US5422876A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Out-of-band loopback control scheme
Assignee: AT&T Labs Inc
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Filing: 1993-09-07
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Granted: 1995-06-06
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Expires: 2013-09-07
Abstract
Abstract A communications method and a network for carrying out the method are provided. The network includes a loopback command system and a first link station connected to a communications link. The link traverses several loopback-capable devices as it extends from the first link station to a second link station remote from the first link station. The loopback command system controls the loopback-capable devices to cause them to loopback. In order to command a loopback of a particular loopback-capable device, the first link station generates an initial loopback value and forwards the same over the link to a downstream loopback-capable device located along the link. Each loopback-capable device receives a loopback value from an upstream device, and compares if the received value is equal to a predetermined value. If the loopback value is equal to the predetermined value, the device is placed into a loopback state. Otherwise, the loopback value is modified by the device, and the modified loopback value is forwarded to the next downstream device located along the link. The loopback value may be represented by a digital bit word, or by the position of a particular bit within a bit stream of the link.
Inventors
- 👤 Andy Turudic
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:00
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/02; H04J3/14; H04B; H04B17/00; H04B17/40; H04B17/401; H04L; H04L1/00; H04L1/24; H04L1/242; H04L1/243
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
225 words
A loopback command system for use in a communications network, the communications network having a first link station connected to a serial digital bit stream communications link, wherein the link traverses several devices as it extends from a first location, at the first link station, to a second location, and further wherein the loopback command system causes a loopback to occur at one or more of the several devices, said loopback command system comprising: means provided within said first link station for transmitting an initial loopback value over said link; and processing means provided within selected ones of said several devices for processing a received loopback value, and, based on the processing, performing one or both of forwarding a processed loopback value to a downstream device and looping back at the device performing the processing, said processing means further comprising: means for receiving a forwarded loopback value from an upstream device, said forwarded loopback value comprising a modified loopback value if there is an upstream device that is provided with said processing means, said forwarded loopback value otherwise comprising said initial loopback value; means for modifying said forwarded loopback value to form a modified loopback value to be transmitted to a next device along said link; and means for activating a loopback of the receiving device when said forwarded loopback value reaches a predetermined level.
Claim 2
Dependent Claim
225 words
A loopback command system for use in a communications network, the communications network having a first link station connected to a serial digital bit stream communications link, wherein the link traverses several devices as it extends from a first location, at the first link station, to a second location, and further wherein the loopback command system causes a loopback to occur at one or more of the several devices, said loopback command system comprising: means provided within said first link station for transmitting an initial loopback value over said link; and processing means provided within selected ones of said several devices for processing a received loopback value, and, based on the processing, performing one or both of forwarding a processed loopback value to a downstream device and looping back at the device performing the processing, said processing means further comprising: means for receiving a forwarded loopback value from an upstream device, said forwarded loopback value comprising a modified loopback value if there is an upstream device that is provided with said processing means, said forwarded loopback value otherwise comprising said initial loopback value; means for modifying said forwarded loopback value to form a modified loopback value to be transmitted to a next device along said link; and means for activating a loopback of the receiving device when said forwarded loopback value reaches a predetermined level.
Claim 3
Dependent Claim
32 words
The loopback command system according to claim 1, wherein said modifying means, which modifies said forwarded loopback value to form a modified loopback value, comprises means for decrementing said forwarded loopback value.
Claim 4
Dependent Claim
32 words
The loopback command system according to claim 1, wherein said modifying means, which modifies said forwarded loopback value to form a modified loopback value, comprises means for incrementing said forwarded loopback value.
Claim 5
Dependent Claim
26 words
The loopback command system according to claim 1, wherein the forwarded loopback value is represented by a word formed with loopback bits transmitted over said link.
Claim 6
Dependent Claim
46 words
The loopback command system according to claim 4, wherein the level of the forwarded loopback value is defined as a function of the magnitude of said word, and further wherein said modifying means modifies said forwarded loopback value by subtracting a smaller word from said word.
Claim 7
Dependent Claim
14 words
The loopback command system according to claim 5, wherein said smaller word is 1.
Claim 8
Dependent Claim
46 words
The loopback command system according to claim 4, wherein the level of the forwarded loopback value is defined as a function of the magnitude of said word, and further wherein said modifying means modifies said forwarded loopback value by adding a smaller word to said word.
Claim 9
Dependent Claim
14 words
The loopback command system according to claim 7, wherein said smaller word is 1.
Claim 10
Dependent Claim
95 words
The loopback command system according to claim 1, wherein said bit stream comprises a superframe, each superframe having several frames of channels, each channel having several bits, and further wherein one bit per frame comprises a superframe bit, and another bit per frame comprises a loopback bit, the superframe bit indicating the boundary of a superframe, said loopback command system further comprising: means for forming a word representing a loopback value with selected ones of respective loopback bits transmitted over several frames, a loopback bit for each frame constituting a particular bit within said word.
