ZyXEL Communications USG 2000 User Manual

Chapter 14 Trunks

ZyWALL USG 2000 User’s Guide

• Add WAN interfaces to trunks to have multiple connections share the traffic 

load. 

• If one WAN interface’s connection goes down, the ZyWALL sends traffic through 

another member of the trunk. 

• For example, you connect one WAN interface to one ISP and connect a second 

WAN interface to a second ISP. The ZyWALL balances the WAN traffic load 

between the connections. If one interface's connection goes down, the ZyWALL 

can automatically send its traffic through another interface.

You can also use trunks with policy routing to send specific traffic types through 
the best WAN interface for that type of traffic. 

• If that interface’s connection goes down, the ZyWALL can still send its traffic 

through another interface.

• You can define multiple trunks for the same physical interfaces. 

You can have the ZyWALL send each local computer’s traffic that is going to the 
same destination through a single WAN interface for a specified period of time. 
This is useful when a server requires authentication. For example, the ZyWALL 
sends a user’s traffic through one WAN IP address when he logs into a server B. If 
the user’s subsequent sessions came from a different WAN IP address, the server 
would deny them. Here is an example.

Figure 266   Link Sticking   

LAN user A logs into server B on the Internet. The ZyWALL uses ge2 to send the 
request to server B.