Patent EP0582537A2 successfully refreshed from Google Patents.
EP0582537A2
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EP
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Transmission of high-priority, real-time traffic on low-speed communications links
Assignee: International Business Machines Corp
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Filing: 1993-07-16
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Granted: —
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Expires: 2013-07-16
Abstract
Abstract A protocol is defined for mixed data/voice/multimedia communications systems to transmit and receive high-priority, real-time traffic over low-speed digital communication links by embedding such high-priority traffic in low-priority, non-real-time traffic. High-priority, real-time packets are thus transmitted without delay by preempting low-priority packets. Low-priority, non-real-time packets are held during preemption, and low -priority transmission is automatically resumed after transmission of high-priority packets has been completed. A protocol is defined for communications systems to exchange information, at the time that a communication link is activated, defining their link capabilities for handling high-priority, real-time packets and to agree on how this high-priority traffic will be transmitted on the communication link.
Inventors
- 👤 Israel Cidon
- 👤 Richard M. Doney
- 👤 John Ellis Drake, Jr.
- 👤 Elizabeth Anne Hervatic
- 👤 Kenneth Harvey Potter, Jr.
- 👤 Theodore Ernest Tedijanto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 14:49
CPC Classifications
H; H04; H04L; H04L47/00; H04L47/10; H04L47/24; H04L47/2425; H04L47/2433; H04L12/00; H04L12/64; H04L12/6418; H04L47/2416; H04L47/245; H04L9/00; H04L9/40; H04L2012/6445; H04L2012/6459; H04L2012/6464; H04L2012/6478; H04L69/00; H04L69/30; H04L69/32; H04L69/322; H04L69/324
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
81 words
A packet-switched communications system for mixed low-priority and high-priority traffic characterized in that it comprises: means for embedding high-priority packets within low-priority packets based on distinctive pattern codes attached to said packets, means responsive to a distinctive start-preempt pattern for transmitting the high-priority packet immediately, means for buffering a low-priority packet that may be preempted by a high-priority packet, and means responsive to a distinctive end-preempt pattern for resuming transmission of a preempted low-priority packet temporarily stored in said buffering means.
Claim 2
Dependent Claim
72 words
A communications system for transmitting mixed low-priority and high-priority traffic characterized in that it comprises: means for distinguishing between low-priority and high-priority packets, means for generating a start-preempt pattern to interrupt transmission of a low-priority packet, means for buffering remainder of low-priority packet that has been preempted, means for generating an end-preempt pattern at the completion of transmission of all high-priority packets and the resumption of transmission of the interrupted low-priority packet.
Claim 3
Dependent Claim
43 words
A communication system according to claim 2 in which: said distinguishing means is a pattern detector having stored therein the patterns identifying respectively a low-priority packet and a high-priority packet and further having comparative means for matching received patterns with said stored patterns.
Claim 4
Dependent Claim
103 words
A communications system for receiving mixed low-priority and high-priority traffic characterized in that it comprises: means for distinguishing between low-priority and high-priority received packets, means for detecting start of preempting high-priority packets, means for comparing bit patterns in received signals with stored distinctive flag patterns to determine whether a particular pattern is a complete packet or an interrupted low-priority packet, means for receiving multiple high-priority packet without resuming preempted low-priority packet, means for buffering low-priority packet that may be preempted by a high-priority packet, means for resuming reception of preempted low-priority packet, means for completing low-priority packet temporarily stored in said buffering means.
Claim 5
Independent Claim
155 words
A method for embedding high-priority communication packets within low-priority communication packet in a packet-switched communications system characterized in that it comprises the steps of: a) prefixing each low-priority packet with a characteristic start flag; b) prefixing each high-priority packet with a characteristic start-preempt pattern of bits; c) suffixing each low-priority packet with a characteristic ending flag; d) suffixing each high-priority packet with a characteristic end-preempt pattern of bits; e) using the starting flag to initiate transmission of packets and to establish byte alignment with a packet frame; f) using the start-preempt pattern of bits to interrupt the transmission of low-priority packets and buffer non-transmitted low-priority bits while transmission of high-priority bits continues; g) using the end-preempt pattern of bits following the completion of transmission of a high-priority packet to indicate the resumption of the transmission of the interrupted low-priority packet; and h) using the ending flag to return the communications system to the idle state.
Claim 6
Independent Claim
137 words
A method for receiving packet-switched communication signals in which high-priority packets are embedded in low-priority packets characterized in that it comprises the steps of: a) monitoring incoming signal bit streams for the presence of preassigned patterns of starting and ending flags and start-preempt and end-preempt flags; b) responding to a starting flag to effect byte alignment and to enter a ready state for receiving and buffering low-priority packets; c) responding to a start-preempt flag to suspend reception of low-priority packet and accept and relay a high-priority packet immediately; d) responding to an end-preempt flag to resume reception of the suspended low-priority packet; e) responding to an ending flag to relay the completed low-priority packet, f) responding to the failure to detect an end-preempt flag after a high-priority packet by aborting further reception until a normal flag occurs.
Claim 7
Dependent Claim
60 words
A method for receiving packet-switched communication signals according claim 6 further comprising: set of flag conditions that when received return the receiver to a non-error state, set of error states that allow recovering of some packets prior to returning to a non-error state, and a finite state machine defining the conditions under which transitions occur between non-error and error states.
Claim 8
Independent Claim
86 words
A method for communications systems at each end of a communication links to determine whether preempt/resume is required for each link-direction at the time of link activation characterized in that it comprises: means to exchange link capabilities between adjacent communication systems over the communications systems over the communication link at link activation time, means for each communications system to independently computer whether preempt/resume protocol extension should be enable, and means for communications systems not supporting preempt/resume protocol extension to activate link with communications system supporting extension.
References Cited (Backward Citations)
WO1984002628A1
Cited
WO1987003445A1
Cited
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