EP0214625A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Flow control scheme for a switching network
Assignee: AT&T Inc
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Filing: 1986-09-05
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Granted: —
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Expires: 2006-09-05
Abstract
Abstract A flow control mechanism for a packet switching system (100) that provides for the continuous dynamic control of station window size beginning with call setup and extending through the duration of the call. A station window size can be of a first magnitude at call setup time when system traffic may be low. The window size can be subsequently reduced to free up port buffer space (103) as system traffic increases. This permits the serving of more calls during periods of heavy traffic.
Inventors
- 👤 Andrew Dejongh Franklin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 14:33
CPC Classifications
H; H04; H04L; H04L47/00; H04L47/10; H04L47/18; H04L47/16; H04L47/27; H04L47/30
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
344 words
A method of operating a packet switching system having a controller and a plurality of ports with each port having a port buffer and an associated station, said packet switching system further having a data bus connected to said controller and to said ports, said method comprising the steps of: a) storing in said controller information specifying the free buffer space currently available in each port buffer of said system; b) establishing a call between a first and a second one of said stations by transmitting a message from said first station to said controller over said bus with said message specifying a requested receiving station buffer size to be used on said call for receiving data at said first station from said second station; c) operating said controller to determine whether said buffer space requested by said first station can be allocated to said call; d) operating said controller to allocate said buffer space requested by said first station when said requested amount of space is currently available in said port buffers of the ports serving said first and second stations; e) transmitting a message from said controller to said second station over said bus specifying a window size equal to said allocated space for use by said second station in transmitting data to said first station; f) transmitting a message over said bus from said second station to said controller specifying a requested receiving station buffer size to be used in receiving data at second station from said first station; g) operating said controller to determine whether said buffer space requested by said second station can be allocated to said call; h) allocating said buffer space requested by said second station when said requested amount of space is currently available in said port buffers of the ports serving said first and second stations; and i) transmitting a message over said bus from said controller to said first station specifying a window size equal to said last named allocated space for use by said first station in transmitting data to said second station.
Claim 2
Independent Claim
344 words
A method of operating a packet switching system having a controller and a plurality of ports with each port having a port buffer and an associated station, said packet switching system further having a data bus connected to said controller and to said ports, said method comprising the steps of: a) storing in said controller information specifying the free buffer space currently available in each port buffer of said system; b) establishing a call between a first and a second one of said stations by transmitting a message from said first station to said controller over said bus with said message specifying a requested receiving station buffer size to be used on said call for receiving data at said first station from said second station; c) operating said controller to determine whether said buffer space requested by said first station can be allocated to said call; d) operating said controller to allocate said buffer space requested by said first station when said requested amount of space is currently available in said port buffers of the ports serving said first and second stations; e) transmitting a message from said controller to said second station over said bus specifying a window size equal to said allocated space for use by said second station in transmitting data to said first station; f) transmitting a message over said bus from said second station to said controller specifying a requested receiving station buffer size to be used in receiving data at second station from said first station; g) operating said controller to determine whether said buffer space requested by said second station can be allocated to said call; h) allocating said buffer space requested by said second station when said requested amount of space is currently available in said port buffers of the ports serving said first and second stations; and i) transmitting a message over said bus from said controller to said first station specifying a window size equal to said last named allocated space for use by said first station in transmitting data to said second station.
Claim 3
Dependent Claim
112 words
The method of claim 1 in combination with the steps of: a) operating said controller to determine that insufficient port buffer space is currently available to allocate in said port buffers the amount of buffer space specified in said message transmitted from said first station to said controller; b) operating said controller to allocate in said port buffers a lesser amount of buffer space than that specified in said message sent by said first station; and c) transmitting a message over said bus from said controller to said second station specifying a window size equal to said lesser amount for use by said second station in transmitting data to said first station.
Claim 4
Dependent Claim
114 words
The method of claim 2 in combination with the steps of: a) operating said controller to determine that insufficient port buffer space is currently available to allocate in said port buffers the amount of buffer space specified in said message transmitted from said second station to said controller; b) operating said controller to allocate in said port buffers a lesser amount of buffer space than that specified in said message transmitted by said second station; and c) transmitting a message over said bus from said controller to said first station specifying a window size equal to said last named lesser amount for use by said first station in transmitting data to said second station.
Claim 5
Dependent Claim
24 words
The method of claim 3 wherein all messages transmitted between said controller and said stations are transmitted sent via an end to end protocol.
