Support for multi-homing protocols

The present invention solves these problems with a new proxy binding update request and proxy binding acknowledgment messages having new indicators and identification information. Namely, the home agent/local mobility anchor will exchange proxy binding update messages and proxy binding acknowledge messages that include information such as mobile node identification (MN-ID), home network prefix (HNP), but can also include selective information fields such as, access type, handover indicator (HO), and interface identification (interface ID) By including new access type, indicator, and identification information, the local mobility anchor can respond to a binding update request message with a better understanding of the new connectivity request from the mobile node.

TECHNICAL FIELD OF THE INVENTION

A method for allocating addressing for a mobile node on a communication system using a handover indicator, access type indicator, and other identification fields.

BACKGROUND OF THE INVENTION

IP-based mobile systems provide for communication between at least one mobile node and a wireless communication network. The term “mobile node” includes a mobile communication unit (e.g., mobile terminal, “smart phones”, nomadic devices such as laptop PCs with wireless connectivity, as described in greater detail below). Among other elements, the wireless communication system includes a home network and a foreign network. The mobile node may change its point of attachment to the Internet through these networks, but the mobile node will always be associated with a single home network for IP addressing purposes. The home network includes a home agent and the foreign network includes a foreign agent—both of which control the routing of information packets into and out of their network.

The mobile node, home agent and foreign agent may be called different names depending on the nomenclature used on any particular network configuration or communication system. For instance, a “mobile node” encompasses PC's having cabled (e.g., telephone line (“twisted pair”), Ethernet cable, optical cable, and so on) connectivity to the wireless network, as well as wireless connectivity directly to the cellular network, as can be experienced by various makes and models of mobile terminals (“cell phones”) having various features and functionality, such as Internet access, e-mail, messaging services, and the like. Mobile nodes are sometimes called a user equipment, mobile unit, mobile terminal, mobile device, or similar names depending on the nomenclature adopted by particular system providers. Generally, there is also a correspondence node, which may be mobile or fixed, that may be located on the network for communicating with the mobile node.

A home agent may also be referred to as a Local Mobility Anchor, Home Mobility Manager, Home Location Register, and a foreign agent may be referred to as a Mobile Access Gateway, Serving Mobility Manager, Visited Location Register, and Visiting Serving Entity. The terms mobile node, home agent and foreign agent are not meant to be restrictively defined, but could include other mobile communication units or supervisory routing devices located on the home or foreign networks. Foreign networks can also be called serving networks.

Registering the Mobile Node

Foreign agents and home agents periodically broadcast an agent advertisement to all nodes on the local network associated with that agent. An agent advertisement is a message from the agent on a network that may be issued under the Mobile IP protocol (RFC 2002) or any other type of communications protocol. This advertisement should include information that is required to uniquely identify a mobility agent (e.g. a home agent, a foreign agent, etc.) to a mobile node. Mobile nodes examine the agent advertisement and determine whether they are connected to the home network or a foreign network.

The mobile node will always be associated with its home network and sub-network for IP addressing purposes and will have information routed to it by routers located on the home and foreign network. If the mobile node is located on its home network, information packets will be routed to the mobile node according to the standard addressing and routing scheme. If the mobile node is visiting a foreign network, however, the mobile node obtains appropriate information from the agent advertisement, and transmits a registration request message (sometimes called a binding update request) to its home agent through the foreign agent. The registration request message will include a care-of address for the mobile node. A registration reply message (also called a binding update acknowledge message) may be sent to the mobile node by the home agent to confirm that the registration process has been successfully completed.

The mobile node keeps the home agent informed as to its location on foreign networks by registering a “care-of address” with the home agent. The registered care-of address identifies the foreign network where the mobile node is located, and the home agent uses this registered care-of address to forward information packets to the foreign network for subsequent transfer onto the mobile node. If the home agent receives an information packet addressed to the mobile node while the mobile node is located on a foreign network, the home agent will transmit the information packet to the mobile node's current location on the foreign network using the applicable care-of address. That is, this information packet containing the care-of address will then be forwarded and routed to the mobile node on the foreign network by a router on the foreign network according to the care-of address.

