Patent EP0410139A2 successfully refreshed from Google Patents.
EP0410139A2
Expired / Lapsed
EP
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ATM switching system having dual ATM switch structure
Assignee: Fujitsu Ltd
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Filing: 1990-06-21
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Granted: —
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Expires: 2010-06-21
Abstract
Abstract An ATM switching system includes two ATM switches which are the same as each other. Each of the ATM switches includes a switch buffer (10a, 10b), and a cell counter (11a, 11b) which indicates the number of cells in the switch buffer. Each of the ATM switches also includes a difference calculator (13a, 13b), which calculates the difference between the number of cells in the two switch buffers when one of the ATM switches is changed from an out-of-service state to a slave mode. At this time, the other ATM switch operates in a master mode. Each of the ATM switches further includes a dummy cell generator (12a, 12b), which generates a number of dummy cells which corresponds to the difference calculated by the difference calculator. The generated dummy cells are written into the switch buffer in the slave mode. When it is determined that when all of the dummy cells have been output from the switch buffer, the two ATM switches are synchronized each other.
Inventors
- 👤 Naoyuki Izawa
- 👤 Yoshihiro Uchida
- 👤 Masami Murayama
- 👤 Yasuhiro Aso
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 10:09
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/55; H04L49/552; H04L49/10; H04L49/103; H04L49/15; H04L49/1515; H04L49/1523; H04L49/25
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
486 words
An ATM (asynchronous transfer mode) switching system including: a first ATM switch (110A) having input lines and output lines; a second ATM switch (110B) having input lines and output lines, said first ATM switch having a structure identical to said second ATM switch; input means (100), coupled to said first and second ATM switches, for supplying cells via an input transmission line to said input lines of said first and second ATM switches; and select means (120, 120₁), coupled to said first and second ATM switches, for selecting either one of said first ATM switch or said second ATM switch so that the output lines of a selected one of the first and second ATM switches are coupled to an output line extending from said ATM switching system and operates in a master mode, characterized in that each of said first and second ATM switches includes: buffer means (10a, 10b; 20a, 20b; 30a, 30b), provided at a crosspoint where a corresponding one of said input lines and a corresponding one of said output lines cross, for temporarily storing said cells supplied from said corresponding one of the input lines and for outputting said cells to said corresponding one of the output lines; counter means (11a, 11b; 21a, 21b; 31a, 31b), coupled to said buffer means, for counting a number of said cells in said buffer means and for outputting a counter value indicative of the number of said cells; difference calculating means (13a, 13b; 23a, 23b; 33a, 33b), Coupled to said counter means of said first ATM switch and said counter means of said second ATM switch, for calculating a difference between the counter values in said counter means of said first and second ATM switches when said selected one of the first and second ATM switches is in an in-service state and the other one of said first and second ATM switches is in an out-of-service state, and; dummy cell generating means (12a, 12b; 22a, 22b; 32a, 32b), coupled to said difference calculating means and said buffer means, for generating a number of dummy cells corresponding to said difference produced by said difference calculating means and for writing said dummy cells into said buffer means of the other one of the first and second ATM switches which is in the out-of-service state so that the other one of the first and second ATM switches in the out-of-service state is changed to a slave mode from the out-of-service state, and in that said ATM switching system further comprises control means (130) for determining whether or not said dummy cells in said buffer means of the other one of the first and second ATM switches in the slave mode have been output therefrom, so that when it is determined by said control means that all of said dummy cells have been output from said buffer means, the first and second ATM switches are synchronized with each other.
Claim 2
Dependent Claim
486 words
An ATM (asynchronous transfer mode) switching system including: a first ATM switch (110A) having input lines and output lines; a second ATM switch (110B) having input lines and output lines, said first ATM switch having a structure identical to said second ATM switch; input means (100), coupled to said first and second ATM switches, for supplying cells via an input transmission line to said input lines of said first and second ATM switches; and select means (120, 120₁), coupled to said first and second ATM switches, for selecting either one of said first ATM switch or said second ATM switch so that the output lines of a selected one of the first and second ATM switches are coupled to an output line extending from said ATM switching system and operates in a master mode, characterized in that each of said first and second ATM switches includes: buffer means (10a, 10b; 20a, 20b; 30a, 30b), provided at a crosspoint where a corresponding one of said input lines and a corresponding one of said output lines cross, for temporarily storing said cells supplied from said corresponding one of the input lines and for outputting said cells to said corresponding one of the output lines; counter means (11a, 11b; 21a, 21b; 31a, 31b), coupled to said buffer means, for counting a number of said cells in said buffer means and for outputting a counter value indicative of the number of said cells; difference calculating means (13a, 13b; 23a, 23b; 33a, 33b), Coupled to said counter means of said first ATM switch and said counter means of said second ATM switch, for calculating a difference between the counter values in said counter means of said first and second ATM switches when said selected one of the first and second ATM switches is in an in-service state and the other one of said first and second ATM switches is in an out-of-service state, and; dummy cell generating means (12a, 12b; 22a, 22b; 32a, 32b), coupled to said difference calculating means and said buffer means, for generating a number of dummy cells corresponding to said difference produced by said difference calculating means and for writing said dummy cells into said buffer means of the other one of the first and second ATM switches which is in the out-of-service state so that the other one of the first and second ATM switches in the out-of-service state is changed to a slave mode from the out-of-service state, and in that said ATM switching system further comprises control means (130) for determining whether or not said dummy cells in said buffer means of the other one of the first and second ATM switches in the slave mode have been output therefrom, so that when it is determined by said control means that all of said dummy cells have been output from said buffer means, the first and second ATM switches are synchronized with each other.
