IP networks were originally designed to communicate packets between a host and a corresponding node. A corresponding node can send data packets to the IP host by setting the destination of these packets to that of the IP host. The IP network discovers the connectivity of the network nodes and routes the data packets using standard topologies and IP protocols such as Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP). With the knowledge of the network and the IP forwarding mechanisms, data packets flow from the corresponding node to the IP host typically along the shortest route in the network. Current IP networks predominantly use a specific IP addressing scheme and routing protocols known as IP version 4 (IPv4).
With the development of data applications such as Voice over IP (VoIP), Short Message Service (SMS), Multi-Media Messaging Service (MMS) in mobile networks it became necessary to extend signaling and routing protocols to enable communication with mobile devices that can attach to the network from anywhere via a local access point. With that objective in mind, Mobile IPv4 (MIPv4) was developed. Mobile IPv4 allows for communication between mobile devices and between mobile devices and application servers connected to the network. These application servers can provide a variety of services to the mobile devices, including Sprint Nextel's Push-To-X services, where X can be, for example, weather, sports, etc., and other various IP Multimedia Subsystem (IMS) services. Additionally, these application servers may be a SIP proxy/gateway or a media gateway (SIP Proxy/GW/MGW) to the network.
FIG. 1 illustrates a conventional network architecture implementing MIPv4. As illustrated in FIG. 1, a SIP Proxy/GW/MGW 100 is coupled to a home agent (HA-1) 120. A mobile communications device 200 communicates with the network through mobile data gateway/foreign agent (MDG/FA) 210 and home agent (HA-2) 220.
As is known, with current MIPv4 communications, when the mobile device 200 communicates with the SIP Proxy/GW/MGW 100, or vice versa, the communication route for data traffic must always pass through a home agent. This architecture can present problems.
Such an architecture does not allow data traffic to flow along the shortest route from the SIP Proxy/GW/MGW to the mobile communications device. This un-optimized route for data traffic causes several deficiencies in communication quality. First, because the route may be unnecessarily long, the end-to-end transmission delay can be significantly longer. Longer delays may cause significant quality degradation in delay-sensitive services such as VoIP and Push-to-Talk over Cellular (PoC). Typically, delay in a mobile network is longer than fixed networks. Thus, additional delay may be particularly detrimental in mobile networks. Second, traffic to all the mobile communications devices registered with a home agent must pass through the home agent, which causes congestion. In addition, a single home agent failure could unnecessarily disrupt all traffic routed through the home agent. Thus, routing performance could be degraded in the network due to the requirement that a home agent is in the forwarding path for networks using conventional MIPv4 routing. Third, more network bandwidth is required to carry traffic in a non-optimal way. A requirement for more network bandwidth leads to a more expensive network.
Therefore, there is a need for an improved system and method for route optimization in an IP network.