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Retain your mobile number

Technologies utilized in an MNP project include leading edge IT and telco systems to provide a robust and fully redundant operating environment complemented by a tested, efficient application. By Vinita Gupta

Mobile Number Portability (MNP) gives subscribers the ability to keep their phone numbers when changing their service from one mobile provider to another. Many countries like Australia, Egypt, and France etc and including those in North America had deployed MNP solutions and India is looking at it. However, deploying of MNP is not so easy job; it involves processes, regulatory issues and technologies.

When we talk of porting a number, we are talking about moving it from one network to another. To complete this process, the operator pairs the subscriber’s mobile number and the recipient’s network ID and updates the same in a master database. This database can take the form of a centralized database, a distributed database or a combination of a centralized and distributed database.

Several regulatory issues drive the technology choices in the implementation of the MNP. Three key issues that have significant impact on the MNP architecture and implementations are:

• Who is responsible to route the call correctly to a ported number?
• How operators facilitate the process of porting a number from one operator to another, and where you administer and maintain master portability data?
• What are the other non-voice services affected by portability and how are they addressed?

Routing of numbers

Take an example of a subscriber named Amit who has moved his telephone service from operator (donor network) ‘A’ to operator (recipient network) ‘B’, and if someone named Rahul is calling Amit from operator (originating network) ‘C’. In addition, operator ‘C’ may route a call through an intermediate operator ‘D’ (transit network) such as a national long distance operator.

Several call routing models are possible:

Indirect routing model: The originating network routes the call based on the current numbering plan without any considerations to portability of the number. Call routing to the original service provider takes place. If number porting has not happened, the call completes in the normal manner. Otherwise, the donor network will determine that number is no longer serviced by it and will reroute the call to the new service provider that is the recipient network.

The benefit of this model is that it has no impact on other networks who are not involved with the ported subscriber. Specifically, in countries where only mobile numbers are portable, fixed line operators are not impacted by the MNP.

This scheme also reduces the number of queries that have to be made to determine the correct operator for the subscriber. This is because a query is required only when a call is made for a ported number. However, this advantage diminishes as more and more subscribers port their numbers.

“The disadvantage of this model is its inefficiency in routing the calls and is not scalable when a large number of subscribers have ported their numbers. All calls are routed through the donor network even though they no longer service the subscriber. The donor network incurs an unnecessary cost and somehow has to be compensated,” stated Ravi Ravishankar, Director, Product Marketing, Tekelec.

Direct routing model: With this approach, either the originating network or transit network is responsible for determining if the number is ported and route the call directly to the recipient network. This is known as the “all call queries” model.

This is an efficient and scalable model and mimics the current routing schemes, which is directly between an originating and terminating operator (and may involve transit carriers). This approach requires that a Number Portability (NP) Query be made at the originating network for every call, irrespective of whether or not the subscriber is ported. India is considering this model for routing.

Process of porting

When a subscriber needs to change his operator, he contacts the new operator and asks for their service. The new operator takes a written request from the subscriber and sends it to the central facilitator, they inform the present operator about it, and they in turn clarify it with the subscriber that they really want to port their number.

Once the clarification is done, the next step now is that the subscriber details have to be taken out from the old operator to a new one. Once this process is completed the central facilitator sends the subscriber’s ported information to every operator. All this is done electronically.

Raymond Cheung, Executive Vice President and CEO, Syniverse Asia Pacific revealed that the MNP or centralized database administrator may provide routing information to a service provider, but the service provider performs the actual routing process. As for time, most countries require calls to ported numbers to be routed in the same amount of time as a call to a non-ported number. The calls are routed in fractions of a second, so usually the calling party cannot detect any delay.

To route a call or a message, the calling party/message creator’s network, or in some countries the second-to-last network to route a call/message to its normal destination, is responsible for checking whether the number is ported or not. It does this by sending a query to a database of ported numbers. If the number is ported, the response back to the querying network contains a “routing number” that identifies which network (the recipient network) that the call should be routed to in order for the call to be completed.

“Many major operators have a connection to the central database and they receive updates from the master database that are stored locally in their local copy of the database. The routing of calls is handled within their network between the switches, and their local copy of the master database tells them whether to route the call to the original operator or, if the number was ported, to the recipient (new) operator. If smaller operators and authorized third-party users are not able to afford or simply do not want to manage a copy of the local database, they may have an SS7/C7 or an IP-based connection to a query response database that is a copy of the master database,” said Cheung.

Impact on non-voice services

The impact of MNP is not limited to voice-services. Many other services that involve phone numbers would be impacted by MNP. Delivery of SMS, mobile payment, prepaid validation and roaming are all impacted by MNP and have to be addressed in the MNP solution.

Although MNP brings significant advantage to the subscriber, many technology, regulatory and business issues have to be addressed for succesfull implementation of MNP. MNP decisions have to be made in real-time by the network while handling several millions calls. Other issues such as preventing looping of calls due to incorrect data have to be addressed. Scalability and reliability of network solutions are of paramount importance.

Ravishankar mentioned that the key for the NP solution in telecom network is SS7 Signaling. Today SS7 Signaling technology makes everything happen in the network—from setting up and tearing down the calls to delivering of SMS, validating accounts, enabling subscriber to roam and many other. The NP solutions are also built using the SS7 Signaling technology.

“Tekelec is a signaling solution provider; it provides high performance, highly scalable network nodes that are deployed in the core of an operator’s network. These network nodes download the NP data from centrally administered master data and facilitate routing of calls and delivery of services to the subscriber, irrespective of where the subscriber is currently served. We offer NP solutions for voice, SMS, MMS and pre-paid calls. In India

we are doing some trials,” said Ravishankar.

Let us therefore wait and see when India implements the MNP solution. However, one thing is clear—the move to introduce MNP will force cellular operators to offer better quality of services in order to keep the churn rate low.

vinita.gupta@expressindia.com