Claim 3
Dependent Claim
475 words
An ATM (asynchronous transfer mode) switching system including: a first ATM switch (110A) having input lines and output lines; a second ATM switch (110B) having input lines and output lines, said first ATM switch having a structure identical to said second ATM switch; input means (100), coupled to said first and second ATM switches, for supplying cells via an input transmission line to said input lines of said first and second ATM switches; and select means (120, 120₁), coupled to said first and second ATM switches, for selecting either one of said first ATM switch or said second ATM switch so that the output lines of a selected one of the first and second ATM switches are coupled to an output transmission line extending from said ATM switching system and operates in a master mode, characterized in that each of said first and second ATM switches includes: buffer means (10a, 10b; 40a, 40b), provided at a crosspoint where a corresponding one of said input lines and a corresponding one of said output lines cross, for temporarily storing said cells supplied from said corresponding one of the input lines and for outputting said cells to said corresponding one of the output lines; counter means (11a, 11b; 41a, 41b), coupled to said buffer means, for counting a number of said cells in said buffer means and for outputting a counter value indicative of the number of said cells, said counter value in said counter means of said selected one of the first and second ATM switches which is in an in-service state being written into said counter of the other one of the first and second ATM switch which is in an out-of-service state so that the other one of the first and second ATM switch is changed to a slave mode from the out-of-service state; and difference calculating means (13a, 13b; 42a, 42b), coupled to said counter means of said first ATM switch and said counter means of said second ATM switch, for calculating a difference between the counter values in said counter means of said first and second ATM switches when said selected one of the first and second ATM switches is in the in-service state and the other one of the first and second ATM switches is in the out-of-service state, and in that said ATM switching system further comprises control means (130) for determining whether or not a number of cells which corresponds to the counter value written into said buffer means of the other one of the first and second ATM switches which is in the slave mode has been output from said buffer means, so that when it is determined by said control means that said number of cells has been output from said buffer means in the slave mode, the first and second ATM switches are synchronized with each other.
Claim 4
Dependent Claim
475 words
An ATM (asynchronous transfer mode) switching system including: a first ATM switch (110A) having input lines and output lines; a second ATM switch (110B) having input lines and output lines, said first ATM switch having a structure identical to said second ATM switch; input means (100), coupled to said first and second ATM switches, for supplying cells via an input transmission line to said input lines of said first and second ATM switches; and select means (120, 120₁), coupled to said first and second ATM switches, for selecting either one of said first ATM switch or said second ATM switch so that the output lines of a selected one of the first and second ATM switches are coupled to an output transmission line extending from said ATM switching system and operates in a master mode, characterized in that each of said first and second ATM switches includes: buffer means (10a, 10b; 40a, 40b), provided at a crosspoint where a corresponding one of said input lines and a corresponding one of said output lines cross, for temporarily storing said cells supplied from said corresponding one of the input lines and for outputting said cells to said corresponding one of the output lines; counter means (11a, 11b; 41a, 41b), coupled to said buffer means, for counting a number of said cells in said buffer means and for outputting a counter value indicative of the number of said cells, said counter value in said counter means of said selected one of the first and second ATM switches which is in an in-service state being written into said counter of the other one of the first and second ATM switch which is in an out-of-service state so that the other one of the first and second ATM switch is changed to a slave mode from the out-of-service state; and difference calculating means (13a, 13b; 42a, 42b), coupled to said counter means of said first ATM switch and said counter means of said second ATM switch, for calculating a difference between the counter values in said counter means of said first and second ATM switches when said selected one of the first and second ATM switches is in the in-service state and the other one of the first and second ATM switches is in the out-of-service state, and in that said ATM switching system further comprises control means (130) for determining whether or not a number of cells which corresponds to the counter value written into said buffer means of the other one of the first and second ATM switches which is in the slave mode has been output from said buffer means, so that when it is determined by said control means that said number of cells has been output from said buffer means in the slave mode, the first and second ATM switches are synchronized with each other.
