KR20040020781A - Method for transmitting oam(operation, administration, and maintenance) packet in ethernet passive optical network - Google Patents

Abstract

PURPOSE: A method for transmitting an OAM(Operation, Administration and Maintenance) packet in a PON(Passive Optical Network) is provided to prevent blocking of even an OAM packet using a MAC client packet format in a PAUSE operation by correcting the PAUSE operation defined in IEEE802.3 Clause31 and Annex31B. CONSTITUTION: In transmitting a OAM packet in an EPON(Ethernet PON) including one OLT(Optical Line Terminal) and at least one ONU(Optical Network Unit) connected to the OLT, an MAC control layer recognizes an OAM frame so as not to block OAM data in a PAUSE operation, identifies the recognized OAM data and transmits it to a lower layer of the MAC. When PAUSE occurs at a point 'A', the OAM packet can be transmitted by the method 2 and, at a point 'B', the OAM packet can be transmitted by necessarily using both the method 1 and the method 2.

Description

METHOD FOR TRANSMITTING OAM (OPERATION, ADMINISTRATION, AND MAINTENANCE) PACKET IN ETHERNET PASSIVE OPTICAL NETWORK}

The present invention relates to an Ethernet passive fluorescence subscriber network, and more particularly, to collision between IEEE 802.3 PAUSE frame and OAM (operation, administration, and maintenance) packet using slow protocol in Ethernet passive fluorescence subscriber network structure.

Currently, MAC technology for Gigabit Ethernet and ATM PON has already been standardized, the contents of which are described in IEEE 802.3z and ITU-T G.983.1. ATM-PON was first standardized in the form of PON (Passive Optical Network). ATM-PON transmits up and down in the form of a frame that binds ATM cells in a certain size.OLT (Optical Line Termination) ) Inserts the downstream cells to be distributed to each ONU (Optical Network Unit) within this frame.

1 shows a physical network structure of a typical passive fluorescence subscriber network.

As shown in FIG. 1, the passive fluorescence subscriber network includes one OLT 100 and at least one ONU 110-1 to 110-3 connected to the OLT 100. 1 illustrates an example in which three ONUs 110-1 to 110-3 are connected to one OLT 100. At least one end user (user, network device) 120-1 to 120-3 may be connected to the ONUs 110-1 to 110-3, respectively. Data 131 to 133 transmitted by the users 120-1 to 120-3 are transmitted to the OLT 100 via the ONUs 110-1 to 110-3.

In the Ethernet Passive Optical Network (EPON) structure, which transmits an 802.3 Ethernet frame through a point-to-multipoint network, as shown in FIG. 1, in case of uplink transmission, each ONU is transmitted in a time division multiplexing (TDM) manner. The data is accessed, but the data is not collided by using a method called ranging in an optical distribution network (ODN). In other words, in the uplink transmission, the ONUs 110-1 to 110-3 are multiplexed and transmitted to the OLT 100. In the downlink transmission, the ONUs receiving the data broadcast by the OLT 100 are transmitted. 110-1 to 110-3 select and receive only the data to be received from the data.

To this end, a field is provided in a dedicated ATM cell or a general ATM cell capable of sending and receiving messages at regular intervals in up and down frames. With the development of Internet technology, subscribers demand more bandwidth, and are relatively expensive equipment, bandwidth is limited, and Gigabit Ethernet can secure higher bandwidth than ATM technology that requires bandwidth segmentation and IP packet segmentation. The goal is to to end transmission. Therefore, the PON structure of the subscriber network requires an Ethernet method rather than an ATM.

Currently, EPON standardization is underway in September 2003 under the name Ethernet in the First Mile (EMF) at IEEE 802.3ah. Draft v1.0 is underway and Draft v2.0 will be created in November. The issue of standardization is the matter of matching between OAM layer and other layers in relation to layering.

