For many users, Least Cost Routing (or LCR) is the most valuable automatic control function associated with their telephone system.

And even though the growing use of virtual and discounted long distance services accessed via local exchange lines/trunks is making LCR less applicable, it still is an area in which dramatic savings can be realized without degradation of service.

Least Cost Routing (sometimes referred to as Automatic Route Selection) is still applicable for three main reasons:

Long-distance calls, and often local calls, can be placed over many different services, at widely varying rates;

The optimum facility for any given call depends on factors such as urgency, time of day, availability of facilities;

If there are more than three or four factors to consider, individual users cannot be expected to reliably choose the optimum facility. (Too much time is required.)

The 3 Levels of Least Cost Routing

Route Advance
A standard capability with many PBX systems. This feature routes outgoing calls to alternate facilities when the first trunk group is busy.

For example, in a system with Headquarters T1, Band-5 WATS and local trunks, Route Advance could be established so that headquarters’ calls would first seek the T1 channels.

In the event that the T1 is busy, calls would “advance” to the Band-5 lines. And finally, if the Band-5 lines were busy, calls would be advanced to the local trunks.

In this arrangement, separate access codes would need to be dialed to select Band-5 or local facilities directly. Queuing (see below) can also be applied to Route Advance configurations.

Automatic Route Selection (ARS)
This configuration allows for a single access code (usually “9″) to be dialed for all outgoing calls. After the call is dialed, the system then sorts through a hierarchy of routes to place the call on the lowest-cost available facility.

Hierarchies may vary according to number called, calling station, time of day, etc. Calls may be allowed to overflow to local trunks, or they may be blocked. A warning tone can be configured to alert the caller before it overflows to a different route.

As in the case of Route Advance, queuing and repetitive search can also be applied to ARS arrangements.

Queuing
This type of arrangement places callers in line to wait for facilities when all authorized routes are in use. This enables more traffic onto fewer and lower cost facilities.

The most common types of Queuing are:
Off-Hook Queuing functions so that the outbound caller stays on the line after dialing the call, and the call goes through immediately when a facility is available. This type of queuing is preferable when a maximum wait time of 30 seconds or less is programmed into the system. Off-hook queuing is an acceptable mode for waits up to one minute.

Call-Back Queuing functions so that the outbound caller hangs up after dialing the call until a facility is available. When this happens the number is dialed automatically. Call-back queuing is preferable if waits of longer than one minute are allowed.

Least Cost Routing, where applicable, is still an area that can provide considerable cost savings.

Submitted by: TelCon Associates, Inc.