PATENT DOCUMENT

Publication Number: US-8311552-B1
Application Number: US-6589905-A
Country: US
Kind Code: B1

Title: Dynamic allocation of host IP addresses

Abstract:
The present invention facilitates dynamic allocation of home IP addresses for a mobile node, when it is roaming away from a home network and supported by a foreign network. After the mobile node obtains a care-of address from the foreign network, a stateful or stateless configuration process is used to dynamically allocate a home IP address for the mobile node. In the stateful approach, a binding update message is used to request a home IP address for the mobile node from its home agent. In a stateless embodiment, the mobile node will create a home IP address, which is sent to the home agent for verification via the binding update message. The home agent will receive the home IP address in the binding update message, verify the home IP address, and send acknowledgement of the verification, assuming the home IP address is verified, to the mobile node.

Claims:
1. A method for dynamically allocating an IP address for a mobile node comprising:
 receiving directly from a mobile node at a home agent of the mobile node, a binding update message comprising request indicia representing a request to allocate a home IP address for the mobile node when the mobile node roams to a foreign network from a home network of the mobile node that includes the home agent; 
 allocating the home IP address for the mobile node at the home agent in response to directly receiving from the mobile node the request to allocate the home IP address when the mobile node roams to the foreign network; and 
 sending the home IP address to the mobile node. 
 
     
     
       2. The method of  claim 1  wherein the home IP address is sent to the mobile node in a binding acknowledgement message. 
     
     
       3. The method of  claim 1  wherein the binding update message further comprises identifier indicia identifying the mobile node, the method further comprising associating the home IP address with the identifier indicia. 
     
     
       4. The method of  claim 1  wherein the binding update message further comprises a care-of address for the mobile node, the method further comprising associating the care-of address with the home IP address. 
     
     
       5. The method of  claim 1  wherein the binding update message is the first binding update message sent by the mobile node upon moving to a new access point or foreign network. 
     
     
       6. The method of claim I wherein the binding update message is received from the mobile node via a foreign network. 
     
     
       7. A method for dynamically allocating an IP address for a mobile node comprising:
 sending to a home agent directly from a mobile node a binding update message comprising request indicia representing a request to allocate a home IP address for the mobile node when the mobile node roams to a foreign network from a home network of the mobile node that includes the home agent; and 
 receiving the home IP address for the mobile node, wherein the home agent allocates the home IP address in response to directly receiving from the mobile node the request to allocate the home IP address when the mobile node roams to the foreign network. 
 
     
     
       8. The method of  claim 7  wherein the home IP address is received in a binding acknowledgement message. 
     
     
       9. The method of  claim 7  wherein the binding update message further comprises identifier indicia identifying the mobile node. 
     
     
       10. The method of  claim 7  further comprising obtaining a care-of address for the mobile terminal and sending the care-of address to the home agent in the binding update message. 
     
     
       11. The method of  claim 7  wherein the binding update message is the first binding update message sent by the mobile node upon moving to a new access point or foreign network.