The OAM packet of IEEE802.3ah Draft v1.0 is defined to follow the packet format of Slow protocol of IEEE802.3 Clause 43. Annex 43B. The slow protocol is used for link aggregation and follows the method of transmitting about 5 times per second on average. This slow protocol is a MAC client protocol and therefore divided into MAC client data. Therefore, according to Draft, the location of the OAM sublayer is also divided into MAC client layers.

2 illustrates the OAM packet format determined in Draft v1.0. In this case, the type field 210 indicating the slow protocol in the OAM packet 200 is indicated as 88-09, and the subtype 212 is newly defined as OAM to distinguish it from other protocols using the existing slow protocol.

In this case, the problem is that a conflict between the existing Ethernet functionality and the OAM operation occurs in the process of applying the OAM layer of Draft v1.0 to the Ethernet protocol stack.

In general, the priority of transmitting data in MAC has a higher MAC Control data than MAC Client data. In addition, general OAM packet is classified as Control packet and has a relatively high priority, or separate channel for OAM packet transmission is operated so that OAM packet is not interrupted by other packet transmission or processing. However, since the OAM packet defined in the Draft of EFM is classified as MAC Client data as described above, the existing MAC has a lower priority than the MAC Control data.

This is specifically a problem when conflicting with PAUSE operation. The PAUSE operation, defined in Clause 31. Annex 31B of IEEE802.3, is a link-based flow control protocol intended to prevent buffer overflows. The station receiving the PAUSE frame controls the flow by not sending data frames to the sending station for a certain period of time. When the MAC Control sublayer receives the PAUSE frame from the opposite station, it blocks the MAC Client data transmission for a certain time. In detail, the MACControl sublayer receiving the PAUSE frame starts a timer to stop the transmission according to the contents of the frame and informs the MAC client of the upper level of the MAC client data to block transmission of the MAC client data. Data that can be blocked by PAUSE is limited to MAC Client data only and does not affect MAC Control data.

3 is a diagram illustrating a MAC control sublayer 320 supporting an inter-layer service interface. Referring to FIG. 3, the MA_DATA.request primitive is blocked by notifying the upper layer through the MA_CONTROL.indication primitive. In this case, when the PAUSE operation is driven, the EPON OAM packet that comes down through MA_DATA.request primitive is blocked as well as general user data. That is, modification of existing PAUSE operation is required to introduce OAM sublayer in EPON.

Accordingly, an object of the present invention is to provide a method for determining the priority between each data frame by modifying the PAUSE operation defined in IEEE802.3 Clause31 and Annex31B to solve the above problems.

That is, an object of the present invention is to provide a method for preventing a PAUSE operation from blocking OAM packets using a MAC client packet format.

1 is a view showing a physical network structure of a typical passive fluorescence subscriber network,

2 is a diagram illustrating an operation, administration, and maintenance (OAM) packet format determined in Draft v1.0;

3 illustrates a MAC Control sublayer supporting an inter-layer service interface;

4 is a view for explaining the position and operation of the OAM layer in IEEE802.3ah Draft v1.0 Clause 55,

5 is a view showing a PAUSE operation in the existing MAC Control defined in IEEE802.3 Annex 31B,

6 is a view showing the contents of the operand_list of the MA_CONTROL.indication primitive to inform the MAC Client when the existing PAUSE,

7 is a view for explaining the position and operation of the OAM layer according to the present invention;

8 is a view showing the contents of the operand_list of the MA_CONTROL.indication primitive to inform the MAC Client when the PAUSE according to the present invention,

9 illustrates a method for determining priority among data frames in accordance with the present invention.

FIG. 10 is a diagram illustrating defining MA_OAM.indication primitive and MA_OAM.request primitive informing a MAC client when PAUSE is performed according to the present invention; FIG.

FIG. 11 is a diagram illustrating a MA_OAM primitive defined according to the present invention and modified with an existing IEEE802.3 Clause 31 fig31B-1. FIG.

12 is a diagram illustrating a case where a timeslot is divided into a section for a dedicated channel for OAM and a section for general data;

13 is a diagram illustrating a new layer in which the position of the OAM layer is changed for OAM data transmission according to the present invention.

