Method and apparatus for routing ATM cells in an AD-ATM LAN
First Claim
1. A communications network for transfer of Asynchronous Transfer Mode (ATM) cells between mobile users, said network comprising:
- a plurality of relocatable switching nodes, said switching nodes being coupled to one another via a high speed backbone link; and
one or more wireless access links included in each of said switching nodes adapted to couple to said mobile users, wherein a first mobile user transmitting data to a second mobile user in said network is associated with a source home node and said second mobile user receiving data is associated with a destination home node, and wherein said ATM cells in a connection between said first mobile user and said second mobile user are substantially always routed along a path from said first mobile user including said source home node and along a path from said source home node to said destination home node and then along a path including said destination home node to said second mobile user, wherein in-sequence delivery of said ATM cells between said first and second mobile user is enabled to be maintained,further including a source local node and a destination local node selected from said plurality of switching nodes, said source local node associated with a present position of said first mobile user, and said destination local node associated with a present position of said second mobile user, wherein said ATM cells transmitted from said first mobile user are initially received at said source local node and said ATM cells received at said second mobile user are ultimately transmitted from said destination local node,wherein said source local node and said destination local node are updatable as a mobile user moves throughout said network.
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Accused Products
Abstract
A system and method for routing ATM cells in a wireless ATM local area network (LAN) that use portable base station (PBS) switching nodes. Routing of cells to and from mobile users within the network is accomplished utilizing a novel routing scheme which preserves cell sequence. Each user transmitting data to another user is associated with a Source Home Station or node and each user receiving data is associated with a Destination Home Station or node. When a connection is established in the network between a first mobile user and a second mobile user, the ATM cells are routed along a fixed path from the first mobile user to the associated Source Home Station and along a fixed path between the Source Home Station to the Destination Home Station and then along a fixed path from the Destination Home Station to the second destination user. In this way cell sequence is maintain by utilizing the Source Home to Destination Home path. Mobile users within the network are also associated with a Local PBS which can be different from the Home Stations as the mobile moves around the network. The Local PBSs associated with the mobile user are slowly updated to be the Home Stations to cure inefficient routing.
203 Citations
23 Claims
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1. A communications network for transfer of Asynchronous Transfer Mode (ATM) cells between mobile users, said network comprising:
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a plurality of relocatable switching nodes, said switching nodes being coupled to one another via a high speed backbone link; and one or more wireless access links included in each of said switching nodes adapted to couple to said mobile users, wherein a first mobile user transmitting data to a second mobile user in said network is associated with a source home node and said second mobile user receiving data is associated with a destination home node, and wherein said ATM cells in a connection between said first mobile user and said second mobile user are substantially always routed along a path from said first mobile user including said source home node and along a path from said source home node to said destination home node and then along a path including said destination home node to said second mobile user, wherein in-sequence delivery of said ATM cells between said first and second mobile user is enabled to be maintained, further including a source local node and a destination local node selected from said plurality of switching nodes, said source local node associated with a present position of said first mobile user, and said destination local node associated with a present position of said second mobile user, wherein said ATM cells transmitted from said first mobile user are initially received at said source local node and said ATM cells received at said second mobile user are ultimately transmitted from said destination local node, wherein said source local node and said destination local node are updatable as a mobile user moves throughout said network. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A communications network for transfer of Asynchronous Transfer Mode (ATM) cells between mobile users, said network comprising:
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a plurality of relocatable switching nodes, said switching nodes being coupled to one another via a high speed backbone link; and one or more wireless access links included in each of said switching nodes adapted to couple to said mobile users, wherein a first mobile user transmitting data to a second mobile user in said network is associated with a source home node and said second mobile user receiving data is associated with a destination home node, and wherein said ATM cells in a connection between said first mobile user and said second mobile user are substantially always routed along a path from said first mobile user including said source home node and along a path from said source home node to said destination home node and then along a path including said destination home node to said second mobile user, wherein in-sequence delivery of said ATM cells between said first and second mobile user is enabled to be maintained, further including a source local node and a destination local node selected from said plurality of switching nodes, said source local node associated with a present position of said first mobile user, and said destination local node associated with a present position of said second mobile user, wherein said ATM cells transmitted from said first mobile user are initially received at said source local node and said ATM cells received at said second mobile user are ultimately transmitted from said destination local node, wherein said first mobile user may move from a first location to a second location during a connection thereby associating itself with a new source local node, and wherein cell sequence is preserved in said connection by issuance of a "Tail" signal from said source local node associated with said first location. - View Dependent Claims (12, 13)
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14. A communications network for transfer of Asynchronous Transfer Mode (ATM) cells between mobile users said network comprising:
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a plurality of relocatable switching nodes, said switching nodes being coupled to one another via a high speed backbone link; and one or more wireless access links included in each of said switching nodes adapted to couple to said mobile users, wherein a first mobile user transmitting data to a second mobile user in said network is associated with a source home node and said second mobile user receiving data is associated with a destination home node, and wherein said ATM cells in a connection between said first mobile user and said second mobile user are substantially always routed along a path from said first mobile user including said source home node and along a path from said source home node to said destination home node and then along a path including said destination home node to said second mobile user, wherein in-sequence delivery of said ATM cells between said first and second mobile user is enabled to be maintained, further including a source local node and a destination local node selected from said plurality of switching nodes, said source local node associated with a present position of said first mobile user, and said destination local node associated with a present position of said second mobile user, wherein said ATM cells transmitted from said first mobile user are initially received at said source local node and said ATM cells received at said second mobile user are ultimately transmitted from said destination local node, wherein said first mobile user may move from a first location to a second location during a connection thereby associating itself with a new source local node, and wherein said source home node associated with said first mobile is operable to record sequence numbers of cells for its own active virtual channels (VCs), wherein said source home node notifies said first mobile user of the last sequence number of a cell received through said new source local node, and wherein said mobile retransmits appropriate cells if the last sequence number differs from said last sequence number received at said source home node.
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15. A communications network for transfer of Asynchronous Transfer Mode (ATM) cells between mobile users, said network comprising:
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a plurality of relocatable switching nodes, said switching nodes being coupled to one another via a high speed backbone link; and one or more wireless access links included in each of said switching nodes adapted to couple to said mobile users, wherein a first mobile user transmitting data to a second mobile user in said network is associated with a source home node and said second mobile user receiving data is associated with a destination home node, and wherein said ATM cells in a connection between said first mobile user and said second mobile user are substantially always routed along a path from said first mobile user including said source home node and along a path from said source home node to said destination home node and then along a path including said destination home node to said second mobile user, wherein in-sequence delivery of said ATM cells between said first and second mobile user is enabled to be maintained, further including a source local node and a destination local node selected from said plurality of switching nodes, said source local node associated with a present position of said first mobile user, and said destination local node associated with a present position of said second mobile user, wherein said ATM cells transmitted from said first mobile user are initially received at said source local node and said ATM cells received at said second mobile user are ultimately transmitted from said destination local node, wherein said second mobile user is operable to update said local destination node by sending a signaling request including a sequence number of a last received cell through the new local node to said destination home node, and said destination home node is operable to retransmit appropriate ATM cells to said new local node if the last sequence number transmitted from said destination home node does not match said sequence number of said last received cell at said second mobile user.