Description:
This application claims the benefit of U.S. provisional application Ser. No. 60/548,496 filed Feb. 27, 2004 and U.S. provisional application Ser. No. 60/569,790 filed May 10, 2004, the disclosures of which are hereby incorporated by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates in general to mobile communications, and in particular to dynamically allocating home IP addresses in a mobile communication environment. 
     BACKGROUND OF THE INVENTION 
     The rapid acceptance and expansion of the Internet and mobile communications has led to consumers demanding greater functionality from their mobile nodes, such as personal computers, personal digital assistants, telephones, and the like. In particular, consumers want the ability to move from one network access point to another on the same or different networks without disrupting communication connectivity. 
     Newer Internet Protocols (IPs), such as IPv6, support such functionality by allowing a mobile node to move from one wireless access point or base station to another without disrupting communications. However, each mobile node must be provided with a home IP address. Currently, service providers must manually configure static home IP addresses for the mobile nodes of their millions of subscribers. This provisioning process is very cumbersome, time consuming, and expensive. Accordingly, there is a need for the ability to dynamically allocate and use home IP addresses for mobile nodes in an efficient and cost-effective manner, including when the mobile node is roaming in a foreign network. 
     SUMMARY OF THE INVENTION 
     The present invention facilitates dynamic allocation of home IP addresses for a mobile node, when the mobile node is roaming away from a home network and being supported by a foreign network. After the mobile node obtains a care-of address from the foreign network, a stateful or stateless configuration process is used to dynamically allocate a home IP address for the mobile node. In the stateful approach, a binding update message is used to request a home IP address for the mobile node from a home agent for the mobile node. The binding update message will also include an identifier for the mobile node, and perhaps the care-of address. Upon receiving the binding update message, the home agent will allocate a home IP address for the mobile node and send the home IP address to the mobile node, perhaps in a binding acknowledgement message sent in response to the binding update message. In a stateless embodiment, the mobile node will create a home IP address, and then send the home IP address to the home agent for verification via the binding update message. The home agent will receive the home IP address in the binding update message, verify the home IP address for the mobile node, and send acknowledgement of the verification, assuming the home IP address is verified, to the mobile node. Again, the acknowledgement may be provided in a binding acknowledgement message, which is sent to the mobile node by the home agent. 
     In either embodiment, the home agent may update domain name servers, which are accessible via the home network for the mobile node or foreign networks, to allow correspondent nodes to obtain the home IP address for the mobile node. The home agent may allow other correspondent nodes to communicate with the mobile node directly or indirectly using the home IP address. The care-of address for the mobile node may be sent with the binding update messages, wherein the home agent will associate the care-of address with the home IP address of the mobile node, and perhaps the identifier indicia for the mobile node. The care-of addresses may be obtained in a stateful or stateless configuration. As such, the stateful approach would allow the mobile node to obtain the care-of address from the foreign network. The mobile node may create the home IP address based on an identifier for the mobile node and prefix information for the home network. A stateless approach would entail the mobile node creating the care-of address based on an identifier for the mobile node and a prefix for and obtained from the foreign network. 
     Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the invention, and together with the description serve to explain the principles of the invention. 
         FIG. 1  is a block representation of a communication environment according to one embodiment of the present invention. 
         FIG. 2  is a communication flow diagram according to one embodiment of the present invention. 
         FIG. 3  is a communication flow diagram according to a second embodiment of the present invention. 
         FIG. 4  is a block representation of a mobile node according to one embodiment of the present invention. 
         FIG. 5  is a block representation of a home agent according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the invention and illustrate the best mode of practicing the invention. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the invention and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims. 
     With reference to  FIG. 1 , a block representation of a communication environment  10  is illustrated according to one embodiment of the present invention. The communication environment  10  allows a mobile node  12 , such as a personal computer, personal digital assistant, telephone, or the like, to facilitate wireless communications via the mobile node&#39;s home network  14  or other networks via an appropriate access point  16 . Generally, the home network  14  will include a home agent  18  to facilitate communications via the home network  14 , and in particular other networks, which are generally referred to as foreign networks  20 . The home agent  18  may take different forms, including that of a traditional home agent and authentication, authorization, and accounting (AAA) server. The home network  14  may be connected to the foreign networks  20  directly or via an intermediate network, such as the Internet  22 . 
     In operation, the mobile node  12  may facilitate communications through the home network  14  via the access point  16 , or through the foreign networks  20  via access points  24 . When roaming in a foreign network  20 , the mobile node  12  will interact with the home agent  18  as will be described below, to support such roaming and allow other entities to reach the mobile node  12  directly or indirectly through the home agent  18 . When using Internet Protocol version 6 (IPv6), a mobile node  12  can move from one access point  16 ,  24  to another without losing network connectivity. When moving from one network to another or from one access point  16 ,  24  to another, the mobile node  12  must register with the home agent  18  and be provided with a home IP address to facilitate communications. At present, the home IP address must be statically provisioned, and the various network elements in the home network  14  as well as in the foreign networks  20  must be provisioned such that the statically configured home IP address for the mobile node  12  is globally known and trackable via the home agent  18 . Unfortunately, this process of statically configuring the home IP addresses for each mobile node  12  is manually intensive and expensive. The present invention allows for the home IP address to by dynamically allocated as necessary when the mobile node  12  moves from one network to another. 
