WO2012034384A1

WO2012034384A1 - Method and system for link maintenance under energy-saving state in ethernet passive optical networks

Info

Publication number: WO2012034384A1
Application number: PCT/CN2011/071624
Authority: WO
Inventors: 何苑凌; 臧美燕; 张德智; 袁立权
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-09-14
Filing date: 2011-03-09
Publication date: 2012-03-22
Also published as: CN102404188A

Abstract

The present invention discloses two solutions for a method for link maintenance under an energy-saving state in Ethernet Passive Optical Networks, wherein one solution includes: an Optical Network Unit (ONU) wakes up periodically in an energy-saving state according to a default sleep period or a sleep period configured by an Optical Line Terminal (OLT), and receives and transmits data frames for maintaining links when it wakes up periodically. The present invention also discloses two solutions for a link maintenance system for link maintenance under an energy-saving state in Ethernet Passive Optical Networks, wherein in one solution a configuration unit of the system is used by an OLT to configure a sleep period for an ONU; a link maintenance unit is used by the ONU to implement link maintenance by receiving and transmitting data frames for maintaining links when the ONU periodically wakes up in the energy-saving state according to a default sleep period or a sleep period configured by the OLT. Application of the method and system of the present invention enables link maintenance under the energy-saving state.

Description

Method and system for maintaining link in energy-saving state of Ethernet passive optical network

The present invention relates to the field of Ethernet Passive Optical Network (EPON), and more particularly to a method and system for maintaining a link in an energy-saving state in an EPON system. Background technique

1G-EPON and 10G-EPON respectively. A new generation of broadband passive optical access technology based on IEEE802.3-2005 Section 5 and IEEE 802.3av standards. The system usually consists of optical line terminals (OLT, Optical Line Terminal). The optical network unit (ONU), the optical network termination (ONT), and the optical distribution network (ODN) are formed on the user side, as shown in FIG. 1 . The ODN is composed of a single-mode optical fiber, a passive optical device such as an optical splitter, and an optical connector. The ODN provides an optical transmission medium for the physical connection between the OLT and the ONU/ONT. The ODN is usually a point-to-multipoint structure, that is, one OLT connects multiple ONUs.

A link maintenance mechanism is defined in IEEE 802.3-2005 Section 5 Clause 64.3. Taking the user-side terminal as an ONU as an example, for each ONU that is in the registered state, if the OLT does not send a GATE Multi-Point Control Protocol (MPCP) message to the ONU within 50 ms, then The ONU sends an empty GATE MPCP packet. If the OLT does not receive the report (REPORT) MPCP packet within 1 second, the OLT considers that a serious link error has occurred between the OLT and the ONU. The state machine corresponding to the ONU migrates to the deregistered state, and then re-initiates the registration process of the ONU. An ONU that is in the registered state sends an empty REPORT MPCP packet to the OLT if it does not send a REPORT MPCP packet to the OLT within 50 ms. If the ONU does not receive the OLT within 1 second A GATE MPCP message sent to itself is considered to have a link critical error, migrated to the WATCHDOG TIMEOUT state, and then re-registered. It can be seen from the above rules that for an ONU in the registered state, the OLT needs to send 4 messages to the ONU at intervals of up to 50 ms. Similarly, the ONU needs to send packets to the OLT at intervals of up to 50 ms.

Some business layer protocols also have a link maintenance mechanism. For example, the Internet Group Management Protocol (IGMP) protocol sends an IGMP Query (QUERY) protocol frame to the user at regular intervals. The user must return an IGMP Report (REPORT) protocol frame. If the server does not receive an IGMP REPORT response within a certain period of time, it will consider that the user no longer needs the multicast stream and will stop sending multicast data to the user.