Claim 6
Independent Claim
128 words
A method of operating a packet switching system having a controller and a plurality of ports with each port having a port buffer and an associated station, said method comprising the steps of: a) storing in said controller information specifying the free buffer space currently available in each port buffer of said system; b) operating said controller to establish station window sizes and port buffer space to be used on a call connection between a first and a second station; and c) transmitting messages from said controller to said first and second stations, respectively, with said messages specifying the station window size to be used on said call for transmitting data from said second to said first station and from said first station to said second station, respectively.
Claim 7
Independent Claim
128 words
A method of operating a packet switching system having a controller and a plurality of ports with each port having a port buffer and an associated station, said method comprising the steps of: a) storing in said controller information specifying the free buffer space currently available in each port buffer of said system; b) operating said controller to establish station window sizes and port buffer space to be used on a call connection between a first and a second station; and c) transmitting messages from said controller to said first and second stations, respectively, with said messages specifying the station window size to be used on said call for transmitting data from said second to said first station and from said first station to said second station, respectively.
Claim 8
Dependent Claim
188 words
The method of claim 5 in combination with the additional steps of: a) operating said controller to determine port buffer availability when a call from a third station is made to said first station while said call between said first and second stations remains extant; b) operating said controller to determine that th(l buffer space assigned to said call between said first and second station must be reduced to serve said call between said first and third stations; c) operating said controller to allocate port buffer space for said call between said first and third stations by reducing priorly allocated port buffer space for said first mentioned call and by allocating at least some of said reduced space to said last mentioned call; d) transmitting messages from said controller to said first and third stations to specify station window sizes equal to said las named allocation for use in transmitting data between said first and third stations; and e) transmitting messages from said controller to said first and second stations to specify new station window sizes to be used in exchanging data between said first and second stations.
Claim 9
Dependent Claim
23 words
The method of claim 6 wherein all messages transmitted between said controller and said stations are transmitted via an end to end protocol.
Claim 10
Independent Claim
119 words
A method of operating a packet switching system with said method comprising the steps of: a) sending messages from a first and a second station involved on a call to a controller requesting a specified amount of buffer space to be used by each station in receiving data from the other station involved on said call; b) operating said controller to determine the amount of space in the buffers of said system that can be allocated for exchanging data between said first and second stations; and c) sending a message from said controller to each station on said call specifying the window size to be used by each station in transmitting data to the other station on said call.
Claim 11
Independent Claim
119 words
A method of operating a packet switching system with said method comprising the steps of: a) sending messages from a first and a second station involved on a call to a controller requesting a specified amount of buffer space to be used by each station in receiving data from the other station involved on said call; b) operating said controller to determine the amount of space in the buffers of said system that can be allocated for exchanging data between said first and second stations; and c) sending a message from said controller to each station on said call specifying the window size to be used by each station in transmitting data to the other station on said call.
Claim 12
Dependent Claim
190 words
The method of claim 8 in combination with the steps of: a) initiating a call from a third station to said first station while said call between said first and second stations remains extant; b) sending a message from said third station to said controller requesting a specified amount of buffer space for receiving data at said third station from said first station; c) operating said controller to determine the amount of space in the buffers of said system that can be allocated for transmitting data between said first station and said third station; d) operating said controller to determine that the buffer space allocated to said first call for transmitting data between said second and first stations must be reduced to serve said call between said first station and said third station; e) sending a message from said controller to said first station reducing the window size for the transmission of data to said second station from said first station; and f) sending messages from said controller to said first and third stations specifying the window sizes to be used in transmitting data between said first and third stations.
Claim 13
Dependent Claim
23 words
The method of claim 9 wherein all messages sent between said controller and said stations are sent in an end to end protocol.
Claim 14
Independent Claim
122 words
A method of operating a packet switching system with said method comprising the steps of: a) sending a message from a first station to a controller requesting a specified amount of receiving station buffer space to be used by said first station in receiving data on a call from a second station; b) operating said controller to determine whether said requested space can be allocated within the buffers of said system; c) determining that said requested space can be allocated; d) allocating said requested buffer space in the buffers of said system; and e) sending a message from said controller to said second station specifying the window size to be used by said second station in transmitting data to said first station.
Claim 15
Independent Claim
122 words
A method of operating a packet switching system with said method comprising the steps of: a) sending a message from a first station to a controller requesting a specified amount of receiving station buffer space to be used by said first station in receiving data on a call from a second station; b) operating said controller to determine whether said requested space can be allocated within the buffers of said system; c) determining that said requested space can be allocated; d) allocating said requested buffer space in the buffers of said system; and e) sending a message from said controller to said second station specifying the window size to be used by said second station in transmitting data to said first station.
