Protection switching of virtual connections at the data link layer
DCFirst Claim
1. A ring network, comprising:
- a number of network elements, each including first and second switch fabrics;
at least two uni-directional busses coupled between the first and second switch fabrics;
a number of ring segments coupled between adjacent network elements to form first and second routes for transporting cells using virtual connections wherein, for each virtual connection, one route is the working route and the other route is the protection route;
wherein the first and second switch fabrics of each network element are associated with one of the first and second routes; and
wherein the first and second switch fabrics of each network element separately track the status of a number of virtual connections such that when an error is detected by one of the switch fabrics associated with a working route for a virtual connection, the switch fabric detecting the error communicates the change in state for the virtual connection to the other switch fabric over one of the first and second uni-directional busses to be used in a switching decision.
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Abstract
A ring network is provided. The ring network includes a number of network elements, each including first and second switch fabrics. At least two uni-directional busses are coupled between the first and second switch fabrics. A number of ring segments are coupled between adjacent network elements to form first and second routes for transporting cells using virtual connections wherein, for each virtual connection, one route is the working route and the other route is the protection route. The first and second switch fabrics of each network element are associated with one of the first and second routes. The first and second switch fabrics of each network element separately track the status of a number of virtual connections such that when an error is detected by one of the switch fabrics associated with a working route for a virtual connection, the switch fabric detecting the error communicates the change in state for the virtual connection to the other switch fabric over one of the first and second uni-directional busses to be used in a switching decision.
60 Citations
30 Claims
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1. A ring network, comprising:
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a number of network elements, each including first and second switch fabrics; at least two uni-directional busses coupled between the first and second switch fabrics; a number of ring segments coupled between adjacent network elements to form first and second routes for transporting cells using virtual connections wherein, for each virtual connection, one route is the working route and the other route is the protection route; wherein the first and second switch fabrics of each network element are associated with one of the first and second routes; and wherein the first and second switch fabrics of each network element separately track the status of a number of virtual connections such that when an error is detected by one of the switch fabrics associated with a working route for a virtual connection, the switch fabric detecting the error communicates the change in state for the virtual connection to the other switch fabric over one of the first and second uni-directional busses to be used in a switching decision. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A network element for a ring network having first and second routes for transporting cells using virtual connections wherein, for each virtual connection, one route is the working route and the other route is the protection route, the network element comprising:
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a first ring interface module that is coupled to the first route, a second ring interface module that is coupled to the second route; an access interface module having first and second switch fabrics that are coupled to the first and second interface modules, respectively; first and second uni-directional busses that provide a communication path between the first and second switch fabrics; wherein the ring interface modules generate error cells when an error is detected on the route associated with the ring interface module that affects one or more of the virtual connections transmitted on the route; and wherein the first and second switch fabrics of the access interface module track the state of the virtual connections such that when an error cell is received by a switch fabric that is associated with a working route for a virtual connection, the switch fabric communicates the change in state of the virtual connection to the other switch fabric over one of the first and second uni-directional busses to be used in making a switching decision. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A network element for a ring network having first and second routes for transporting cells using virtual connections wherein, for each virtual connection, one route is the working route and the other route is the protection route, the network element comprising:
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a first ring interface module that is coupled to the first route; a second ring interface module that is coupled to the second route; an access interface module having first and second switch fabrics that are coupled to the first and second interface modules, respectively; first and second unidirectional busses that provide a communication path between the first and second switch fabrics; wherein the first and second switch fabrics of the access interface module track the state of the virtual connections such that when a change in state of a virtual connection is detected by one of the first and second switch fabrics, the one switch fabric communicates the detected change to the other switch fabric over one of the first and second unidirectional busses to be used in making a switching decision.
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14. A method for protection switching in a ring network having first and second routes for transporting cells using virtual connections wherein, for each virtual connection, one route is the working route and the other route is the protection route, the method comprising:
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detecting an error in one of the first and second routes (the “
errored route”
);generating error cells for each virtual connection that is affected by the detected error; injecting the error cells to be transmitted downstream on the errored route; receiving the error cells at a first switch fabric at a downstream network element associated with the errored route; communicating the change in state of the errored route to a second switch fabric of the downstream network element associated with the other of the first and second routes (the “
other route”
);determining whether the state of the other route is acceptable for a protection switch; when the state of the other route is acceptable, and the other route is configured as the protection route for a virtual connection, automatically configuring the second switch fabric to establish the other route to be the working route for the virtual connection; when the state of the other route is not acceptable, and the other route is configured as the protection route for a virtual connection, responding to the first switch fabric with a message that the protection switch is denied; and notifying a processor associated with the first and second switch fabrics that the protection switch was denied. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for protection switching in a ring network having first and second routes for transporting cells using virtual connections wherein, for each virtual connection, one route is the working route and the other route is the protection route, the method comprising:
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monitoring the first and second routes for changes in at least one selected condition at first and second switch fabrics of a network element; communicating a change in state of one of the first and second routes (the “
changed route”
) detected by one of the first and second switch fabrics to the other of the first and second switch fabrics associated with the other of the first and second routes (the “
other route”
);determining whether the state of the other route is acceptable for a protection switch; when the state of the other route is acceptable, and the other route is configured as the protection route for a virtual connection, automatically configuring the other of the first and second switch fabrics to establish the other route to be the working route for the virtual connection; when the state of the other route is not acceptable, and the other route is configured as the protection route for a virtual connection, responding to the one of the first and second switch fabrics with a message that the protection switch is denied; and notifying a processor associated with the first and second switch fabrics that the protection switch was denied. - View Dependent Claims (26, 27, 28)
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29. A method for protection switching in a ring network having first and second routes for transporting cells using virtual connections wherein, for each virtual connection, one route is the working route and the other route is the protection route, the method comprising:
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detecting an error in one of the first and second routes (the “
errored route”
);generating error cells for each virtual connection that is affected by the detected error; injecting the error cells to be transmitted downstream on the errored route; receiving the error cells at a first switch fabric at a downstream network element associated with the errored route; communicating the change in state of the errored route to a second switch fabric of the downstream network element associated with the other of the first and second routes (the “
other route”
);determining whether the state of the other route is acceptable for a protection switch; when the state of the other route is acceptable, and the other route is configured as the protection route for a virtual connection, automatically configuring the second switch fabric to establish the other route to be the working route for the virtual connection; and when the errored route returns to an acceptable condition, configuring the first switch fabric to establish the errored route as the working route for the virtual connection. - View Dependent Claims (30)
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Specification