US4646287A
Expired / Lapsed
US
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Idle period signalling in a packet switching system
Assignee: Nokia of America Corp
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Filing: 1984-12-07
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Granted: 1987-02-24
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Expires: 2004-12-07
Abstract
Abstract Trunk controllers (131) at each end of a trunk (118) of a packet switching system (FIGS. 1A and 1B) include an idle packet generator (1419) and an idle packet detector (1420). During idle periods, when packets are not available for transmission, the transmitter of each idle trunk controller generates and transmits a continuous sequence of flags (801/810) on the trunk. Periodically during the idle periods, the idle packet generator generates and provides to the transmitter (1403) for transmission an idle packet (800). An idle packet is structured like a normal packet. However, it is marked as an idle packet by the packet identification (PID) field (804) and contains pseudo-random bits in the data field (806). The receiver (1402) of the other trunk controller receives the idle code and packets including idle packets, discards the idle code, and sends all packets to the idle packet detector. The detector identifies idle packets by their PID field and discards them--blocks them from propagating further--while allowing other packets to pass therethrough.
Inventors
- 👤 Mikiel L. Larson
- 👤 Anne A. Robrock
- 👤 Wing N. Toy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:22
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/40; H04L69/00; H04L69/28
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
76 words
A packet switching system having a first and a second portion thereof interconnected for communication by a communication link, comprising: means associated with the first portion for transmitting on the link idle code when packets are not being transmitted thereon and further for occasionally transmitting on the link a packet of a first type; and means associated with the second portion for discarding both idle code and packets of the first type received on the link.
Claim 2
Dependent Claim
76 words
A packet switching system having a first and a second portion thereof interconnected for communication by a communication link, comprising: means associated with the first portion for transmitting on the link idle code when packets are not being transmitted thereon and further for occasionally transmitting on the link a packet of a first type; and means associated with the second portion for discarding both idle code and packets of the first type received on the link.
Claim 3
Dependent Claim
78 words
A packet switching system having a first and a second switching node interconnected for communication by a trunk, comprising: means for transmitting on the trunk idle code when packets are not being transmitted thereon; and means associated with the first node for occasionally transmitting on the trunk a packet of a first type when no other packets are available for transmission; means associated with the second node for discarding packets of the first type received on the trunk.
Claim 4
Dependent Claim
78 words
A packet switching system having a first and a second switching node interconnected for communication by a trunk, comprising: means for transmitting on the trunk idle code when packets are not being transmitted thereon; and means associated with the first node for occasionally transmitting on the trunk a packet of a first type when no other packets are available for transmission; means associated with the second node for discarding packets of the first type received on the trunk.
Claim 5
Dependent Claim
75 words
The system of claim 2 wherein the means for transmitting a packet of the first type comprise: means for occasionally generating a packet of the first type for transmission on the trunk; and wherein the means for transmitting idle code comprise: means associated with the first node and cooperative with the generating means for transmitting on the trunk idle code when not transmitting packets thereon and further for transmitting on the trunk the generated packet.
Claim 6
Dependent Claim
40 words
The system of claim 2 wherein the discarding means comprise: means for identifying packets of the first type received on the trunk; and means responsive to the identifying means for discarding received packets identified as being of the first type.
Claim 7
Dependent Claim
30 words
The system of claim 4 wherein the discarding means further comprise: means for receiving on the trunk idle code and packets transmitted by transmitting means associated with the first node.
Claim 8
Dependent Claim
131 words
A packet switching system having a first and a second switching node interconnected for communication by a trunk, comprising: means for generating packets marked as idle packets; means cooperative with the generating means for periodically transmitting from the first node on the trunk a generated idle packet when other packets are not available for transmission and further for transmitting from the first node on the trunk idle code when packets are not being transmitted thereon from the first node; means for receiving at the second node packets and idle code transmitted on the trunk from the first node and further for discarding the idle code; means cooperative with the receiving means for identifying received idle packets; and means responsive to the identifying means for discarding received packets identified as idle packets.
Claim 9
Dependent Claim
131 words
A packet switching system having a first and a second switching node interconnected for communication by a trunk, comprising: means for generating packets marked as idle packets; means cooperative with the generating means for periodically transmitting from the first node on the trunk a generated idle packet when other packets are not available for transmission and further for transmitting from the first node on the trunk idle code when packets are not being transmitted thereon from the first node; means for receiving at the second node packets and idle code transmitted on the trunk from the first node and further for discarding the idle code; means cooperative with the receiving means for identifying received idle packets; and means responsive to the identifying means for discarding received packets identified as idle packets.
Claim 10
Dependent Claim
23 words
The system of claim 6 wherein the generating means comprise: means for generating packets each including idle data and an idle packet identifier.
Claim 11
Dependent Claim
22 words
The system of claim 7 wherein the identifying means comprise: means for inspecting the identifier of received packets to identify idle packets.
Claim 12
Dependent Claim
32 words
The system of claim 6 wherein the generating means comprise: means for generating periodically when packets are not available for transmission a packet marked as an idle packet and including idle data.
