Maintaining Consistent Network Connections While Moving Through Wireless Networks

Abstract

A proxy server ( 208 ) provides an anchor point for access network changes in a wireless environment. One example embodiment uses the concept of proxy server in order to preserve a uniform connectivity to a gateway service node while roaming across different networks through a handover mechanism. In one embodiment, the client connects to a proxy server through one access network ( 204 ), and the proxy server manages and keeps track of the user session toward the gateway service node. The client then connects to any packet service network, including Internet, through the proxy. When the client moves from one network to another, it indicates the change to the proxy and proxy, using a handover mechanism, switches the access network while maintaining the user session toward the gateway service node. The handover mechanism involved is efficient, with minimal messaging overhead, and preserves the application layer IP address of the client. Therefore, the data connections do not suffer from interruptions due to roaming through different networks and the service is seamlessly continued.

1 . A method of wireless communication, comprising the steps of:
 when a multifunction mobile client is in a GPRS session, routing GPRS control and user traffic to an SGSN;   routing at least the GRPS control traffic to a GGSN through a proxy server transparently to the client; and   routing the GPRS user traffic to a GGSN, either directly from the SGSN or through the proxy server.   
   
   
       2 . The method of  claim 1 , wherein the route of the user traffic is determined at the proxy server and this information becomes available to the SGSN and the GGSN by the proxy server. 
   
   
       3 . The method of  claim 2 , wherein the route of the user traffic is specified by the tunnel end point provided by the proxy server, where if the SGSN is specified as the tunnel end point for user traffic, then the user traffic is routed from the SGSN directly to GGSN bypassing the proxy server, and where if the proxy server is specified as the tunnel end point for user traffic, then the user traffic is routed from the SGSN to the GGSN through the proxy server. 
   
   
       4 . The method of  claim 1 , wherein the routing of either GPRS control traffic or GPRS control and user traffic from the SGSN to the proxy server happens through an address resolution mechanism internal to an address resolution node, accessed by SGSN. 
   
   
       5 . The method of  claim 1 , wherein the routing of either GPRS control traffic or GPRS control and user traffic from the proxy to the GGSN happens through an address mapping mechanism and an address resolution mechanism internal to the proxy and an address resolution node, accessible by a proxy. 
   
   
       6 . The method of  claim 1 , wherein the GPRS user traffic route can be changed any time by updating the user traffic tunnel end point to be either the proxy server or the SGSN. 
   
   
       7 . The method of  claim 1 , wherein when the mobile client switches to a non-GPRS, IP-based access technology during a GPRS session, using the proxy server as a wireless gateway for the client while continuing to communicate at least some GPRS control and user traffic through the proxy server. 
   
   
       8 . The method of  claim 7 , wherein the IP-based access technology is a wireless local area network. 
   
   
       9 . The method of  claim 7 , wherein the client's application layer IP address does not change when access networks are changed, wherein the proxy server maintains the control of the user session and keeps the IP address the same. 
   
   
       10 . The method of  claim 7 , wherein access networks can be changed while maintaining service continuity, by the proxy server maintaining the control of the user session toward the GGSN while switching the access networks. 
   
   
       11 . A method of wireless communication, comprising the steps of:
 when a multifunction mobile client accesses a GPRS network using an IP-based access technology:
 routing control traffic and user traffic to a proxy server; and 
 transparently to the mobile client, routing the control traffic and user traffic from the proxy server to a GGSN. 
   
   
   
       12 . The method of  claim 11 , further comprising the steps of, when the mobile client switches to a GPRS access technology, routing control and user traffic from the mobile client to an SGSN; and
 transparently to the mobile client, routing at least GPRS control traffic from the SGSN to the proxy server; and routing the GPRS user traffic to the GGSN, either directly from the SGSN or through the proxy server   
   
   
       13 . The method of  claim 12 , wherein the route of the user traffic is determined at the proxy server and this information becomes available to the SGSN and the GGSN by the proxy server. 
   
