. The higher the number, the bigger the weight (the more traffic sent).