When mobile nodes move from one foreign network to another foreign network, problems are sometimes encountered with the registration of the care of addressing with the home agent or local mobility anchor. Further, multiple interfaces may be supported on a single or multiple foreign networks, which can include the different communication access types 802.11d, 802.11g, FIRM, WiFi, WiMax, CDMA, or LTE. Problems can be encountered when the mobile node becomes coupled to different access types on a single or multiple networks. Thus, it is a primary objective of this invention to provide addressing support for a mobile node where there is a handover to a new foreign network, a handover to a second access type on the same foreign network (multiple access types are supported on the foreign network), and/or multiple interfaces are supported for connecting a mobile node to a foreign network.

SUMMARY OF THE INVENTION

The present invention solves these problems with a new proxy binding update request and proxy binding acknowledgement messages having new indicators and identification information. Namely, the home agent/local mobility anchor will exchange proxy binding update messages and proxy binding acknowledge messages that include information such as mobile node identification (MN-ID), home network prefix (HNP), but can also include selective information fields such as, access type, handover indicator (HO), and interface identification (interface ID). By including new access type, indicator, and identification information, the local mobility anchor can respond to a binding update request message with a better understanding of the new connectivity request from the mobile node. The proxy binding update request and acknowledgement messages may require new fields or expanded fields for the transmission of the additional information, and the local mobility anchor/home agent will also need to expand its binding cache entry table to support these new information fields. The invention can be implemented using a new protocol application or modified messages from prior registration applications.

The objects and features of the invention will become more readily understood from the following detailed description and appended claims when read in conjunction with the accompanying drawings in which like numerals represent like element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

InFIG. 1, the overall architecture of the IP-based mobile system is shown with a mobile mode125, a home network110and foreign networks130and150, respectively. As shown inFIG. 1, the home network110has a home agent or local mobility anchor113. The local mobility anchor113is coupled to the mobility agent gateway155on foreign network150by communication link112, and local mobility anchor113is coupled to the mobility agent gateway135on foreign network130by communication link115.

The mobility agent gateway135is coupled to the mobile node125through the radio access system comprised of the base station transceiver139coupled to the antenna/transmitter137through the wireless communication link127. The mobility agent gateway155is coupled the mobile node125using a second communication access type, such as WiMax or WiFi, which is supported by the interface141and wireless communication link157.FIG. 1also shows a connection to mobile node125from the foreign agent135through connection176and second access interface177. This interface is connected to mobile node125through wireless communication link180. In this embodiment, the communication access type supported by connection interface177is the same as the second communication access type supported by interface141. This embodiment has a limitation that multiple interfaces may be supported on the networks, but on any given foreign network (such as network150or130), only one interface will be supported for each communication access type.

Mobile node125is shown electronically coupled to the foreign networks150and130via the wireless communication link157and127, respectively. The mobile node125, however, can communicate with any transceiver or access network coupled to a foreign network. That is, communications links127and157are radio transmitted links, but these links can be composed of any connection between two or more nodes on a network or users on networks or administrative domains.

The terms Local Mobility Anchor, home agent, and foreign agent may be as defined in the Mobile IP Protocol (RFC 2002), but these agents are not restricted to a single protocol or system. In fact, the term home agent, as used in this application, can refer to a home mobility manager, home location register, home serving entity, or any other agent at a home network110having the responsibility to manage mobility-related functionality for a mobile node125. Likewise, the term mobility agent gateway, as used in this application, can refer to a foreign agent, serving mobility manager, visited location register, visiting serving entity, or any other agent on a foreign network having the responsibility to manage mobility-related functionality for a mobile node125.

In the mobile IP communications system shown inFIG. 1, the mobile node125is identified by a permanent IP address. While the mobile node125is coupled to its home network110, the mobile node125receives information packets like any other fixed node on the home network110. When mobile, the mobile node125can also locate itself on foreign network, such as network130or150. When located on foreign network130or150, the home network110sends data communications to the mobile node125by “tunneling” the communications to the foreign network130or150.

