KR20160071221A - Apparatus for Passive Optical Networks and system having the same - Google Patents

Abstract

The present application relates to an optical communication apparatus based on a passive optical network (PON) and an ethernet passive optical network (EPON) system including the same. The optical communication apparatus based on a PON according to an embodiment of the present invention is connected an optical line terminal (OLT) of an EPON through an optical cable. The optical communication apparatus includes: a signal receiving unit that receives an optical signal from the optical line terminal; and a subscriber unit that controls connection and maintenance of a plurality of optical network terminals (ONTs). According to the present invention, costs for constructing lines can be saved.

Description

[0001] The present invention relates to a PON-based optical communication apparatus and an EPON system including the optical communication apparatus.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PON-based optical communication device and an EPON system including the optical communication device, and more particularly, to a PON-based optical communication device and an EPON system including the PON-based optical communication device.

As the Internet traffic continues to grow rapidly and the wired / wireless integrated network becomes visible, the development of optical subscriber technology represented by fiber-to-the-home (FTTH) is accelerating. PON (Passive Optical Network) technology, which is leading the FTTH market, is a point-to-multipoint optical subscriber technology that uses a passive branching device that does not require power supply as a remote node (RN).

Therefore, PON technology can not only provide a high bandwidth to subscribers but also is widely used because OSP (Outside Plant) is constituted only as a passive element, thereby greatly reducing the operating cost of the network.

PON technology is classified into two types according to difference of multiplexing and multiple access schemes. First, it is time division multiplexing-based TDM (Time Division Multiplexing) -PON and the second is wavelength division multiplexing based WDM (Wavelength Division Multiplexing) to be. In this case, the TDM-PON includes B-PON (Broadband PON), G-PON (Gigabit-capable PON) standardized by ITU-T, and E-PON (Etherent PON) standardized by IEEE.

Recently, ITU-T and IEEE have evolved each PON standard to 10G speed class in order to meet the bandwidth requirement of the user. ITU-T has developed XG-PON1 (10 Gigabit PON) connecting G-PON, IEEE 10G-EPON standard connecting E-PON has been completed.

Korean Patent Laid-Open No. 10-2012-0074964 (July 6, 2012)

The present application aims to provide a PON-based optical communication apparatus and an EPON system including the PON-based optical communication apparatus capable of optimizing national history and reducing the cost of constructing a line.

A PON-based optical communication apparatus according to an embodiment of the present invention is a PON-based optical communication apparatus connected to an optical line terminal (OLT) of an Ethernet passive optical network (EPON) system through an optical cable, A signal receiving unit for receiving an optical signal transmitted from the apparatus; And a PON subscriber unit for controlling connection and maintenance of a plurality of optical network terminals (ONTs) according to a control signal included in the optical signal.

Here, the PON-based optical communication apparatus according to an embodiment of the present invention may be installed in a main distribution frame (MDF) or a communication box (BBx) in an area where a plurality of optical network units are located.

Here, the signal receiver may include a plurality of channels for distinguishing and transmitting traffic of the optical signal, and may designate an SLA (Service Level Agreement) according to each channel.

Here, the signal receiver may set predetermined bandwidths and priorities respectively set in the channels, and may transmit optical signals classified according to the traffic through corresponding channels.

Here, the signal receiving unit may receive the optical signal from a first PON-based optical communication device connected with the optical line terminating device in a ring structure.

Here, the PON-based optical communication apparatus according to an embodiment of the present invention may further include a signal transmission unit for transmitting the received optical signal to a second PON-based optical communication apparatus connected with the ring structure.

In the PON-based optical communication apparatus according to an embodiment of the present invention, when the signal transmission unit is directly connected to the optical line terminating apparatus, the direct connection is designated as a RPL (Ring Protection Link) .

Here, the PON-based optical communication apparatus according to an embodiment of the present invention may notify the occurrence of an error to the optical line terminal when the reception abnormality is detected in at least one of the CFM OAM reception state, the Ethernet OAM reception state, have.