Claim 5
Dependent Claim
382 words
An ATM switching system (asynchronous transfer mode) including: a first ATM switch (110A) having input lines and output lines; a second ATM switch (110B) having input lines and output lines, said first ATM switch having a structure identical to said second ATM switch, each of said first and second ATM switches including buffer means, provided at a crosspoint where a corresponding one of said input lines and a corresponding one of said output lines cross, for temporarily storing cells supplied from said corresponding one of the input lines and for outputting said cells to said corresponding one of the output lines; input means (100), coupled to said first and second ATM switches, for supplying said cells via an input transmission line to said input lines of said first and second ATM switches; and select means (120, 120₁), coupled to said first and second ATM switches, for selecting either one of said first ATM switch or said second ATM switch so that the output lines of a selected one of the first and second ATM switches are coupled to an output transmission line extending from said ATM switching system and operates in a master mode, characterized in that said ATM switching system comprises: dummy cell generating means (12a, 12b; 22a, 22b; 32a, 32b), coupled to said first and second ATM switches, for generating a predetermined number of dummy cells and for writing said dummy cells into said buffer means of the other one of the first and second ATM switches which is in an out-of-service state; and control means (11a, 11b, 21a, 21b, 31a, 31b; 13a, 13b, 23a, 23b, 33a, 33b; 130), coupled to said first and second ATM switches, for determining whether or not all of said dummy cells have been output from said buffer means after the other one of the first and second ATM switches is changed from said out-of-service state to a slave mode, the other one of said first and second ATM switches operating in an in-service state where said selected one of the first and second ATM switches is in a master mode, so that when it is determined by said control means that all of said dummy cells have been output from said buffer means, the first and second ATM switches are synchronized with each other.
Claim 6
Dependent Claim
382 words
An ATM switching system (asynchronous transfer mode) including: a first ATM switch (110A) having input lines and output lines; a second ATM switch (110B) having input lines and output lines, said first ATM switch having a structure identical to said second ATM switch, each of said first and second ATM switches including buffer means, provided at a crosspoint where a corresponding one of said input lines and a corresponding one of said output lines cross, for temporarily storing cells supplied from said corresponding one of the input lines and for outputting said cells to said corresponding one of the output lines; input means (100), coupled to said first and second ATM switches, for supplying said cells via an input transmission line to said input lines of said first and second ATM switches; and select means (120, 120₁), coupled to said first and second ATM switches, for selecting either one of said first ATM switch or said second ATM switch so that the output lines of a selected one of the first and second ATM switches are coupled to an output transmission line extending from said ATM switching system and operates in a master mode, characterized in that said ATM switching system comprises: dummy cell generating means (12a, 12b; 22a, 22b; 32a, 32b), coupled to said first and second ATM switches, for generating a predetermined number of dummy cells and for writing said dummy cells into said buffer means of the other one of the first and second ATM switches which is in an out-of-service state; and control means (11a, 11b, 21a, 21b, 31a, 31b; 13a, 13b, 23a, 23b, 33a, 33b; 130), coupled to said first and second ATM switches, for determining whether or not all of said dummy cells have been output from said buffer means after the other one of the first and second ATM switches is changed from said out-of-service state to a slave mode, the other one of said first and second ATM switches operating in an in-service state where said selected one of the first and second ATM switches is in a master mode, so that when it is determined by said control means that all of said dummy cells have been output from said buffer means, the first and second ATM switches are synchronized with each other.
Claim 7
Dependent Claim
84 words
An ATM switching system as claimed in claim 1, characterized in that: when said dummy cells are written into said buffer means, said counter value in said counter means indicates a total number of cells which corresponds to the sum of the number of said dummy cells and a number of cells which are already stored at this time; and said control means (130) comprises means (130) for determining whether or not said total number of cells has been output from said buffer means.
Claim 8
Dependent Claim
91 words
An ATM switching system as claimed in claim 1 or 4, characterized in that said control means (130) comprises: first means (130) for resetting said counter means of the other one of the first and second ATM switches in the slave mode to zero when said dummy cells are written into said buffer means so that said counter value in said counter means indicates the number of said dummy cells; and second means (130) for determining whether or not all of said dummy cells have been output from said buffer means.
Claim 9
Dependent Claim
70 words
An ATM switching system as claimed in claim 5, characterized in that said counter value in said counter means (11a, 11b; 21a, 21b; 31a, 31b) indicates the number of said dummy cells which is equal to the counter value of said counter means indicative of a number of cells in said buffer means of said selected one of the first and second ATM switches which is in the in-service state.
Claim 10
Dependent Claim
66 words
An ATM switching system as claimed in any of claims 1 or 4 to 6, characterized in that: said select means (120, 120₁) has a terminal to which a switch signal is applied; and said control means (130) comprises switch signal generating means (130) for generating said switch signal after it is determined that all of said dummy cells have been output from said buffer means.
