What is claimed is:
1. A bidirectional line switched ring network comprising:
a plurality of optical transmission equipment sets connected in a ring form,
wherein optical transmission equipment provided in a node on the transmission side performs transmission to each lower-order channel by attaching a transmission-side node ID, and,
optical transmission equipment provided in a node on the reception side collates the received transmission-side node ID with an expected value of the transmission-side node ID having been set in advance, and when the collation does not match, the optical transmission equipment in the node on the reception side prevents a misconnection in the event of a failure by inserting an alarm indication signal.
2. The bidirectional line switched ring network according to claim 1,
wherein the transmission-side node ID is transmitted using the V3 byte.
3. The bidirectional line switched ring network according to claim 2,
wherein functions of inserting the transmission-side node ID into the V3 byte, collating with the expected value, and squelching can be set ineffective.
4. The bidirectional line switched ring network according to claim 2,
wherein, using the V3 bytes for three frames, the transmission-side node ID and a channel ID are additionally transmitted to each VT channel, so that the time slot interchange (TSI) of the VT channel is enabled in a pass-through node.
5. The bidirectional line switched ring network according to claim 4,
wherein, using the first to sixth bits of the H4 byte, the time slot interchange (TSI) is enabled in the pass-through node.
6. The bidirectional line switched ring network according to claim 2,
wherein the transmission-side node ID is transmitted using the V4 byte, in place of the V3 byte.
7. A bidirectional line switched ring network comprising:
a plurality of optical transmission equipment sets connected in a ring form,
wherein optical transmission equipment provided in a node on the transmission side performs transmission to each higher-order channel by attaching a transmission-side node ID, and,
optical transmission equipment provided in a node on the reception side collates the received transmission-side node ID with an expected value of the transmission-side node ID having been set in advance, and when the collation does not match, the optical transmission equipment in the node on the reception side prevents a misconnection in the event of a failure by inserting an alarm indication signal.
8. The bidirectional line switched ring network according to claim 7,
wherein the transmission-side node ID is transmitted using the H3 byte.
9. The bidirectional line switched ring network according to claim 8,
wherein, using the H3 bytes for three frames, the transmission-side node ID and a channel ID are additionally transmitted to each STS channel, so that the time slot interchange (TSI) of the STS channel is enabled in a pass-through node.
10. A bidirectional line switched ring network comprising:
two bidirectional line switched ring networks each comprising a plurality of optical transmission equipment sets connected in a ring form, being interconnected with lower-order channels including a work channel and a protection channel,
wherein, in regard to two nodes provided in each of the two bidirectional line switched ring networks, one node being connected to the lower-order work channel while the other node being connected to the lower-order protection channel, as an expected source node ID to be transmitted from a source node to the lower-order work channel, either an ID of a source node transmitting to the own node, or an ID of a source node transmitting to the node connected to the lower-order protection channel, is set.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method to save power in data communication, the method comprising:
transmitting a plurality of symbols each of which containing an overhead portion and at least a portion of a respective data transmission unit (DTU) by:
transmitting the overhead portion of a first symbol of the plurality of symbols and the at least a portion of a respective DTU of the first symbol when the at least a portion of the respective DTU of the first symbol contains payload data; and
transmitting the overhead portion of a second symbol of the plurality of symbols without transmitting the at least a portion of a respective DTU of the second symbol when the at least a portion of the respective DTU of the second symbol contains no payload data.
2. The method as recited in claim 1, wherein each symbol contains a respective plurality of DTUs, and wherein transmitting the overhead portion of a second symbol of the plurality of symbols without transmitting the at least a portion of a respective DTU of the second symbol when at least a portion of the respective DTU of the second symbol contains no payload data comprises transmitting the overhead portion of the second symbol without transmitting the respective plurality of DTUs of the second symbol when each of the respective plurality of DTUs of the second symbol contains no payload data.
3. The method as recited in claim 1, wherein the transmitting comprises transmitting in accordance with Very-high-speed Digital Subscriber Line 2 (VDSL2) standards.
4. The method as recited in claim 1, further comprising:
determining whether or not a first DTU that corresponds to one or more of the plurality of symbols contains no payload data; and
marking the first DTU to indicate the first DTU as containing no payload data when it is determined that the first DTU contains no payload data.
5. The method as recited in claim 4, wherein marking the first DTU comprises setting a value of a sequence identification (SID) in the overhead portion of the first DTU to 255.
6. The method as recited in claim 4, wherein marking the first DTU comprises setting a value of a time stamp (TS) in the overhead portion of the first DTU to 255 and a value of a sequence identification (SID) in the overhead portion of the first DTU to 255.