To this end, the present invention is an Ethernet passive fluorescence subscriber network consisting of one optical line terminal (OLT) and at least one optical network unit (ONU) connected to the OLT, OAM (operation, administration, and maintenance) A method of transmitting a packet, the method comprising: identifying an OAM frame so as not to block OAM data during a PAUSE operation in a MAC control layer, and separating the identified OAM data in the MAC control layer to a layer below a MAC Including the process of transmission.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the reference numerals to the components of the drawings, it should be noted that the same reference numerals as much as possible even if displayed on different drawings.

4 is a diagram illustrating the position and operation of the OAM layer in IEEE802.3ah Draft v1.0 Clause 55.

In the current draft, the definition of whether the location of the MA_DATA.request primitive to be blocked by PAUSE is the 'A' position or the 'B' position in FIG. 4 is not clearly defined. Therefore, the present invention proposes a solution in consideration of both cases.

Referring to FIG. 4, it can be seen that general user data descended from the upper layer and OAM data generated by OAM Control are multiplexed in the control multiplexor 316 and delivered to the MAC control sublayer 320. In the case of blocking point 'A' in FIG. 4, only general user data is blocked, and in case of 'B', both general user data and OAM data are blocked. When only general user data is blocked as 'A', the OAM data is transmitted below the MAC Control 320 through primitive, so the MAC Control 320 confirms that this is OAM data, and then operates normally. Should be defined.

If the point of blocking is 'B' and both general user data and OAM data are blocked, OAM data is also not transmitted below the MAC Control sublayer 320. This should include modifying the MA_CONTROL.indication that informs PAUSE to distinguish and block OAM. That is, in the PAUSE state, since the existing MAC does not transmit any MAC Client data, in order to transmit the OAM packet, the operation prevents OAM data from being blocked in the 1.MAC Client layer 300 and 2.MAC Control 320. It is necessary to define the function that the delivered OAM data is assembled into a frame and transmitted below the MAC.

For convenience, the operation of the present invention will be described by dividing into 1) a case where 'B' blocks both general user data and OAM data and 2) a case where 'blocks' A blocks only general user data.

1) When blocking point is 'B', both general user data and OAM data are blocked

As described above, when 'B' is blocked in FIG. 4, the problem must be solved from the time point at which MAC Control notifies the PAUSE of the MAC Client. That is, since the MAC Client should be able to block the OAM and general data to block the MA_CONTROL. Newly defines operand_list, a parameter of indication.

FIG. 6 is a diagram illustrating contents of an operand_list of a MA_CONTROL.indication primitive that informs a MAC client of a conventional PAUSE. The existing operand_list defines only paused and not_paused states to distinguish between PAUSE state and non-PAUSE state.

8 is a view showing the contents of the operand_list of the MA_CONTROL.indication primitive to inform the MAC Client when the PAUSE according to the present invention. The present invention further defines the EPON_paused state in addition to the existing paused and not_paused states so that the MAC client receiving this operand_list can block only general data except EPON OAM data.

2) When the blocked point is 'A' and only general user data is blocked

5 is a diagram illustrating a PAUSE operation in a conventional MAC Control defined in IEEE802.3 Annex 31B. Referring to FIG. 5, in the PAUSED state, it can be seen that both MA_CONTROL.request and MA_DATA.request are delivered and processed in an upper layer. Therefore, MAC Control allows MA_DATA.request primitive delivery so that OAM packet can be transmitted in PAUSE state, but only when the primitive type = 88-09 shows slow protocol and subtype is OAM for EPON. Criteria to allow transmission to the MAC layer should be added. This is illustrated in FIG. 7.

7 is a view for explaining the position and operation of the OAM layer according to the present invention.

