DYNAMIC IP ADDRESS ALLOCATION SYSTEM AND METHOD

摘要

In a General Packet Radio Service (GPRS) network, a system and method of dynamically allocating an Internet Protocol (IP) address to a mobile terminal (MT) (11) operating in the network. A Gateway GPRS Service Node (GGSN) (15) requests IP addresses over the Gi interface (21) from a Radius server (20) in an IP-based network. A Conditional PDP Address (CPA) parameter is stored in the MT's Home Location Register (HLR) (31) as part of the user subscriber data, and is passed to the GGSN during the GPRS Attach procedure. The CPA parameter indicates whether the subscriber is entitled to a backup IP address in case of failure to obtain one over the Gi interface, and whether the MT is a user of a real-time application. A timer (18) in the GGSN sets a maximum time period (Ti) that the GGSN will wait for a response from the server, and a counter (19) sets the maximum number of requests (Ni) that are sent. A Network Access Server (NAS) (17) in the GGSN sends a request for an IP address from the GGSN to the server, and determines whether Ti expires without receiving a response from the server. If no response is received, the GGSN allocates an IP address. A public IP address is allocated only if the MT is a user of a real-time application. Otherwise, a private IP address is allocated.