Device and method for providing mobile internet call service

A device for providing a mobile Internet call service, comprising:

• a communicator configured to perform communication for a mobile Internet call service;
• a memory configured to store a main call number list including a plurality of main call numbers or network address translation (NAT) information for a call connection, wherein the plurality of main call numbers is a call number frequently contacted by a user through a mobile voice over Internet protocol (mVoIP) call service, wherein the plurality of main call numbers are predetermined, wherein the call number is not stored if the call number is not one of the predetermined plurality of main call numbers;
• and
• a controller including a processor configured to:
• measure a number of call connection attempts of each call number of a plurality of call numbers for a predetermined amount of time;
• designate a priority of each call number of the plurality of call numbers in a descending order of the measured predetermined number of call connection attempts;
• when power of the device is turned on, send a NAT signal that is configured to obtain NAT information for a mobile Internet call of the main call numbers;
• acquire the NAT information for a call connection and store the acquired NAT information;
• generate a light weight session having minimum resource and associated with corresponding main call numbers of the predetermined main call numbers using the NAT information and maintain the generated light weight session;
• and
• when a mobile Internet call request is made for one of the main call numbers, perform the call connection using the light weight session as stored, and
• wherein the light weight session is in a state that the NAT information is stored in advance and a session for the call connection to the main call numbers are maintained to reduce a waiting time for the call connection.