Chapter 11 Trunks
Maybe you have two connections with different bandwidths. For
For some traffic connections, you might want to use least load first load balancing in order to even out the distribution of the traffic load.
11.4 Load Balancing Algorithms
The following sections describe the load balancing algorithms that the ZyWALL can use to decide which interface the traffic (from the LAN) should use for a session3. The available bandwidth you configure on the ZyWALL refers to the actual bandwidth provided by the ISP and the measured bandwidth refers to the bandwidth an interface is currently using.
11.4.1 Least Load First
The least load first algorithm uses the current (or recent) outbound bandwidth utilization of each trunk member interface as the load balancing index(es) when making decisions about to which interface a new session is to be distributed. The outbound bandwidth utilization is defined as the measured outbound throughput over the available outbound bandwidth.
11.4.1.1 Least Load First Example 1
The following example shows two WAN interfaces on the ZyWALL connected to the Internet. The configured available outbound bandwidths for WAN 1 and WAN 2 are 512K and 256K respectively.
Figure 143 Least Load First Example 1
The outbound bandwidth utilization is used as the load balancing index. In this example, the measured (current) outbound throughput of WAN 1 is 412K and WAN 2 is 198K. The ZyWALL calculates the load balancing index as shown in the table below.
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.
Table 63 Least Load First: Example 1
INTERFACE | OUTBOUND |
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| LOAD BALANCING INDEX |
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AVAILABLE (A) |
| MEASURED (M) | (M/A) | |
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WAN 1 | 512 K |
| 412 K | 0.8 |
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WAN 2 | 256 K |
| 198 K | 0.77 |
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3.In the load balancing section, a session may refer to normal
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ZyWALL USG 1000 User’s Guide |
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