KR20160067033A - Optical line terminal and method for registering optical network unit in passive optical network with time division multiplexing and wavelength division multiplexing - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an optical line termination apparatus and a registration method for registering an optical network unit end unit in a passive optical network of a time division multiplexing and wavelength division multiplexing system.
To this end, the apparatus includes a user network interface card supporting various passive optical network (PON) protocols, a main network interface card for recovering packets received from the service network interface card, Wherein the user network interface card is connected to an integrated passive optical network MAC (PON MAC) processor capable of supporting various passive optical network protocols and to the integrated passive optical network MAC (PON MAC) processor, And an optical transceiver including an optical transmitter and a tunable optical receiver, wherein the integrated passive optical network MAC (PON MAC) processor sets a wavelength of use of the wavelength tunable optical transmitter and the wavelength tunable optical receiver , The wavelength tunable optical transmission device and the wavelength tunable optical receiver It registers the optical network termination unit (ONU) using the same wavelength and using a wavelength set.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical line termination apparatus and method for registering optical line termination units in a passive optical network of a time division multiplexing (WDM)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical network terminal unit (ONU) in a next generation passive optical network (NG-PON) using Time Division Multiplexing (TDM) and Wavelength Division Multiplexing (WDM) An optical line terminal (OLT) and a method for registering an optical network unit (OLT).

With the expansion of smart devices such as smart phones and the explosion of demand for broadband multimedia such as IPTV (Internet Protocol Television), the upgrading of the subscriber network is becoming the biggest issue in the telecommunication industry.

In order to upgrade the existing xDSL (Digital Subscriber Line) -based subscriber network, it is necessary to construct a fiber to the home (FTTH) that replaces the existing copper wire with optical fiber. Alternative technologies are needed to overcome the difference between communication demand and supply during FTTH construction. Do. Among these technologies, a passive optical network (hereinafter referred to as PON) is the most economical optical network configuration method.

1 is a structural view of a general PON.

As shown in FIG. 1, a PON uses a passive element such as a passive splitter (2) that does not require power supply for a plurality of subscribers to use one optical fiber (Feeder Fiber) And has a point-to-multipoint network structure that branches to an optical fiber (Distribution Fiber, 9). A system 1 of a PON optical line terminal (OLT) (hereinafter referred to as "OLT") is located at a network side end point of the optical distribution network (ODN) (ONT) 4 to 8 (ONT) are located in the ONT. The ONTs 4 to 8 mean equipment that accommodates a single subscriber and an optical network unit (ONU) 3 is an equipment that accommodates a single subscriber, Refers to equipment that is installed and accommodates the ability to aggregate multiple subscriber lines and is configured in various forms to accommodate existing xDSL subscriber lines or Ethernet subscriber lines prior to a complete FTTH transition.

Various transmission schemes are used for information exchange between the OLT and the ONU or ONT. However, most Gigabit Ethernet PONs (hereinafter referred to as " GE-PON ") according to the IEEE 802.3ah standard, G-PON ") scheme, which is an international standard of ITU-T G.984 or a Gigabit-capable PON (G-PON) scheme.

The GE-PON scheme has a transmission rate of 1 Gbps (Gigabits per second), which is downlink and uplink, and can accommodate a variable-length Ethernet frame as it is. The GE-PON method has been widely used in Japan, Korea, and China because it is relatively inexpensive and can efficiently provide IP services. However, in order to provide Time Division Multiplexing (TDM) service There is a problem that transmission efficiency is deteriorated due to the necessity of separate equipment, multi-point control protocol (MPCP) overhead and 8B / 10B coding.

The G-PON method provides 2.5 G downlink and 1.25 G uplink transmission rate, and can efficiently provide variable-length IP service and TDM service using the newly defined GEM (G-PON Encapsulation Method) frame structure. In addition, the G-PON scheme can transmit an ATM (Asynchronous Transfer Mode) protocol used in a mobile communication network without any additional overhead. The G-PON scheme can efficiently provide voice service through a frame transmission control of 125usec (8kHz) period, and is known as an efficient system with relatively low overhead due to NRZ (non-return-to-zero) coding .

The G-PON method has already been introduced and activated, and the operators are increasing the transmission distance of the PON and increasing the number of branches of the optical splitter in order to accommodate more subscribers. However, when the number of branches of 32 to 128 branches is applied to one optical fiber, the bandwidth for simultaneous provision per subscriber is limited to about 18 to 35 Mbps according to the number of branches.

Therefore, technology to provide gigabit bandwidth per subscriber is needed to realize future IT infrastructure vision such as ultra-wideband, convergence, and intelligence. Especially, over-the-top (OTT) subscribers are surging than CATV subscribers, and IP traffic is growing tenfold yearly due to the emergence of 3D TVs, smart TVs, 4G smartphones, and UHD technology products. It is urgent to construct a rapid optical subscriber network. The PON technology for this purpose is a 10 Gigabit class PON (10Gigabit-capable PON, hereinafter referred to as "XG-PON") technology, which is an ITU-T G.987 international standard.

However, in order to expand subscriber service to gigabit-class, most global operators are required to maximize the investment structure that has already been invested, rather than providing 10-gigabit service to 64 to 128 subscribers, (OSP: Outside Plant), but it has a strong tendency to upgrade to a PON with a transfer rate of up to 40G, which is a service rate that is increased by more than four times.