Referring to FIG. 7, the reference for transitioning from the PAUSE state to the SEND DATA FRAME state is indicated by 'C' in the drawing. The content of this condition is “MA_DATA.request (DA, m_sdu, service_class) ** as shown in FIG. 7. (type = 88-09) * (subtype = OAM) "In this condition, we receive MA_DATA.request and check the type and subtype so that the transition can be made only when the condition is satisfied.

9 illustrates a method for determining priority among data frames according to the present invention. That is, when PAUSE occurs at the 'A' point, 2) the OAM packet can be transmitted in the PAUSE state, and at the 'B' point, the OAM packet can be transmitted only when both 1) method and 2) method are used.

FIG. 10 is a diagram illustrating defining a MA_OAM.indication primitive and a MA_OAM.request primitive informing a MAC client when a PAUSE is performed according to the present invention.

Referring to FIG. 10, the third embodiment of the present invention relates to a method of newly defining service primitives for OAM rather than newly defining fields or variables in order to distinguish OAM data. will be. In FIG. 10, it can be seen that the service primitive coming down from the upper layer of the MAC control 320 is added with the MA_OAM primitive unlike the existing IEEE802.3. In the MAC control 320, when the PAUSE operation is driven, that is, when the PAUSE frame is received from the opposite station, the MAC control 320 blocks the transmission of the MAC client data for a predetermined time. For this purpose, the MAC control 320 may block only general data coming down through the MA_DATA.request primitive by notifying the upper layer through the MA_CONTROL.indication primitive. In the present invention, since the service primitive coming down from the MAC control upper layer includes the MA_OAM primitive 430 as well as the MA_DATA primitive 410 and the MA_Control primitive 420 as well as the existing IEEE802.3, the MAC control 320 is Even if the general data coming down through the MA_DATA.request primitive is blocked during the PAUSE operation, the OAM data coming down through the MA_OAM.request primitive 430 is not blocked. Therefore, it can be seen that only MAC_DATA is affected by PAUSE in MAC Control. In FIG. 10, GATE represents a function of providing an opportunity to descend down.

A detailed state diagram thereof is shown in FIG. 11, which is a modification of FIG. 5 representing an IEEE802.3 PAUSE operation as in FIG. 7.

5 and 11, since only the MA_DATA primitive 410 and the MA_Control primitive 420 exist, conventionally, a transmission operation 412 for a control frame and a transmission operation 422 for a data frame during a PAUSE operation. Only considered for. However, according to the third embodiment of the present invention, since the service primitive ie the MA_OAM primitive 430 is added for the OAM, the transmission operation 432 for the OAM frame is added to the PAUSE operation.

Specifically, referring to 142 of FIG. 11 for transmission of a control frame during a PAUSE operation, when receiving a MA_CONTROL.request primitive from an upper layer, the control frame is transmitted. In addition, referring to 422 of FIG. 11, when a data frame is transmitted, when a MA_DATA.request is received from a higher layer and a MA_CONTROL.request primitive is not received, a data frame is transmitted. According to the present invention, referring to 432 of FIG. 11, when an OAM frame is transmitted, when an MA_OAM.request is received from an upper layer and the MA_CONTROL.request primitive and the MA_CONTROL.request primitive are not received, the OAM frame is transmitted.

The method of defining primitives for the OAM of FIG. 11 may be implemented by using the following application, which corresponds to FIG. 12. 12, it can be seen that a total of 2ms timeslot is divided into a dedicated channel for OAM and a section for general data. Although each time slot has a section in which a control frame such as MPCP (Multi Point Control Protocol) is transmitted at a time for OAM, it is omitted since it does not affect in FIG. 12. The biggest feature of FIG. 12 is that a window dedicated to OAM is opened to allocate a dedicated channel. This can be done by defining an OAM primitive as shown in FIG. The meaning of allocating a channel for OAM transmission means that unlike general user data, OAM can be sent without being allocated a time for low concentration through MPCP messages. This allows OAM data to be successfully transmitted even in the event of an Rx failure in the ONU. Even when an Rx failure occurs, OAM data can be transmitted successfully. If Rx failure occurs, ONU notifies OLT through OAM message. However, due to Rx failure, if the ONCP does not believe the MPCP message to which time is allocated, the ONU will not be able to continue sending OAM messages. Therefore, this can be solved by allocating a dedicated channel so that priority can be given regardless of whether the MPCP message is allocated.

