Optical line terminal and optical network unit

• US 9,596,046 B2
• Filed: 03/12/2013
• Issued: 03/14/2017
• Est. Priority Date: 02/24/2009
• Status: Active Grant

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Kubo, Ryogo, Kani, Jun-ichi, Otaka, Akihiro
• Primary Examiner(s): Vanderpuye, Ken N
• Assistant Examiner(s): LAMBERT, DAVID W
• Application Number:
  US13/796,800
• Publication Number:
  US 20130202302A1
• Time in Patent Office: 1,463 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 10/25 Arrangements specific to fibre transmission
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04Q 11/0067 Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
• CPC Class Codes: H04Q 2011/0079 Operation or maintenance aspects
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

An optical line terminal which includes an observing unit that observes information of any one or all of an arrival interval of frames, an instantaneous bandwidth under use of a flow, a queue length of a queue temporarily storing the frames, and a traffic type, and a stop determining unit that dynamically determines a sleep time to be a period in which a sleep state where partial functions of the ONU are stopped is maintained, on the basis of the information obtained by the observing unit. The ONU is entered into a sleep state, immediately after communication ends, after a predetermined waiting time passes from when the communication ends, or after a waiting time determined on the basis of the information passes from when the communication ends.

Claims

1. An optical line terminal in an optical network in which the optical line terminal (OLT) and an optical network unit (ONU) communicate with each other through an optical fiber transmission path, the OLT including:

an observing unit that observes information selected from the group consisting of at least one of protocol information of frames transmitted to the ONU, protocol information of frames received from the ONU, priority information of frames transmitted to the ONU, priority information of frames received from the ONU and combinations of the foregoing, wherein the protocol information of frames transmitted to or received from the ONU is protocol-type or priority information that is in a header of client data traffic input from and/or output to outside of a passive optical network (PON) and transmitted over the PON;

a table that describes a plurality of previously designated sleep times, each previously designated sleep time being a period in which non-used functions of the ONU are stopped, wherein the previously designated sleep times are set prior to the observing unit observing the frames of information that would lead to initiating a sleep state for each of the priority information and/or the protocol information; and

a table associating unit that dynamically selects the sleep time of the ONU from among the plurality of previously designated sleep times described in the table, wherein the previously designated sleep time is selected on the basis of the priority information and/or the protocol information obtained by the observing unit in real time,

wherein a control signal to notify the ONU of a sleep state entering request and the selected sleep time is transmitted to the ONU at a time selected from the group consisting of immediately after communication with the ONU ends, after a predetermined time passes from when the communication with the ONU ends, or after a time determined on the basis of the priority information and/or the protocol information passes from when the communication with the ONU ends.

2. An optical line terminal according to claim 1, wherein the previously designated sleep times are T(0), T(1), . . . , T(n) milliseconds where T(0) >

T(1) >

. . . >

T(n), and wherein the previously designated sleep times are set to traffic having priorities of 0, 1, 2, . . . , n, respectively.

3. An optical line terminal according to claim 1, wherein the previously designated sleep times are 50 ms, 30 ms, 10 ms, and 5 ms that are set to traffic having priorities of 0, 1, 2, and 3, respectively.

4. A method of controlling a sleep state of an optical network unit in an optical network in which an optical line terminal (OLT) and the optical network unit (ONU) communicate with each other through an optical fiber transmission path, the method including:

a step that the OLT observes information selected from the group consisting of at least one of protocol information of frames transmitted to the ONU, protocol information of frames received from the ONU, priority information of frames transmitted to the ONU, priority information of frames received from the ONU and combinations of the foregoing, wherein the protocol information of frames transmitted to or received from the ONU is protocol-type or priority information that is in a header of client data traffic input from and/or output to outside of a passive optical network (PON) and transmitted over the PON;

a step that the OLT dynamically selects a sleep time of the ONU from among a plurality of previously designated sleep times described in a table on the basis of the priority information and/or the protocol information observed in real time, each of the plurality of previously designated sleep times being a period in which non-used functions of the ONU are stopped, wherein the previously designated sleep times are set prior to the observing unit observing the frames of information that would lead to initiating a sleep state for each of the priority information and/or the protocol information;

a step that the OLT transmits a control signal to notify the ONU of a sleep state entering request and the selected sleep time to the ONU at a time selected from the group consisting of immediately after communication with the ONU ends, after a predetermined time passes from when the communication with the ONU ends, or after a time determined on the basis of the priority information and/or the protocol information passes from when the communication with the ONU ends;

a step that the ONU recognizes the sleep state entering request and the selected sleep time using the control signal received from the OLT; and

a step that the ONU enters into the sleep state at a time selected from the group consisting of immediately after the control signal is received, after a predetermined time passes from when the control signal is received, or after a time designated by the OLT passes from when the control signal is received, and returns to a normal state after the sleep time passes.

5. A method of controlling a sleep state of an optical network unit in an optical network according to claim 4, wherein the previously designated sleep times are T(0), T(1), . . . , T(n) milliseconds where T(0) >

T(1) >

, . . . , >

T(n), and wherein the previously designated sleep times are set to traffic having priorities of 0, 1, 2, . . . , n, respectively.