Here, the PON-based optical communication apparatus according to an embodiment of the present invention may change the function of the signal transmission unit and the signal reception unit under the control of the optical line termination apparatus, The signal transmission direction can be switched.

Here, the PON-based optical communication apparatus according to an embodiment of the present invention, when a reception error is detected in at least one of the CFM OAM reception state, the Ethernet OAM reception state, and the optical signal reception state, The signal transmission direction can be switched.

Here, the signal receiver may receive a control signal including an operation and maintenance (OAM) message.

Here, the OAM message is generated according to IEEE 802.3, Clause 57, and may further include an item for displaying an OAM protocol data unit in the Ethernet header area.

Here, the OAM protocol data unit may be one in which a plurality of PON-based optical communication devices form a ring structure with the optical line termination device and are interconnected and the optical line termination device controls each PON-based optical communication device.

Here, the OAM protocol data unit may include a "SourcePU ID #" including an identifier indicating a PON-based optical communication device that transmits the OAM message in the ring structure connection, a number of PON-based optical communication devices receiving the OAM message Quot; PU ID List count "indicating the PON-based optical communication apparatus receiving the OAM message, and" Destination PU ID # "

Herein, the subscriber unit is configured to receive the PON-based optical communication apparatus, if the identifier of the PON-based optical communication apparatus is the same as the identifier of the PON-based optical communication apparatus received by the "SourcePU ID # You can drop a message.

Here, the OAM protocol data unit includes a "flag" which indicates whether the OAM message is set for the PON-based optical communication device or the optical network terminal, an "LLID List count" And "Destination LLID" indicating a list of identifiers of optical subscribers.

An EPON system according to an embodiment of the present invention is an EPON (Ethernet Passive Optical Network) system. The EPON system includes an optical line termination device (not shown) installed in a home office and connected to a back bone network through an optical signal transmitted / (OLT); A plurality of optical subscriber units are installed in a main distribution frame (MDF) in a region where a plurality of optical network terminals (ONTs) are located, and the optical signals are transmitted / A PON-based optical communication device; And an optical cable connecting between the optical line terminal and the PON-based optical communication device.

In addition, the means for solving the above-mentioned problems are not all enumerating the features of the present invention. The various features of the present invention and the advantages and effects thereof will be more fully understood by reference to the following specific embodiments.

According to the PON-based optical communication device and the EPON system including the PON-based optical communication device according to an embodiment of the present invention, it is possible to optimize the national history and reduce the cost of constructing the line.

According to the PON-based optical communication apparatus and the EPON system including the PON-based optical communication apparatus according to an embodiment of the present invention, in an access network using a large-capacity optical line termination device capable of supporting a 10 Gbps transmission rate, Network can be formed, and FTTH coverage over 70 km can be secured.

According to the PON-based optical communication device and the EPON system including the PON-based optical communication device according to an embodiment of the present invention, optical cores that may occur in the installation of a wide area optical fiber center can be saved.

FIG. 1 is a block diagram showing an EPON system according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional EPON system.
3 is a schematic view showing a connection form of a ring structure of an EPON system according to an embodiment of the present invention.
4 is a flowchart showing a line anomaly detection method of an EPON system according to an embodiment of the present invention.
5 and 6 are tables showing an OAM structure of a PON-based optical communication apparatus according to an embodiment of the present invention.
FIGS. 7 and 8 are tables showing an OAM structure at the time of operation control for an optical network subscriber unit in a PON-based optical communication apparatus according to an embodiment of the present invention.
9 is a table showing operation control of an optical subscriber unit of a PON-based optical communication apparatus according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order that those skilled in the art can easily carry out the present invention. In the following detailed description of the preferred embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In the drawings, like reference numerals are used throughout the drawings.

In addition, in the entire specification, when a part is referred to as being 'connected' to another part, it may be referred to as 'indirectly connected' not only with 'directly connected' . Also, to "include" an element means that it may include other elements, rather than excluding other elements, unless specifically stated otherwise.

FIG. 1 is a block diagram showing an EPON system according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional EPON system.

Referring to FIG. 1, an EPON system according to an embodiment of the present invention may include an optical line termination device 100, a PON-based optical communication device 200, and an optical cable 300.