The mobile node125keeps the local mobility anchor113informed of its current location, or foreign network association, by registering a care-of address with the local mobility anchor113. Essentially, the care-of address represents the foreign network where the mobile node125is currently located. If the local mobility anchor113receives an information packet addressed to the mobile node125while the mobile node125is located on a foreign network130, the local mobility anchor113will “tunnel” the information packet to foreign network130for subsequent transmission to mobile node125.

The foreign agent135participates in informing the local mobility anchor113of the mobile node125current care-of address. The foreign agent135also receives information packets for the mobile node125after the information packets have been forwarded to the foreign agent135by the local mobility anchor113. Moreover, the foreign agent135serves as a default router for out-going information packets generated by the mobile node125while connected to the foreign network130.

The mobile node125participates in informing the local mobility anchor125of its current location and requests connections to the associated foreign network. When the mobile node125transitions to connecting to a different access type on the foreign network or a wholly different foreign network (handover), the mobile node125obtains appropriate information regarding the address of the foreign network and/or the foreign agent from an agent advertisement.

When first connected to the local mobility anchor113, mobile node125would have created an entry on the binding cache entry table inFIG. 2that specified the mobile node identification for the mobile node125. The access type field of information is included in the proxy binding update request and the binding cache entry table inFIG. 2, with the mobile node identification field.FIG. 2is a binding cache entry table160that possesses at least column and row entries for the mobile node identification165and the access type167. Other fields are maintained on the binding cache entry table, but these are the pertinent entries for the consideration of the present invention.

Because each access type on the networks shown onFIG. 1are limited to a single interface from each foreign network, the local mobility anchor will check subsequent proxy binding update requests received from the mobile node125to determine if this proxy binding update request has the same access type indicator as previously maintained on the binding cache entry table160for that mobile node125. If the same access type indicator is found in a proxy binding update request as previously maintained on the binding cache entry table160for that mobile node125, the local mobility anchor113will recognize the situation as a handover of the mobile node125to a new foreign network, such as a handover of mobile node125from foreign network130to foreign network150. The local mobility anchor113will create a new binding cache entry for the mobile node, and the care-of addressing and home network prefix will be changed to designate the new foreign network as the network where the mobile node125can be located, which information will be transmitted to the proper mobility access gateway135and the mobile node125.

If the comparison with the information in the proxy binding update request shows a different access type connection for the mobile node125, the local mobility anchor will determine if the home network prefix should designate the foreign network where the mobile node125was previously located without any indication of a handover to a new foreign network. If that is the case, the entry for the mobile node125will be modified on the binding cache entry table to indicate that the mobile node125is still connected to the first foreign network130, which information will be transmitted to the proper mobility access gateway135and the mobile node125.

That is, this comparison may simple show the new connection for the mobile node125is to a new access type, as opposed to a handover to a new foreign network. If so, the local mobility anchor113will respond to the proxy binding update request with a proxy binding update response having a home network prefix indicator that points to the first foreign network130. In this manner, a receipt of new proxy binding update request at the local mobility anchor113does not automatically create a new home network prefix for this mobile node, which solves some of the problems with determining when a mobile node is simply connecting to a new access type on the same network or being handed over to a new foreign network.

InFIG. 3, the overall architecture of the IP-based mobile system is shown with a mobile mode225, a home network210and foreign networks230and250, respectively. As shown inFIG. 3, the home network210has a home agent or local mobility anchor213. The local mobility anchor213is coupled to the mobility agent gateway255on foreign network250by communication link212, and local mobility anchor213is coupled to the mobility agent gateway235on foreign network230by communication link215.

The mobility agent gateway235is coupled to the mobile node225through the radio access system comprised of the base station transceiver239coupled to the antenna/transmitter237through the communication link227. The mobility agent gateway255is coupled to a second access type, such as WiMax or WiFi, through interface241coupled to the mobile node225by communication link257.FIG. 3also shows a second connection of the same access type as supported by interface241for the connection of the mobile node225to foreign agent255through connection276and second access interface277. This interface is connected to mobile node225through communication link280.