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16. A method for routing ATM cells in a network of mobile users which includes a plurality of high speed switching nodes adapted to be coupled to one another, said method comprising the steps of:
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establishing a source home node for a source mobile user and a destination home node for a destination mobile user for use in a connection between said source user and said destination user; and routing said ATM cells along a path from said source mobile user including said source home node, and along a path from said source home node to said destination home node, and then along a path including said destination home node to said destination user, further including the step of establishing a local node associated with a present position of a mobile user, wherein data transferred to and from said mobile user travels through said local node, wherein said local node and said source home node for a mobile user may be different nodes in said network and said local node and said destination home node for a mobile user may be different nodes in said network, further including the step of updating said local node to be said source home node and updating said local node for said mobile user to be said destination home node. - View Dependent Claims (17, 18)
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19. A method for routing ATM cells in a network of mobile users which includes a plurality of high speed switching nodes adapted to be coupled to one another, said method comprising the steps of:
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establishing a source home node for a source mobile user and a destination home node for a destination mobile user for use in a connection between said source user and said destination user; and routing said ATM cells along a path from said source mobile user including said source home node, and along a path from said source home node to said destination home node, and then along a path including said destination home node to said destination user, further including the step of establishing a local node associated with a present position of a mobile user, wherein data transferred to and from said mobile user travels through said local node, wherein a mobile user may move from a first location to a second location during a connection thereby associating itself with a new local node, and wherein a procedure for updating a source local node includes the step of issuing a "Tail" signal from a local node associated with said first location through the old local node, and waiting at said source home node for said Tail signal before serving cells from said second location of said mobile. - View Dependent Claims (20)
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21. A method for routing ATM cells in a network of mobile users which includes a plurality of high speed switching nodes adapted to be coupled to one another, said method comprising the steps of:
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establishing a source home node for a source mobile user and a destination home node for a destination mobile user for use in a connection between said source user and said destination user; and routing said ATM cells along a path from said source mobile user including said source home node, and along a path from said source home node to said destination home node, and then along a path including said destination home node to said destination user, further including the step of establishing a local node associated with a present position of a mobile user, wherein data transferred to and from said mobile user travels through said local node, wherein a mobile user may move from a first location to a second location during a connection thereby associating itself with a new local node, and wherein a procedure for updating a source local node includes the steps of; generating from said mobile user a handoff request to said new local node; forwarding said handoff request to said source home node through said old local node; setting up a connection between said new local node and said source home node; notifying said mobile user from said new local node of a new VPI and VCI and a sequence number of a last received one of said ATM cells; and retransmitting from said destination home node appropriate ones of said ATM cells if said sequence number is not equal to the sequence number of its last transmitted cell.
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22. A method for routing ATM cells in a network of mobile users which includes a plurality of high speed switching nodes adapted to be coupled to one another, said method comprising the steps of:
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establishing a source home node for a source mobile user and a destination home node for a destination mobile user for use in a connection between said source user and said destination user; and routing said ATM cells along a path from said source mobile user including said source home node, and along a path from said source home node to said destination home node, and then along a path including said destination home node to said destination user, further including the step of establishing a local node associated with a present position of a mobile user, wherein data transferred to and from said mobile user travels through said local node, wherein a mobile user may move from a first location to a second location during a connection thereby associating itself with a new local node, wherein the old local node was the same node as said source home node, a procedure for updating a source local node and preserving a sequence of said ATM cells including the steps of; generating from said mobile user a handoff request to said new local node; forwarding said handoff request to said source home node; setting up a connection between said new local node and said source home node; notifying said mobile user from said new local node of a new VPI and VCI.
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23. A method for routing ATM cells in a network of mobile users which includes a plurality of high speed switching nodes adapted to be coupled to one another, said method comprising the steps of:
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establishing a source home node for a source mobile user and a destination home node for a destination mobile user for use in a connection between said source user and said destination user; and routing said ATM cells along a path from said source mobile user including said source home node, and along a path from said source home node to said destination home node, and then along a path including said destination home node to said destination user, further including the step of establishing a local node associated with a present position of a mobile user, wherein data transferred to and from said mobile user travels through said local node, wherein a mobile user may move from a first location to a second location during a connection thereby associating itself with a new local node, and wherein a procedure for updating a destination local node includes the steps of; generating from said mobile user a handoff request to said new local node with a sequence number included of a last one of said ATM cells received; forwarding said handoff request to said destination home node through the old local node; setting up a connection between said new local node and said source home node; notifying said mobile user from said new local node of a new VPI and VCI; and retransmitting form said mobile user appropriate ones of said ATM cells if said sequence number is not equal to the sequence number of its last transmitted cell.
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Specification