Claim 11
Dependent Claim
28 words
The loopback command system according to claim 9, wherein the first bit in time of the selected respective loopback bits comprises the most significant bit of said word.
Claim 12
Dependent Claim
37 words
The loopback command system according to claim 10, wherein said most significant bit of said word comprises a loopback bit that is transmitted immediately after the indication by said superframe bit of the boundary of a superframe.
Claim 13
Dependent Claim
23 words
The loopback command system according to claim 1, wherein the forwarded loopback value is represented by a loopback bit transmitted over said link.
Claim 14
Dependent Claim
57 words
The loopback command system according to claim 12, wherein the level of the forwarded loopback value is defined as a function of the position of said loopback bit relative to a position bit, and further wherein said modifying means modifies said forwarded loopback value by shifting the position of said loopback bit relative to the position bit.
Claim 15
Dependent Claim
32 words
The loopback command system according to claim 13, wherein said position bit comprises a superframe pulse which corresponds to the beginning of a new superframe within the bit stream of said link.
Claim 16
Dependent Claim
56 words
The loopback command system according to claim 12, wherein said modifying means comprises means for shifting the position of said loopback bit by one frame, and said loopback activating means comprises means for activating a loopback of the receiving device when the position of said forwarded loopback bit coincides with the position of the position bit.
Claim 17
Dependent Claim
32 words
The loopback command system according to claim 14, wherein said position bit comprises a superframe pulse that corresponds to the beginning of a new superframe within the bit stream of said link.
Claim 18
Dependent Claim
98 words
The loopback command system according to claim 12, wherein said modifying means comprises means for shifting the position of said loopback bit within the link's bit stream, and wherein said loopback activating means comprises voting means for determining if said forwarded loopback bit coincides with the position of the position bit for N consecutive occurrences of the position bit within the bit stream of the communications link, and means for activating a loopback of the receiving device when the position of said forwarded loopback bit coincides with the position of the position bit for said N consecutive occurrences.
Claim 19
Dependent Claim
206 words
A loopback control method for use in a communications network, the communications network having a first link station connected to a serial digital bit stream communications link, wherein the link traverses several devices as it extends from a first location, at the first link station, to a second location, and further wherein the loopback control method causes a loopback to occur at one or more of the several devices, said method comprising: transmitting from said first link station an initial loopback value over said link; and at selected ones of said several devices, processing a received loopback value, and, based on the processing, performing one or both of forwarding a processed loopback value to a downstream device and looping back at the device performing the processing, said processing comprising the steps of: receiving a forwarded loopback value from an upstream device, said forwarded loopback value comprising a modified loopback value when there is an upstream device that performs said processing, said forwarded loopback value otherwise comprising said initial loopback value; modifying said forwarded loopback value to form a modified loopback value to be transmitted to a downstream device; and activating a loopback of the receiving device when said forwarded loopback value has reached a predetermined level.
Claim 20
Dependent Claim
206 words
A loopback control method for use in a communications network, the communications network having a first link station connected to a serial digital bit stream communications link, wherein the link traverses several devices as it extends from a first location, at the first link station, to a second location, and further wherein the loopback control method causes a loopback to occur at one or more of the several devices, said method comprising: transmitting from said first link station an initial loopback value over said link; and at selected ones of said several devices, processing a received loopback value, and, based on the processing, performing one or both of forwarding a processed loopback value to a downstream device and looping back at the device performing the processing, said processing comprising the steps of: receiving a forwarded loopback value from an upstream device, said forwarded loopback value comprising a modified loopback value when there is an upstream device that performs said processing, said forwarded loopback value otherwise comprising said initial loopback value; modifying said forwarded loopback value to form a modified loopback value to be transmitted to a downstream device; and activating a loopback of the receiving device when said forwarded loopback value has reached a predetermined level.
Claim 21
Dependent Claim
28 words
The method according to claim 18, wherein said modifying, which includes modifying said forwarded loopback value to form a modified loopback value, comprises decrementing said forwarded loopback value.
Claim 22
Dependent Claim
28 words
The method according to claim 18, wherein said modifying, which includes modifying said forwarded loopback value to form a modified loopback value, comprises incrementing said forwarded loopback value.
Claim 23
Dependent Claim
24 words
The method according to claim 18, wherein said forwarded loopback value is represented by a word formed with loopback bits transmitted over said link.
Claim 24
Dependent Claim
44 words
The method according to claim 21, wherein the level of said forwarded loopback value is defined as a function of the magnitude of said word, and further wherein said modifying includes modifying said forwarded loopback value by subtracting a smaller word from said word.
