User`s guide

Chapter 5 WAN & 3G Cellular Screens
LAN-Cell 2 User’s Guide
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The LAN-Cell'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 LAN-Cell use
the other WAN interface for a domain name if the configured WAN interface's connection
goes down. See DDNS on page 309 for details.
When configuring a VPN rule, you have the option of selecting one of the LAN-Cell's domain
names in the My Address field.
Load Balancing Introduction
On the LAN-Cell, 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.
Load Balancing Algorithms
The LAN-Cell uses three load balancing methods (least load first, weighted round robin and
spillover) to decide which WAN interface the traffic for a session
1
(from the LAN) uses.
The following sections describe each load balancing method. The available bandwidth you
configure on the LAN-Cell refers to the actual bandwidth provided by the ISP and the
measured bandwidth refers to the bandwidth an interface is currently using.
TCP/IP Priority (Metric)
The metric represents the "cost of transmission". A router determines the best route for
transmission by choosing a path with the lowest "cost". RIP routing uses hop count as the
measurement of cost, with a minimum of "1" for directly connected networks. The number
must be between "1" and "15"; a number greater than "15" means the link is down. The
smaller the number, the lower the "cost".
1 The metric sets the priority for the LAN-Cell's routes to the Internet. Each route must
have a unique metric.
2 The priorities of the WAN interface routes must always be higher than the dial-backup
and traffic redirect route priorities.
Lets say that you have the WAN operation mode set to active/passive, meaning the LAN-Cell
will use the second highest priority WAN interface as a back up. The WAN route has a metric
of "2", the Cellular route has a metric of "3", the traffic-redirect route has a metric of "14" and
the dial-backup route has a metric of "15". In this case, the WAN route acts as the primary
default route. If the WAN route fails to connect to the Internet, the LAN-Cell tries the Cellular
route next. If the Cellular route fails, the LAN-Cell tries the traffic-redirect route. In the same
manner, the LAN-Cell uses the dial-backup route if the traffic-redirect route also fails.
1. In the load balancing section, a session may refer to normal connection-oriented, UDP and SNMP2 traffic.