Load Balancing Introduction; Load Balancing Algorithms - ZyXEL Communications ZyWall 35 User Manual

You can use policy routing to specify the WAN port that specific services go through. An ISP
may give traffic from certain (more expensive) connections priority over the traffic from other
accounts. You could route delay intolerant traffic (like voice over IP calls) through this kind of
connection. Other traffic could be routed through a cheaper broadband Internet connection that
does not provide priority service. If one WAN port's connection goes down, the ZyWALL can
automatically send its traffic through the other WAN port. See
details.
The ZyWALL's NAT feature allows you to configure sets of rules for one WAN port and
separate sets of rules for the other WAN port. Refer to
You can select through which WAN port you want to send out traffic from UPnP-enabled
applications (see
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
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 session
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.
1. In the load balancing section, a session may refer to normal connection-oriented, UDP and
SNMP2 traffic.
Chapter 7 WAN Screens
Chapter 23 on page 373).
Section 21.10 on page 346
Chapter 19 on page 315
Chapter 17 on page 293
for details.
ZyWALL 35 User's Guide
for
for details.
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(from the LAN)
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