So, most global operators are putting off the introduction of XG-PON technology and switching directly to a 40G class PON. Accordingly, for economic and practical reasons, ITU-T G.989 proposes a PON with time division multiplexing and wavelength division multiplexing (TWDM) as a next generation passive optical network (NG-PON) Quot; -PON ") as a standard technology.

NG-PON does not affect PONs such as G-PON and XG-PON by using the same ONT Management Control Interface (OMCI) as the existing PON technology. For this purpose, a new wavelength that does not overlap with the wavelength used in the existing PON is allocated to the NG-PON.

FIG. 2 is a diagram showing a wavelength allocated to the PON and a wavelength allocated to the NG-PON.

As shown in FIG. 2, wavelengths of upstream (US) 1310 nm and downstream (DS) 1490 nm are allocated to the existing G-PON and 1270 nm and 1577 nm are allocated to the XG-PON.

Further, as shown in FIG. 2, four additional wavelengths are allocated to the uplink and downlink for the NG-PON. Therefore, in the ITU-T G.989 international standard, a wavelength of 1524 to 1540 nm was allocated to the upstream wavelength and a wavelength of 1596 to 1603 nm was allocated to the downstream wavelength in relation to the NG-PON.

As shown in Fig. 2, eight up-and-down wavelengths are allocated to the NG-PON, and channels 1 to 4 are basically used. The remaining channels 5 to 8 can be additionally selected for the NG-PON, and the point-to-point WDM (Wavelength Division Multiplexing) scheme can be selected and used for the mobile backhaul.

3 is a diagram showing a communication structure between the OLT and the ONT of the NG-PON system.

The NG-PON should provide a capacity of at least 40 G to the subscriber connected through the 64 branch distributor in the same optical fiber used by the existing G-PON and XG-PON OLT and ONT. However, since a capacity of 40 G is not required for each subscriber, it is sufficient to provide a maximum access speed of 10 G.

In addition, the NG-PON must provide backward compatibility and can be used without problems in an optical distribution network (ODN) using a radio frequency video overlay, and an external optical amplifier Amplifier should be used to provide an optical power budget of up to 35dBm.

3, a coexistence element (CE) is disposed in the OLT in the communication structure between the OLT and the ONT of the NG-PON, and the existing G-PON, XG-PON, Enabling the overlay (RF overlay) device to be connected to the same optical distribution network (ODN).

In the OLT of the NG-PON, 10 G-class PON MAC is used as it is, and an optical device capable of changing the wavelength for each wavelength assigned to a plurality of 10 G-class PON MACs is used. FIG. 3 shows an NG-PON to which four wavelengths are allocated for convenience.

The ONU of the NG-PON uses the same 10G class PON MAC as that of the NG-PON OLT, and uses a wavelength variable optical element so that the wavelength can be varied according to the number of connected terminal devices.

The present invention provides an OLT and a method for simultaneously registering a G-PON subscriber and an XG-PON subscriber and registering a 40G-class NG-PON subscriber.

According to an aspect of the present invention, there is provided an apparatus for recovering packets received from a user network interface card and a service network interface card supporting various passive optical network (PON) protocols, The user network interface card includes an integrated passive optical network MAC (PON MAC) processor capable of supporting various passive optical network protocols and a main passive optical network adapter connected to the integrated passive optical network MAC (PON MAC) processor And an optical transceiver including a wavelength tunable optical transmission device and a tunable optical reception device, wherein the integrated passive optical network MAC (PON MAC) processor comprises a wavelength tunable optical transmission device and a wavelength tunable optical reception device, And the wavelength variable optical transmission element and the wavelength variable optical fiber (ONU) using the same wavelength as the set use wavelength is registered in the receiving element.

The method includes the steps of: (a) assigning an initial light wavelength to a wavelength variable optical transmission element and a wavelength variable optical reception element; (b) transmitting the wavelength variable optical transmission element and the wavelength variable optical reception element Measuring and registering a round trip delay (RTD) of an optical network unit (ONU) using optical wavelengths equal to the optical wavelengths allocated to the ONUs, and (c) when the round trip delay is measured, And determining a normal operation state.

As the traffic growth rate is accelerating, it is expected that the transition to the next generation PON that accommodates 10G speed, long distance transmission of 40Km or longer and wireless backhaul will start, and the development of ubiquitous information and communication environment will radically increase the demand for high- PON is expected to be introduced within a few years.

The present invention can accommodate one 10G class PON and a conventional 1G class PON at the same time as the PON increases in speed, and can integrate NG-PON, which is the next generation optical subscriber technology, (Total) PON OLT system, which can be applied to all access networks.

The present invention can provide a reliable service to a user and enlarge service availability by duplicating a major component in the OLT system and providing an OLT system capable of PON line protection switching.

In addition, the present invention enables one network interface card configuration and one PON MAC chip to be used in common, rather than individually implementing the system according to various standards and functions. That is, according to the development of the chip integration technology, the present invention integrates one common function and detailed functions into one chip, and can meet the specifications according to the user's demand. Therefore, the present invention can produce a uniform product, thereby reducing the manufacturing cost due to an increase in the production amount.