Claim 16
Dependent Claim
124 words
The method of claim 11 in combination with the steps of: a) sending a message from said second station to said controller requesting a specified amount of receiving station buffer space to be used by said second station in receiving data on said call from said first station; b) operating said controller to determine whether the said buffer space requested by said second station can be allocated with the buffers of said system; c) determining that said last named requested space can be allocated; d) allocating said last named requested buffer space in the buffers of said system; and e) sending a message from said controller to said first station specifying the window size to be used in transmitting data to said second station.
Claim 17
Dependent Claim
145 words
The method of claim 12 in combination with the steps of: a) initiating a call from a third station to said first station by sending a message to said controller from said third station requesting a specified amount of receiving station buffer space to be used by said third station in receiving data from said first station; b) operating said controller to determine that the buffer space in allocated to said first named call for transmitting data from said second to said first station must be reduced; c) reducing the buffer space allocated to said first named call; d) sending a message to said second station reducing the window size on the transmission of data to said first station; and e) sending messages to said first and third stations specifying the window sizes to be used in transmitting data between said first and third stations.
Claim 18
Independent Claim
169 words
A method of operating a packet switching system comprising the steps of: a) sending a message from a first station to a controller requesting a specified amount of receiving station buffer space for use in receiving data on a call from a second station; b) storing in said controller information specifying the free buffer space currently available in each port buffer of said packet switching system; c) operating said controller in response to the receipt of said message to determine whether said buffer space requested by said first station is available in said port buffers; d) determining that said requested space is currently available in said port buffers; e) allocating said buffer space by sending a message from said controller to said second station upon said determination specifying the window size to be used in said second station in transmitting data from said second station to said first station; and f) storing said window size information in said second station for use in transmitting data to said first station.
Claim 19
Independent Claim
169 words
A method of operating a packet switching system comprising the steps of: a) sending a message from a first station to a controller requesting a specified amount of receiving station buffer space for use in receiving data on a call from a second station; b) storing in said controller information specifying the free buffer space currently available in each port buffer of said packet switching system; c) operating said controller in response to the receipt of said message to determine whether said buffer space requested by said first station is available in said port buffers; d) determining that said requested space is currently available in said port buffers; e) allocating said buffer space by sending a message from said controller to said second station upon said determination specifying the window size to be used in said second station in transmitting data from said second station to said first station; and f) storing said window size information in said second station for use in transmitting data to said first station.
Claim 20
Dependent Claim
136 words
The method of claim 14 in combination with the steps of: a) sending a message from said second station to said controller requesting a specified amount of receiving station buffer space to be used for receiving data on said call from said first station; b ) operating said controller to determine whether the buffer space requested by said second station is available in said port buffers; c) determining that said last named requested space is available in said port buffers; d) allocating said last named buffer space by sending a message from said controller to said first station specifying the window size to be used by said first station in transmitting data to said second station; and e) storing said window size information in said first station for use in transmitting data to said second station.
Claim 21
Dependent Claim
158 words
The method of claim 15 in combination with the steps of: a) initiating a call from a third station to said first station while said call between said first and second stations remain extant; b) transmitting a message from said third station to said controller requesting a specified amount of receiving station buffer space for use in receiving data on said call from said first station; c) operating said controller to determine that the buffer space allocated for use in transmitting data from said first station to said second station must be reduced; d) reducing said last named buffer space; e) sending a message from said controller to said first station reducing the window size for the transmission of data from said first station to said second station; and f) sending messages from said controller to said first and third stations specifying the buffer window size to be used in transmitting data between said first and third stations.
Claim 22
Dependent Claim
22 words
The method of claim 16 wherein all messages sent between said controller and said stations are in an end to end protocol.
