ZyXEL Communications ZYWALL USG ZLD 2.21 Support Notes page 19

Step 3. Go to CONFIGURATION > Network > Routing > Policy Route, add
policy routes for VoIP traffic and HTTP traffic.
a. Add a policy route for VoIP traffic:
Source: LAN1_subnet
Destination: Any
Service: SIP
Next Hop: select the newly created WAN trunk WAN_Trunk_VoIP
Please note that to make sure this policy route applies to all VoIP traffic,
including both the SIP signaling and RTP (voice data), we need to enable SIP
ALG. Go to Configuration > Network > ALG, enable SIP ALG.
Step 3. For all other traffic, we use the two WAN connections to perform load
balancing. Go to Network > WAN > General.
Choose Active/Active Mode.
Set the Load Balancing Algorithm to Least Load First.
To avoid the situation where traffic from the same LAN host may be sent over
different WAN interfaces, which may cause servers to refuse the connection due
to a different source IP, we enable and set "WAN Interface to Local Host
Mapping Timeout" to a specific time period.
For Load Balancing Index (es), we choose Outbound Only.
Set the available outbound bandwidth for the two WAN connections according
to the bandwidth obtained from each ISP.
All contents copyright (c) 2010 ZyXEL Communications Corporation.
ZyXEL
– ZyWALL USG Support Notes
19