Hereinafter, an EPON system according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.

Conventionally, as shown in FIG. 2, when an optical line terminal (OLT) 10 located at the national office transmits an optical signal through an optical cable, the optical signal is branched by a splitter (ONT: Optical Network Terminal or ONU: Optical Network Unit, 400). The splitter s is connected to a main distribution frame (MDF) or a communication box (BBx, Broadcast Cabinet, BBS: Broad Cast Shelter, BBH : Broad Cast House), and the splitter s and the optical line terminating device 10 can be connected by an optical cable. That is, it is possible for a plurality of optical network units 400 to share one optical cable by the splitter s.

2, the conventional optical line terminal 10 may include a switch control unit 11, a switch subscriber unit 12, a PON control unit 13, and a PON subscriber unit 14 . The optical line terminating device 10 performs a function of connecting a subscriber network and a backbone network to each other and transmits an optical signal to the optical network terminal 400 so that each optical signal can be transmitted to the corresponding optical network terminal 400. [ Can play a role.

Specifically, the switch control unit 11 manages the operation of the switch subscriber unit 12 and performs routing and security setting of each optical signal connected through the switching at the switch subscriber unit 12 . Here, the switch subscriber unit 12 provides a switch interface for connection with downlink equipment, and may include a switch network unit for providing an interface for connection with uplink equipment, though not shown.

The PON control unit 13 manages the PON function and can control the operation of the PON subscriber unit 14. [ Here, the PON subscriber unit 14 may provide a PON subscriber interface and may perform connection with the optical subscriber unit 400, which is a downlink equipment.

At present, however, an access network using a high-capacity optical line termination device capable of supporting a 10-Gbps transmission speed has been proposed according to the evolution of the network structure, and a facility centered on a wide area of the national history is constructed so as to accommodate the capacity of a large- . Here, when a large-capacity optical line terminating device is installed in a wide-area national history, the demand for a long-distance optical core extending to each main distribution box or communication box may additionally occur. That is, when the conventional method as shown in FIG. 2 is used, an excessive amount of optical cables must be newly installed.

Meanwhile, in order to solve this problem, it is possible to consider arranging a large-capacity optical fiber end device in advance, but excessive investment cost may be a problem in consideration of the capacity and cost. That is, a large-capacity optical line terminal can accommodate up to 5000 subscribers. However, since the proper accommodating size is about 500 subscribers in the case of forward placement, the effect that can be obtained compared to the cost required for forward placement of a large- .

In order to solve the above-described problems, in an embodiment of the present invention, a method of advancing and disposing a part of functions of the optical line terminating device 10 to the main distributing box or the communication box is proposed.

1, in the EPON system according to the embodiment of the present invention, the function of the PON subscriber unit 14 is performed by the PON-based optical communication apparatus 200 provided in the main distribution panel or the communication box can do. In this case, when the optical line terminal 100 transmits an optical signal, the PON subscriber unit 14 can perform the function of the PON subscriber unit 14 in the forward PON-based optical communication device 200, It is possible to distinguish each of the optical network units 400 to which optical signals should be transmitted. Each of the separated optical signals may then be branched through a plurality of splitter s and transmitted to the corresponding optical network terminal 400. [ In particular, since optical communication at a rate of 10 Gbps is supported between the optical line terminal 100 and the PON-based optical communication device 200, the PON-based optical communication device 200 can transmit optical signals to the plurality of splitter s . The optical line terminating device 100 and the PON-based optical communication device 200 may be connected to an access network supporting a 10 Gbps transmission speed and may be connected to an optical cable (not shown) for connecting the optical line terminating device 100 and the PON- 300) may support a transmission rate of 10 Gbps. However, the transmission rate of the EPON system according to an exemplary embodiment of the present invention is not limited to 10 Gbps, and various transmission rates including 2.5 Gbps, 40 Gbps, and 100 Gbps may be supported according to the embodiment.

