Perle Systems IOLINK-520 manual WAN Topologies, Bandwidth On Demand, Point-to-Point, Multipoint

Introduction

WAN Topologies

The IOLINK router may be connected to other IOLINK routers in two configurations: Multipoint or Point-to-Point. The WAN routing method used is set in the WAN Set-Up Menu under the Link Operation option.

Point-to-Point

In a Point-to-Point configuration, two IOLINK routers are connected together with one or two WAN links. Each link may be set to an always active (unconditional) state or a backup/recovery (conditional) state.

A single link may be used for general traffic, and the second link may be used for disaster recovery or increased throughput. The Bandwidth on Demand feature controls the conditional behavior of the second link in a Point-to- Point configuration.

The Time of Day connect feature may be used in a Point-to-Point configuration to provide specific hours of access or increased throughput.

Multipoint

In a Multipoint configuration, an IOLINK router is connected to more than one other IOLINK router. A Multipoint configuration consists of three or more IOLINK routers connected together on the same wide area network.

A dual-link IOLINK router that is connected to two different IOLINK routers (one on each link) is in a Multipoint configuration.

The Time of Day connect feature may be used in a Multipoint configuration to provide specific hours of access.

Bandwidth On Demand

Each IOLINK router has the ability to automatically enable or disable a second link based on traffic activity, time of day, or main link failure.

The Bandwidth on Demand feature allows you to use a second link only when required, thus saving the cost of having the second link up and connected all of the time. The second link could be connected to an inexpensive dial-up line that is only required when the main link fails or is exceeding a predefined traffic throughput level.

Bandwidth on Demand is accomplished by using the intelligence of the IOLINK router to measure the utilization of the primary link. When it approaches saturation, Bandwidth on Demand will initialize and loadshare with a second stand-by link. This will effectively increase the throughput of the IOLINK router, thereby alleviating the saturation and avoiding data loss. The second link is then deactivated when traffic levels drop off to where the primary link can adequately handle the traffic load once again.

When the stand-by link is activated, the IOLINK router raises the outgoing control signals. This control-signal transition is then used to initiate autodial or auto call-setup procedures on the interface device. This autodial feature is standard on most of the modems and terminal adapters on the market.

When the second link is deactivated, the IOLINK router lowers the outgoing control signals. This control-signal transition is used to disconnect the call and bring down the link. The second link then remains in stand-by mode until the bridge/router determines that the link must be used again.

1.18— IOLINK-PRO & 520 Reference Manual