When the EPON system is in a power-saving state, the ONU's reception and transmission are turned off, or the transmission is turned off. Because the prior art needs to send a data frame for maintaining a link between the ONU and the OLT to implement a link maintenance mechanism, and the data frame cannot be sent in a power saving state (including the data frame that maintains the link cannot be normally sent), Therefore, in fact, in the energy-saving state, the existing technology is still used, and the link maintenance mechanism cannot be implemented. In this case, there is a possibility that the ONU is deregistered or the service-level link is interrupted. However, the requirement for energy saving cannot affect the registration of the service and ONU. Therefore, how to maintain the link in the energy-saving state has become a problem to be solved, and there is no effective solution at present. Summary of the invention

In view of the above, the main object of the present invention is to provide a method and system for maintaining a link in an energy-saving state of an Ethernet passive optical network, which can implement link maintenance in an energy-saving state.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A method for maintaining a link in an energy-saving state of an Ethernet passive optical network, the method comprising: an optical network unit (ONU) periodically waking up in an energy-saving state according to a default sleep cycle or a sleep cycle configured by an optical line terminal (OLT); Receive and send data to maintain the link when it is awake frame.

The manner in which the OLT configures the sleep cycle for the ONU includes: an OLT extended operation management and maintenance (OAM) message, and the configured sleep cycle is added to the extended OAM message and sent to the ONU.

The default sleep period or the configured sleep period is smaller than the maximum transmission time interval of the data frame that the system requires to maintain the link.

The implementation manner of the periodic wakeup includes: a manner of triggering after a timer or a counter expires, or a manner in which the ONU responds to an OLT message.

A system for maintaining a link in an energy-saving state of an Ethernet passive optical network, the system comprising: a configuration unit and a first link maintenance unit;

a configuration unit, configured by the OLT to configure a sleep cycle for the ONU;

The first link maintaining unit is configured to perform link maintenance by receiving and transmitting data frames for maintaining the link when the ONU periodically wakes up in the power saving state according to a default sleep cycle or a sleep cycle configured by the OLT.

The configuration unit is further configured to: extend the OAM message by the OLT, add the configured sleep period to the extended OAM message, and send the sleep period to the ONU, and implement the OLT to configure the ONU for the ONU. Sleep cycle.

A method for maintaining a link in an energy-saving state of an Ethernet passive optical network, the method comprising: setting a transmission frequency of a protocol packet or a data packet between an ONU and an OLT for maintaining a link; and transmitting a signal for maintaining a link In the case of a protocol message or a data packet, the transmission time interval is greater than or equal to the sleep period of the ONU according to the set transmission frequency.

The method further includes: setting, by the OLT, the sending time interval by using an extended OAM message, or adjusting, by the ONU, the sending time interval according to the sleep period. A system for maintaining a link in an energy-saving state of an Ethernet passive optical network, the system comprising: a setting unit and a second link maintaining unit;

a setting unit, configured to set a sending frequency of a protocol packet or a data packet used by the ONU and the OLT to maintain the link;

The second link maintaining unit is configured to enable the link period to be greater than or equal to the sleep period of the ONU according to the set transmission frequency, and implement link maintenance by sending a protocol packet or a data packet for maintaining the link.

The second link maintaining unit is further configured to set the sending time interval by the OLT by using an extended OAM message, or adjust the sending time interval according to the sleep period by the ONU.

The present invention has two solutions, one of which includes: The ONU periodically wakes up in a power saving state according to a default sleep cycle or an OLT configured sleep cycle; and receives and transmits a data frame for maintaining a link when periodically waking up.

According to the present invention, since there is a sleep cycle, even in a power-saving state, it can periodically wake up in a power-saving state according to a sleep cycle, and can receive and transmit a data frame for maintaining a link, thereby realizing a chain in a power-saving state. Road maintenance mechanism. DRAWINGS

1 is a schematic diagram of a basic structure of a prior art EPON network;

2 is a flowchart of maintaining an ONU of an MPCP protocol link in a sleep mode according to Embodiment 1 of the present invention;

FIG. 3 is a flowchart of an ONU of a link for maintaining a service layer protocol in a sleep mode according to Embodiment 2 of the present invention. detailed description

The basic idea of the invention is: The invention has two sets of solutions, one of which includes: ONU The power cycle is periodically awakened according to the default sleep cycle or the sleep cycle configured by the OLT; the data frame for maintaining the link is received and transmitted during the periodic wakeup.

The implementation of the technical solution will be further described in detail below with reference to the accompanying drawings.

