Local area communication network utilizing a round robin access scheme with improved channel utilization
First Claim
1. A local communication network comprisinga communication bus for transmitting data packets including an inbound channel, an outbound channel, and means for connecting said inbound channel to outbound channel such that data packets are transmitted in the same direction on said inbound channel and said outbound channel,a plurality of stations S1-SN located along and connected to said communication bus where each of said stations have a respective index corresponding to the location of its connection to said bus such that carrier signals having data packets are transmitted from said stations on said outbound channel in a round robin format, each of said stations including for each round of said round robin format,transmit means for transmitting carrier signals having data packets on said outbound channel past each station connected to said outbound channel having a higher index than the respective transmit station,receive means connected to said inbound channel such that data packets are propagated past each of said receive means in the same order as the respective indices of said stations connected to said outbound channel thereby achieving said round robin format, andmeans for controlling the transmission and reception of said data packets, said control means includingmeans for sensing a first carrier signal transmitted by one of said stations having a lower index on said outbound channel,means for detecting the end of said first carrier signal and means responsive thereto for transmitting a second carrier signal having a data packet on said outbound channel,means for aborting transmission of said second carrier signal if a third carrier signal is sensed within a predetermined period of time td where td is the time for a station to detect the presence or absence of a carrier signal on said bus.
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Abstract
Disclosed is a local area communication network based upon a broadcast communication system comprising an inbound channel and an outbound channel, a plurality of stations connected to both the inbound and the outbound channels, transmitting on the outbound channel which utilizes an access protocol where the the access protocol used by the stations connected to the bus is a distributed algorithm and is based upon a conflict-free round robin (RR) access scheme. The time required to switch from one active user to the next in a round is minimized (on the order of carrier detection time, and is independent of the end-to-end network propagation delay. This improvement is particularly significant when the channel data rate is so high, or the end-to-end propagation delay is so large, or the packet size is so small as to render the end-to-end propagation delay a significant fraction of, or larger than, the transmission time of a packet. Moreover, some features of the present invention make it particularly suitable for voice applications. In view of integrating voice and data, a voice/data protocol is described which allows it to meet the bandwidth requirement and maximum packet delay constraint for voice communication at all times, while guaranteeing a minimum bandwidth requirement for data traffic. The voice/data protocol constitutes a highly adaptive allocation scheme of channel bandwidth, which allows data users to steal the bandwidth unused by the voice application.
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Citations
66 Claims
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1. A local communication network comprising
a communication bus for transmitting data packets including an inbound channel, an outbound channel, and means for connecting said inbound channel to outbound channel such that data packets are transmitted in the same direction on said inbound channel and said outbound channel, a plurality of stations S1-SN located along and connected to said communication bus where each of said stations have a respective index corresponding to the location of its connection to said bus such that carrier signals having data packets are transmitted from said stations on said outbound channel in a round robin format, each of said stations including for each round of said round robin format, transmit means for transmitting carrier signals having data packets on said outbound channel past each station connected to said outbound channel having a higher index than the respective transmit station, receive means connected to said inbound channel such that data packets are propagated past each of said receive means in the same order as the respective indices of said stations connected to said outbound channel thereby achieving said round robin format, and means for controlling the transmission and reception of said data packets, said control means including means for sensing a first carrier signal transmitted by one of said stations having a lower index on said outbound channel, means for detecting the end of said first carrier signal and means responsive thereto for transmitting a second carrier signal having a data packet on said outbound channel, means for aborting transmission of said second carrier signal if a third carrier signal is sensed within a predetermined period of time td where td is the time for a station to detect the presence or absence of a carrier signal on said bus.
- 46. A local area communication network comprising a communication bus including an inbound channel and an outbound channel, and means for connecting said inbound channel to said outbound channel such that carrier signals having data packets are transmitted in the same direction on said inbound channel and said outbound channel in a round robin format, a plurality of stations S1-SN located along and connected to said communication bus where each of said stations have a respective index corresponding to the location of its connection to said bus, each of said stations including a transmitting tap connected to said outbound channel for transmitting data packets, means for sensing a carrier signal flowing in a certain direction on said outbound channel, means for detecting an end of said carrier signal with a certain time period, and means responsive to said end of carrier for starting transmission of one of said data packets thereby achieving a round robin format.
