Methods and apparatus for restoring connections in an ATM network
First Claim
1. A method of operating a switch in a network including a plurality of switches, a source device, and a destination device, the method comprising the steps of:
- monitoring to detect a node or link failure affecting a connection in an established communication path between the source and destination devices thereby affecting a call using the established communication path;
operating the switch in response to the detection of a node or link failure, to determine if the switch is on the source or destination device side of the node or link failure;
if it is determined that the switch is on the source side of a detected node or link failure, operating the switch to initiate a re-routing operation, the re-routing operation involving the steps of;
assigning a new virtual connection identifier to the affected call;
accessing alternate route information stored in a routing table included within the switch to identify an alternate route to be used to re-establish the connection with the destination device; and
transmitting a re-route set-up message used to re-establish the connection with the destination device.
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Accused Products
Abstract
Methods and apparatus for detecting faults and restoring connections in networks including, e.g., ATM networks are described. The restoration methods of the present invention can be applied on an application by application or user by user basis. In accordance with the present invention virtual connections affected by link or node failures are restored through re-routing as opposed to establishing a completely new connection between a source and a destination device. VPI/VCI values are assigned at the time of re-routing thereby avoiding the potential problem of VPI/VCI exhaustion which may be encountered when backup VPI/VCI values are assigned at the time a communication session is initiated. The connection restoration process of the present invention is initiated by a node on the source side of a connection detecting a failure and initiating a re-routing operation or transmitting a message to the source switch to initiate a re-routing operation. A node on the destination device side of a failed connection is used for initiating the release of network resources reserved at the switches which were used as part of the no longer used path of the re-routed call. The destination device side node (switch) detecting a fault transmits a re-route release message to downstream switches. Restoration methods applicable to pre-planned hop-by-hop, pre-planned source routing and dynamic source routing embodiments are described. In one embodiment, ATM assured mode data transport operation on signaling channels is used to detect node and/or link failures.
352 Citations
32 Claims
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1. A method of operating a switch in a network including a plurality of switches, a source device, and a destination device, the method comprising the steps of:
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monitoring to detect a node or link failure affecting a connection in an established communication path between the source and destination devices thereby affecting a call using the established communication path; operating the switch in response to the detection of a node or link failure, to determine if the switch is on the source or destination device side of the node or link failure; if it is determined that the switch is on the source side of a detected node or link failure, operating the switch to initiate a re-routing operation, the re-routing operation involving the steps of; assigning a new virtual connection identifier to the affected call; accessing alternate route information stored in a routing table included within the switch to identify an alternate route to be used to re-establish the connection with the destination device; and transmitting a re-route set-up message used to re-establish the connection with the destination device. - View Dependent Claims (2, 3)
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4. A method of operating a switch in a network including a plurality of switches, a source device, and a destination device, the method comprising the steps of:
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monitoring to detect a node or link failure affecting a connection in an established communication path between the source and destination devices thereby affecting a call using the established communication path; operating the switch in response to the detection of a node or link failure, to determine if the switch is on the source or destination device side of the node or link failure; if it is determined that the switch is on the destination side of a detected node or link failure, operating the switch to initiate a limited capacity release operation; if it is determined that the switch is on the source side of a detected node or link failure, operating the switch to initiate a re-routing operation, the re-routing operation involving the steps of; assigning a new virtual connection identifier to the affected call; accessing alternate route information stored in a routing table included within the switch to identify an alternate route to be used to re-establish the connection with the destination device; and transmitting a re-route set-up message used to re-establish the connection with the destination device. - View Dependent Claims (5, 6, 7, 8)
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9. A method of operating a switch in a network including a plurality of switches, a source device, and a destination device, the method comprising the steps of:
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monitoring to detect a node or link failure affecting a connection in an established communication path between the source and destination devices thereby affecting a call using the established communication path; operating the switch in response to the detection of a node or link failure, to determine if the switch is on the source or destination device side of the node or link failure; if it is determined that the switch is on the source side of a detected node or link failure, operating the switch to initiate a re-routing operation, the re-routing operation involving the steps of; assigning a new virtual connection identifier to the affected call; accessing alternate route information stored in a routing table included within the switch to identify an alternate route to be used to re-establish the connection with the destination device; and transmitting a re-route set-up message used to re-establish the connection with the destination device; and further, in response to receiving a re-route setup message including a call identifier, operating the switch to perform a resource availability check to determine if sufficient resources are available to service the call identified in the re-route setup message request. - View Dependent Claims (10, 11)
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12. A method of operating a switch in a network including a plurality of switches, a source device, and a destination device, the method comprising the steps:
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monitoring to detect a node or link failure affecting a connection in an established communication path between the source and destination devices thereby affecting a call using the established communication path; operating the switch in response to the detection of a node or link failure, to determine if the switch is on the source or destination device side of the node or link failure; if it is determined that the switch is on the source side of a detected node or link failure, operating the switch to initiate a re-routing operation, the re-routing operation involving the steps of; assigning a new virtual connection identifier to the affected call; accessing alternate route information stored in a routing table included within the switch to identify an alternate route to be used to re-establish the connection with the destination device; and transmitting a re-route set-up message used to re-establish the connection with the destination device; and further, upon receiving a re-route setup message including a call identifier, performing the following steps; determining if a call record in the switch corresponding to the call identifier, included in the re-route setup message, was created or updated in response to a previous re-route setup message corresponding to the same failure event; and upon determining that a call record in the switch corresponding to the call identifier, included in the re-route setup message, was created or updated in response to a previous re-route setup message corresponding to the same failure event performing the step of; transmitting a re-route loop clear message.
