Mobile Number Portability (MNP)

Mobile number portability (MNP) enables mobile telephone users to retain their mobile telephone numbers when changing from one mobile network carrier to another.

MNP is implemented in different ways across the globe. The International and European standard is for a customer wishing to port his/her number to contact the new network (recipient), which then sends the number portability request (NPR) to the current network (donor). This is known as "recipient-led" porting. The UK and India are the only exceptions to implement the donor-led system. The customer wishing to port his/her number is required to contact the donor to obtain a code (Porting Authorization Code (PAC) in the UK and Unique Porting Code (UPC) in India) which is then given to the recipient network.

In Pakistan, "recipient-led" porting model is implemented.

MNP Benefits

MNP allows consumers to choose between competing providers based on price, quality, type of service and coverage without the inconvenience of changing their mobile number.

Mobile Number portability is a key aspect of deregulation to ensure competition in the telecom industry. MNP is not a subscriber service. It is a network feature that allows the subscriber to keep a unique mobile phone number. The absence of MNP may give the existing cellular mobile operators a significant competitive advantage over new entrants in the market. MNP is the important mechanism to enhance fair competition among different operators.

Technical Aspects

A significant technical aspect of MNP is related to the routing of calls or mobile messages (SMS, MMS) to a number once ported. There are various flavors of call routing implementation across the globe, which are:

  • Onward Routing
  • Query on release
  • Call drop back

In Pakistan Telecom industry Onward Call Routing technique suited the best, and hence this technique is being used to facilitate ported subscribers to make or receive calls.

Onward Routing Call Forwarding

The switch architecture for commonly used global digital technologies has the ability to forward an inbound call to a number resident on that switch to another number or route, either internally within the same switch or externally using carriage to another switch or network location. This solution is the simplest option to implement MNP since it requires little, if any, modification of the donor switch.


  • Easy to implement, requiring few changes, if any, to the mobile switches
  • No impact on the fixed network operator call handling
  • Quick roll out is possible
  • The switch changes, ports, trunks and signaling area are all reusable or recoverable to the DONOR OPERATOR when the call forwarding
  • function is no longer required; either due to the customer disconnecting service or returning to service with the DONOR OPERATOR
  • Switch memory, call processing, trunks, trunk ports and signaling capacity are all fungible resources.


  • Potential to overload the call forwarding capacity, necessitating the deployment of extra capacity
  • SMS messages cannot be forwarded in this way
  • International calls terminating to a ported mobile number cannot be traced by the RO’s billing system
  • The DONOR OPERATOR remains involved each time the customer ports or disconnects
  • Calls forwarded to a recipient’s switch rely on the integrity of the Donor Operator network for the grade of service offered to its customers

Query on Release

The originating switch routes the call to the Donor Operator which then returns a message to the originating network indicating that the number has been ported away from that operator. The Donor Operator must track every number in its inventory and must track which numbers are ported out. In this case, the DO does not advise the originating switch of the destination route, only that the number is ported and the originating switch must therefore conduct a database query to find out where to send the call.

This plan does not require the Donor Operator to know the current operator of all of the numbers ported out from its number ranges. Once the customer leaves the Donor Operator, there is no need for the Donor Operator to be kept aware of where the customer has service.


  • No additional Donor Operator /Recipient Operator trunk ports and trunks are required.
  • Donor Operator call processing capacity is not impacted
  • Only a minor amount of SS7 signaling capacity and link usage to accommodate the inbound call


  • Common Database required
  • Connectivity to the common database is required from all operators
  • Query of the database is delayed slightly when the call is first routed to the Donor Operator
  • All calls are processed twice by the originating operator
  • Call delay is introduced

Call Drop Back

The donor network receives the call from the originating operator and, through the use of an internal database, checks if the number is ported. If the number is marked as ported, then the call is released with a message sent to the originating operator to redirect the call to another operator. The drop back method requires modification to the Donor Operator’s switches to check every incoming call destined for its customers to confirm that the mobile number is ported.

NPC (Number Portability Clearing House):

The NPC is hosted at PMD and is the platform providing Centralized Ordering, Port Provisioning and Number Administration information for Ported Numbers. The NPC comprises of a Hardware & Software platform having:

  • Centralized Reference Database, Serving as the Repository for Ported Numbers.
  • Interface Processes, which provide Centralized ordering, Port Provisioning & Number Administration Information for Ported Numbers.