Claim 25
Dependent Claim
12 words
The method according to claim 22, wherein said smaller word is 1.
Claim 26
Dependent Claim
44 words
The method according to claim 21, wherein the level of said forwarded loopback value is defined as a function of the magnitude of said word, and further wherein said modifying includes modifying said forwarded loopback value by adding a smaller word to said word.
Claim 27
Dependent Claim
12 words
The method according to claim 24, wherein said smaller word is 1.
Claim 28
Dependent Claim
88 words
The method according to claim 18, wherein said bit stream comprises superframes, each superframe having several frames of channels, each channel having several bits, and further wherein one bit per frame comprises a superframe bit, and another bit per frame comprises a loopback bit, the superframe bit indicating the boundary of a superframe, said method further comprising: forming a word representing a loopback value with selected ones of respective loopback bits transmitted over several frames, a loopback bit for each frame constituting a particular bit within said word.
Claim 29
Dependent Claim
26 words
The method according to claim 26, wherein the first bit in time of the selected respective loopback bits comprises the most significant bit of said word.
Claim 30
Dependent Claim
35 words
The method according to claim 27, wherein the most significant bit of said word includes the loopback bit that is transmitted immediately after the indication by said superframe bit of the boundary of a superframe.
Claim 31
Dependent Claim
21 words
The method according to claim 18, wherein the forwarded loopback value is represented by a loopback bit transmitted over said link.
Claim 32
Dependent Claim
55 words
The method according to claim 29, wherein the level of said forwarded loopback value is defined as a function of the position of said loopback bit relative to a position bit, and further wherein said modifying includes modifying said forwarded loopback value by shifting the position of said loopback bit relative to the position bit.
Claim 33
Dependent Claim
30 words
The method according to claim 30, wherein said position bit includes a superframe pulse that corresponds to the beginning of a new superframe within the bit stream of said link.
Claim 34
Dependent Claim
50 words
The method according to claim 30, wherein said modifying includes shifting the position of said loopback bit by one frame, and further wherein said loopback activating comprises activating a loopback of the receiving device when the position of said processed loopback bit coincides with the position of the position bit.
Claim 35
Dependent Claim
30 words
The method according to claim 32, wherein said position bit comprises a superframe bit that corresponds to the beginning of a new superframe within the bit stream of said link.
Claim 36
Dependent Claim
112 words
Apparatus for placement along a transmission link, said apparatus being capable of entering a loopback state upon receipt of a loopback command signal which comprises a loopback value, said apparatus comprising: means for receiving a forwarded loopback value from a position upstream from said apparatus along a transmission link; means for modifying said forwarded loopback value to form a modified loopback value; means for forwarding said modified loopback value in a downstream direction along said transmission link; means for determining when said forwarded loopback value is equal to a predetermined value; and means for entering said apparatus into a loopback state when said forwarded loopback value is equal to said predetermined value.
Claim 37
Dependent Claim
112 words
Apparatus for placement along a transmission link, said apparatus being capable of entering a loopback state upon receipt of a loopback command signal which comprises a loopback value, said apparatus comprising: means for receiving a forwarded loopback value from a position upstream from said apparatus along a transmission link; means for modifying said forwarded loopback value to form a modified loopback value; means for forwarding said modified loopback value in a downstream direction along said transmission link; means for determining when said forwarded loopback value is equal to a predetermined value; and means for entering said apparatus into a loopback state when said forwarded loopback value is equal to said predetermined value.
Claim 38
Dependent Claim
117 words
Apparatus for placement along a transmission link, said apparatus being capable of entering a loopback state upon receipt of a loopback command signal which comprises a loopback value equal to a predetermined value, said apparatus comprising: means for receiving a forwarded loopback value from a position upstream from said apparatus along a transmission link; means for modifying said forwarded loopback value to form a modified loopback value; means for forwarding said modified loopback value in a downstream direction along said transmission link; means for determining when said modified loopback value is equal to said predetermined value; and means for entering said apparatus into a loopback state when said modified loopback value is equal to said predetermined value.
Claim 39
Dependent Claim
117 words
Apparatus for placement along a transmission link, said apparatus being capable of entering a loopback state upon receipt of a loopback command signal which comprises a loopback value equal to a predetermined value, said apparatus comprising: means for receiving a forwarded loopback value from a position upstream from said apparatus along a transmission link; means for modifying said forwarded loopback value to form a modified loopback value; means for forwarding said modified loopback value in a downstream direction along said transmission link; means for determining when said modified loopback value is equal to said predetermined value; and means for entering said apparatus into a loopback state when said modified loopback value is equal to said predetermined value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-06-05 | 1998-12-05 | 1999-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-05 | 2002-12-05 | 2003-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-05 | 2006-12-05 | 2007-06-06 | $7700.00 | Window Closed / Lapsed |