     When the mobile node  12  roams away from the home network  14  and connects to a foreign network  20  via an access point  24 , the foreign network  20  will provide a care-of address for the foreign network  20 . The care-of address may be a Global Unicast Address with a network prefix corresponding to the foreign network  20 . The mobile node  12  can obtain this address using stateless auto-configuration, or by using a stateful configuration method such as Dynamic Host Control Protocol. The stateless auto-configuration allows the mobile node  12  to generate its own addresses by using a combination of local information already available to the mobile node  12 , as well as non-local information that may be provided by an access router (AR)  26  on the foreign network  20 . For example, the access routers  26  may advertise the prefixes that identify the subnet or subnets that are associated with the foreign network  20 . The mobile node  12  may generate an interface identifier that uniquely identifies an interface on the subnet. An address, such as the care-of address, is formed by combining the prefix and the interface identifier. 
     For stateful configuration, the mobile node  12  would obtain pertinent addresses, such as the care-of address, from a server (not shown) on the foreign network  20 . In addition to addresses, other information may be obtained using stateless auto-configuration or stateful configuration methods. 
     In the communication environment  10  of  FIG. 1 , a node that can communicate or correspond with the mobile node  12  is referred to as a correspondent node  28 , which may take the same forms as the mobile node  12 . In a basic operation, the correspondent node  28  sends packets to the mobile node  12  using the mobile node&#39;s home IP address. The home agent  18  will intercept these packets and tunnel them to the mobile node&#39;s current care-of address on the foreign network  20 . Similarly, the mobile node  12  may send packets to the correspondent node  28  through the home agent  18 . 
     In a more efficient embodiment, route optimization may be used, wherein the correspondent node  28  may ultimately send packets directly to the mobile node&#39;s care-of address, and the mobile node  12  may send packets directly to the correspondent node  28  using an appropriate address, without having the home agent  18  relay packets between the mobile node  12  and the correspondent node  28 . Notably, the correspondent node  28  may need to interact with the home agent  18  directly or indirectly during initial communications to obtain the care-of address for the mobile node  12 . Alternatively, once an initial packet has been sent to the mobile node  12  through the home agent  18 , the mobile node  12  may send the care-of address to the correspondent node  28 . Such operation is set forth in the standards for IPv6, and should be well known to those skilled in the art. 
     Once the care-of address is obtained for the mobile node  12 , the mobile node  12  will send a binding update message to the home agent  18 . The binding update message effectively registers the mobile node&#39;s care-of address in association with the mobile node  12  with the home agent  18 . For the present invention, the binding update message is used to assist in dynamically allocating the home IP address for the mobile node  12 . 
     In a first embodiment, a stateful configuration method is used, wherein the binding update message is modified to include a request for the home agent  18  to allocate a home IP address for the mobile node  12 . The binding update message will include the care-of address currently assigned to the mobile node  12 , as well as identifier indicia for the mobile node  12 . The identifier indicia may be any type of mobile node identifier, including a network address identifier, mobile node name, or mobile node identification number. The home agent  18  will be able to identify the mobile node  12  based on the identifier indicia, allocate a home IP address for the mobile node  12 , and associate the care-of address and the home IP address with the mobile node  12 . In response to the binding update message, the home agent  18  will send a binding acknowledgement message back to the mobile node  12 , wherein the binding acknowledgement message will include the home IP address allocated for the mobile node  12 . 
     In an alternative embodiment, a stateless auto-configuration approach is taken for allocating a home IP address for the mobile node  12 . In particular, the mobile node  12  will have access to home network information such as a home network prefix and the mobile node&#39;s identifier indicia, and will create a home IP address based on the home network prefix and identifier indicia. The home IP address created at the mobile node  12  is then sent to the home agent  18  in a binding update message, which will include a request to verify the home IP address for the mobile node  12  having the provided identifier indicia. The home agent  18  will then verify the home IP address as being valid and usable by the mobile node  12  and will respond with appropriate verification or denial in the binding acknowledgement message. Thus, the present invention uses the binding update messages to support dynamic allocation of home IP addresses for the mobile node  12 . Once the home agent  18  has allocated a home IP address or verified a home IP address for the mobile node  12 , it may update domain name servers  30  or other entities in the home network  14 , foreign networks  20 , or the Internet  22 , to allow other entities such as correspondent nodes  28  to obtain the home IP address, which is dynamically associated with the mobile node  12 , to facilitate communications. 
