Communication management apparatus, communication apparatus, and communication method

摘要

A communication management apparatus includes a token-circulation-order-information storing unit that stores token circulation order, a token-frame processing unit that determines whether transmission right acquiring apparatus information of the token frame indicates the own apparatus and transmits a token frame in which first transmission right acquisition determination information indicating a sequence number of a communication apparatus that can acquire a transmission right in the token circulation order, second transmission right acquisition determination information indicating the number of frames that can be transmitted during one token frame circulation, and transmission right acquiring apparatus information indicating the next transmission destination of the token frame after the own apparatus acquired from the token circulation order are set, and a data-frame-communication processing unit that transmits and receives the data frame, thereby to reduce time required until a communication node that acquired the token frame transmits data.

主权项

1. A communication management apparatus that manages transmission of data in a network in which the communication management apparatus and one or more communication apparatuses are connected by an Ethernet cable, the communication management apparatus comprising:
a token-circulation-order storing unit that stores token circulation order for circulating a token frame in the network; a token-frame receiving unit that receives the token frame and determines whether transmission right acquiring apparatus information for acquiring a transmission right next in the received token frame indicates the communication management apparatus; a token-frame transmitting unit that transmits the token frame in which: a first transmission right acquisition determination information indicating sequence numbers of the one or more communication apparatuses that can acquire the transmission right in the token circulation order is set, a second transmission right acquisition determination information indicating a specific number of frames that can be transmitted while the token frame circulates once from the communication management apparatus is set, wherein the specific number is variable based on a calculation, and the transmission right acquiring apparatus information that indicates a next transmission destination of the token frame, after the communication management apparatus, acquired from the token circulation order is set; and a data-frame-communication processing unit that performs reception processing for data frames from other communication nodes and, when the transmission right is acquired, converts data stored in the communication management apparatus into a first set of data frames in frame unit and transmits one or more of the data frames in the first set of data frames, wherein: the first transmission right acquisition determination information comprises:
a token circulation number indicating a first sequence number counted from the communication management apparatus in the token circulation order of a communication apparatus set in the transmission right acquiring apparatus information, anda transmission permitted station value indicating a second sequence number in the token circulation order of a communication apparatus that can transmit a data frame; andthe token-frame transmitting unit sets “1” in the token circulation number and sets, in the transmission permitted station value, a value corresponding to information in the received token frame, wherein: in the received token frame, when the second transmission right acquisition determination information is “0” and the number of transmittable frames “0” setting station information, which indicates a communication apparatus that sets the second transmission right acquisition determination information to “0”, is set:
the token-frame receiving unit does not give a transmission instruction for a data frame to the data-frame-communication processing unit, andthe token-frame transmitting unit sets the number of transmittable frames “0” setting station information in the transmission permitted station value of the token frame, and wherein the communication management apparatus further comprises a number-of-transmittable-frames “0” setting-station storing unit, wherein a third sequence number of a communication apparatus to which the transmission right is preferentially given when the second transmission right acquisition determination information is “0” is stored in a changed-destination-information-during-priority-processing storing unit, the token-frame-receiving unit stores, when the token-frame receiving unit receives a token frame in which the transmission right acquiring apparatus information indicates the communication management apparatus and the second transmission right acquisition determination information is “0”, contents of the number-of-transmittable-frames “0” setting station information in the number-of-transmittable-frames “0” setting-station storing unit, and the token-frame transmitting unit sets, in the transmission permitted station value, the third sequence number stored in the changed-destination-information-during-priority-processing storing unit.