Claim 23
Independent Claim
726 words
A method of operating a network of packet switching systems interconnected to each other by trunks, each packet switching system having a data bus, a controller connected to a said data bus, each of said packet switching systems further having a plurality of ports each of which is connected to said data bus of its system and to an associated station individual to each port, each of said ports having an associated port buffer, said method comprising the steps of: a) establishing a call between a first station in a first one of said systems and a second station in a second one of said systems by transmitting a message over said bus of said first system from said first station to said controller of said first system with said message specifying a requested receiving station buffer size for use on said call in receiving data at said first station from said second station; b) storing in said controller of said first system information specifying the free buffer space currently available in each port buffer of said first system; c) operating said controller of said first system to determine whether said receiving buffer space requested by said first station in said message can be allocated within the port buffers of said first system; d) allocating said buffer space requested by said first station when said requested amount of space is available within the port buffers of said first system for the transmission of data from said second station to said first station; e) transmitting a message from said controller of said first system over said buses of each system and over said trunks to the controller of said second system specifying the buffer space allocated in said first system for the transmission of data from said second station to said first station; f) storing in said controller of said second system information specifying the free buffer space currently available in each port buffer of said second system; g) operating said controller of said second system to determine whether said buffer space specified by said controller of said first system in said last named message can be allocated within the port buffers of said second system; h) operating said controller of said second system to allocate said buffer space requested by said controller of said first system when said requested amount of space is available within the port buffers of said second system; i) transmitting a message from said controller of said second system over said bus of said second system to said second station specifying a window size equal to said allocated space within the port buffers of said second system for use by said second station in transmitting data to said first station; j) transmitting a message from said second station over said bus of said second system to said controller of said second system specifying a requested receiving station buffer size for use in receiving data at said second station from said first station; k) operating said controller of said second system to determine whether said receiving buffer space requested by said second station can be allocated within the port buffers of said second system; 1) operating said controller of said second system to allocate said buffer space requested by said second station when said requested amount of space is available within the port buffers of said second system; m) transmitting a message from said controller of said second system over said buses of both system and over said trunks to the controller of said first system specifying the buffer space allocated in said second system for the transmission of data from said first station to said second station; n) operating said controller of said first system to determine whether said buffer space specified by said controller of said second system in said last named message can be allocated within the port buffers of said first system; o) allocating said buffer space specified by said controller of said second system when said requested amount of space is available within the port buffers of said first system; and p) sending a message from said controller of said first system over said bus of said first system to said first station specifying a window size equal to said last named allocated space to be used by said first station in transmitting data to said second station.
Claim 24
Independent Claim
726 words
A method of operating a network of packet switching systems interconnected to each other by trunks, each packet switching system having a data bus, a controller connected to a said data bus, each of said packet switching systems further having a plurality of ports each of which is connected to said data bus of its system and to an associated station individual to each port, each of said ports having an associated port buffer, said method comprising the steps of: a) establishing a call between a first station in a first one of said systems and a second station in a second one of said systems by transmitting a message over said bus of said first system from said first station to said controller of said first system with said message specifying a requested receiving station buffer size for use on said call in receiving data at said first station from said second station; b) storing in said controller of said first system information specifying the free buffer space currently available in each port buffer of said first system; c) operating said controller of said first system to determine whether said receiving buffer space requested by said first station in said message can be allocated within the port buffers of said first system; d) allocating said buffer space requested by said first station when said requested amount of space is available within the port buffers of said first system for the transmission of data from said second station to said first station; e) transmitting a message from said controller of said first system over said buses of each system and over said trunks to the controller of said second system specifying the buffer space allocated in said first system for the transmission of data from said second station to said first station; f) storing in said controller of said second system information specifying the free buffer space currently available in each port buffer of said second system; g) operating said controller of said second system to determine whether said buffer space specified by said controller of said first system in said last named message can be allocated within the port buffers of said second system; h) operating said controller of said second system to allocate said buffer space requested by said controller of said first system when said requested amount of space is available within the port buffers of said second system; i) transmitting a message from said controller of said second system over said bus of said second system to said second station specifying a window size equal to said allocated space within the port buffers of said second system for use by said second station in transmitting data to said first station; j) transmitting a message from said second station over said bus of said second system to said controller of said second system specifying a requested receiving station buffer size for use in receiving data at said second station from said first station; k) operating said controller of said second system to determine whether said receiving buffer space requested by said second station can be allocated within the port buffers of said second system; 1) operating said controller of said second system to allocate said buffer space requested by said second station when said requested amount of space is available within the port buffers of said second system; m) transmitting a message from said controller of said second system over said buses of both system and over said trunks to the controller of said first system specifying the buffer space allocated in said second system for the transmission of data from said first station to said second station; n) operating said controller of said first system to determine whether said buffer space specified by said controller of said second system in said last named message can be allocated within the port buffers of said first system; o) allocating said buffer space specified by said controller of said second system when said requested amount of space is available within the port buffers of said first system; and p) sending a message from said controller of said first system over said bus of said first system to said first station specifying a window size equal to said last named allocated space to be used by said first station in transmitting data to said second station.
Claim 25
Dependent Claim
23 words
The method of claim 18 wherein all messages sent between said controllers and said stations are sent in an end to end protocol.
References Cited (Backward Citations)
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