A method for maintaining a link in an energy-saving state of an Ethernet passive optical network, the method mainly includes the following two aspects:

The first aspect: The ONU periodically wakes up in a power-saving state according to a default sleep cycle or a sleep cycle configured by the OLT; and receives and transmits a data frame for maintaining the link when periodically waking up.

Further, the manner in which the OLT configures the sleep cycle for the ONU includes: the OLT extends the OAM message, and adds the configured sleep period to the extended OAM message, and sends the OAM message to the ONU. The 0 AM is an abbreviation of Operation, Administraion & Maintenance, and refers to operation, management, and maintenance.

Further, the default sleep period or the configured sleep period is less than the maximum transmission interval of the data frame that the system requires to maintain the link.

Further, the implementation of the periodic wakeup includes: a method of triggering after a timer or a counter is timed out, or a manner of responding to the 0LT message by the 0NU.

Further, the energy saving state includes multiple implementation modes such as a sleep mode or a hiccup mode. The sleep mode refers to a case where the reception and transmission of the ONU are both closed; the hiccup mode refers to a case where the transmission of the ONU is turned off, and the reception of the ONU is turned on.

Corresponding to the foregoing implementation scheme, a system for maintaining a link in an energy-saving state of an Ethernet passive optical network, the system comprising: a configuration unit and a first link maintenance unit. Wherein, the configuration unit is configured to configure a sleep cycle for the ONU to be 0NU; the first link maintenance unit is configured to receive and transmit the link for maintaining the link when the ONU periodically wakes up in the energy-saving state according to the default sleep cycle or the sleep cycle configured by the OLT. The data frame implements link maintenance.

Here, the configuration unit is further configured to add the configured sleep period to the extended 0AM message by using the 0LT extended 0AM message, and send the method to the ONU to implement the 0LT as 0NU. Configure the sleep cycle.

Here, the default sleep period or configured sleep period is less than the maximum transmission interval of the data frame that the system requires to maintain the link.

The second aspect is: setting a transmission frequency of a protocol packet or a data packet for maintaining a link between the ONU and the OLT; sending a protocol packet or a data packet for maintaining the link, and setting a transmission interval according to the set transmission frequency Greater than or equal to the sleep period of the ONU.

Further, the sending time interval may be set by the OLT by extending the OAM message, or may be adjusted by the ONU according to the sleep cycle. This ensures that the data packets sent between the ONU and the OLT can meet the requirements of maintaining the link.

It should be noted here that the sleep cycle referred to herein is not limited to the present description, and any description that can implement the sleep cycle function is within the scope of the present invention, such as a wake-up cycle, a wake-up interval, and the like.

Corresponding to the foregoing implementation scheme, a system for maintaining a link in an energy-saving state of an Ethernet passive optical network, the system comprising: a setting unit and a second link maintaining unit. The setting unit is configured to set a transmission frequency of a protocol packet or a data packet between the ONU and the OLT for maintaining a link; and the second link maintaining unit is configured to make the transmission time interval greater than or equal to the ONU according to the set transmission frequency. During the sleep cycle, link maintenance is achieved by sending protocol messages or data packets for maintaining the link.

Here, the second link maintaining unit is further configured to set a transmission time interval by the OLT through the extended OAM message, or adjust the transmission time interval according to the sleep period by the ONU.

In summary, the present invention is a solution for implementing a link maintenance mechanism in an energy-saving state, which can meet the needs of system energy conservation, and can close the receiving and/or transmitting of the optical module during sleep or snoring to achieve The purpose of energy saving. At the same time, it cooperates with the media access control (MAC layer) and the link maintenance mechanism of the service layer to avoid the ONU deregistration or service disconnection.

The invention is illustrated by way of example below.

Embodiment 1: In the sleep mode, the process of maintaining an ONU of the MPCP protocol link is used for In the sleep mode, the maintenance link mechanism of the MPCP protocol is guaranteed to operate normally. It should be noted that the MPCP protocol is a link maintenance mechanism for the MAC layer, and will not be described.

The process shown in Figure 2 includes the following steps:

Step 101: The ONU of the EPON system starts the energy saving mode.

Step 102: The ONU enters the sleep mode and turns off the sending and receiving functions of the optical module.

