Patents by Inventor Kent K. Leung

Kent K. Leung has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7227863
    Abstract: Methods and apparatus for maintaining Mobile IP operation in a Home Agent are disclosed. In a Home Agent, a Mobile Node is registered and a registration entry is created in a mobility binding table for the Mobile Node. A multicast message is then sent to a virtual router group to which the Home Agent belongs and with which the Home Agent shares a virtual IP address. The multicast message notifies the virtual router group of the registration. A similar process may be performed when a Mobile Node is de-registered. When an active or non-active Home Agent is initialized, it sends a multicast mobility binding table request to the redundancy group indicating that bindings are requested. The Home Agent may then receive bindings in response to the request and update its mobility binding table with the received bindings.
    Type: Grant
    Filed: November 9, 2001
    Date of Patent: June 5, 2007
    Assignee: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Madhavi W. Chandra
  • Patent number: 7224673
    Abstract: Methods and apparatus for compressing registration request and reply messages are disclosed. A compressed registration request is sent by a Mobile Node to a Foreign Agent or a Home Agent (in the case of a co-located care-of address). Communication with the Mobile Node is performed using compressed registration messages, while communication between a Foreign Agent and Home Agent is performed using standard registration request and reply formats. Thus, when a Foreign Agent receives a compressed registration request, it expands the registration request and sends it to the Home Agent for processing. Upon receipt of the registration reply from the Home Agent, the Foreign Agent compresses the registration reply and sends it to the Mobile Node. When a Mobile Node registers directly with the Home Agent via a co-located care-of address, the registration request and reply messages need not be expanded, since the Home Agent is capable of interpreting, processing and generating compressed registration messages.
    Type: Grant
    Filed: May 24, 2002
    Date of Patent: May 29, 2007
    Assignee: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Alpesh Patel
  • Patent number: 7168090
    Abstract: Methods and apparatus for authenticating a mobile node are disclosed. A server is configured to provide a plurality of security associations associated with a plurality of mobile nodes. A packet identifying a mobile node may then be sent to the server from a network device such as a Home Agent. A security association for the mobile node identified in the packet may then be obtained from the server. The security association may be sent to the network device to permit authentication of the mobile node. Alternatively, authentication of the mobile node may be performed at the server by applying the security association.
    Type: Grant
    Filed: June 10, 2004
    Date of Patent: January 23, 2007
    Assignee: Cisco Technology, Inc.
    Inventor: Kent K. Leung
  • Patent number: 7152238
    Abstract: Methods and apparatus for sending a registration request packet on behalf of a node that supports PPP but does not support Mobile IP is implemented in a Foreign Agent. The method comprises accepting a call from the node and receiving authentication information associated with a PPP authentication protocol from the node, the authentication information enabling a PPP node to be authenticated. From this authentication information, a PPP node profile is obtained. The PPP node profile includes registration information associated with the node that enables proxy registration to be performed by the Foreign Agent on behalf of the node, where the registration information associated with the node identifies a Home Agent associated with the node. The registration information may also include other information that may be pertinent to the composition of a registration request packet.
    Type: Grant
    Filed: December 29, 2000
    Date of Patent: December 19, 2006
    Assignee: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Gopal K. Dommety
  • Patent number: 7149229
    Abstract: Methods and apparatus for updating accounting information for a mobile node operating according to Mobile IP Protocol are disclosed. A network device which supports Mobile IP composes a request packet for the mobile node. The request packet identifies the mobile node and includes at least one counter associated with accounting information pertaining to the mobile node. The request packet is then sent to a server adapted for performing accounting. The server then logs the accounting information for the mobile node. The server may then send a reply packet to the network device acknowledging logging of the accounting information pertaining to the mobile node. A bill for Mobile IP services may then be generated from the accounting information.
    Type: Grant
    Filed: January 8, 1999
    Date of Patent: December 12, 2006
    Assignee: Cisco Technology, Inc.