   
       14 . The method of  claim 12 , wherein the GPRS user traffic route can be changed any time by updating the user traffic tunnel end point to be either the proxy server or the SGSN. 
   
   
       15 . The method of  claim 12 , wherein the route of the user traffic is specified by the tunnel end point provided by the proxy server, where if the SGSN is specified as the tunnel end point for user traffic, then the user traffic is routed from the SGSN directly to the GGSN bypassing the proxy server, and where if the proxy server is specified as the tunnel end point for user traffic, then the user traffic is routed from the SGSN to the GGSN through the proxy server, thereby separating the control and user traffic. 
   
   
       16 . The method of  claim 2 , wherein the routing of traffic from the proxy to the GGSN happens using an address mapping mechanism and an address resolution mechanism internal to the proxy server and an address resolution node, transparently to the mobile client. 
   
   
       17 . The method of  claim 12 , wherein the client's application layer IP address does not change when access networks are changed by the proxy server maintaining the control of a user session upon handover and keeping the IP address the same. 
   
   
       18 . The method of  claim 12 , wherein access networks can be changed while maintaining service continuity by the proxy server maintaining control of a user session toward the GGSN and switching access networks upon handover. 
   
   
       19 . A wireless network system, comprising:
 a proxy server adapted to support both GPRS traffic and a non-GPRS and IP-based traffic from a mobile client and to communicate with a GGSN through GPRS protocol;   wherein when the mobile client uses a GPRS access network:
 GPRS control traffic is sent to the GGSN through a proxy server, transparently to the mobile client; and 
 GPRS user traffic is sent to the GGSN either through the proxy server or directly from an SGSN; and 
   wherein when the mobile client uses a non-GPRS, IP-based access network:
 both control traffic and user traffic are sent to the proxy server; and 
 transparently to the mobile client, both control traffic and user traffic are routed to the GGSN. 
   
   
   
       20 . The system of  claim 19 , wherein the routing to the proxy server is by use of an address resolution mechanism internal to an address resolution node and the routing from the proxy server to the GGSN is by use of an address mapping mechanism and an address resolution mechanism internal to the proxy and the address resolution node. 
   
   
       21  The system of  claim 19 , wherein when the mobile client uses a GPRS access network, the routing of the user traffic is decided by proxy by use of specifying the tunnel end point of the user traffic. 
   
   
       22 . The system of  claim 19 , wherein when the mobile client uses a GPRS access network, the user traffic is routed to the GGSN through the proxy server if the proxy server is specified as a tunnel end point of the user traffic; and the user traffic is routed directly to the GGSN if the SGSN is specified as the tunnel end point of the user traffic. 
   
   
       23 . The system of  claim 19 , wherein when the mobile client uses a GPRS access network, the user traffic route can be changed any time by updating the tunnel end point of the user traffic; where the tunnel end point of the user traffic can be either proxy or SGSN. 
   
   
       24 . The system of  claim 19 , wherein when the mobile client changes from a first access network of a first type to a second access network of a second type, the proxy server acts as an anchor point for at least the control traffic and maintains the route toward the GGSN and switches the control path between two access networks. 
   
   
       25 . The system of  claim 19 , wherein when the mobile client changes from a first access network of a first type to a second access network of a second type, the user traffic is routed according to the type of the access network. 
   
   
       26 . The system of  claim 20 , wherein the first access network type is a GPRS access network, and wherein the second access network type is a WLAN access network. 
   
   
       27 . The system of  claim 19 , wherein the client's IP address does not change when access networks are changed by the proxy server acting as the anchor point and maintaining control of the user session and keeping the IP address the same upon access network change. 
   
   
       28 . The system of  claim 19 , wherein access networks can be changed while maintaining service continuity by the proxy server acting as the anchor point and maintaining the control of the user session toward the GGSN and switching between the access networks.