COMMUNICATION SYSTEM, COMMUNICATION DEVICE, INTEGRATED CIRCUIT, AND COMMUNICATION METHOD
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Accused Products
Abstract
A communication system includes communication devices that are connected with one another in a ring via a serial link. In the communication system, one communication device issues a standby packet for causing each communication device connected to a part of the link that is not involved with data transfer to switch to standby mode. Each communication device connected to this part of the link relays the standby packet from an immediately preceding communication device in the link to an immediately succeeding communication device in the link, and after relaying the standby packet, causes the own device to switch to standby mode. Further, a communication device that performs communication with said one communication device issues a loopback packet for causing each communication device connected to a part of the link that is involved with data transfer to switch to loopback mode. Each communication device connected to this part of the link relays the loopback packet from an immediately preceding communication device in the link to an immediately succeeding communication device in the link, and after relaying the loopback packet, causes the own device to switch to loopback mode.
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Citations
24 Claims
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1-12. -12. (canceled)
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13. A communication system including a first communication device and a plurality of second communication devices, the first communication device and the second communication devices being connected with one another in a ring via a serial link, wherein
the first communication device comprises: -
a first command processing unit operable to, when a downlink is not used for data packet transfer, issue a standby packet to a partner device that is one of the second communication devices with which the first communication device performs communication, the downlink being a part of the serial link extending from the first communication device to the partner device; and a first data transfer unit operable to (i) transmit a write data packet to be written via the downlink, and (ii) receive a read data packet to be read via an uplink, which is a part of the serial link extending from the partner device to the first communication device, and each of the second communication devices comprises; a second command processing unit operable to, when the uplink is not used for the data packet transfer and the own device is the partner device, issue the standby packet to the first communication device; a second data transfer unit operable to receive the write data packet via the downlink and transmit the read data packet via the uplink; a packet relay unit operable to, in accordance with a destination of a packet input to the own device, relay the input packet to one of the first and second communication devices that immediately succeeds the own device in the ring; and a standby control unit operable to, when the input packet relayed by the packet relay unit of the own device is the standby packet, cause the own device to switch to standby mode. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A communication device included in a plurality of communication devices that are connected with one another in a ring via a serial link and that constitute a communication system, the serial link being made up of (i) a downlink, which is a part of the serial link that extends from a master communication device to a slave communication device, the master communication device and the slave communication device being included in the plurality of communication devices, and (ii) an uplink, which is a part of the serial link that extends from the slave communication device to the master communication device, the communication device comprising:
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a command processing unit operable to issue, to a partner device that is one of the plurality of communication devices with which the own device performs communication, (i) a standby packet for causing one or more of the plurality of communication devices connected to one of the downlink and the uplink that is not used for data packet transfer to switch to standby mode, and (ii) a loopback packet for causing one or more of the plurality of communication devices connected to one of the downlink and the uplink that is used for the data packet transfer to switch to loopback mode; a data transfer unit operable to transfer a write data packet to be written via the downlink, and to transfer a read data packet to be read via the uplink; a packet relay unit operable to, in accordance with a destination of a packet input to the own device, relay the input packet to one of the plurality of communication devices that immediately succeeds the own device in the ring; and a standby control unit operable to (i) when the input packet relayed by the packet relay unit is the standby packet, cause the own device to switch to the standby mode, and (ii) when the input packet relayed by the packet relay unit is the loopback packet, cause the own device to switch to the loopback mode.
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23. An integrated circuit used by a communication device included in a plurality of communication devices that are connected with one another in a ring via a serial link and that constitute a communication system, the serial link being made up of (i) a downlink, which is a part of the serial link that extends from a master communication device to a slave communication device, the master communication device and the slave communication device being included in the plurality of communication devices, and (ii) an uplink, which is a part of the serial link that extends from the slave communication device to the master communication device, the integrated circuit comprising:
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a command processing circuit operable to issue, to a partner device that is one of the plurality of communication devices with which the own device performs communication, (i) a standby packet for causing one or more of the plurality of communication devices connected to one of the downlink and the uplink that is not used for data packet transfer to switch to standby mode, and (ii) a loopback packet for causing one or more of the plurality of communication devices connected to one of the downlink and the uplink that is used for the data packet transfer to switch to loopback mode; a data transfer circuit operable to transfer a write data packet to be written via the downlink, and to transfer a read data packet to be read via the uplink; a packet relay circuit operable to, in accordance with a destination of a packet input thereto, relay the input packet to one of the plurality of communication devices that immediately succeeds the own device in the ring; and a standby control circuit operable to (i) when the input packet relayed by the packet relay circuit is the standby packet, cause the own device to switch to the standby mode, and (ii) when the input packet relayed by the packet relay circuit is the loopback packet, cause the own device to switch to the loopback mode.
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24. A communication method used in a communication system including a first communication device and a plurality of second communication devices, the first communication device and the second communication devices being connected with one another in a ring via a serial link, wherein
the communication method causes the first communication device to perform the steps of: -
when a downlink is not used for data packet transfer, issuing a standby packet to a partner device that is one of the second communication devices with which the first communication device performs communication, the downlink being a part of the serial link extending from the first communication device to the partner device; and transmitting a write data packet to be written via the downlink and receiving a read data packet to be read via an uplink, which is a part of the serial link extending from the partner device to the first communication device, and the communication method causes each of the second communication devices to perform the steps of; issuing the standby packet to the first communication device when the uplink is not used for the data packet transfer and the own device is the partner device; receiving the write data packet via the downlink and transmitting the read data packet via the uplink; in accordance with a destination of a packet input to the own device, relaying the input packet to one of the first and second communication devices that immediately succeeds the own device in the ring; and causing the own device to switch to standby mode when the input packet that has been relayed in the own device is the standby packet.
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Specification