ZyWALL 5/35/70 Series User’s Guide

You can select through which WAN port you want to send out traffic from UPnP-enabled applications (see Chapter 28 on page 452).

The ZyWALL's DDNS lets you select which WAN interface you want to use for each individual domain name. The DDNS high availability feature lets you have the ZyWALL use the other WAN interface for a domain name if the configured WAN interface's connection goes down. See Section 26.10.2 on page 424 for details.

When configuring a VPN rule, you have the option of selecting one of the ZyWALL's domain names in the My Address field.

7.3 Load Balancing Introduction

On the ZyWALL, load balancing is the process of dividing traffic loads between the two WAN interfaces (or ports). This allows you to improve quality of services and maximize bandwidth utilization.

See also policy routing to provide quality of service by dedicating a route for a specific traffic type and bandwidth management to specify a set amount of bandwidth for a specific traffic type on an interface.

7.4 Load Balancing Algorithms

The ZyWALL uses three load balancing methods (Least Load First, Weighted Round Robin and Spillover) to decide which WAN port the traffic for a session1 (from the LAN) should use.

The following sections describe each load balancing method. The available bandwidth you configure on the ZyWALL refers to the actual bandwidth provided by the ISP and the measured bandwidth refers to as the bandwidth an interface is currently using.

7.4.1 Least Load First

The least load first algorithm uses the current (or recent) outbound and/or inbound bandwidth utilization of each WAN interface as the load balancing index(es) when making decisions about to which WAN interface a new LAN-originated session is to be distributed. The outbound bandwidth utilization is defined as the measured outbound throughput over the available outbound bandwidth and the inbound bandwidth utilization is defined as the measured inbound throughput over the available inbound bandwidth.

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

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Chapter 7 WAN Screens