ZyXEL Communications 5 Series - Figure 100 Load Balancing: Least Load First; Table 36 Least Load First: Example 1; Table 37 Least Load First: Example 2

Chapter 9 WAN Screens
ZyWALL 5/35/70 Series User’s Guide
178
Since WAN 2 has a smaller load balancing index (meaning that it is less utilized than WAN 1),
the ZyWALL will send the subsequent new session traffic through WAN 2.
Example 2
This example uses the same network scenario as in Figure 99 on page 177, but uses both the
outbound and inbound bandwidth utilization in calculating the load balancing index. If the
measured inbound stream throughput for both WAN 1 and WAN 2 is 1600K, the ZyWALL
calculates the average load balancing indices as shown in the table below.
Since WAN 1 has a smaller load balancing index (meaning that it is less utilized than WAN 2),
the ZyWALL will send the next new session traffic through WAN 1.
To configure Least Load First, select Least Load First in the Load Balancing Algorithm
field.
Figure 100 Load Balancing: Least Load First
Table 36 Least Load First: Example 1
INTERFACE
OUTBOUND
LOAD BALANCING INDEX
(M/A)
AVAILABLE (A) MEASURED (M)
WAN 1 512 K 412 K 0.8
WAN 2 256 K 198 K 0.77
Table 37 Least Load First: Example 2
INTERFACE
OUTBOUND INBOUND
AVERAGE LOAD
BALANCING INDEX
(OM / OA + IM / IA) / 2
AVAILABLE
(OA)
MEASURED
(OM)
AVAILABLE
(IA)
MEASURED
(IM)
WAN 1 512 K 412 K 8000 K 1600 K ( 0.8 + 0.2) / 2 = 0.5
WAN 2 256 K 198 K 2000 K 1600 K ( 0.77 + 0.8 ) / 2 = 0.79