Mobile node225is shown electronically coupled to the foreign networks250and230via the wireless communication link257(or280) and227, respectively. The mobile node225, however, can communicate with any transceiver or access network coupled to a foreign network. That is, communications links227,280and241are radio transmitted links, but these links can be composed of any connection between two or more nodes on a network or users on networks or administrative domains.

The terms Local Mobility Anchor, home agent, and foreign agent may be as defined in the Mobile IP Protocol (RFC 2002), but these agents are not restricted to a single protocol or system. In fact, the term home agent, as used in this application, can refer to a home mobility manager, home location register, home serving entity, or any other agent at a home network210having the responsibility to manage mobility-related functionality for a mobile node225. Likewise, the term mobility agent gateway, as used in this application, can refer to a foreign agent, serving mobility manager, visited location register, visiting serving entity, or any other agent on a foreign network having the responsibility to manage mobility-related functionality for a mobile node225.

In the mobile IP communications system shown inFIG. 3, the mobile node225is identified by a permanent IP address. While the mobile node225is coupled to its home network210, the mobile node225receives information packets like any other fixed node on the home network210. When mobile, the mobile node225can also locate itself on foreign network, such as network230or250. When located on foreign network230or250, the home network210sends data communications to the mobile node225by “tunneling” the communications to the foreign network230or250.

The mobile node225keeps the local mobility anchor213informed of its current location, or foreign network association, by registering a care-of address with the local mobility anchor213. Essentially, the care-of address represents the foreign network where the mobile node225is currently located. If the local mobility anchor213receives an information packet addressed to the mobile node225while the mobile node225is located on a foreign network230, the local mobility anchor213will “tunnel” the information packet to foreign network230for subsequent transmission to mobile node225.

The foreign agent235participates in informing the local mobility anchor213of the mobile node225current care-of address. The foreign agent235also receives information packets for the mobile node225after the information packets have been forwarded to the foreign agent235by the local mobility anchor213. Moreover, the foreign agent235serves as a default router for out-going information packets generated by the mobile node225while connected to the foreign network230.

The mobile node225participates in informing the local mobility anchor225of its current location and requests connections to the associated foreign network. When the mobile node225transitions to connecting to foreign network250, the mobile node225obtains appropriate information regarding the address of the foreign network250and/or the foreign agent255from an agent advertisement.

When first connected to the local mobility anchor213, mobile node225would have created an entry on the binding cache entry table inFIG. 2that specified the mobile node identification for the first access type. The access type field of information is included in this binding cache entry table inFIG. 2, with the mobile node identification field.FIG. 2is a binding cache entry table260that possesses at least column and row entries for the mobile node identification265and the access type267.

In the system shown onFIG. 3, multiple access types on a single foreign network250are supported by multiple interfaces, such as interface241and277. Because the correspondence of the same access type on the binding cache entry table ofFIG. 2may not indicate an inherent handover to a different foreign network from the prior connected foreign network, the proxy binding update request will include a handover indicator for the analysis by the local mobility anchor213.

The handover indicator would include a new field in the transmission packet that would indicate a handover to the same access type on the same foreign network or a handover to a new foreign network. This information could also be indicated by a flag or other indicator to show the type of handover that will be initiated, e.g. flag “1” equals handover to same access type on same foreign network, flag “0” equals handover to different foreign network. The new field could also indicate if the handover status is unknown, or this is an initial request for a proxy binding update request. Other fields can be maintained on the binding cache entry table, and the transmission packets may be expanded to accommodate the new access type field of information.

The local mobility anchor213will check subsequent proxy binding update requests received from the mobile node225to determine the handover indicator status. If the handover indicator indicates that the mobile node is being connected to a different foreign network, the local mobility anchor113will initiate a protocol for a handover of the mobile node225to a new foreign network, such as a handover of mobile node225from foreign network250to foreign network230. The local mobility anchor213will create a new binding cache entry for the mobile node, and the care-of addressing and home network prefix will be changed to designate the new foreign network as the network where the mobile node225can be located, which information will be transmitted to the proper mobility access gateway235and the mobile node225.