Claim 13
Dependent Claim
32 words
The system of claim 6 wherein the transmitting means further comprise means for generating for transmission on the trunk idle code when packets are not available for transmission from the first node.
Claim 14
Dependent Claim
36 words
The system of claim 6 further comprising: means responsive to the receiving means and to the identifying means for signalling error when an idle packet is not periodically identified while other packets are not being received.
Claim 15
Dependent Claim
60 words
A packet switching node having a port for connecting to a communication trunk, comprising: means for transmitting at the port idle code when packets are not being transmitted thereat and further for occasionally transmitting at the port a packet of a first type; and means for discarding both idle code and packets of the first type received at the port.
Claim 16
Dependent Claim
60 words
A packet switching node having a port for connecting to a communication trunk, comprising: means for transmitting at the port idle code when packets are not being transmitted thereat and further for occasionally transmitting at the port a packet of a first type; and means for discarding both idle code and packets of the first type received at the port.
Claim 17
Dependent Claim
35 words
The node of claim 12 wherein the transmitting means comprise: means for occasionally generating a packet of a first type; and means cooperative with the generating means for transmitting at the port the generated packet.
Claim 18
Dependent Claim
40 words
The node of claim 12 wherein the discarding means comprise: means for identifying packets of the first type received at the port; and means responsive to the identifying means for discarding received packets identified as being of the first type.
Claim 19
Dependent Claim
21 words
The node of claim 14 wherein the discarding means further comprise: means for receiving packets and idle code at the port.
Claim 20
Dependent Claim
98 words
A packet switching node having a port for connecting to a communication trunk, comprising: means for generating packets marked as idle packets; means cooperative with the generating means for periodically transmitting at the port a generated idle packet when other packets are not available for transmission and further for transmitting at the port idle code when packets are not being transmitted thereat; means for receiving idle code and packets at the port; means cooperative with the receiving means for identifying received idle packets; and means responsive to the identifying means for discarding received packets identified as idle packets.
Claim 21
Dependent Claim
98 words
A packet switching node having a port for connecting to a communication trunk, comprising: means for generating packets marked as idle packets; means cooperative with the generating means for periodically transmitting at the port a generated idle packet when other packets are not available for transmission and further for transmitting at the port idle code when packets are not being transmitted thereat; means for receiving idle code and packets at the port; means cooperative with the receiving means for identifying received idle packets; and means responsive to the identifying means for discarding received packets identified as idle packets.
Claim 22
Dependent Claim
23 words
The node of claim 16 wherein the generating means comprise: means for generating packets each including idle data and an idle packet identifier.
Claim 23
Dependent Claim
22 words
The node of claim 17 wherein the identifying means comprise: means for inspecting the identifier of received packets to identify idle packets.
Claim 24
Dependent Claim
32 words
The node of claim 16 wherein the generating means comprise: means for generating periodically when packets are not available for transmission a packet marked as an idle packet and including idle data.
Claim 25
Dependent Claim
21 words
The node of claim 16 wherein the receiving means further comprise means for receiving at the port and discarding idle code.
Claim 26
Dependent Claim
36 words
The node of claim 16 further comprising: means responsive to the receiving means and to the identifying means for signalling error when an idle packet is not periodically identified while other packets are not being received.
Claim 27
Dependent Claim
64 words
A trunk controller for a packet switching system, the controller having a port for connecting to a communication trunk, comprising: means for transmitting at the port idle code when packets are not being transmitted on the trunk and further for occasionally transmitting at the port a packet of a first type; and means for discarding packets of the first type received at the port.
Claim 28
Dependent Claim
64 words
A trunk controller for a packet switching system, the controller having a port for connecting to a communication trunk, comprising: means for transmitting at the port idle code when packets are not being transmitted on the trunk and further for occasionally transmitting at the port a packet of a first type; and means for discarding packets of the first type received at the port.
Claim 29
Dependent Claim
35 words
The controller of claim 22 wherein the transmitting means comprise: means for occasionally generating a packet of a first type; and means cooperative with the generating means for transmitting at the port the generated packet.
Claim 30
Dependent Claim
40 words
The controller of claim 22 wherein the discarding means comprise: means for identifying packets of the first type received at the port; and means responsive to the identifying means for discarding received packets identified as being of the first type.
Claim 31
Dependent Claim
29 words
The node of claim 24 wherein the discarding means further comprise: means for receiving at the port packets and idle code and further for discarding the received idle code.
Claim 32
Dependent Claim
111 words
A trunk controller for a packet switching system, the controller having a port for connecting to a communication trunk, comprising: means for generating packets marked as idle packets; means cooperative with the generating means for periodically transmitting at the port a generated idle packet when other packets are not available for transmission and further for transmitting at the port idle code when packets are not being transmitted thereat; means for receiving both packets and idle code at the port and for discarding the idle code; means cooperative with the receiving means for identifying received idle packets; and means responsive to the identifying means for discarding received packets identified as idle packets.