1 is a schematic view of a general PON,
2 is a diagram showing a wavelength assigned to a PON and a wavelength assigned to an NG-PON,
3 is a diagram showing a communication structure between an OLT and an ONT in the NG-PON system,
4 is a configuration diagram of an NG-PON OLT according to an embodiment of the present invention,
5 is a configuration diagram of a main switchboard of an OLT according to an embodiment of the present invention.
6 is a configuration diagram of an NG-PON network card according to an embodiment of the present invention, and Fig.
7 is a state transition diagram of an NG-PON MAC according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It can be easily carried out. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

And throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between. Also, when a component is referred to as " comprising "or" comprising ", it does not exclude other components unless specifically stated to the contrary . In addition, in the description of the entire specification, it should be understood that the description of some elements in a singular form does not limit the present invention, and that a plurality of the constituent elements may be formed.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a diagram illustrating a configuration of an optical line termination device of a passive optical network providing up to 80 ports of a 10G passive optical network interface according to the present invention and up to 16 ports of a 10G Base-LX interface as an up- .

The PON OLT according to the present invention has 96 ports of 10G Base-KR interfaces 41 to 48 defined in IEEE 802.3ap, and a main processor (CPU, 11, 13) and a PCIe (Peripheral Component Interconnect Express) (L3) and / or Layer 3 (L3) switching under the control of the main processors 11 and 13 through a high-speed layer 2 (L2) And two main switch boards (101, 102) having main switching fabrics (12, 14) for performing a main switching operation. The specific configuration of the main switch boards 101 and 102 will be described later with reference to FIG.

In the 10G class PON, since a plurality of subscribers are connected through the ONU having the aggregation switch function, rather than the general subscriber (i.e., subscriber through the ONT), the OLT has to manage tens of thousands of subscribers. Therefore, in order to prevent many subscribers from experiencing a service failure due to an unexpected cause of the equipment, the two main switch boards 101 and 102 must be redundant with each other and the two main switch boards 101 and 102, The status information must be continuously synchronized through the mutually defined channel 50. [ Accordingly, the main switch board (for example, the second main switch board 102) in the standby mode matches the address table and the status management variable with the main switch board (for example, the first main switch board 101) , So that the service can be restored within a short period of time through a redundant switching (that is, the main switch board in the standby mode becomes the operating mode) when an unexpected service fault condition occurs.

Various network interface cards 401 to 404 are connected to the two main switch boards 101 and 102. A G-PON interface card and a XG-PON interface Card, a G-PON card for a conventional 1G service, and IEEE 802.3ae such as 1000Base-TX, 1000Base-LX, and 10G Base-LR.

The OLT according to the present invention is a user network interface (UNI) card, which includes an 8-port 1G G-PON interface card, an 8-port 10G G-PON interface card, XG-PON interface card, 8-port XGE-PON interface card and NG-PON interface card. Referring to FIG. 4, the OLT according to the present invention includes a network interface unit (NIU) card, an 8-port Ethernet card having a 10G Base-LR interface, An Ethernet card with a 1000 Base-LR interface can be implemented. However, the embodiment shown in FIG. 4 is only one embodiment, and the present invention is not limited thereto and can accommodate various network interface cards.

In order to electrically connect the network interface cards 401 to 404 and the main switch boards 101 and 102 in consideration of the limitations of the high-speed connection and the difficulty of the PCB (Printed Circuit Board) A 10 Gigabit Media Independent Interface (XGMII) method or an XAUI (X Attachment Unit Interface) method defined in IEEE 802.3ae is used in order to implement a backplane of a 10G class. This is because conventional FR4 technology used to fabricate printed circuit boards can only transmit data at a transmission rate of up to 5G on a 50cm or more backboard. For example, if a 10G-level backplane is implemented using the XGMII scheme, uplink and downlink 72 signal lines including 32-bit data signals and 4-bit control signals operating at 156.25 MHz DDR (Double Data Rate) If you implement a 10G-class backplane, you must use 16 3.125G signal lines.

However, in order to switch the 96-port 10G ports at high speed, the main switching fabric 12, 14 must be able to analyze 10G-class packet streams transmitted from a number of UNI cards and NIU cards, do. Accordingly, in order to provide 96 10G-class interfaces, connectors corresponding to 96 times of the existing signal lines are required in the main switching fabric 12, 14. As a result, the number of pins of the main switching fabric 12, 14 in the main switch boards 101, 102 becomes too large. In addition, when the main switch boards 101, 102 are implemented as chips, There are constraints due to size. In addition, various problems may occur in implementing OLT, such as increasing the number of connectors of the backplane of the main switch boards 101 and 102, increasing the size of the system board.

In order to solve such a problem, each of the network interface cards 401 to 404 and the main switch boards 101 and 102 are connected to each other by a 10G-level electrical signal using two differential signals of 10G Base- do. That is, the OLT according to the present invention uses a pair of differential-mode signal lines capable of transmitting an electric signal at a transmission rate of 10.3125G using a general 10G Base-KR technology defined in IEEE 802.3ap. Accordingly, even if the OLT accommodates 96 ports, only 4 * 96 = 384 signals need to be used. Therefore, the height of the system board can be reduced and the size of the backplane can be reduced.