Here, the PON-based optical communication apparatus 200 according to an embodiment of the present invention may include a signal receiving unit 210 and a PON subscriber unit 220, as shown in FIG. The PON-based optical communication device 200 can be controlled from the optical line terminal 100 through Ethernet and transmits the optical signal to a plurality of optical network units 400 under the control of the optical line terminal 100 It can transmit and receive.

Specifically, the signal receiving unit 210 can receive the optical signal transmitted from the optical line terminal 100 at a rate of 10 Gbps. At this time, the signal receiving unit 210 may include a plurality of channels for receiving the optical signal, and the channel may include a control channel for receiving a control signal and a data channel for receiving a data signal. In addition, the channel may be classified according to traffic of an optical signal, and an SLA (Service Level Agreement) may be specified according to each channel. Accordingly, the signal receiver 210 may set predetermined bandwidths and priority levels for each channel, and may transmit the optical signals classified according to the traffic through corresponding channels. For example, it is possible to transmit the traffic of each optical signal through a channel having a different bandwidth according to the priority, after distinguishing the priorities as upper, middle, and lower.

3, a plurality of PON optical communication devices 200a, 200b, and 200c may be connected to the optical line terminating device 100 in a ring structure to form a 10G EPON system. That is, instead of receiving the optical signal directly connected to the optical line terminal 100, the signal receiving unit 210 may be connected to another PON-based optical communication apparatus, for example, a first PON-based optical communication apparatus 200a. ≪ / RTI >

In addition, the PON optical communication device 200b receiving the optical signal from the first PON-based optical communication device 200a transmits the received optical signal to the neighboring second PON-based optical communication device 200c connected by the ring structure can do. At this time, the PON-based optical communication device 200b may further include a signal transmission unit 230 for transmitting the optical signal. Here, a plurality of optical network units 400 connected to the plurality of PON optical communication devices 200a, 200b, and 200c connected to the ring structure may be included. In this case, when the optical signal is transmitted to neighboring PON optical communication devices 200a, 200b, and 200c, each of the PON optical communication devices 200a, 200b, and 200c transmits optical signals to the optical network terminal 400 connected thereto It is possible to confirm whether or not the optical signal is included.

On the other hand, when the signal transmission unit 230 is directly connected to the optical line terminal 100, it is possible to designate the direct connection line as an RPL (Ring Protection Link) to prevent loop formation of the optical signal. That is, the optical line terminal 100 may block an optical signal inputted through the RPL. Instead, since the optical line terminating device 100 and the PON optical communication devices 200a, 200b, 200c form a ring structure, it is possible to switch to the opposite side connection line when an abnormality occurs in any of the connecting lines. That is, when the optical signal is transmitted and received in the form of the ring structure, if it is determined that a problem has occurred in the connection, the signal receiving unit 210 and the signal transmitting unit 230 reverse the respective functions So that it is possible to prepare for a line abnormality or the like.

More specifically, as shown in FIG. 4, after the connection of the ring structure is established (S10), the reception state of a CFM (Operation, Administration, Maintenance) (S21, S22, S23) by checking the Ethernet OAM reception state and the optical state of the optical fiber. That is, if the reception abnormality is detected in at least one of the reception state of the CFM OAM message, the reception state of the Ethernet OAM, and the state of the optical fiber lane, it can be determined that an abnormality has occurred in the optical line (S31, S32, S33). If the reception abnormality is detected, the line can be switched in the opposite direction by switching connection ports (a, b) of the optical line terminal 100 (S40). However, after a preset time (for example, 5 seconds) has elapsed to prevent the connection ports a and b from being switched in succession according to the detection result of each abnormality sensing means, It is possible to restrict the signal transmission direction of the structure to be switched (S40).

Meanwhile, the signal receiving unit 210 according to an embodiment of the present invention may receive a control signal including an OAM (Operation, Administration, Maintenance) message. Here, the signal receiving unit 210 can secure a separate bandwidth and a high priority for the OAM message upon receiving the OAM message, thereby preventing the OAM from being omitted in the transmission / reception process. The OAM message may be generated according to IEEE 802.3, clause 57, and may be modified to include an item indicating "OAM protocol data unit" in the Ethernet header area as shown in FIG. Herein, the "OAM protocol data unit" is a structure in which a plurality of PON-based optical communication devices 200a, 200b, 200c form a ring structure with the optical line termination device 100, And may be used to control each of the PON-based optical communication devices 200a, 200b, and 200c.

