US 7,539,186 B2
Packet filtering for emergency service access in a packet data network communication system
Naveen Aerrabotu, Gurnee, Ill. (US); Mark E. Pecen, Palatine, Ill. (US); and Yilin Zhao, Northbrook, Ill. (US)
Assigned to Motorola, Inc., Schaumburg, Ill. (US)
Filed on Mar. 31, 2003, as Appl. No. 10/403,946.
Prior Publication US 2004/0190522 A1, Sep. 30, 2004
Int. Cl. H04L 12/56 (2006.01)
U.S. Cl. 370—389 22 Claims
OG exemplary drawing
 
1. A method for communicating data packets for an anonymous user device in a packet data network communication system, the method comprising:
receiving an emergency call attach request from the user device) the emergency call attach request including an identity for the user device;
determining whether the identity for the user device is a valid identity for the packet data network communication system;
in the event that the identity for the user device is not a valid identity for the packet data network communication system:
setting a level of service access for the user device to emergency service access only,
granting the emergency call attach request,
establishing a PDP context for an emergency call,
assigning an interim IP address to the user device for emergency service access only, and
determining at least one authorized IP address that is permitted to send data packets to and receive data packets from the interim IP address while the PDP context for the emergency call is active, wherein the PDP context for the emergency call remains active through a predetermined callback period and wherein the at least one authorized IP address corresponds to at least one device used to provide communication for emergency services in response to the emergency call;
receiving data packets directed to the interim IP address while the PDP context for IP emergency call is active;
determining source IP addresses for the received data packets;
in the event that a received data packet includes a source IP address which corresponds to the at least one authorized IP address, routing the received data packet to the interim IP address;
in the event that a received data packet includes a source IP address which does not correspond to the at least one authorized IP address, redirecting the received data packet to a third party to thereby prohibit communication between the interim IP address and unauthorized source IP addresses while the PDP context for the emergency call is active; and
upon termination of the PDP context for the emergency call, prohibiting communication of data packets to or from the user device in the event that the identity for the user device is not a valid identity for the packet data network communication system.