Referring to FIG. 4, the main switch boards 101 and 102 and the respective network interface cards 401 to 404 are connected using interfaces 10 to 10 of the 10G BASE-KR scheme.

4, each network interface card 401 to 404 is connected to a lower end of a passive optical network MAC (PON MAC) (hereinafter referred to as a 'PON MAC') processing unit 15 to 18 An optical transceiver 405 (also referred to as an 'optical module') can be implemented in a variety of optical transceivers, depending on delivery speed, distance, and requirements.

For example, if the network interface cards 401 to 404 are PON cards, the optical transceiver 405 uses a Burst Mode optical transceiver for the PON. In case of a general gigabit Ethernet interface card, a small form factor pluggable (SFP) Type optical transceiver is used. For example, when the network interface cards 401 to 404 are XG-PON interface cards capable of providing 10G service, the XG-PON interface card accommodates eight PON interface ports, And performs protocol processing for XG-PON such as frame processing suitable for PON method. Here, Small Form Factor Pluggable (SFP) refers to a Gigabit class optical transceiver.

Each of the UNI cards 401 and 402 extracts Ethernet packets in the PON frame, and then transmits the packets to the main switch boards 101 and 102 to exchange the packets with the destinations. Packets outputted from the PON MAC processing units 15 to 18 of the UNI cards 401 and 402 are converted into XAUI interface signals and transmitted to the physical layer processing units PHY 23 to PHY 26, The physical layer processing units (PHY, 23 to 26) which are KR type transceivers convert XAUI type signals into 10G Base-KR signals and then transmit them to the main switch boards 101 and 102 through the differential mode two pair signal lines.

The main switching fabric 12,14 in the main switch boards 101 and 102 analyzes each header of the Ethernet frames and analyzes the headers of corresponding Ethernet frames and determines service priorities according to Class of Service (CoS) and Type of Service (ToS) Quality of service (QoS), virtual LAN (VLAN) analysis, and performs L2 switching according to the requirements.

When only the bridge function and the aggregation function of L2 are required for the OLT, the main switching fabric 12 and 14 perform packet exchange according to the MAC destination address by the L2 header. When the routing function of L3 is requested to the OLT, the main switching fabric 12, 14 performs L3 packet exchange through the IP header. That is, in response to a request for an OLT in the network, the main switching fabric 12, 14 determines L2 or L3 switching.

The packets exchanged in the main switch boards 101 and 102 are transmitted to the NIU cards 403 and 404 corresponding to the corresponding destinations. The main switch boards 101 and 102 output the output signals in the 10G Base-KR system. The physical layer processing units (PHY, 29, 30) of the 10G-class Ethernet card 403 receiving the signal output in the 10G Base-KR system convert the 10G base-KR system signal into the XAUI signal, ) To the XFI physical layer processing unit (XFI PHY 32). The XFI physical layer processing unit 32 converts the XAUI signal into an XFI signal and outputs the signal.

On the other hand, the 10G-class Ethernet card 403 transmits signals converted to XFI through a separate XFI physical layer processing unit (XFI PHY) 32 to the remote upper side through an optical transceiver of XFP (10 Gbps Small Form Factor Pluggable) or SFP + To the router of the network. Here, XFP refers to a standard for designating mechanical and electrical interface specifications between an optical transceiver and a physical layer (PHY) processing unit. And XFI denotes the interface signal between the 10G PHY and the optical transceiver.

Recently, SFP + optical transceivers are used because they are converted to high-speed SFI due to size constraints. However, if there is no 10G interface in the upper network router or other aggregation switch, an existing interface such as 1G Ethernet card 404 should be provided in order to access Gigabit Ethernet (GbE). Here, SFI denotes an interface.

Referring to FIG. 4, the 1G-class Ethernet card 404 is connected to each of the main switch boards 101 and 102, which are duplicated through eight 10G Base-KR lines. Among the signals from the main switch boards 101 and 102 Demultiplexing unit (MuX / DeMUX) 34 for selecting a signal of the main switch board in an operation mode and outputting the configuration of the output interface in the main switch boards 101 and 102 to a serial deserializer (SerDes) The optical transceivers 35 and 36, which are SFP optical transceivers of 1G class Ethernet (1GbE), can be directly connected. However, in a typical implementation, in a 10G class PON, the upper network router will also be extended to 10G or higher interfaces. Here, the term desdes means a component that is connected after the optical transceiver to convert parallel data to serial and convert serial data to parallel.

When the configuration management of the OLT is initially set, the PON protocol to be used is designated. The management program corresponding to the designated protocol is stored by a local processor (LCPU: 19, 20, 28) The OLT is initialized and controlled by the processors (LCPU, 19, 20, 28). To this end, the local processors (LCPU, 19, 20) and the PON MAC processors 15 to 18 are connected through a 16-bit local bus. A detailed description thereof will be described later with reference to Fig.

Each UNI card and NIU card stores state and control resisters in a programmable device CPLD (Complex Programmable Logic Device) 21, 22, 27 and 33, and main processors 11 and 13 in main switch boards 101 and 102, Write function with respect to the CPLDs 21, 22, 27 and 33 via the external bus 49. [ Only the main switch board, which is the operation mode of the main switch boards 101 and 102, becomes the master of the external bus 49 and the main switch board in the standby mode does not control the external bus 49 .