       FIGS. 2 and 3  illustrate communication flow diagrams for the stateful and stateless techniques for dynamically allocating home IP addresses for the mobile node  12  when roaming to a foreign network  20 . In both scenarios, the care-of address is obtained from the access router  26  using a stateless configuration technique. With particular reference to  FIG. 2 , a stateful embodiment for dynamically allocating a home IP address is illustrated. Assume that the mobile node  12  initially recognizes that it has moved from the home network  14  to a foreign network  20  (step  100 ). As such, the mobile node  12  may listen for foreign network information, which may include the foreign network prefix to be used for creating a care-of address for the mobile node  12  (step  102 ). Upon receiving the foreign network information, the mobile node  12  will create a care-of address based on the foreign network prefix and identifier indicia associated with the mobile node  12  (step  104 ). Once the care-of address is created, the mobile node  12  will send a binding update message to the home agent  18  (step  106 ). In this embodiment, the request for a home IP address is provided in the first binding update message that the mobile node  12  sends to the home agent  18  upon engaging the foreign network  20 . The binding update message will include the care-of address and identifier indicia for the mobile node  12 , as well as a request for a home IP address (step  106 ). The home agent  18  will then allocate a home IP address for the mobile node  12  (step  108 ) and send the home IP address to the mobile node  12  in a binding acknowledgement message (step  110 ). 
     Based on the identifier indicia, the home agent  18  will provide name indicia for the mobile node  12  for the domain name server  30  (step  112 ) and then send a Domain Name Server (DNS) update to the domain name server  30  (step  114 ). The DNS update will include the home IP address and name indicia for the mobile node  12 . The domain name server  30  will then update its registry (step  116 ). At this point, the correspondent node  28  can access the domain name server  30  using the appropriate name indicia for the mobile node  12  to obtain the most current home IP address for the mobile node  12  (steps  118  and  120 ). 
     Turning now to  FIG. 3 , the stateless configuration technique of the present invention for dynamically allocating a home IP address for the mobile node  12  is illustrated. Assume that the mobile node  12  initially recognizes that it has moved from the home network  14  to a foreign network  20  (step  200 ). As such, the mobile node  12  may listen for foreign network information, which may include the foreign network prefix to be used for creating a care-of address for the mobile node  12  (step  202 ). Upon receiving the foreign network information, the mobile node  12  will create a care-of address based on the foreign network prefix and identifier indicia associated with the mobile node  12  (step  204 ). 
     At this point, stateless configuration of the home IP address is implemented, wherein the mobile node  12  will create the home IP address based on home network information, such as the home network prefix and the mobile node&#39;s identifier indicia (step  206 ). Once the home IP address is created, the mobile node  12  will send a binding update to the home agent  18  with a request to verify the home IP address as well as the identifier indicia for the mobile node  12  (step  208 ). The home agent  18  will verify that the home IP address is appropriate for the mobile node  12  associated with the identifier indicia provided in the binding update (step  210 ). Assuming the home IP address is properly verified, the home agent  18  will send a binding acknowledgement message indicating whether the home IP address was verified (step  212 ). 
     Based on the identifier indicia, the home agent  18  will provide name indicia for the mobile node  12  for the domain name server  30  (step  214 ) and then send a Domain Name Server (DNS) update to the domain name server  30  (step  216 ). The DNS update will include the home IP address and name indicia for the mobile node  12 . The domain name server  30  will then update its registry (step  218 ). At this point, the correspondent node  28  can access the domain name server  30  using the appropriate name indicia for the mobile node  12  to obtain the most current home IP address for the mobile node  12  (steps  220  and  222 ). 
     From the above, the present invention allows for dynamic allocation of home IP addresses, and in certain embodiment supports this functionality by modifying the binding update and binding acknowledgement messages generally used in mobile Internet protocols, such as IPv6. In select embodiments, the initial binding update message is triggered when the mobile node  12  moves to a foreign network  20 . The initial binding update messages are used to either request that a home IP address be allocated by the home agent  18  or request that a created home IP address be verified by the home agent  18 . The term “allocation” is used to cover both of the embodiments described above, wherein the verification process is simply a step in the allocation technique provided by the present invention. Those skilled in the art will recognize that other messages may be used to obtain the functionality afforded by the present invention. As such, the appended claims are to be construed accordingly. 
     With reference to  FIG. 4 , a block representation of a mobile node  12  is illustrated. The mobile node  12  will generally include a control system  32  having memory  34  with the requisite software  36  and data  38  to operate as described above. The control system  32  will be associated with a user interface  40  to facilitate input and output functions associated with a user, as well as a communication interface  42  to facilitate communications with the home network  14  or the foreign networks  20  via appropriate access points  16 ,  24 . The communication interface  22  will generally be a wireless communication interface supporting cellular or local wireless communication techniques such as those used in wireless local area networks. However, the communication interface  42  may support a physical wired connection with the access points  16 ,  24 . 
       FIG. 5  is a block representation of a home agent  18  according to one embodiment of the present invention. The home agent  18  may be implemented in any type of routing, switching, bridging, or serving node, and will include a control system  44  associated with memory  46  with the requisite software  48  and data  50  to operate as described above. The control system  44  will also be associated with a network interface  52  to facilitate communications via the home network  14 . 
     Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present invention. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.

Metadata:
Filing Date: 20050225
Publication Date: 20121113
Grant Date: 20121113
Priority Date: 20040227
Inventors: KHALIL MOHAMED
AKHTAR HASEEB
Assignee: APPLE INC
CPC Classifications: [{"code": "H04L61/5076", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W8/26", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L61/5076", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W80/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L61/4511", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W80/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L61/4511", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W8/26", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 47114588