Performance Impacts Due to Number Portability Under Various Routing Schemes

Abstract

Number portability allows a user to keep her telephone number as she moves to another provider. Number portability has been adopted by more and more countries around the world. A number that has a new provider is called a ported number. Traversal of a call to a ported number may involve three different networks: the Originating Network where the call originates, the Donor Network who initially assigned the telephone number to the subscriber, and the Recipient Network that currently hosts the subscriber's number. Currently, there are four major schemes used for routing a call to ported numbers. As of now, there has been very little quantitative study on how these schemes perform as more and more numbers are ported since there has been an an increasing trend of more subscribers choosing number portability; therefore, employing a more stable and efficient routing scheme is important. In this paper, we present a simulation study of the four routing schemes for number portability and discuss their performances under various scenarios from a connection setup delay point of view. From the simulation results, we show that of the four schemes, the ACQ scheme shows more stable performance to the ported rate, and its performance is not much affected by the system load.However, at a low ported rate, other schemes can be reasonably competitive, particularly, from the total routing delay's perspective, the OR scheme shows better performance, because it has less external links and less facilities; while with a lower ported rate, the QoR scheme is less relatively affected by its components' service rate.