摘要:
In a loop transmission system utilizing specific patterns, a specified station for sending the specific patterns sends a specific pattern S or a specific frame S' which is not delayed in each station in advance of sending a specific pattern G used for data exchanging in each station, thereby ensuring rapid detection of abnormality of the specific pattern G.
摘要:
A loop transmission system including a plurality of stations connected in series in a looped transmission line to transfer data among the stations, wherein the stations include a supervising station and at least one terminal station and the transmission line is duplicated so that when a fault occurs in currently used one of the transmission lines, the other transmission line which has been used as a spare is used for transmission of data, while the supervising station sends out a specific signal to the spare transmission line and the terminal stations each determines one of the transmission lines through which the specific signal is detected, as the spare.
摘要:
A method of switching transmission lines for a transmission control system in which a plurality of stations are linked with loop type transmission lines having a stand-by transmission line characterized in that each of the stations is operable to switch the active transmission line to the stand-by transmission line in response to the detection of abnormality in the carrier wave and a station transmitting the carrier wave is operable to halt the transmission of the carrier wave on the active transmission line so that the overall transmission line is switched to the stand-by transmission line, thereby minimizing the system down time.
摘要:
A station diagnosis method in a communications network system including a closed ring transmission line and a plurality of data stations which can be connected to the ring transmission line by a plurality of line concentrators disposed in the ring transmission line wherein an internal ring transmission line is formed in the line concentrators so that the operation states of the line concentrators are diagnosed by transmitting diagnosis data through the internal ring transmission line.
摘要:
In a communication network having a plurality of stations interconnected through a double ring transmission line, a station which detects a failure in the ring transmission line sends out a failure notice data, and a station which has received the failure notice data stops the send-out of its own data and relays the received data. A station which cannot receive the failure notice data loops back and transmission line to form a closed ring transmission line which bypasses a failure location.
摘要:
In a ring communications system including a plurality of line concentrators that are connected in the form of a ring, the line concentrators are connected together via a main ring, and the terminal stations connected to the line concentrators are connected to the main ring via ring subsidiaries. The main ring and the ring subsidiaries are connected together via ring connection switches that so work as to connect or disconnect the main ring and the ring subsidiaries. The ring connection switch is so constructed as to maintain the connected condition even when the power source of the line concentrator is in the turned-off state.
摘要:
In a communication system having first and second ring transmission lines for connecting a plurality of stations and for providing opposite signal transmission direction, a first station, which is located just downstream side of an failure point occurred in the first transmission line, sends out a beacon signal along said first transmission line while causing an intentional failure in the second transmission line on its downstream side and a second station, which is located just upstream side of the failure point on the first transmission line, forms a first loop-back path (WRAPA) by detecting the intentional failure on the second transmission line if the second station has received the beacon signal. The first station forms a second loop-back path (WRAPB) by receiving the beacon from the second transmission line which is sent back by the second station.
摘要:
A local area network communication system in which a repeating installation sets a ring number of a ring from which a communication frame was taken out as a source address of the frame. The repeating installation also sets a ring number of a ring to which a communication frame is to be sent. When a station receives the frame, the station checks the source address of the frame to identify the ring number of the ring to which the source station belongs and checks the destination address to identify the ring number of the ring to which the station itself belongs.
摘要:
A communication method applied to a communication system is provided for enhancing communication performance such as a throughput and a turn around time in the so-called intra-computer communication. In the communication procedure, when a source end system (SES) like a host computer transfers data to a destination end system (DES) such as a LAN or a WAN through a communication control system (CCS), the CCS served as a virtual destination receives the data and transmits an acknowledge (+Cresp) to the SES. In response to the acknowledge (+Crest), the SES performs the next transfer of the data. In response to the last acknowledge, the SES operates to output an indication about completion of the data transmission (End TX-C). The CCS continues to transfer the data temporarily received from the SES to the DES unless the CCS receives the acknowledge from the DES. The acknowledge +Cresp contains information about an amount of data transferred from the CCS to the DES. The SES operates to calculate an amount of data to be transferred on the basis of the amount of transferred data contained in the information, a window size and the amount of data so far transferred to the CCS.
摘要:
A method for performing a duplicated address test used for a network including a first ring transmission line, a second ring transmission line having a signal transmission direction opposite to that of the first ring transmission line, and a plurality of stations connected to at least one of these ring transmission lines. Each of these stations has a flag DAC representing whether or not the duplicated address test is performed, and some of the plural stations constitute a plurality of control nodes having a configuration function of the network. The flag DAC of each of the stations is reset at a time instant when a power source of this station is turned on, and also when any of the control nodes receives the sent out configuration control frame. Each of the stations having the reset flags DAC sents out the duplicated address test frame to either the first or second transmission line to which the station is connected when a token frame to control a transmission right is captured. When another station having the same address as that of a source station receives the test frame, a discriminator indicative of an address duplication is added to this test frame.