ZyXEL Communications ISG50 User Manual

Chapter 13 Trunks

ISG50 User’s Guide

The following table describes the items in this screen. 

Configuration > Network > Interface > Trunk

Show Advance 
Settings / Hide 
Advance Settings

Click this button to display a greater or lesser number of configuration fields.

Enable Link 
Sticking

Enable link sticking to have the system route sessions from one source to the 
same destination through the same link for a period of time. This is useful for 
accessing server that are incompatible with a user's sessions coming from 
different links.

For example, this is useful when a server requires authentication. 

This setting applies when you use load balancing and have multiple WAN 
interfaces set to active mode.

Timeout

Specify the time period during which sessions from one source to the same 
destination are to use the same link.

Passive Connection 
Disconnect

Select this to drop a passive mode interface’s connections when the trunk’s 
active mode interface comes back up. 

Enable Default 
SNAT

Select this to have the ISG50 use the IP address of the outgoing interface as 
the source IP address of the packets it sends out through its WAN trunks. The 
ISG50 automatically adds SNAT settings for traffic it routes from internal 
interfaces to external interfaces.

Default Trunk 
Selection for 
Forwarding Traffic

Select the WAN trunk the ISG50 uses for routing traffic going through the 
ISG50.

Default Trunk 
Selection for  
System Service 
Traffic

Select the WAN trunk the ISG50 uses for routing traffic originating from the 
ISG50 itself. This includes the PBX traffic. The trunk can only have one member 
interface set to active mode. 

User Configuration 

You can create your own User Configuration trunks. 

System Default

The ISG50 automatically adds all external interfaces into the pre-configured 
system default SYSTEM_DEFAULT_WAN_TRUNK. You cannot delete it. 

Add

Click this to create a new user-configured trunk.

Edit

Double-click an entry or select it and click Edit to open a screen where you can 
modify the entry’s settings. 

Remove

To remove a user-configured trunk, select it and click Remove. The ISG50 
confirms you want to remove it before doing so.

Object References

Select an entry and click Object References to open a screen that shows 
which settings use the entry. See 

 for an example.

#

This field is a sequential value, and it is not associated with any interface.

Name

This field displays the label that you specified to identify the trunk.

Algorithm

This field displays the load balancing method the trunk is set to use. 

Apply

Click this button to save your changes to the ISG50. 

Reset

Click this button to return the screen to its last-saved settings.