Specifically, the "OAM protocol data unit" may include a plurality of fields as shown in FIG. In the connection of the ring structure, a "SourcePU ID #" including an identifier indicating a PON-based optical communication apparatus 200a, 200b, 200c that transmits the OAM message, a PON-based optical communication apparatus PU ID List count "indicating the number of the PON-based optical communication apparatuses 200a, 200b, 200c, and" Destination PU ID # "indicating the PON-based optical communication apparatuses 200a, 200b, 200c receiving the OAM message. .

Here, the PON subscriber unit 220 controls connection and maintenance of a plurality of optical network units 400 in accordance with a control signal included in the optical signal, 200b and 200c are identical to the identifiers of the PON-based optical communication apparatuses 200a, 200b and 200c received by the "SourcePU ID #" or the identifiers of the received PON-based optical communication apparatuses 200a, 200b, 200c are within the "Destination PU ID List" If not, the received OAM message can be dropped. Here, when "SourcePU ID #" is the same as the identifier of the received PON-based optical communication apparatuses 200a, 200b, 200c, it is determined that the originator and the receiver of the OAM message coincide with each other, , The OAM message can be dropped. If the received PON-based optical communication apparatuses 200a, 200b, 200c are not included in the "Destination PU ID List ", it is possible to drop the PON-based optical communication apparatuses 200a and 200b for processing of OAM messages without delay. In this case, the transmission efficiency of the OAM message can be increased.

Meanwhile, the optical line terminal 100 can perform setting and control of the optical network terminal 400 in addition to the PON-based optical communication device 200 using the above-described OAM message. That is, the OAM protocol data unit may include a "flag" indicating which of the PON-based optical communication device 200 and the optical network unit 400 the OAM message is set for. An "LLID List count" indicating the number of optical network units 400 and a "Destination LLID" indicating a list of identifiers of the optical network units 400 to be received.

In addition, specific operational control of the optical network unit 400 of the PON-based optical communication device 200 using the above-described OAM message will be described with reference to FIGS. 7 and 8. FIG. Specifically, there may be a case where the optical line terminal 100 requests the optical network terminal 400 to confirm the specific value set in the optical network terminal 400. For example, the optical line terminal 100 may request an inquiry about the "MAC (Media Access Channel) Limit" or "MAC Entry" of the optical network terminal 400. In this case, the PON subscriber unit 220 can request the inquiry to each optical network terminal 400 using the OAM message received from the optical line terminal 100.

That is, the optical line terminal 100 may input an opcode indicating an inquiry about a specific value, for example, Ox02, in the Ethernet header area of the OAM message, and the optical line terminal 400 can be input. For example, the PON-based optical communication device 200 to which the optical subscriber unit 400 having the specific value is connected, and the optical subscriber unit 400, such as a branch and a leaf, connected to the PON- Information about the location of the device 400 may be displayed.

8, in response to the inquiry request for the specific value, the PON subscriber unit 220 collects the specific values collected from the plurality of optical network units 400 and transmits the OAM message to the optical line terminal To the terminating device 100. In this case, the PON subscriber unit 220 may input an opcode indicating that the response is a response to the specific value, for example Ox03. In the OAM protocol data unit area, the specific value and the width And a branch and a leaf of the optical network terminal 400 having the specific value. Accordingly, the optical line terminal 100 receiving the OAM message can inquire a specific value possessed by a desired optical network unit 400.

In addition, the optical line terminating apparatus 100 can perform operation control of the optical network terminal 400, such as inquiry and setting of various values, as shown in FIG.

