ZyXEL
– ZyWALL USG Support Notes
All contents copyright (c) 2010 ZyXEL Communications Corporation.
14
Spill-over
When choosing the Spill-over load balancing algorithm, the USG will send outbound traffic to the first interface member in the WAN trunk until its maximum
allowable bandwidth is reached. Then the USG will send the excess outbound traffic to the second interface member in the WAN trunk.
This algorithm is used when the first WAN connection is free or has a lower billing rate than the second WAN connection. The company can use this load
balancing algorithm to reduce Internet fees while avoiding congestion on the first WAN connection.
See the example below:
WAN1 (free connection) bandwidth: 1M
WAN2 (billing connection) bandwidth: 800K
Total outbound traffic is 1.5M. The traffic distribution among the two connections:
WAN1: 1M
WAN2: 0.5M
2.2 Customized Usage of WAN Connection for Specific Traffic Type
In some cases, the network administrator may prefer to send out some specific type of traffic over a specific WAN connection. For example, the ISP for WAN1
connection is also the company’s ITSP (VoIP provider). Therefore, network administrator can set the gateway to send VoIP traffic out over WAN1.
Both ZyNOS ZyWALL and USG ZyWALL can achieve this application by Policy Route.