ZyXEL 2WG Guida Utente

 Chapter 8 WAN and 3G Screens

ZyWALL 2WG User’s Guide

Round Robin routes traffic on a rotating basis and is activated only when a WAN interface has 
more traffic than the configured available bandwidth. On the ZyWALL with two WAN 
interfaces, an amount of traffic is sent through the first interface. The second interface is also 
given an equal amount of traffic, and then the same amount of traffic is sent through the first 
interface again; and so on. This works in a looping fashion until there is no outgoing traffic.
Similar to the Round Robin (RR) algorithm, the Weighted Round Robin (WRR) algorithm sets 
the ZyWALL to send traffic through each WAN interface in turn. In addition, the WAN 
interfaces are assigned weights. An interface with a larger weight gets more of the traffic than 
an interface with a smaller weight. 
This algorithm is best suited for situations when the bandwidths set for the two WAN 
interfaces are different.
For example, in the figure below, the configured available bandwidth of WAN1 is 1M and 
WAN2 is 512K. You can set the ZyWALL to distribute the network traffic between the two 
interfaces by setting the weight of WAN1 and WAN2 to 2 and 1 respectively. The ZyWALL 
assigns the traffic of two sessions to WAN1 for every one session's traffic assigned to WAN2.

Figure 111   Weighted Round Robin Algorithm Example

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. 

Time Frame

You can set the ZyWALL to get the measured bandwidth using the average 

bandwidth in the specified time interval. 
Enter the time interval between 10 and 600 seconds. 

Load Balancing 

Index(es)

Specify the direction of the traffic utilization you want the ZyWALL to use in 

calculating the load balancing index. 
Select Outbound Only, Inbound Only or Outbound + Inbound.

Interface

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

Available 

Inbound 

Bandwidth 

This field is applicable when you select Outbound + Inbound or Inbound Only in 

the Load Balancing Index(es) field. 
Specify the inbound (or downstream) bandwidth (in kilo bites per second) for the 

interface. This should be the actual downstream bandwidth that your ISP provides. 

Available 

Outbound 

Bandwidth

This field is applicable when you select Outbound + Inbound or Outbound Only in 

the Load Balancing Index(es) field. 
Specify the outbound (or upstream) bandwidth (in kilo bites per second) for the 

interface. This should be the actual upstream bandwidth that your ISP provides. 

Table 34   Load Balancing: Least Load First (continued)