Patent ID: 8233394

Claim:
A method for preventing overload in telecommunications networks with IMS by always-on for a call received by a user; the method comprising: sending by said user a request message in order to activate a new PDP Context to his or her SGSN, which sends it to a GGSN; sending by the GGSN an Accounting Request message to an AAA server, further including in the 3GPP Vendor Attributes field of said Accounting Request message the GGSN and SGSN IP addresses which are providing service to said user; and if the GGSN is going to deactivate said PDP Context for having been inactive for a preestablished period of time, an association including user IP address, GGSN IP address, SGSN IP address in the AAA server is not eliminated, and furthermore the GGSN informs a P-CSCF in which said user is present, the P-CSCF adding an indicator describing that said user is registered in IMS but without an active PDP Context; and, when an incoming call is received: an S-CSCF of the network sends a PDP Context request to the P-CSCF in which said user is present; said P-CSCF verifies the status of the user PDP Context using said indicator, and if the PDP Context is not active, said PDP Context is activated again for which the P-CSCF informs the GGSN about the IP address which must be assigned to said user, and if said IP address of the association has not been assigned by the GGSN to another user, an attempt is made to reactivate the PDP Context using the address given by the P-CSCF wherein the GGSN uses a Network-Requested PDP context activation procedure, an Access-Request consultation to the AAA server using the IP address as the main consultation parameter being necessary; the AAA server uses said IP address as an index and responds to the GGSN using an Access-Accept message with the SGSN IP address under which the user is located; and if said IP address has been assigned to another user, a restart is carried out after the failure of the call attempt.