Synchronization for matching the state variables of the duplicated main switch boards 101 and 102 is performed through a separate channel 50. A separate external bus 49 is supported for communication between the local processors (LCPU, 19, 20, 28), which are management processors in each network interface card, and the main processor 11, 13 for system operation management, (49) may be implemented using an Ethernet scheme. 5, a 10/100 Fast Ethernet (FE) switch 59 is provided in the main switch board, and all local processors (LCPU, 19, 20, 28) and main processor Lt; RTI ID = 0.0 > 11, < / RTI >

5 is a detailed configuration diagram of a first main switch board 101 of an OLT according to an embodiment of the present invention.

The first main switch board 101 inputs and outputs signals to and from the NIU cards 403 and 404 and the UNI cards 401 and 402 and 96 10G Base-KR signal lines 41 to 48, And a main processor 11 for real-time controlling the main switching fabric 12 via a PCIe bus 66. The main switching fabric 12 is connected to the main switching fabric 12, The first main switch board 101 includes a volatile memory (DDR) 56 for operating the related software, and a non-volatile memory for storing the initial boot program and the system operation program Volatile memory (FLASH, 57, RTC / NVRAM, 58).

A serial communication (RS232c) drive chip 55 is provided for the operation console port of the OLT and a console port 53 on the front side connected to the serial communication (RS232c) drive chip 55 is provided. An external management port is provided with an RJ45 Ethernet port (MGMT) 52 and an Ethernet processing unit (10 / 100BASE-T PHY) 54. A 10/100 Fast Ethernet switch (10/100 FE switch, 59) is provided for communication channels between the main processor 11 and the local processors (LCPU, 19, 20, 28) of each network interface card 401, 402, 403 / RTI >

The main processor 11 drives an operation management program such as fault management, configuration management, and performance management of the OLT. In detail, the initialization and the state control during operation of each network interface are performed by the local processors (LCPU, 19, 20, 28) of the respective network interface cards 401, 402, 403 And. However, it is not necessary to directly access the CPLDs 21, 22, 27, 33 including the board type recognizer storage of each network interface card 401, 402, 403, 404 and the in- Access is performed by the main processor 11 via the local bus 49. [ Also, the main processor 11 also manages the CPLD 60 for centralized management of the board room detachment information and the board failure state through the local bus 49.

The OLT can be used as a backhaul equipment for mobile communication networks. In order to use it as a carrier Ethernet switch, it is necessary to distribute a network synchronous clock signal. To do this, the main switchboard receives E1 / T1 network synchronization signal (E1 / T1 clock) from the external network and transmits 1PPS (Pulse Per Second) and TOD (Time of Date) And a system clock module (SCM) 61 capable of receiving a composite clock signal (SCM).

The system clock module 61 restores necessary network synchronization signals under the control of the main processor 11 connected via the SPI bus and then outputs a frame synchronization pulse Frame_Sync and a system clock Sysclk to the UNI cards 401 and 402, As shown in FIG. The system clock module 61 may be implemented as a separate card according to the mounting structure of the apparatus. The present embodiment shows a case where the system clock module 61 is mounted in the main switch board due to insufficient slots in the mounting structure.

6 shows the NG-PON interface card.

FIG. 6 shows a configuration of an NG-PON network interface card that allocates four wavelengths to wavelength division multiplexing, which are accommodated in an OLT for an NG-PON. In actual implementation, the OLT can accommodate a number of NG-PON network interface cards. Here, the four wavelengths accommodated in the OLT for NG-PON are, as shown in FIG. 2, four wavelengths of the upstream wavelengths of 1524 to 1540 nm defined in ITU-T G.989 and four wavelengths of downstream wavelengths of 1596 to 1603 nm As the wavelength, for example, the downstream wavelengths are four wavelengths out of the wavelengths of 1596.34, 1597.19, 1598.04, 1598.89, 1599.75, 1600.60, 1601.46 and 1602.31 nm.

In the present invention, all of 10G / 10G, 10G / 1G, 10G / 2.5G, and the like capable of satisfying both the 10GE-PON standard such as 802.3av and the XG-PON standard such as ITU-T G.987 and the downward / Speed 10 G-class PON "MAC processing units 205, 206, and 207, respectively. The NG-PON standard is based on G-PON, but the same standard can be applied to 10GE-PON.

In the actual implementation of the present invention, a plurality of independent PON ports are provided. In FIG. 6, an NG-PON network interface card having three integrated 10G class PON MAC processors 205, 206, and 207 is illustrated. The NG-PON interface card has a local processor (LCPU, 201) that controls and manages a plurality of integrated 10G-class PON MAC processing units 205, 206, 207 via a local control bus 214. The NG-PON interface card is provided with a volatile memory 203 (for example, DDR2) and a non-volatile memory 202 (for example, FLASH memory) for driving the local processor (LCPU) An RS232c serial communication port is used as a management port of the local processor (LCPU) 201, and an RS232c drive chip (not shown) and an external console port (not shown) are provided.

