Method and system for handling a dynamic host configuration protocol internet protocol version 4 address release

A packet data network gateway (PGW) in a mobile communication system, the PGW comprising:

• a transceiver for transmitting and receiving a signal;
• and
• a controller for allocating an IP version 4 (IPv4) address and an IP version 6 (IPv6) address to a terminal to establish a packet data network (PDN) connection between the terminal and the PGW, for detecting release of the IPv4 address allocated to the terminal, for identifying a PDN type associated with the PDN connection in response to detecting the release of the IPv4 address, for transmitting, to a serving gateway (SGW), a binding revocation message if the identified PDN type is IPv4 and IPv6, the binding revocation message including information indicating that the IPv4 address is released and the PDN connection is maintained, and for receiving, from the SGW, a binding revocation acknowledge message in response to the binding revocation message.