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13. A method of operating a switch in a network including a plurality of switches, a source device, and a destination device, the method comprising the steps:
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monitoring to detect a node or link failure affecting a connection in an established communication path between the source and destination devices thereby affecting a call using the established communication path; operating the switch in response to the detection of a node or link failure, to determine if the switch is on the source or destination device side of the node or link failure; if it is determined that the switch is on the source side of a detected node or link failure, operating the switch to initiate a re-routing operation, the re-routing operation involving the steps of; assigning a new virtual connection identifier to the affected call; and wherein a single communication path is used to service a plurality of different calls corresponding to different applications, and wherein the switch provides calls using the same path different degrees of protection from premature connection release upon detecting a node or link failure affecting the single communication path.
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14. A method of operating a switch in a network including a plurality of switches, a source device, and a destination device, the method comprising the steps:
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monitoring to detect a node or link failure affecting a connection in an established communication path between the source and destination devices thereby affecting a call using the established communication path; operating the switch in response to the detection of a node or link failure, to determine if the switch is on the source or destination device side of the node or link failure; if it is determined that the switch is on the source side of a detected node or link failure, operating the switch to initiate a re-routing operation, the re-routing operation involving the step of; assigning a new virtual connection identifier to the affected call; and wherein the step of initiating a re-routing operation further includes the steps of; determining if the switch detecting the failure is a source switch for the affected call; if it is determined that the switch detecting the failure is the source switch for the affected call, transmitting a re-route setup message; and if it is determined that the switch detecting the failure is not a source switch for the affected call transmitting a crank back message to the source switch for the affected call to cause the source switch to perform a re-route operation. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of operating a switch in a network including a plurality of switches, a source device, and a destination device, the method comprising the steps:
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monitoring to detect a node or link failure affecting a communication path between the source and destination devices; operating the switch in response to the detection of a node or link failure, to determine if the switch is on the source or destination device side of the node or link failure; and if it is determined that the switch is on the destination side of a detected node or link failure, operating the switch to initiate a limited capacity release operation to release reserved switch capacity no longer used by the affected communication path. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A switch for use in a network including a plurality of other switches, a source device, and a destination device, the switch comprising:
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means for monitoring to detect node or link failures affecting a connection in an established communication path; means for determining, in response to the detection of a node or link failure, if the switch is on the source or destination device side of the node or link failure; means for initiating a re-routing operation when it is determined that the switch is on the source side of a node or link failure, wherein said means for initiating includes; means for assigning a new virtual connection identifier to the affected call; means for accessing alternate route information stored in a routing table included within the switch to identify an alternate route to be used to re-establish the connection with the destination device; and means for transmitting a re-route set-up message used to re-establish the connection with the destination device.
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31. A switch for use in a network including a plurality of other switches, a source device, and a destination device, the switch comprising:
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means for detecting a node or link failure affecting a communication path between the source and destination devices; means for determining, if the switch is on the source or destination device side of a detected node or link failure; and means for initiating a limited capacity release operation to release reserved switch capacity no longer used by the affected communication path. - View Dependent Claims (32)
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Specification