6. A method of controlling a sleep state of an optical network unit in an optical network according to claim 4, wherein the previously designated sleep times are 50 ms, 30 ms, 10 ms, and 5 ms that are set to traffic having priorities of 0, 1, 2, and 3, respectively.

7. An optical network system, including:

one optical line terminal (OLT) and one optical network unit (ONU), wherein the OLT performs point-to-point communication with the ONU through an optical fiber transmission path,

the OLT including;

an observing unit that observes information selected from the group consisting of at least one of protocol information of frames transmitted to the ONU, protocol information of frames received from the ONU, priority information of frames transmitted to the ONU, priority information of frames received from the ONU and combinations of the foregoing, wherein the protocol information of frames transmitted to or received from the ONU is protocol-type or priority information that is in a header of client data traffic input from and/or output to outside of a passive optical network (PON) and transmitted over the PON;

a table that describes a plurality of previously designated sleep times, each previously designated sleep time being a period in which non-used functions of the ONU are stopped, wherein each of the sleep times is set prior to the observing unit observing the frames of information that would lead to initiating a sleep state for each of the priority information and/or the protocol information; and

a table associating unit that dynamically selects the sleep time of the ONU from among the plurality of previously designated sleep times described in the table on the basis of the priority information and/or the protocol information obtained by the observing unit in real time,

wherein a control signal to notify the ONU of a sleep state entering request and the selected sleep time is transmitted to the ONU at a time selected from the group consisting of immediately after communication with the ONU ends, after a predetermined time passes from when the communication with the ONU ends, or after a time determined on the basis of the priority information and/or the protocol information passes from when the communication with the ONU ends,

the ONU including;

a sleep unit that stops non-used functions to enter into a sleep state,

wherein a sleep state entering request and the selected sleep time being a period in which the sleep state is maintained are recognized using a control signal received from the OLT, wherein the ONU is entered into the sleep state by the sleep unit at a time selected from the group consisting of immediately after the control signal is received, after a predetermined time passes from when the control signal is received, or after a time designated by the OLT passes, and the ONU returns to a normal state after the selected sleep time passes.

8. An optical network system according to claim 7, wherein the previously designated sleep times are T(0), T(1), . . . , T(n) milliseconds where T(0) >

T(1) >

. . . . >

T(n), and wherein the previously designated sleep times are set to traffic having priorities of 0, 1, 2, . . . , n, respectively.

9. An optical network system according to claim 7, wherein the previously designated sleep times are 50 ms, 30 ms, 10 ms, and 5 ms that are set to traffic having priorities of 0, 1, 2, and 3, respectively.

10. An optical network system, including:

one optical line terminal (OLT) and a plurality of optical network units (ONU),

wherein the OLT performs point-to-multi-point communication with the plurality of ONUs through an optical fiber transmission path,

the OLT including;

an observing unit that observes information selected from the group consisting of at least one of protocol information of frames transmitted to the ONU, protocol information of frames received from the ONU, priority information of frames transmitted to the ONU, priority information of frames received from the ONU and combinations of the foregoing, wherein the protocol information of frames transmitted to or received from the ONU is protocol-type or priority information that is in a header of client data traffic input from and/or output to outside of a passive optical network (PON) and transmitted over the PON;

a table that describes a plurality of previously designated sleep times, each previously designated sleep time being a period in which non-used functions of at least one of the plurality of ONUs are stopped, wherein each of the sleep times is set prior to the observing unit observing the frames of information that would lead to initiating a sleep state for each of the priority information and/or the protocol information; and

a table associating unit that dynamically selects the sleep time of at least one of the plurality of ONUs from among the plurality of previously designated sleep times described in the table on the basis of the priority information and/or the protocol information obtained by the observing unit in real time,

wherein a control signal to notify at least one of the plurality of ONUs of a sleep state entering request and the selected sleep time is transmitted to the at least one of the plurality of ONUs at a time selected from the group consisting of immediately after communication with the at least one of the plurality of ONUs ends, after a predetermined time passes from when the communication with the at least one of the plurality of ONUs ends, or after a time determined on the basis of the priority information and/or the protocol information passes from when the communication with the at least one of the plurality of ONUs ends,

at least one of the plurality of ONUs including;

a sleep unit that stops non-used functions to enter into a sleep state, wherein a sleep state entering request and the selected sleep time being a period in which the sleep state is maintained are recognized using a control signal received from the OLT, and wherein the at least one of the plurality of ONUs is entered into the sleep state by the sleep unit at a time selected from the group consisting of immediately after the control signal is received, after a predetermined time passes from when the control signal is received, or after a time designated by the OLT passes, and the at least one of the plurality of ONUs returns to a normal state after the sleep time passes.

11. An optical network system according to claim 10, wherein the previously designated sleep times are T(0), T(1), . . . , T(n) milliseconds where T(0) >

T(1) >

. . . . >

T(n), and wherein the previously designated sleep times are set to traffic having priorities of 0, 1, 2, . . . , n, respectively.

12. An optical network system according to claim 10, wherein the previously designated sleep times are 50 ms, 30 ms, 10 ms, and 5 ms that are set to traffic having priorities of 0, 1, 2, and 3, respectively.