Chapter 8 Trunk

•If that interface’s connection goes down, the ZyWALL can still send its traffic through another interface.

•You can define multiple trunks for the same physical interfaces.

Link Sticking

You can have the ZyWALL send each local computer’s traffic that is going to the same destination through a single WAN interface for a specified period of time. This is useful when a server requires authentication. For example, the ZyWALL sends a user’s traffic through one WAN IP address when he logs into a server B. If the user’s subsequent sessions came from a different WAN IP address, the server would deny them. Here is an example.

Figure 100 Link Sticking

1

 

 

 

 

B

wan1

2

3

 

wan2

 

 

 

 

 

 

 

 

 

 

 

 

 

LAN

A

Load Balancing Algorithms

The following sections describe the load balancing algorithms 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.

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.

Here the ZyWALL has two WAN interfaces connected to the Internet. The configured available outbound bandwidths for WAN 1 and WAN 2 are 512K and 256K respectively.

3.In the load balancing section, a session may refer to normal connection-oriented, UDP or SNMP2 traffic.

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ZyWALL 110/310/1100 Series User’s Guide