    Inventor: Kent K. Leung
  • Patent number: 7130629
    Abstract: Methods and apparatus for performing registration on behalf of a session associated with a mobile node are disclosed. The mobile node composes a registration request including a NAI identifying a userID and a sub-NAI that uniquely identifies a session associated with the NAI. The mobile node then sends the registration request. When the Home Agent authenticates the mobile node, the Home Agent returns an IP address associated with the session. The NAI and sub-NAI may then be mapped to this IP address in a mobility binding table associated with the Home Agent as well as a visitor table associated with the Foreign Agent to which the mobile node has roamed.
    Type: Grant
    Filed: March 8, 2000
    Date of Patent: October 31, 2006
    Assignee: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Gopal Dommety
  • Patent number: 7079504
    Abstract: Methods and apparatus for optimizing IP multicast data transmission in a mobile IP environment include a Foreign Agent that is capable of receiving an information request associated with a host membership report sent from a mobile node and for providing information identifying a Home Agent associated with the mobile node to a multicast router process to enable the multicast router process to send a join host group message to the Home Agent. A Home Agent receives the join host group message and sends the join host group message toward a source of IP multicast data packets. Both the Foreign Agent and the Home Agent set up a data path between the Home Agent and the Foreign Agent, thereby enabling data packets addressed to the multicast group address to be forwarded by the Home Agent to the Foreign Agent. The Home Agent does not replicate multicast IP data packets addressed to the multicast group address prior to being forwarded by the Home Agent to the Foreign Agent.
    Type: Grant
    Filed: July 6, 2004
    Date of Patent: July 18, 2006
    Assignee: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Gopal K. Dommety
  • Patent number: 7079520
    Abstract: Methods and apparatus for establishing communication between a Mobile Node and a Home Agent are disclosed. The Home Agent receives a registration request packet from the Mobile Node, the registration request packet including an IP source address and a Home Agent address. The Home Agent then detects from the registration request packet when network address translation has been performed. When it has been detected that network address translation has been performed, a tunnel is set up between the Home Agent address and the IP source address.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: July 18, 2006
    Assignee: Cisco Technology, Inc.
    Inventors: Gaetan Feige, Rabih A. Dabboussi, Kent K. Leung, Milind M. Kulkarni
  • Patent number: 7042864
    Abstract: Methods and apparatus for enabling a Mobile Node supporting mobile IP to roam without an assigned IP address and receive lookups indicating that a Corresponding Node wants to send information to the Mobile Node are disclosed. A name lookup may be sent from a Corresponding Node to a Home Agent that has previously registered the Mobile Node. The name lookup may be sent through an intermediate device, including a Domain Name Server, such that the intermediate device contacts the Home Agent. During the name lookup process, an IP address is allocated to the Mobile Node and a data path is established between the Home Agent and the Mobile Node via a Foreign Agent. When the lookup is completed successfully, the Home Agent sends the IP address allocated to the Mobile Node in the name lookup process to the device requesting the lookup. The IP address of the Mobile Node may then be used by the Corresponding Node to “push” information to the Mobile Node.
    Type: Grant
    Filed: August 1, 2000
    Date of Patent: May 9, 2006
    Assignee: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Gopal K. Dommety
  • Patent number: 6982967
    Abstract: Methods and apparatus for enabling mobility of a node that does not support Mobile IP include sending a node attachment message from an access point to a Foreign Agent indicating that a node has been detected in a vicinity of the Foreign Agent. The Foreign Agent composes and sends a registration request to a Home Agent on behalf of the node. The Home Agent sends a registration reply to the Foreign Agent. The Foreign Agent then sends an attachment acknowledgment message to the access point indicating whether the node is now capable of receiving packets via the Foreign Agent. While the node is visiting the Foreign Agent, the access point redirects packets sent by the node to the Foreign Agent.
    Type: Grant
    Filed: June 29, 2000
    Date of Patent: January 3, 2006
    Assignee: Cisco Technology, Inc.
