Label selection for end-to-end label-switched traffic through a communications network
First Claim
1. A method of label selection for end-to-end transport of label switched traffic through a communications network between a source node and a destination node, the method comprising the steps of:
- a) launching a request message toward the destination node from the source node, the request message including a label list having one or more label identifiers indicative of respective corresponding labels available for use by the source node; and
b) revising the label list at each successive hop between the source node and the destination node, based on labels available for use by each respective hop, to produce a reduced label list;
whereby the reduced label list includes any label identifiers indicative of respective corresponding labels available for end-to-end transport of label switched traffic between the source node and the destination node; and
wherein the communications network uses wave division multiplexing (WDM) for transport of said label switched traffic, the label switched traffic made up of packets containing labels used to switch the packets between the source node and the destination node, each label comprising a respective data transport wavelength.
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Abstract
In a method of label selection for end-to-end transport of label switched traffic through a communications network between a source node and a destination node, a request message is launched toward the destination node from the source node. The request message includes a label list having one or more label identifiers indicative of respective corresponding labels available for use by the source node. The label list is revised, at a cross-connect service each successive hop between the source node and the destination node, based on labels available for use by each respective hop, to produce a reduced label list. The reduced label list includes label identifiers indicative of respective corresponding labels available for end-to-end transport of label switched traffic between the source node and the destination node.
60 Citations
24 Claims
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1. A method of label selection for end-to-end transport of label switched traffic through a communications network between a source node and a destination node, the method comprising the steps of:
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a) launching a request message toward the destination node from the source node, the request message including a label list having one or more label identifiers indicative of respective corresponding labels available for use by the source node; and
b) revising the label list at each successive hop between the source node and the destination node, based on labels available for use by each respective hop, to produce a reduced label list;
whereby the reduced label list includes any label identifiers indicative of respective corresponding labels available for end-to-end transport of label switched traffic between the source node and the destination node; and
wherein the communications network uses wave division multiplexing (WDM) for transport of said label switched traffic, the label switched traffic made up of packets containing labels used to switch the packets between the source node and the destination node, each label comprising a respective data transport wavelength. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
a) selecting one of the label identifiers from the reduced label list; and
b) setting up an end-to-end label switched path between the source node and the destination node using the respective label corresponding to the selected label identifier.
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6. A method as claimed in claim 5, wherein the one of the label identifiers is selected at random.
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7. A method as claimed in claim 5, wherein the step of setting up an end-to-end label switched path comprises a step of sending a mapping message containing the selected label identifier from the destination node toward the source node, the mapping message retracting the path traversed by the request message.
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8. A method as claimed in claim 7, further comprising, upon receipt of the mapping message at each hop, a step of assigning the label to the end-to-end label switched path if the label corresponding to the selected label identifier is still available for use by the hop.
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9. A method as claimed in claim 7, further comprising, upon receipt of the mapping message at each hop, a step of sending a mapping failure message to the destination node if the label corresponding to the selected label identifier is not available for use by the hop.
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10. A method as claimed in claim 9, further comprising, upon receipt of the mapping failure message by the destination node, the steps of:
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a) revising the reduced label list by removing the selected label identifier, b) if the reduced label list is empty, sending a request rejection message to the source node; and
c) if the reduced label list contains at least one label identifier;
i) selecting a new label identifier from the reduced label list; and
ii) setting up an end-to-end label switched path between the source node and the destination node using the respective label corresponding to the selected label identifier.
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11. A communications network for label selection for end-to-end transport of label switched traffic though the communications network, the communications network comprising:
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a) a source node adapted to launch a request message toward a destination node, the request message including a label list having one or more label identifiers indicative of respective corresponding labels available for use by the source node;
b) at least one hop intermediate the source node and the destination node, each hop comprising a respective intermediate node adapted to revise the label list based on labels available for use by the respective hop, to produce a reduced label list; and
wherein the communications network uses wave division multiplexing (WDM) for transport of label switched traffic, the label switched traffic made up of packets containing labels used to switch the packets between the source node and the destination node, each label comprising a respective data transport wavelength. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
a) select one of the label identifier from the reduced label list; and
b) set up an end-to-end label switched path between the source node and the destination node using the respective label corresponding to the selected label identifier.
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16. A communications network as claimed in claim 15, wherein the destination node is adapted to set up an end-to-end label switched path by sending a mapping message containing the selected label identifier toward the source node, the mapping message retracing the path traversed by the request message.
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17. A communications network as claimed in claim 16, wherein each intermediate node is responsive to reception of the mapping message to assign the label corresponding to the selected label identifier to the end-to-end label switched path if the label is still available for use by the respective hop.
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18. A communications network as claimed in claim 16, wherein each intermediate node is responsive to reception of the mapping message to send a mapping failure message to the destination node if the label corresponding to the selected label identifier is not available for use by the receptive hop.
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19. A communications network as claimed in claim 18, wherein the destination node is responsive to reception of the mapping failure message to:
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a) revise the reduced label list by removing the selected label identifier;
b) if the reduced label list is empty, send a request rejection message to the source node; and
c) if the reduced label list contains at least one label identifier;
i) select a new label identifier from the reduced label list; and
ii) set up an end-to-end- label switched path between the source node and the destination node using the respective label corresponding to the selected label identifier.
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20. An intermediate node of a communications network adapted for end-to-end transport of label switched traffic through the communications network between a source node and a destination node, the intermediate node comprising:
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a) a label availability list including label identifiers indicative of labels available for conveying label switched tic through a respective communications link connected to the intermediate node;
b) a buffer adapted to receive a request message propagated through the communications network from the source node, the request message including a label list having label identifiers indicative of labels available for conveying label switched traffic between the source node and the intermediate node;
c) a processor adapted to revise the label list included in the received request message, based on the label availability list, to produce a reduced label list; and
wherein the communications network uses wave division multiplexing (WDM) for transport of label switched traffic, the label switched traffic made up of packets containing labels used to switch the packets between the source node and the destination node, each label comprising a respective data transport wavelength. - View Dependent Claims (21, 22, 23, 24)
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Specification