The LCPU 201 is connected to the main switchboard 101 through a Fast Ethernet physical layer processing unit (PHY) 204 connected to a port such as a Media Independent Interface (MII) or a Reduced Media Independent Interface (RMII) 102 and the main processors 11, 13 in an Ethernet manner. Communication between the local processor (LCPU) 201 and the main processors 11 and 13 is performed through an interprocessor communication (IPC) protocol. For this purpose, it is necessary to define a detailed IPC protocol. However, Can be easily implemented from known technologies, and a detailed description thereof will be omitted.

The local processor LCPU 201 drives the initial program stored in the nonvolatile memory 202 according to the initially set initial value when the power is applied to the integrated 10G class PON MAC processing unit 205 , 206, and 207 are initialized. The integrated 10G class PON MAC processing units 205, 206 and 207 allocate the initial wavelength to the variable transmission elements 215, 217 and 219 and the variable reception elements 216, 218 and 220 through the serial control buses. Then, the integrated 10G class PON MAC processing units 205, 206, and 207 process the PON MAC protocol according to the state transition process (shown in FIG. 7), and the subscriber terminal apparatuses , I.e., the ONT and / or the ONU.

Since the subscriber terminal devices using different wavelengths are connected to one optical line, a wavelength division multiplexing (WDM) filter 223 is provided to divide the upstream wavelength and the downstream wavelength or to multiplex the downstream wavelengths. A wavelength division multiplexer 221 for multiplexing four transmission wavelengths using a defined standard wavelength (see FIG. 2), a wavelength division multiplexer for separating four different wavelengths from an optical signal input from the same optical line And a neutralizer 222. In actual implementation, these configurations are not separate configurations, but may include wavelength tunable optical transmission devices 215, 217, 219, wavelength tunable optical reception devices 216, 218, 220, wavelength division multiplexer 221, (222) are integrated in one package, and are implemented using a CFP (C form factor pluggable) type connector.

The optical signals input to one PON network interface card are received through the optical transceiver for CFP or NG-PON, and input to the integrated 10G class PON MAC processing units 205, 206, and 207 according to the XFI or SFI standard.

The integrated 10G class PON MAC processing units 205, 206, and 207 analyze the input PON frame according to the PON scheme and recover the user communication packets according to the defined PON protocol. The Ethernet packets recovered by the integrated 10G class PON MAC processing units 205, 206, and 207 are output in the XAUI manner. The XAUI Ethernet packet is transmitted to the main switch board through two differential mode signal lines of 10G BASE-KR type of backplane. To this end, the network interface card includes a physical layer processing unit (PHY, 211, 212, 213) for XAUI-10G base-KR conversion and converts the XAUI system signal into a 10G base-KR system signal.

Since the redundancy is required according to the size of the OLT, the integrated 10G class PON MAC processing units 205, 206 and 207 can select either the XAUI-Primary signal path or the XAUI-Secondary signal path for redundancy , And the physical layer processing units (PHY, 211, 212, and 213) perform a 2 * 2 cross point switching function.

The integrated 10G class PON MAC processing units 205, 206, and 207 include packet buffers 208, 209, and 210 for temporarily buffering transmission and reception packets.

The integrated 10G PON MAC processing units 205, 206, and 207 receive the 9.95 G bit stream converted into the electric signal from the CFP type optical transceiver, extract the clock, and decode the FEC according to the presence or absence of the FEC (Forward Error Correction) ) Processing, scrambling, and decoding processing to recover error-free frames, and processes PON frame analysis and related PON MAC protocols.

In the reverse direction, the integrated 10G class PON MAC processing units 205, 206, and 207 inquire the storage location and size information of the packet data stored in the packet buffers 208, 209, and 210 according to the service priority classification, Reads the actual packets from the buffers 208, 209 and 210, and schedules the packets according to the priority, and transmits the packets to the CFP type optical transceiver. At this time, if the rate limitation is per port, the processing is performed within the speed limit, and the proper shaping function for the traffic is handled.

When there is a packet to be transmitted from the local processor 201 to the upper network side, the integrated 10G class PON MAC processing units 205, 206, and 207 receive the packets through the local bus and store them in the packet buffers 208, 209, and 210, And inserts the stored packets into the flow to the upper network at an appropriate timing according to the priority. At this time, queue scheduling is performed according to each classification level according to each QoS priority, and various queue services such as SP (strict priority) method and WRR (weighted round robin) are performed.

7 is a state transition diagram of the integrated 10G class PON MAC processing units 205, 206, and 207 of the OLT.

First, when the power is applied, the integrated 10G class PON MAC processing units 205, 206, and 207 are reset and transition to the initialized state (T1) under the control of the local processor 201.

In the initialization state T1, the integrated 10G class PON MAC processing units 205, 206, and 207 transmit the initial light wavelength stored in the memory to the wavelength tunable optical transmission devices 215, 217, and 219 and the wavelength tunable optical reception devices 216, And initializes all the resources of the integrated 10G class PON MAC processing units 15 and 16 to be operable.

At this time, the use wavelengths of the wavelength tunable optical transmission devices 215, 217, and 219 and the wavelength tunable optical reception devices 216, 218, and 220 are determined by using a serial control bus to the corresponding port in the connected CFP type optical transceiver.