    Inventor: Kent K. Leung
  • Patent number: 6963918
    Abstract: An invention is disclosed that includes a Foreign Agent that supports Mobile IP and is configured to enable a node visiting the Foreign Agent to send IP packets including voice information via an IP address obtained from an H.323 gateway. This is accomplished, in part, by sending an agent advertisement identifying an H.323 gateway on the foreign network. A packet is received from the node, where the packet is addressed to the H.323 gateway and requests an IP address associated with a destination. A packet including the requested IP address is forwarded to the node. An IP packet addressed to the IP address and including voice information may then be received from the node. A node visiting the Foreign is capable of sending IP packets including voice information and receives an agent advertisement identifying an H.323 gateway on a foreign network associated with the Foreign Agent. The node sends a packet addressed to the H.323 gateway, where the packet requests an IP address associated with a destination.
    Type: Grant
    Filed: June 29, 2000
    Date of Patent: November 8, 2005
    Assignee: Cisco Technology, Inc.
    Inventor: Kent K. Leung
  • Patent number: 6959341
    Abstract: Methods and apparatus for implementing a Home Agent supporting Mobile IP and being capable of allocating one or more networks to a mobile router which registers with the Home Agent comprise receiving a registration request packet from the mobile router, the registration request packet including a network allocation extension indicating one or more networks being requested by the mobile router from the Home Agent. The one or more networks are allocated to the mobile router corresponding to the network allocation extension of the registration request packet. A registration reply packet including a network allocation extension identifying the one or more networks allocated to the mobile router is then sent to the mobile router.
    Type: Grant
    Filed: December 20, 2000
    Date of Patent: October 25, 2005
    Assignee: Cisco Technology, Inc.
    Inventor: Kent K. Leung
  • Patent number: 6947451
    Abstract: In a router or packet processing node supporting Mobile IP, a method for causing packets to be retransmitted from a sender to a mobile node is disclosed. A plurality of packets having associated update information are received. The packets are intended for the mobile node. The update information associated with at least one of the received packets is stored. When the mobile node is disconnected from the sender and reconnects to the sender, without waiting for a timeout the sender is directed to retransmit a last portion of packets to the mobile node based on the stored update information. Apparatus and computer readable medium embodiments are also disclosed.
    Type: Grant
    Filed: November 20, 2002
    Date of Patent: September 20, 2005
    Assignee: Cisco Technology, Inc.
    Inventors: Gopal K. Dommety, Kent K. Leung, Roy Laurens
  • Publication number: 20040260752
    Abstract: An invention is disclosed that optimizes resource management within a PDSN. This is accomplished through the modification of functions of a AAA server. Specifically, when a node (e.g., mobile node) is authenticated by a AAA server in response to a request by a target PDSN to which the node has roamed, the AAA server may send a disconnect request message to a source PDSN indicating that the node has moved from the source PDSN. In this manner, the source PDSN is notified that it should terminate its session with the node and release resources associated with the session (e.g., PPP session). The source PDSN may then send a message to the AAA server indicating whether the session was successfully terminated (and whether the resources associated with that session were released).
    Type: Application
    Filed: June 19, 2003
    Publication date: December 23, 2004
    Applicant: Cisco Technology, Inc.
    Inventors: Madhavi W. Chandra, Kent K. Leung, Parviz Yegani
  • Publication number: 20040234075
    Abstract: Methods and apparatus for authenticating a mobile node are disclosed. A server is configured to provide a plurality of security associations associated with a plurality of mobile nodes. A packet identifying a mobile node may then be sent to the server from a network device such as a Home Agent. A security association for the mobile node identified in the packet may then be obtained from the server. The security association may be sent to the network device to permit authentication of the mobile node. Alternatively, authentication of the mobile node may be performed at the server by applying the security association.
