US5745476A
Expired / Lapsed
US
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Errorless switching techniques in ring network
Assignee: AT&T Inc
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Filing: 1996-07-16
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Granted: 1998-04-28
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Expires: 2016-07-16
Abstract
Abstract A method of performing errorless switching in a ring network having one or more rings and a plurality of transmitting routes. The transmission delays or lengths of at least predetermined sections of the routes are compared, and the comparison is used to determine the value of a first delay added to one of the routes. Another delay is added to enable phase alignment of signals so that errorless switching can be achieved. The delays are then adjusted to reduce cumulative delays which could degrade the quality of data transmission.
Inventors
- 👤 Sid Chaudhuri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:17
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/42; H04L12/437; H04J; H04J3/00; H04J3/02; H04J3/08; H04J3/085; H04J3/06; H04J3/062; H04J3/0626; H04J3/0629; H04J2203/00; H04J2203/0001; H04J2203/0028; H04J2203/0039; H04J2203/0042; H04J2203/0057; H04J2203/006; H04L2012/421
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
168 words
A method of performing errorless switching in a ring network comprising one or more rings and comprising a data transmitting medium exhibiting a transmission delay, said network defining a plurality of data transmitting routes along said transmitting medium including a first route and a second route, said method comprising in combination the steps of comparing the transmission delays of at least predetermined sections said first and second routes; adding a predetermined first delay to at least one of said first and second routes, the value of said first delay depending at least in part on the results of said comparing; adding a predetermined second delay to at least one of said first and second routes for enabling alignment of signals transmitted on said first and second routes and errorless switching between said first and second routes; switching between said first and second routes; and adjusting at least one of said first and second delays for reducing cumulative delays on at least one of said first and second routes.
Claim 2
Independent Claim
168 words
A method of performing errorless switching in a ring network comprising one or more rings and comprising a data transmitting medium exhibiting a transmission delay, said network defining a plurality of data transmitting routes along said transmitting medium including a first route and a second route, said method comprising in combination the steps of comparing the transmission delays of at least predetermined sections said first and second routes; adding a predetermined first delay to at least one of said first and second routes, the value of said first delay depending at least in part on the results of said comparing; adding a predetermined second delay to at least one of said first and second routes for enabling alignment of signals transmitted on said first and second routes and errorless switching between said first and second routes; switching between said first and second routes; and adjusting at least one of said first and second delays for reducing cumulative delays on at least one of said first and second routes.
Claim 3
Dependent Claim
55 words
A method as claimed in claim 1, wherein said value of said first delay is substantially zero in the event that said transmission delay along the one of said first and second routes to which said first delay is added is greater than said transmission delay along the other of said first and second routes.
Claim 4
Dependent Claim
55 words
A method, as claimed in claim 1, wherein said value of said second delay is substantially zero in the event that said transmission delay along the one of said first and second routes to which said second delay is added is greater than said transmission delay along the other of said first and second routes.
Claim 5
Dependent Claim
37 words
A method, as claimed in claim 1, wherein said value of said first delay is substantially equal to two times the delay along one of said sections minus the delay along said ring network as a whole.
Claim 6
Dependent Claim
38 words
A method, as claimed in claim 1, wherein said step of comparing comprises the steps of: storing, data from which the lengths of said sections of said first and second routes can be derived; and comparing said lengths.
Claim 7
Dependent Claim
23 words
A method, as claimed in claim 5, wherein said step of storing data comprises the step of transmitting said data with said signals.
Claim 8
Dependent Claim
33 words
A method, as claimed in claim 1, wherein said step of adjusting at least one of said first and second delays comprises the step of deleting one of said first and second delays.
Claim 9
Dependent Claim
35 words
A method, as claimed in claim 1, wherein said step of adjusting at least one of said first and second delays comprises the step of shifting at least one of said first and second delays.
Claim 10
Dependent Claim
64 words
A method, as claimed in claim 1, wherein said network comprises a first ring, and a second ring, wherein said step of adding said first delay occurs in said first ring and wherein said step of adjusting at least one of said first and second delays comprises the step of shifting at least one of said first and second delays to said second ring.
Claim 11
Dependent Claim
81 words
A method, as claimed in claim 1, wherein said network comprises a first ring, and a second ring, wherein said step of adding said first delay occurs in said second ring, wherein said step of adding a predetermined second delay comprises the step of adding a predetermined second delay to said first ring and wherein said step of adjusting at least one of said first and second delays comprises the step of deleting at least second delay from said first ring.
Claim 12
Dependent Claim
38 words
A method, as claimed in claim 1, wherein said step of adjusting at least one of said first and second delays further comprises the step of adding a third delay to said second route in said second ring.
Claim 13
Independent Claim
138 words
A method of performing errorless protection switching for a ring-configured, high speed link that connects a plurality of switching nodes comprised of an access node and an egress node, the method comprising the steps of: measuring the ring length and the length of a section of the ring which defines a first path for propagation of traffic signals between the access and egress nodes; introducing a first delay in the propagation of said traffic signals only when the length of the section of the ring is less than half of the ring length; and in response to a need for an alternate path to connect the access and egress nodes, introducing a second delay in transmission of traffic signals traversing the alternate path such that traffic signals on the first path and on the alternate path are phase-aligned.
Claim 14
Independent Claim
138 words
A method of performing errorless protection switching for a ring-configured, high speed link that connects a plurality of switching nodes comprised of an access node and an egress node, the method comprising the steps of: measuring the ring length and the length of a section of the ring which defines a first path for propagation of traffic signals between the access and egress nodes; introducing a first delay in the propagation of said traffic signals only when the length of the section of the ring is less than half of the ring length; and in response to a need for an alternate path to connect the access and egress nodes, introducing a second delay in transmission of traffic signals traversing the alternate path such that traffic signals on the first path and on the alternate path are phase-aligned.
Claim 15
Dependent Claim
15 words
The method of claim 12 wherein said first delay is introduced at the egress node.
Claim 16
Dependent Claim
51 words
The method of claim 12, further comprising the step of: in response to a failure of said first path in the propagation of said traffic signals, setting the second delay for the alternate path to be equal to twice the length of the first path minus the length of the ring.
Claim 17
Independent Claim
25 words
The method of claims 13 and 14 further comprising the step of: removing, the first delay at the egress node before setting the second delay.
Claim 18
Dependent Claim
31 words
The method of claim 12 wherein said second delay is set to near zero when the length of the section of the ring is greater than half of the ring length.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-27 | 2001-10-27 | 2002-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-27 | 2005-10-27 | 2006-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-27 | 2009-10-27 | 2010-04-28 | $7700.00 | Window Closed / Lapsed |