Then, the integrated 10G class PON MAC processing units 205, 206, and 207 transit to a state of waiting for a serial number (SN) acquisition (T2). Here, the serial number acquisition wait state T2 is for acquiring the serial number of the ONUs (ONTs) connected to the same optical line and using the same wavelength, and the ID for authentication of ONUs (ONTs).

The integrated 10G class PON MAC processing units 205, 206, and 207 then transition to the ONU_ID allocation state (T3) when a new serial number and existing missing ONU_ID are obtained in the serial number acquisition wait state (T2).

In the ONU_ID allocation state (T3), the integrated 10G class PON MAC processing units (205, 206, 207) allocates a unique ONU_ID to the serial number of the ONU and stores it in the memory.

When the ONU_ID unique to the ONU_ID is assigned in the ONU_ID allocation state T3, the integrated 10G class PON MAC processing units 205, 206, and 207 transition to RTD (Round Trip Delay) measurement standby state T4.

FIG. 7 shows a process of measuring an RTD and registering an ONU with respect to a plurality of ONUs (arbitrary m-th and n-th ONUs). Each state transition within the dotted line can be made independently for each ONU_ID.

The integrated 10G class PON MAC processing units 205, 206, and 207 transit from the RTD measurement wait state (T4) to the ONU initial state (T5-1) to initialize the m-th ONU for RTD measurement with respect to the m-th ONU.

When the ONU initialization is completed in the ONU initialization state (T5-1), the integrated 10G class PON MAC processing units (205, 206, 207) transits to the RTD measurement state (T6-1) and measures the RTD of the corresponding ONU.

When the RTD measurement of the corresponding ONU is completed in the RTD measurement state T6-1, the integrated 10G class PON MAC processing units 205, 206, and 207 recognize that the corresponding ONU is in the normal operation state, .

However, when the measurement is abnormal in the RTD measurement state T6-1 or when the ONU having the corresponding ONU_ID is in the inactive state, the integrated 10G class PON MAC processing units 205, 206, and 207 return to the ONU initialization state T5-1 .

On the other hand, in the ONU operation state (T7-1), the integrated 10G class PON MAC processing units 205, 206, and 207 return to the ONU_SN acquisition waiting state (T2) to wait for a new ONU not registered.

The integrated 10G-class PON MAC processing units 205, 206, and 207 transmit ONU_Pop-1 in the ONU operation state (T7-1) when the ONU becomes a loss of signal (LOS) or a loss of frame Up state (T8-1).

In the ONU_Pop-Up state (T8-1), the integrated 10G class PON MAC processing units 205, 206, and 207 proceed to the Pop_Up test to determine whether the corresponding ONU is operating normally.

If it is determined that the corresponding ONU is normal again in the ONU_Pop-Up state (T8-1), the integrated 10G class PON MAC processing units 15 and 16 return to the ONU operation state (T7-1). However, in the Pop-Up test, if the corresponding ONU is not found to be normal (that is, the Pop-Up test fails), the transition is made to the ONU initialization state (T5-1).

The procedure of T5-2 to T8-2 is performed for the n-th ONU in the same manner.

In the G-PON network, ONT (or ONU) is registered and activated in two types of static / dynamic using PLOAM (physical layer OAM) between OLT and ONT (or ONU). In the dynamic procedure, first, the ONT (or ONU) adjusts the transmission optical power level based on the OLT request. The OLT finds the serial number of the ONTs (or ONUs) connected to its PON network. The OLT assigns an ID to the serial number of the found ONT (or ONU). The OLT measures the arrival time of the upstream transmission from the ONT (or ONU). The OLT passes the EqD (Equalization Delay) to the ONT (or ONU). The ONT (or ONU) applies the transmission time transferred from the OLT. The OLT sends synchronization information (time information) to the header in the packet sent downward. Therefore, all ONTs (or ONUs) transmit information in synchronization with 125 μsec frames.

The OLT manages the bandwidth for each ONT (or ONU). DBA (Dynamic Bandwidth Allocation) is called bandwidth management according to the amount of data required for ONT (or ONU), and an algorithm is used to dynamically allocate bandwidth to subscribers according to the level of the subscriber for efficient bandwidth use. Dynamic bandwidth allocation is a method of requesting allocation from the ONT (or ONU) and appropriately allocating it in the OLT. The dynamic bandwidth allocation requests the bandwidth allocation using DBRu (Dynamic Bandwidth Report-upstream) The bandwidth is allocated in units. The ONT (or ONU) transmits its upstream queue information to the OLT, and the OLT allocates an upstream time slot based on the information.

The ONT (or ONU) transmits queue information when it is transmitted to the upstream, and OLT continuously updates the information and performs scheduling for efficiently performing dynamic bandwidth allocation (DBA) for each T-CONT type . In addition, the NSR-DBA (Non Status Report) method uses a method of allocating bandwidth by analyzing upstream traffic by the OLT itself.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Various permutations, modifications and variations are possible without departing from the spirit of the invention.

Therefore, the scope of the present invention should not be construed as being limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the appended claims.