- 49. A local area communication network comprising a communication bus having an inbound channel and an outbound channel, a plurality of stations S1-SN located along and connected to said bus where each of said stations have a respective index corresponding to the locations of its connection to said bus, each of said stations including means for transmitting and receiving carrier signals having data packets on said bus in a round robin format such that said data packets are propagated past each of said stations in the same direction on said outbound channel to said inbound channel thereby achieving said round robin format, means for sensing a first carrier signal transmitted by one of said stations having a lower index on said outbound channel, and means responsive to the detection of an end of carrier signal on said outbound channel for starting transmission of one of said transmission units on said outbound channel.
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53. A local area communication network comprising a communication bus having an inbound channel and an outbound channel, a plurality of stations S1-SN located along and connected to said communication bus where each of said stations have a respective index corresponding to the location of its connection to said bus, each of said stations including means for transmitting and receiving carrier signals having information data packets on said communication bus in a round robin format wherein said data packets are of a different type, means for integrating said different types of packets on said communication bus such that the data packets are propagated on said inbound channel in the same direction with respect to each of said stations as on said outbound channel thereby achieving a round robin format, and means for controlling the transmission and reception of said data packets, said control means including means for sensing a first carrier signal transmitted by one of said stations having a lower index on said outbound channel, means for detecting the end of said first carrier signal and means responsive thereto for transmitting a second carrier signal having a data packet on said outbound channel, and means for aborting transmission of said second carrier signal if a third carrier signal is sensed within a predetermined period of time td where td is the time for a station to detect the presence or absence of a carrier signal on said bus.
- 54. A local area communication network comprising a communication bus having an inbound channel and an outbound channel, a plurality of stations S1-SN located along and connected to said communication bus where each of said stations have a respective index corresponding to the location of its connected to said bus, each of said stations including a transmitting tap on said outbound channel and means for transmitting and receiving carrier signals having information data packets on said communication bus in a round robin format such that said data packets are propagated past each of said stations on said inbound channel in the same direction with respect to said stations on said outbound channel thereby achieving said round robin format, means for controlling the transmission and reception of said data packets, said control means including means for sensing a first carrier signal transmitted by one of said stations having a lower index on said outbound channel, means for detecting the end of said first carrier signal and means responsive thereto for transmitting a second carrier signal having a data packet on said outbound channel, and means for aborting transmission of said second carrier signal if a third carrier signal is sensed within a predetermined period of time td where td is the time for a station to detect the presence or absence of a carrier signal on said bus.
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64. A local area communication network comprising a communication bus having an outbound channel, a plurality of stations S1-SN located along and connected to said communication bus where each of said stations have a respective index corresponding to the location of its connection to said bus, each of said stations including a transmitting tap connected to said outbound channel, transmit means for transmitting carrier signals having data packets in a round robin format on said outbound channel past each station connected to said outbound channel having a higher index than the respective transmit station, means for sensing a carrier signal on the upstream side of said transmitting tap, means for detecting the end of said first carrier signal and means responsive thereto for transmitting a second carrier signal having a data packet on said outbound channel, and means for aborting transmission of said second carrier signal is sensed within a predetermined period of time td where td is the time for a station to detect the presence or absence of a carrier signal on said bus, thereby achieving said round robin format.
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65. A local area communication network comprising a communication bus, a plurality of stations S1-SN located along and connected to said communication bus where each of said stations have a respective index corresponding to the location of its connection to said bus such that said carrier signals having data packets are transmitted from said stations on said communication bus in a round robin format, each of said stations including, for each round of said round robin format,
transmit means for transmitting carrier signals having data packets on said communication bus past each station connected to said communication bus having a higher index than the respective transmit station, receive means connected to said communication channel such that data packets are propagated past each of said receive means in the same order as the respective indices of said stations connected to said communication bus thereby achieving said round robin format, means for controlling the transmission and reception of said data packets, said control means including means for sensing a first carrier signal transmitted in a certain direction by one of said stations having a lower index on said communication bus, and means for detecting the end of said first carrier signal and means responsive thereto for transmitting a second carrier signal having a data packet on said communication bus.
Specification