The present invention is not limited to the above-described embodiments and the accompanying drawings. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10, 100: optical line terminating device 11, 110: switch control section
12, 120: switch subscriber unit 13, 130: PON control unit
14: PON subscriber
200, 200a, 200b, 200c: PON-based optical communication device 210:
220: PON subscriber 300: Optical cable
400: Optical subscriber unit
S: splitter

Claims (17)

A PON-based optical communication device connected to an optical line terminal (OLT) of an Ethernet Passive Optical Network (EPON) through an optical cable,
A signal receiving unit for receiving an optical signal transmitted from the optical line terminal; And
And a PON subscriber unit for controlling connection and maintenance of a plurality of optical network terminals (ONTs) according to a control signal included in the optical signal.
The method according to claim 1,
Wherein the PON-based optical communication apparatus is installed in a main distribution frame (MDF) or a communication box (BBx) of an area where a plurality of optical network units are located.
2. The apparatus of claim 1, wherein the signal receiver
A plurality of channels for distinguishing and transmitting traffic of the optical signal, and designating an SLA (Service Level Agreement) according to each channel.
4. The apparatus of claim 3, wherein the signal receiver
Wherein the PON-based optical communication apparatus sets a predetermined bandwidth and a priority respectively preset in the channels, and transmits optical signals classified according to the traffic through corresponding channels.
2. The apparatus of claim 1, wherein the signal receiver
And the optical signal is received from a first PON-based optical communication device connected to the optical line termination device in a ring structure.
6. The method of claim 5,
And a signal transmitter for transmitting the received optical signal to a second PON-based optical communication device connected with the ring structure.
The method according to claim 6,
Wherein the direct connection is designated as a ring protection link (RPL) when the signal transmission unit is directly connected to the optical line termination unit, thereby preventing loop formation of the optical signal.
The method according to claim 1,
A PON-based optical communication system that notifies an occurrence of an abnormality to the optical line terminal when a reception abnormality is detected in at least one of a reception state of a CFM (Operation, Administration, Maintenance) message, a reception state of an Ethernet OAM message, Device.
9. The method of claim 8,
The PON-based optical communication apparatus switches the signal transmission direction of the ring structure by replacing the functions of the signal transmission unit and the signal reception unit under the control of the optical line termination unit when the optical line termination unit is informed of the abnormality.
10. The method of claim 9,
And switches the signal transmission direction of the ring structure after a predetermined time when a reception abnormality is detected in at least one of the CFM OAM reception state, the Ethernet OAM reception state, and the optical state of the optical fiber.
2. The apparatus of claim 1, wherein the signal receiver
A PON-based optical communication apparatus that receives a control signal including an OAM (Operation, Administration, Maintenance) message.
12. The method of claim 11,
Wherein the PON-based optical communication apparatus further comprises an item to be generated according to IEEE 802.3, Clause 57, and to display an OAM protocol data unit in an Ethernet header area.
13. The method of claim 12, wherein the OAM protocol data unit
Wherein the plurality of PON-based optical communication devices form a ring structure with the optical line termination device and are interconnected to each other so that the optical line termination device is used to control each PON-based optical communication device.
14. The method of claim 13, wherein the OAM protocol data unit
A " PU ID List count "indicating the number of PON-based optical communication devices receiving the OAM message, a " And "Destination PU ID #" indicating a list of identifiers of the PON-based optical communication devices receiving the OAM message.
15. The system of claim 14, wherein the subscriber unit
If the "SourcePU ID #" is the same as the identifier of the received PON-based optical communication apparatus or if the identifier of the received PON-based optical communication apparatus is not included in the "Destination PU ID List", the received OAM message is dropped PON-based optical communication device.
15. The apparatus of claim 14, wherein the OAM protocol data unit
A "flag" indicating whether the OAM message is set for the PON-based optical communication device or the optical network terminal, an "LLID List count" indicating the number of the receiving optical network units, Destination LLID ".< / RTI >
In an EPON (Ethernet Passive Optical Network) system,
An optical line terminal (OLT) installed in the national office and connecting an optical signal transmitted / received through a subscriber network to a back bone network;
A plurality of optical subscriber units are installed in a main distribution frame (MDF) in a region where a plurality of optical network terminals (ONTs) are located, and the optical signals are transmitted / A PON-based optical communication device; And
And an optical cable connecting the optical line terminal and the PON-based optical communication device.

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