Step 103: The ONU starts the timer T while entering the sleep mode.

Step 104: Determine whether the timer 超时 times out, if yes, execute step 105; otherwise, wait, continue to determine whether the timer 超时 times out.

Step 105: The ONU receives the GATE frame from the OLT after the timer expires.

Step 106: Determine whether there is uplink traffic. If yes, go to step 107; otherwise, go to step 108.

Step 107: If there is uplink traffic, the corresponding REPORT frame is sent according to the rule of Dynamic Bandwidth Allocation (DBA) to achieve the purpose of allocating the uplink bandwidth for the ONU; and then step 102 is performed.

Step 108: If there is no uplink traffic, send an empty REPORT frame to the OLT in the time slot specified by the GATE frame, and the empty REPORT frame is the data frame for maintaining the link; then step 102 is performed.

Here, in this embodiment, the timeout period of the timer T should be less than the maximum REPORT frame acceptance interval specified by the OLT, and the value of the timer T can be set to 50 ms by default.

Here, in this embodiment, the OLT can configure the value of the timer T by extending the OAM message. The format of the extended OAM message is shown in Table 1. It is a table for configuring the extended OAM packet frame format of the sleep cycle.

Octet(s) Field Notes

1 Branch ( 0XC9 ) extended operation

2 Leaf (to be determined) Configure the notification message of the sleep cycle of the ONU in sleep mode.

1 Variable Width is used to indicate the length of the Variable value field, its value is 04 4 Sleep cycle identifies the time that the ONU is held in sleep mode, in units of time quantification

( TQ , Time Quantum )

Table 1

Octet(s) in Table 1 represents bytes; Branch represents variable parts; Leaf represents variable pages; Variable Width represents variable widths.

Embodiment 2: The process of maintaining the ONU of the link of the service layer protocol in the sleep mode, and ensuring the normal operation of the maintenance link mechanism of the service layer protocol in the sleep mode.

Because if the MPCP maintain link mechanism uses other methods than the above-mentioned first embodiment to perform link maintenance, or the system captures the MPCP timer, the manner of interfering with the MPCP state machine,

If the PON system can operate normally, the PON system only needs to ensure that the maintenance link mechanism of the service layer protocol runs normally.

The process shown in Figure 3 includes the following steps:

Step 201: The ONU of the EPON system starts the energy saving mode.

Step 202: The ONU enters a sleep mode to disable the sending and receiving functions of the optical module.

Step 203: The ONU starts the timer T while entering the sleep mode.

Step 204: Determine whether the timer 超时 times out. If yes, execute step 205; otherwise, wait, continue to determine whether the timer 超时 has timed out.

Step 205: The ONU receives the GATE frame from the OLT after the timer expires.

Step 206: The ONU sends an uplink protocol frame for maintaining the link in a time slot specified by the GATE frame; and then step 202 is performed.

Here, in this embodiment, the OLT should send a GATE frame to the ONU before the timer expires to ensure that the uplink protocol frame of the ONU can be sent.

Here, in this embodiment, the timeout period of the timer T should be less than the maximum maintenance link frame acceptance interval specified by the protocol. For different protocols, the default value of timer T is different, and the value of timer T can be set to 50ms by default.

Here, in this embodiment, the OLT can configure the value of the timer T by extending the OAM message. The format of the extended OAM is as shown in Table 1 above.

Embodiment 3: For the doze mode, the ONU responds to the OLT message, and ensures that the MPCP protocol and other protocols maintain the link mechanism in the hiccup mode. The flow of this embodiment includes the following steps:

Step 301: The EPON ONU starts the energy-saving mode, enters the hiccup mode, and disables the sending function of the optical module.

Step 302: The OLT periodically sends a data packet for maintaining the link to 0 during the ONU snoring.

Step 303: The ONU responds to the OLT requesting the ONU during the hiccup mode. When the data packet is maintained, the ONU data transmission is temporarily turned on and the response is made.

Here, the maintenance link data packet includes two types of packets of the MPCP maintenance link and extended OAM messages for querying the status. The extended OAM message definition is as shown in Table 2 below, in order to configure a table of extended OAM packet frame formats for maintaining the data packet transmission period of the link.