If the handover indicator indicates that a handover is being requested to different access type connection for the mobile node225on the same foreign network250, the local mobility anchor213will initiate a protocol for designating a home network prefix for the foreign network250where the mobile node225was previously located without any indication of a handover to a new foreign network. If that is the case, the entry for the mobile node225will be modified on the binding cache entry table to indicate that the mobile node225is still connected to the first foreign network250, which information will be transmitted to the proper mobility access gateway235and the mobile node225.

That is, this handover indicator may simply show the new connection for the mobile node225is to a new interface for the same access type on the same foreign network250, as opposed to a handover to a new foreign network. If so, the local mobility anchor213will respond to the proxy binding update request with a proxy binding update response having a home network prefix indicator that points to the first foreign network250. In this manner, a receipt of new proxy binding update request at the local mobility anchor213does not automatically create a new home network prefix for this mobile node, which solves some of the problems with determining whether a handover of the mobile node care-of addressing is necessary and whether it is necessary to designate a new foreign network or the same foreign network for this care-of addressing for the mobile node.

As an alternative embodiment that is covered by the scope of the invention, when first connected to the local mobility anchor213, mobile node225would have created an entry on the binding cache entry table inFIG. 4that specified the mobile node identification for the first access type and interface identification information. The access type field of information is included in this binding cache entry table inFIG. 4, with the mobile node identification field, and the interface identification information in column269would have indicated the specific interface information for interface241or277.FIG. 2is a binding cache entry table260that possesses at least column and row entries for the mobile node identification265, the access type267, and the interface269.

In the system shown onFIG. 3, multiple access types on a single foreign network250are supported by multiple interfaces, such as interface241and277. Because the correspondence of the same access type on the binding cache entry table ofFIG. 4would include additional information that the local mobility anchor would use to analyze whether the proxy binding update request relates to a handover to a different foreign network230from the prior connected foreign network250or a handover to a different interface for the same access type on the same foreign network250.

In addition to the access type information and the handover indicator described above, the proxy binding update request would include a new field in the transmission packet that would identify the interface that will be used to connect the mobile node to the foreign network. The new field could also indicate if the interface identification is unknown. Other fields can be maintained on the binding cache entry table, and the transmission packets may be expanded to accommodate the new access type field of information.

The local mobility anchor213will check subsequent proxy binding update requests received from the mobile node225to determine the handover indicator status. If the access type, handover indicator and interface identification information indicates that the mobile node is being connected to a different foreign network, the local mobility anchor113will initiate a protocol for a handover of the mobile node225to a new foreign network, such as a handover of mobile node225from foreign network250to foreign network230. The local mobility anchor213will create a new binding cache entry for the mobile node, and the care-of addressing and home network prefix will be changed to designate the new foreign network as the network where the mobile node225can be located, which information will be transmitted to the proper mobility access gateway235and the mobile node225.

If the access type, handover indicator, and interface identification information indicates that a handover is being requested to different access type connection for the mobile node225on the same foreign network250, the local mobility anchor213will initiate a protocol for designating a home network prefix for the foreign network250where the mobile node225was previously located without any indication of a handover to a new foreign network. If that is the case, the entry for the mobile node225will be modified on the binding cache entry table to indicate that the mobile node225is still connected to the first foreign network250, which information will be transmitted to the proper mobility access gateway235and the mobile node225.

That is, the access type, handover indicator, and interface information may simply show the new connection for the mobile node225is to a new interface for the same access type on the same foreign network250, as opposed to a handover to a new foreign network. If so, the local mobility anchor213will respond to the proxy binding update request with a proxy binding update response having a home network prefix indicator that points to the first foreign network250. In this manner, a receipt of new proxy binding update request at the local mobility anchor213does not automatically create a new home network prefix for this mobile node, which solves some of the problems with determining whether a handover of the mobile node care-of addressing is necessary and whether it is necessary to designate a new foreign network or the same foreign network for this care-of addressing for the mobile node.

While preferred embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention.