Least Cost Routing (LCR)

Author: Anagha Ravi

Least Cost Routing (LCR) is the process of selecting the path for outbound (termination) voice traffic routing based on the lowest available cost for a given route.

How is Bandwidth involved with LCR

Most carriers employ LCR (Least Cost Routing) to make routing choices for termination attempts. An LCR is much more simple than it sounds – you can think of it as “which carrier can place this call for me the cheapest?” scenario.

In order to route via LCR, a rate deck helps make the cost determination. A rate deck is a simple table that shows a call destination and cost to complete. Commonly, the rate deck is done at the 6 digit and 7 digit level of the destination phone number (NPA-NXX or NPA-NXX-X). Oftentimes, there are two different costs which can be considered, depending on the locations of the caller and recipient – the call could be rated at an interstate or intrastate level.

Interstate rating: Caller and recipient are in two different states (Tiger using a NC phone and number calls Sergio, who has an NY phone number).

Intrastate rating: Caller and recipient are in the same state (Tiger using an NC phone number and calls Sergio, who has an NC phone number).

Applying this to the earlier call example with Sergio/Tiger, as Tiger places his outbound call via their service provider, it’s likely that their service provider is using an LCR. In the example above, their service provider could have dozens of carriers to choose other than Bandwidth to route the call, and Bandwidth ‘wins’ the traffic by offering a cheaper rate. At the same time, Bandwidth is also using an LCR to determine which vendor to route the call through. The LCR choice is made in the Route Engine and is done in milliseconds.

What are the benefits of LCR

By combining our network with dozens of partner networks, Bandwidth is able to choose the highest quality and lowest cost routes for originating and terminating traffic. For our customers this means excellent quality, excellent price.

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