Here, the implementation that the OLT periodically sends the data packet for maintaining the link to the ONU during the ONU snoring can be achieved by, but not limited to, the following:

Manner 1: Set a timer or counter inside the OLT. The timer expires or the counter reaches a certain value to trigger the OLT to send a data packet to maintain the link to the ONU.

Manner 2: The OLT is controlled by the service module to deliver data packets for maintaining the link.

Manner 3: The OLT is controlled by the message from the upper device and sends the data packet for maintaining the link.

Embodiment 4: Maintaining MPCP in a sleep mode by adjusting the frequency of sending MPCP packets The ONU process of the protocol link is used to ensure that the MPCP protocol maintains the link mechanism in normal operation by adjusting the frequency of sending MPCP packets in the sleep mode. The flow of this embodiment is similar to the flow of the first embodiment. The difference is that the transmission frequency needs to be adjusted in this embodiment, but the transmission frequency is fixed in the first embodiment.

The process of this embodiment includes the following steps:

Step 401: The EPON ONU starts the power saving mode, and adjusts the frequency of the GATE frame sent to maintain the link to once every 200 ms. The MPCP state machine on the OLT sends a GATE frame to the ONU every 200ms.

Step 402: The ONU enters the sleep mode and turns off the sending and receiving functions of the optical module.

Step 403: The ONU starts the timer T while entering the sleep mode, and the timeout period is 200ms.

Step 404: The ONU receives the GATE frame from the OLT after the timer expires.

Step 405: If there is no upstream traffic, send an empty REPORT frame to the OLT within the time slot specified by the GATE frame; return to step 402.

Step 406: If there is uplink traffic, the corresponding REPORT frame is sent according to the rules of the DBA. Go back to step 402.

In this embodiment, the manner in which the ONU obtains the timer T timeout period includes but is not limited to the following two types:

The OLT sends the OAM message to the ONU through the extended OAM message. Table 2 shows the extended OAM message.

Mode 2: The ONU is obtained according to the length of the wakeup period.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A method for maintaining a link in an energy-saving state of an Ethernet passive optical network, the method comprising: the optical network unit (ONU) saving energy according to a default sleep cycle or a sleep cycle configured by an optical line terminal (OLT) The state periodically wakes up; receives and transmits data frames for maintaining the link when periodically waking up.

The method according to claim 1, wherein the manner in which the OLT configures the sleep cycle for the ONU comprises: an OLT extended operation management and maintenance (OAM) message, adding the configured sleep cycle to the extension The subsequent OAM message is sent to the ONU.

The method according to claim 1 or 2, wherein the default sleep period or the configured sleep period is smaller than a maximum transmission time interval of a data frame that the system requires to maintain the link.

The method according to claim 1, wherein the manner of implementing the periodic wakeup comprises: a manner of triggering after a timer or a counter is timed out, or a manner in which the ONU responds to the OLT message.

The system according to claim 5, wherein the configuration unit is further configured to: extend the OAM message by the OLT, add the configured sleep cycle to the extended OAM message, and send the OAM message to the ONU. In a manner, the OLT is configured to configure the sleep cycle for the ONU.

7. The system according to claim 5 or 6, wherein the default sleep period or the configured sleep period is less than a maximum transmission time interval of a data frame that the system requires to maintain the link.

A method for maintaining a link in an energy-saving state of an Ethernet passive optical network, the method comprising: setting a transmission frequency of a protocol packet or a data packet for maintaining a link between an ONU and an OLT; When the protocol packet or data packet of the link is used, the transmission time interval is greater than or equal to the sleep period of the ONU according to the set transmission frequency.

The method according to claim 8, wherein the method further comprises: setting, by the OLT, the sending time interval by using an extended OAM message, or adjusting, by the ONU, the sending time interval according to the sleep period.

A system for maintaining a link in an energy-saving state of an Ethernet passive optical network, the system comprising: a setting unit and a second link maintaining unit;

The system according to claim 10, wherein the second link maintaining unit is further configured to set the sending time interval by an OLT by using an extended OAM message, or adjust the sending by the ONU according to a sleep period. time interval.