Claims (17)

A user network interface card supporting various passive optical network (PON) protocols, and a main switch board for recovering packets received from a service network interface card and providing a packet switching function according to header information of the packet,
The user network interface card comprising:
An integrated passive optical network MAC (PON MAC) processor capable of supporting various passive optical network protocols; And
And an optical transceiver coupled to the integrated passive optical network MAC (PON MAC) processor and including a tunable optical transmitter and a tunable optical receiver,
Wherein the integrated passive optical network MAC (PON MAC) processing unit sets the wavelength of use of the wavelength variable optical transmitting device and the wavelength tunable optical receiving device,
And registering an optical network unit (ONU) using the same wavelength as the set wavelength to the wavelength variable optical transmitting device and the wavelength tunable optical receiving device,
Optical Line Termination.
The method according to claim 1,
The integrated passive optical network MAC (PON MAC)
A serial number (SN) is received from the optical network unit (ONU), and the received serial number is assigned to an ID of the optical network unit (ONU) ONU)
Optical Line Termination.
The method according to claim 1,
The integrated passive optical network MAC (PON MAC)
Measuring a round trip delay (RTD) of the registered optical network unit (ONU)
Determining that the registered ONU is in a normal state when the round trip delay (RTD) is measured,
Optical Line Termination.
The method of claim 3,
The integrated passive optical network MAC (PON MAC)
(ONU) in a normal state is in a signal loss (LOS) or frame loss (LOF) state,
(Pop_Up) test to determine whether the optical network terminal unit (ONU) is in a normal state,
Optical Line Termination.
The method according to claim 1,
The integrated passive optical network MAC (PON MAC)
Registering a plurality of optical network units (ONUs)
Optical Line Termination.
6. The method according to any one of claims 1 to 5,
The main switch board, in order to provide a 10 gigabit class backplane,
(10G) Base-KR (IEEE 802.3ap) differential mode signal line connected to each of the user network interface cards and each service network interface card,
Optical Line Termination.
The method according to claim 6,
Wherein the user network interface card and the service network interface card further comprise storage means for executing a passive optical network protocol specified in an initial configuration among a plurality of passive optical network protocols and each storing its own status and control register,
The main switchboard further includes a main processor,
Wherein the main processor is configured to execute an operation management program, read and write to the storage means for storing its state and control resist via an external bus,
Optical Line Termination.
8. The method of claim 7,
The main switch board has a redundant structure,
Optical Line Termination.
9. The method of claim 8,
Wherein the main switchboard further comprises a main switching fabric,
The integrated passive optical network MAC (PON MAC) processor has a redundant configuration,
The user network interface card comprising:
A first local processor (CPU) for controlling the duplexed integrated passive optical network (MAC) processor to process a passive optical network protocol designated at initial configuration management setup;
A first programmable device that stores its state and control register and is connectable to the main processor via an external bus; And
A multiplexed first physical layer processing means for transferring packets processed by the integrated passive optical network MAC processor to the main switching fabric through the differential mode signal line,
Further comprising an optical line termination device.
10. The method of claim 9,
The user network interface card comprising:
Speed Ethernet physical layer processing means for providing a high-speed Ethernet channel between the first local processor (CPU) and the main processor
Further comprising an optical line termination device.
9. The method of claim 8,
The redundant main switch board includes:
A main switching fabric for transmitting and receiving signals with the user network interface card and the service network interface card using a 10G Base-KR scheme, extracting packets from the transmitted signals and exchanging packets according to header information of the packets; And
Further comprising a memory for storing various programs and data to be executed by the main processor,
Wherein the main processor is connected to the main switching fabric through a PCIe bus to control switching based on L2 and L3 protocols of the main switching fabric and to perform operational management, Direct access to programmable devices,
Optical Line Termination.
12. The method of claim 11,
The main switch board includes:
E1 / T1 network synchronous clock is inputted and a synchronous clock is extracted,
A system clock module for distributing time information and a frame synchronization signal and a system synchronization signal to the user network interface card and the service network interface card;
Further comprising an optical line termination device.
9. The method of claim 8,
The service network interface card
A first service network interface card for transmitting and receiving a 10G class Ethernet signal; And
A second service network interface card for transmitting and receiving the 1G-
Further comprising an optical line termination device.
(a) assigning an initial light wavelength to a wavelength variable optical transmitting element and a wavelength variable optical receiving element;
(b) measuring a round trip delay (RTD) of an optical network unit (ONU) using an optical wavelength equal to the wavelength of light allocated to the tunable optical transmission device and the wavelength tunable optical reception device, ); And
(c) determining that the optical network terminal unit (ONU) is in a normal operating state when the round trip delay is measured
(ONU) registration method.
15. The method of claim 14,
The step (b)
Obtaining a serial number and an ID of the optical network unit (ONU);
Assigning the ID to the serial number;
Initializing the optical network unit (ONU); And
Measuring a round-trip delay of the optical network unit (ONU)
(ONU) registration method.
16. The method of claim 15,
The step (b)
If the round-trip delay is abnormally measured or the optical network unit (ONU) is inactive,
Initializing the optical network unit (ONU)
(ONU) registration method.
17. The method of claim 16,
The step (c)
If the optical network unit (ONU) is in a signal loss (LOS) or frame loss (LOF) state,
Performing a pop-up test of the optical network unit (ONU); And
Determining whether the optical network terminal unit (ONU) is normal according to a result of the pop-up (Pop_Up) test;
(ONU) registration method.

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