EP0453273A2
Expired / Lapsed
EP
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Loop back method for loop type LAN transmission line
Assignee: Panasonic Holdings Corp
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Filing: 1991-04-18
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Granted: —
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Expires: 2011-04-18
Abstract
Abstract A loop back method for a network including a plurality of node units (511, 512, 513, 514) connected in loop by duplexed transmission lines (515, 516) in the opposite directions with each other, wherein the respective node units have a function of detecting failure on the duplexed transmission lines and a loop back function for returning data received from one of the transmission lines to one of the other in the opposite direction, one of the node units commands loop back to all other node units upon detecting failure on the transmission lines, and the one node unit commands the determination of a loop back state to all other node units to thereby perform a loop back operation for the whole network.
Inventors
- 👤 Makoto Miwa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 22:23
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/42; H04L12/437
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
115 words
A loop back method for a network including a plurality of node units connected in loop by duplexed transmission lines in the opposite directions with each other, wherein said respective node units have a function of detecting failure on the duplexed transmission lines and a loop back function for returning data received from one of the transmission lines to one of the other in the opposite direction, one of said node units commands loop back to all other node units upon detecting failure on the transmission lines, and said one node unit commands the determination of a loop back state to all other node units to thereby perform loop back operation for the whole network.
Claim 2
Dependent Claim
29 words
A loop back method according to claim 1, wherein a loop state is specified by searching for node units performing loop back after the loop back has been formed.
Claim 3
Dependent Claim
59 words
A loop back method according to claim 2, wherein when an abnormal loop state is detected by determining that two node units performing loop back in the loops after the loop back has been formed do not exist, all the other node units are commanded to release the loop back, and thereafter a loop back command is transmitted again.
Claim 4
Dependent Claim
159 words
A loop back method for a local area network comprising two loop transmission lines, the transmission directions of which are opposite to each other, and a plurality of local node units and a center node unit connected to said two loop transmission lines, said method being adapted to recover from line faults which occur on said two loop transmission lines such that local node units adjacent to failure location on said transmission lines form loop back, wherein said center node unit, upon detecting line failure on both of said two loop transmission lines, transmits a command for instructing a simultaneous loop back operation to all the local node units, and said center node unit further transmits, after the lapse of a guard time, a command for instructing said local node units to individually determine whether the loop back state is maintained or released to said respective local node units, thereby performing the loop back operation for said whole network.
Claim 5
Dependent Claim
74 words
A loop back method according to claim 4, wherein a failure location on the loop transmission lines is specified by transmitting from said center node unit to said respective local node units, after forming loop back of the whole network, a command for instructing said respective local node units to respond to said center node unit whether each of said respective node units is maintaining the loop back state or has released the same.
Claim 6
Dependent Claim
67 words
A loop back method according to claim 5, wherein said center node unit transmits to all of said local node units a command for instructing each of said local node units to receive the addresses of the local node units maintaining the loop back state due to the specified line failure, comparing said addresses with the address thereof, and responding the result to said center node unit.
Claim 7
Dependent Claim
29 words
A loop back method according to any one of claims 4 ∼ 6, wherein various commands used in the loop back operation are usually transmitted in a cyclic manner.
References Cited (Backward Citations)
No citation records indexed.
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