    Type: Application
    Filed: June 10, 2004
    Publication date: November 25, 2004
    Applicant: Cisco Technology, Inc., A corporation of California
    Inventor: Kent K. Leung
  • Publication number: 20040213260
    Abstract: An invention is disclosed that enables proxy Mobile IP registration to be performed in a secure manner. Various security mechanisms may be used independently, or in combination with one another, to authenticate the identity of a node during the registration process. First, an Access Point receiving a packet from a node verifies that the source MAC address identified in the packet is in the Access Point's client association table. In addition, as a second mechanism, the Access Point ensures that a one-to-one mapping exists for the source MAC address and source IP address identified in the packet in a mapping table maintained by the Access Point. As a third mechanism, a binding is not modified in the mobility binding table maintained by the Home Agent unless there is a one-to-one mapping in the mobility binding table between the source MAC address and the source IP address.
    Type: Application
    Filed: April 28, 2003
    Publication date: October 28, 2004
    Applicant: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Gopal Dommety
  • Publication number: 20040202126
    Abstract: In accordance with one aspect of the invention, methods and apparatus for distributing a Mobile IP registration request to one of a plurality of Home Agents are disclosed. A registration request is received from a Foreign Agent to which the Mobile Node has roamed. One of the plurality of Home Agents is selected. The registration request is then forwarded to the selected one of the plurality of Home Agents. The source IP address of the registration request is an IP address of the Foreign Agent to which the Mobile Node has roamed, thereby enabling the selected one of the plurality of Home Agents to send a Mobile IP registration reply directly to the Foreign Agent without interception by the network device.
    Type: Application
    Filed: May 6, 2002
    Publication date: October 14, 2004
    Applicant: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Alpesh Patel, Stefan B. Raab
  • Patent number: 6795857
    Abstract: Methods and apparatus for enabling a node that does not support Mobile IP to roam from a first Foreign Agent to a second Foreign Agent are disclosed. In a Foreign Agent that supports Mobile IP, a method of registering a node that does not support Mobile IP with a Home Agent that supports Mobile IP includes detecting a node in a vicinity of the Foreign Agent, composing a registration request specifying a node ID associated with the node, and sending the registration request to the Home Agent. When the Home Agent receives the registration request from a first Foreign Agent, the Home Agent updates a mobility binding table to associate the first Foreign Agent with the node. In addition, the Home Agent notifies a second Foreign Agent to update its visitor table to reflect roaming of the node from the second Foreign Agent to the first Foreign Agent.
    Type: Grant
    Filed: September 9, 2002
    Date of Patent: September 21, 2004
    Assignee: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Gopal K. Dommety
  • Patent number: 6765892
    Abstract: Methods and apparatus for optimizing IP multicast data transmission in a mobile IP environment include a Foreign Agent that is capable of receiving an information request associated with a host membership report sent from a mobile node and for providing information identifying a Home Agent associated with the mobile node to a multicast router process to enable the multicast router process to send a join host group message to the Home Agent. A Home Agent receives the join host group message and sends the join host group message toward a source of IP multicast data packets. Both the Foreign Agent and the Home Agent set up a data path between the Home Agent and the Foreign Agent, thereby enabling data packets addressed to the multicast group address to be forwarded by the Home Agent to the Foreign Agent. The Home Agent does not replicate multicast IP data packets addressed to the multicast group address prior to being forwarded by the Home Agent to the Foreign Agent.
    Type: Grant
    Filed: June 26, 2000
    Date of Patent: July 20, 2004
    Assignee: Cisco Technology, Inc.
    Inventors: Kent K. Leung, Gopal K. Dommety
  • Patent number: 6760444
    Abstract: Methods and apparatus for authenticating a mobile node are disclosed. A server is configured to provide a plurality of security associations associated with a plurality of mobile nodes. A packet identifying a mobile node may then be sent to the server from a network device such as a Home Agent. A security association for the mobile node identified in the packet may then be obtained from the server. The security association may be sent to the network device to permit authentication of the mobile node. Alternatively, authentication of the mobile node may be performed at the server by applying the security association.
    Type: Grant
    Filed: January 8, 1999
    Date of Patent: July 6, 2004
    Assignee: Cisco Technology, Inc.
    Inventor: Kent K. Leung