US6157643A
Expired / Lapsed
US
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Switching fabric
Assignee: Nokia Oyj
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Filing: 1999-05-04
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Granted: 2000-12-05
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Expires: 2019-05-04
Abstract
Abstract The present invention relates to a switching fabric for a packet-switched communications network. Said switching fabric comprises a plurality of input ports and a plurality of output ports, and a plurality of switch elements (SE1-SE5) which are arranged in multiple stages and connected with each other into a switching fabric. Each switch element has a plurality of inputs and outputs and each switch element routes a data packet present at its given input to at least one of its outputs on the basis of routing information (SRT) carried by said data packet. In order to reduce internal blocking in the switch, each switch element (SE1) in at least the first switching stage is formed by a routing network element (RE 1 ) and a shift network element (SHE 1 ), connected in series with each other so that the ith output of the routing network element is connected to the ith input of the shift network element, whereby (1) each routing network element routes the data packets according to preset, fixed rules on the basis of the routing information carried by the data packet, and (2) each shift network element shifts the data packet present on its ith input to its jth output, whereby the indices i and j are paired so that (a) within a given time slot, all the values of j are different from each other within a given shift network element, and (b) within a given time slot, a different value of j is assigned to each of the same-valued i's used in the different shift network elements.
Inventors
- 👤 Jian Ma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:05
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L49/00; H04L49/15; H04L49/1553; H04L49/1561; H04L49/1569; H04L49/25; H04L49/256; H04L49/30; H04L49/3081; H04L49/309; H04Q; H04Q3/00; H04Q3/64; H04Q3/68; H04Q3/685
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
330 words
A switching fabric for a packet-switched communications network, said switching fabric comprising a plurality of input ports and a plurality of output ports, and a plurality of switch elements (SE1-SE5) which are arranged in series so as to form a number of successive switching stages and are connected with each other via internal links passing from one switching state to another, whereby said switch elements and said internal links form a connection from a given input port to a desired output port, and whereby each switch element has inputs and outputs, and each switch element routes a data packet present at its given input to at least one of its outputs on the basis of routing information (SRT) carried by said data packet, and the switch element inputs of the first switching stage form said input ports and the outputs of the last switching stage of the fabric form said output ports, wherein each switch element (SE1) in at least the first switching stage is formed by a routing network element (RE j ) and a shift network element (SHE i ), connected in series with each other so that the ith output of the routing network element is connected to the ith input of the shift network element, whereby each routing network element routes the data packets simultaneously present at its inputs according to preset, fixed rules on the basis of the routing information carried by said data packets, whereby the routing information fails to include bits specific to the routing network element, and each shift network element shifts the data packet present on its ith input to its jth output, whereby the indices i and j are paired so that (a) within a given time slot, all the values of j are different from each other in a given shift network element, and (b) within a given time slot, a different value of j is assigned to each of the same-valued i's used in different shift network elements.
Claim 2
Dependent Claim
330 words
A switching fabric for a packet-switched communications network, said switching fabric comprising a plurality of input ports and a plurality of output ports, and a plurality of switch elements (SE1-SE5) which are arranged in series so as to form a number of successive switching stages and are connected with each other via internal links passing from one switching state to another, whereby said switch elements and said internal links form a connection from a given input port to a desired output port, and whereby each switch element has inputs and outputs, and each switch element routes a data packet present at its given input to at least one of its outputs on the basis of routing information (SRT) carried by said data packet, and the switch element inputs of the first switching stage form said input ports and the outputs of the last switching stage of the fabric form said output ports, wherein each switch element (SE1) in at least the first switching stage is formed by a routing network element (RE j ) and a shift network element (SHE i ), connected in series with each other so that the ith output of the routing network element is connected to the ith input of the shift network element, whereby each routing network element routes the data packets simultaneously present at its inputs according to preset, fixed rules on the basis of the routing information carried by said data packets, whereby the routing information fails to include bits specific to the routing network element, and each shift network element shifts the data packet present on its ith input to its jth output, whereby the indices i and j are paired so that (a) within a given time slot, all the values of j are different from each other in a given shift network element, and (b) within a given time slot, a different value of j is assigned to each of the same-valued i's used in different shift network elements.
Claim 3
Dependent Claim
34 words
A switching fabric as defined in claim 1, characterized in that said routing network element routes the incoming data packet to its output corresponding to the output port address interpreted from said routing information.
Claim 4
Dependent Claim
41 words
A switching fabric as defined in claim 1, characterized in that said routing network element routes the incoming data packets so as to sort the data packets to the routing network element outputs into an ascending/descending order of the routing information.
Claim 5
Dependent Claim
90 words
A switching fabric as defined in claim 3, characterized in that said fabric comprises traffic monitoring means (TM i ) in at least one switch element, said means serving to monitor a variable indicating the traffic load imposed on the outputs of said switch element, load detecting means (LD) responsive to said monitoring means so as to select the output subject to the highest traffic load, and conversion means (TC i ) responsive to said load detecting means for translating the routing information on the basis of the selected output.
Claim 6
Dependent Claim
22 words
A switching fabric as defined in claim 4, characterized in that said traffic monitoring means are located in one switch element only.
Claim 7
Dependent Claim
52 words
A switching fabric as defined in claim 1, characterized in that, in the kth shift network element, the value of i is paired with j mod(n) and, in the (k+1)th shift network element, the value of i is paired with (j+1) mod(n), where n is the number of shift network element outputs.
Claim 8
Dependent Claim
51 words
A switching fabric as defined in claim 1, characterized in that in each individual shift network element, the value of j paired with the same value of 1 is changed from one time slot to the next so that the value of j is continuously permutated according to a preset sequence.
Claim 9
Dependent Claim
25 words
A switching fabric as defined in claim 7, characterized in that said preset sequence permutates orderly through all the outputs of said shift network element.
Claim 10
Dependent Claim
80 words
A switching fabric as defined in claim 1, characterized in that said fabric comprises a three-stage block in which the first stage switch elements have n inputs and n outputs, the second stage switch elements have l inputs and k outputs, and the third stage switch elements have m inputs and n outputs, and that the switch elements of the first stage are formed by a routing network element and a shift network element, connected in series with each other.
Claim 11
Dependent Claim
63 words
A switching fabric as defined in claim 9, characterized in that, in the ith shift network element of the first stage, the jth output is connected to the ith input of the jth second stage switch element, and, in the ith switch element of the second stage, the jth output is connected to the ith input of the jth third stage switch element.
Claim 12
Dependent Claim
123 words
A switching fabric as defined in claim 10, characterized in that said fabric comprises N1 three-stage switch element blocks, whereby each stage of the block has N2 switch elements, an input stage of N1'N2 switch elements with N1 outputs in each switch element, whereby the kth output of ith input stage switch element is connected to the ith input of the kth block of the next stage, and an output stage of N1'N2 switch elements with N1 inputs in each switch element, whereby the kth input of ith output stage switch element is connected to the ith output of the kth block of the preceding stage, thus forming a five-stage switching fabric in which said blocks form the second, third and fourth stage.
Claim 13
Dependent Claim
40 words
A switching fabric as defined in claim 10, characterized in that said fabric comprises an aggregate number NS of stages in which the switch elements of (NS-1)/2 first stages are formed by routing network elements combined with shift network elements.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-12-05 | 2004-06-05 | 2004-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-12-05 | 2008-06-05 | 2008-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-12-05 | 2012-06-05 | 2012-12-05 | $7700.00 | Window Closed / Lapsed |