13 illustrates a new layer in which the position of the OAM layer is changed for OAM data transmission according to the present invention. This allows OAM data to be sent in the PAUSE state while using the same data primitives for both OAM and normal data. If the OAM layer is located below the MAC control layer, OAM data is not affected even when PAUSE is in MAC control, so transmission is possible.

PAUSE operation defined in IEEE802.3 results in blocking OAM packets defined in IEEE802.3ah EFM. This is because EPON OAM packet uses slow protocol which is MAC Client data. The present invention solves the conflict between the existing protocol and the current protocol by suggesting a solution to solve this problem.

Claims (10)

In the Ethernet passive fluorescence subscriber network consisting of one optical line terminal (OLT) and at least one optical network unit (ONU) connected to the OLT, a method for transmitting an operation, administration, and maintenance (OAM) packet, Identifying an OAM frame so as not to block OAM data during a PAUSE operation in a MAC control layer, And transmitting the identified OAM data to a layer below the MAC in the MAC control layer. In the Ethernet passive fluorescence subscriber network consisting of one optical line terminal (OLT) and at least one optical network unit (ONU) connected to the OLT, a method for transmitting an operation, administration, and maintenance (OAM) packet, If the MAC control layer notifies PAUSE to the MAC client layer, adding the operand_list for the OAM data so that the OAM data and general data can be separated and blocked; Receiving a PAUSE from a MAC control layer at a MAC client layer, blocking only general data except for the OAM data. The method of claim 2, wherein the operand_list for the OAM data is EPON_paused. In the Ethernet passive fluorescence subscriber network consisting of one optical line terminal (OLT) and at least one optical network unit (ONU) connected to the OLT, a method for transmitting an operation, administration, and maintenance (OAM) packet, If the MAC control layer notifies PAUSE to the MAC client layer, adding the operand_list for the OAM data so that the OAM data and general data can be separated and blocked; Receiving PAUSE from a MAC control layer at a MAC client layer, blocking only general data except for the OAM data; And receiving the OAM data from the MAC client layer in the MAC control layer, checking the type of the OAM data and transmitting the OAM data only to the MAC layer when the OAM data is received. The method of claim 4, wherein Checking the type of the OAM data is characterized by the OAM packet transmission method characterized by indicating that the OAM for slow protocol and EPON. In the Ethernet passive fluorescence subscriber network consisting of one optical line terminal (OLT) and at least one optical network unit (ONU) connected to the OLT, a method for transmitting an operation, administration, and maintenance (OAM) packet, Adding a service primitive for transmitting and receiving the OAM data; And identifying a primitive related to the OAM data during a PAUSE operation in a MAC control layer. 7. The method of claim 6, wherein a service primitive for transmitting and receiving the OAM data is defined as a MA_OAM.request primitive and a MA_OAM.indication primitive. 7. The method of claim 6, wherein the MAC control layer prevents a collision caused by OAM and general data using one primitive by using service primitives related to the transmission and reception of the OAM data. . The method of claim 8, wherein the OAM and general data are allocated by assigning an OAM dedicated channel capable of transmitting a message without being allocated by a Multi Point Control Protocol (MPCP) message for each time slot using service primitives related to transmission and reception of OAM data. OAM packet transmission method characterized by enabling OAM data transmission in case of discrimination and Rx failure. In the Ethernet passive fluorescence subscriber network consisting of one optical line terminal (OLT) and at least one optical network unit (ONU) connected to the OLT, a method for transmitting an operation, administration, and maintenance (OAM) packet, Placing the OAM layer below the MAC control layer so that OAM packets are not affected by PAUSE, And transmitting the OAM packet using the same service primitive as the general data.