7. The method as recited in claim 1, further comprising:
setting a value of a sequence identification (SID) or both a value of a time stamp (TS) and a value of the SID in the overhead portion of each symbol to indicate a nature of content of the at least a portion of a respective DTU of each symbol.
8. The method as recited in claim 7, wherein the value of the SID is set to 255, or the value of the TS is set to 255 and the value of the SID is set to 255, to indicate the at least a portion of a respective DTU of a symbol as containing no payload data.
9. The method as recited in claim 7, wherein the value of the TS is set to 255 and the value of the SID is set to 254 to indicate the at least a portion of a respective DTU of a symbol will be transmitted once and not stored in a retransmission queue or a transmitter.
10. A method to save power in data communication, the method comprising:
defining a second data transmission unit (DTU) such that the second DTU carries a first data packet that corresponds to a first DTU and a second data packet that corresponds to the second DTU; and
transmitting the first DTU and the second DTU with the first DTU carrying no payload data and with the second DTU carrying the first data packet and the second data packet as payload data.
11. The method as recited in claim 10, wherein the first data packet corresponds to the first DTU and a third DTU, and wherein the first DTU, the second DTU, and the third DTU are transmitted with the first DTU and the third DTU carrying no payload data and with the second DTU carrying the first data packet and the second data packet as payload data.
12. The method as recited in claim 10, wherein the first data packet and the second data packet comprise first and second Voice over Internet Protocol (VoIP) data packets.
13. A networking device comprising:
memory; and
a communication unit coupled to the memory, the communication unit configured to:
transmit a plurality of symbols each of which containing an overhead portion and at least a portion of a respective data transmission unit (DTU) by:
transmitting the overhead portion of a first symbol of the plurality of symbols and the at least a portion of a respective DTU of the first symbol when the at least a portion of the respective DTU of the first symbol contains payload data; and
transmitting the overhead portion of a second symbol of the plurality of symbols without transmitting the at least a portion of a respective DTU of the second symbol when the at least a portion of the respective DTU of the second symbol contains no payload data.
14. The networking device as recited in claim 13, wherein each symbol contains a respective plurality of DTUs, and wherein the communication unit transmits the overhead portion of the second symbol without transmitting the respective plurality of DTUs of the second symbol when each of the respective plurality of DTUs of the second symbol contains no payload data.
15. The networking device as recited in claim 13, wherein the communication unit is further configured to:
determine whether or not a first DTU that corresponds to one or more of the plurality of symbols contains no payload data; and
mark the first DTU to indicate the first DTU as containing no payload data when it is determined that the first DTU contains no payload data.
16. The networking device as recited in claim 15, wherein the communication unit marks the first DTU by setting a value of a sequence identification (SID) in the overhead portion of the first DTU to 255.
17. The networking device as recited in claim 15, wherein the communication unit marks the first DTU by setting a value of a time stamp (TS) in the overhead portion of the first DTU to 255 and a value of a sequence identification (SID) in the overhead portion of the first DTU to 255.
18. The networking device as recited in claim 13, wherein the communication unit is further configured to:
define a second DTU such that the second DTU carries a first data packet that corresponds to a first DTU and a second data packet that corresponds to the second DTU; and
transmit the first DTU and the second DTU with the first DTU carrying no payload data and with the second DTU carrying the first data packet and the second data packet as payload data.
19. The networking device as recited in claim 18, wherein the first data packet corresponds to the first DTU and a third DTU, and wherein the first DTU, the second DTU, and the third DTU are transmitted with the first DTU and the third DTU carrying no payload data and with the second DTU carrying the first data packet and the second data packet as payload data.
20. The networking device as recited in claim 18, wherein the first data packet and the second data packet comprise first and second Voice over Internet Protocol (VoIP) data packets.
21. A method to save power in data communication, the method comprising:
receiving a plurality of data packets over a predetermined duration during which a plurality of data transmission units (DTUs) can be formed such that the data packets are received at points in time during the predetermined duration that correspond to formation of more than one of the DTUs;
forming the plurality of DTUs by filling the plurality of data packets into one or more of the DTUs and filling an idle pattern into remaining one or more of the DTUs; and
transmitting the plurality of DTUs.
22. The method as recited in claim 21, wherein the predetermined duration comprises a maximum allowable physical layer delay.
23. The method as recited in claim 21, wherein transmitting the plurality of DTUs comprises transmitting the one or more DTUs filled with the idle pattern before transmitting the one or more DTUs filled with the plurality of data packets.
24. The method as recited in claim 21, wherein transmitting the plurality of DTUs comprises muting sub-carriers that carry the one or more DTUs filled with the idle pattern.