Claim 33
Dependent Claim
111 words
A trunk controller for a packet switching system, the controller having a port for connecting to a communication trunk, comprising: means for generating packets marked as idle packets; means cooperative with the generating means for periodically transmitting at the port a generated idle packet when other packets are not available for transmission and further for transmitting at the port idle code when packets are not being transmitted thereat; means for receiving both packets and idle code at the port and for discarding the idle code; means cooperative with the receiving means for identifying received idle packets; and means responsive to the identifying means for discarding received packets identified as idle packets.
Claim 34
Dependent Claim
23 words
The controller of claim 26 wherein the generating means comprise: means for generating packets each including idle data and an idle packet identifier.
Claim 35
Dependent Claim
22 words
The controller of claim 27 wherein the identifying means comprise: means for inspecting the identifier of received packets to identify idle packets.
Claim 36
Dependent Claim
32 words
The controller of claim 26 wherein the generating means comprise means for generating periodically when packets are not available for transmission a packet marked as an idle packet and including idle data.
Claim 37
Dependent Claim
36 words
The controller of claim 26 further comprising: means responsive to the receiving means and to the identifying means for signalling error when an idle packet is not periodically identified while other packets are not being received.
Claim 38
Independent Claim
71 words
A method of signalling in a packet switching system between a first and a second portion thereof interconnected for communication by a communication link, comprising the steps of: transmitting idle code on the link while packets are not being transmitted thereon; occasionally transmitting from the first portion on the link a packet of a first type; and discarding packets of the first type received on the link at the second portion.
Claim 39
Independent Claim
71 words
A method of signalling in a packet switching system between a first and a second portion thereof interconnected for communication by a communication link, comprising the steps of: transmitting idle code on the link while packets are not being transmitted thereon; occasionally transmitting from the first portion on the link a packet of a first type; and discarding packets of the first type received on the link at the second portion.
Claim 40
Independent Claim
85 words
A method of signalling in a packet switching system between a first and a second switching node interconnected for communication by a trunk, comprising the steps of: transmitting idle code on the trunk from the first node while packets are not being transmitted thereon; occasionally transmitting from the first node on the trunk a packet of a first type; discarding idle code received on the trunk at the second node; and discarding packets of the first type received on the trunk at the second node.
Claim 41
Independent Claim
85 words
A method of signalling in a packet switching system between a first and a second switching node interconnected for communication by a trunk, comprising the steps of: transmitting idle code on the trunk from the first node while packets are not being transmitted thereon; occasionally transmitting from the first node on the trunk a packet of a first type; discarding idle code received on the trunk at the second node; and discarding packets of the first type received on the trunk at the second node.
Claim 42
Dependent Claim
32 words
The method of claim 32 wherein the step of transmitting includes the steps of: occasionally generating a packet of the first type; and transmitting a packet on the trunk the generated packet.
Claim 43
Dependent Claim
36 words
The method of claim 32 wherein the step of discarding packets includes the steps of: identifying packets of the first type received on the trunk; and discarding received packets identified as being of the first type.
Claim 44
Dependent Claim
30 words
The method of claim 34 wherein the steps of discarding are preceded by the step of: receiving both idle code and packets transmitted on the trunk from the first node.
Claim 45
Independent Claim
124 words
A method of idle period signalling in a packet switching system between a first and a second switching node interconnected for communication by a trunk, comprising the steps of: transmitting idle code on the trunk from the first node while packets are not being transmitted thereon; generating a packet marked as an idle packet; periodically transmitting from the first node on the trunk the generated idle packet when other packets are not available for transmission; receiving at the second node idle code transmitted on the trunk from the first node; discarding the received idle code; receiving at the second node a packet transmitted on the trunk from the first node; identifying the received packet as an idle packet; and discarding the identified idle packet.
Claim 46
Independent Claim
124 words
A method of idle period signalling in a packet switching system between a first and a second switching node interconnected for communication by a trunk, comprising the steps of: transmitting idle code on the trunk from the first node while packets are not being transmitted thereon; generating a packet marked as an idle packet; periodically transmitting from the first node on the trunk the generated idle packet when other packets are not available for transmission; receiving at the second node idle code transmitted on the trunk from the first node; discarding the received idle code; receiving at the second node a packet transmitted on the trunk from the first node; identifying the received packet as an idle packet; and discarding the identified idle packet.
Claim 47
Dependent Claim
25 words
The method of claim 36 wherein the step of generating comprises the step of: generating a packet including idle data and an idle packet identifier.
Claim 48
Dependent Claim
26 words
The method of claim 37 wherein the step of identifying comprises the step of: inspecting the identifier of the received packet to identify an idle packet.
Claim 49
Dependent Claim
34 words
The method of claim 37 wherein the step of generating comprises the step of: generating periodically when packets are not available for transmission a packet marked as an idle packet and including idle data.
Claim 50
Dependent Claim
27 words
The method of claim 37 further comprising the step of: signalling error when an idle packet is not identified periodically while other packets are not being received.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-23 | 1990-08-25 | 1991-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-23 | 1994-08-25 | 1995-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-23 | 1998-08-25 | 1999-02-24 | $7700.00 | Window Closed / Lapsed |