Claim 11
Dependent Claim
86 words
An ATM switching system as claimed in claim 2, characterized in that: said select means (120; 120₁) has a terminal to which a switch signal is sent; and said control means comprises switch signal generating means (130) for generating said switch signal after it is determined that said number of cells which corresponds to the counter value written into said buffer means of the other one of the first and second ATM switches which is in the slave mode has been output from said buffer means.
Claim 12
Dependent Claim
46 words
An ATM switching system as claimed in claim 7 or 8, characterized in that said switch signal generating means (130) generates said switch signal which enables the other one of the first and second ATM switches to change from the slave mode to the master mode.
Claim 13
Dependent Claim
69 words
An ATM switching system as claimed in any of claims 1 or 3 to 9, characterized in that: said dummy cell generating means (12a, 12b; 22a, 22b; 32a, 32b) generates the dummy cells, each of which is composed of a header and information; said header includes specific data which serves as an identification of the dummy cells; and said information in each of the dummy cells has arbitrary data.
Claim 14
Dependent Claim
34 words
An ATM switching system as claimed in any of claims 1 or 3 to 10, characterized in that each of said dummy cells has a length identical to that of each of said cells.
Claim 15
Dependent Claim
31 words
An ATM switching system as claimed in any of claims 1 to 11, characterized in that said buffer means (10a, 10b; 20a, 20b; 30a, 30b; 40a, 40b) comprises an elastic memory.
Claim 16
Dependent Claim
378 words
An ATM switching system (asynchronous transfer mode) including: a first ATM switch (110A) having input lines and output lines; a second ATM switch (110B) having input lines and output lines, said first ATM switch having a structure identical to said second ATM switch, each of said first and second ATM switches including buffer means, provided at a crosspoint where a corresponding one of said input lines and a corresponding one of said output liens cross, for temporarily storing cells supplied from said corresponding one of the input lines and for outputting said cells to said corresponding one of the output lines; input means (100), coupled to said first and second ATM switches, for supplying said cells via an input transmission line to said input lines of said first and second ATM switches; and select means (120, 120₁), coupled to said first and second ATM switches, for selecting either one of said first ATM switch or said second ATM switch so that the output lines of a selected one of the first and second ATM switches are coupled to an output transmission line extending from said ATM switching system and operates in a master mode, characterized in that said ATM switching system comprises: counter means (11a, 11b; 41a, 41b), coupled to said first and second ATM switches, for counting a number of cells in said buffer means of said selected one of the first and second ATM switches which is in an in-service state so that said selected one of the first and second ATM switches operates in a master mode; and control means (13a, 13b, 42a, 42b; 130), coupled to said first and second ATM switches and said counter means, for determining whether or not a number of cells which is equal to said number of cells counted by said counter means has been output from said buffer means of the other one of the first and second ATM switches after the other one of the first and second ATM switches is changed from an out-of-service state to a slave mode, so that when it is determined by said control means that said number of cells has been output from said buffer means in the slave mode, the first and second ATM switches are synchronized with each other.
Claim 17
Dependent Claim
378 words
An ATM switching system (asynchronous transfer mode) including: a first ATM switch (110A) having input lines and output lines; a second ATM switch (110B) having input lines and output lines, said first ATM switch having a structure identical to said second ATM switch, each of said first and second ATM switches including buffer means, provided at a crosspoint where a corresponding one of said input lines and a corresponding one of said output liens cross, for temporarily storing cells supplied from said corresponding one of the input lines and for outputting said cells to said corresponding one of the output lines; input means (100), coupled to said first and second ATM switches, for supplying said cells via an input transmission line to said input lines of said first and second ATM switches; and select means (120, 120₁), coupled to said first and second ATM switches, for selecting either one of said first ATM switch or said second ATM switch so that the output lines of a selected one of the first and second ATM switches are coupled to an output transmission line extending from said ATM switching system and operates in a master mode, characterized in that said ATM switching system comprises: counter means (11a, 11b; 41a, 41b), coupled to said first and second ATM switches, for counting a number of cells in said buffer means of said selected one of the first and second ATM switches which is in an in-service state so that said selected one of the first and second ATM switches operates in a master mode; and control means (13a, 13b, 42a, 42b; 130), coupled to said first and second ATM switches and said counter means, for determining whether or not a number of cells which is equal to said number of cells counted by said counter means has been output from said buffer means of the other one of the first and second ATM switches after the other one of the first and second ATM switches is changed from an out-of-service state to a slave mode, so that when it is determined by said control means that said number of cells has been output from said buffer means in the slave mode, the first and second ATM switches are synchronized with each other.
References Cited (Backward Citations)
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