KR20100096772A - Method for using common virtual local area network and passive optical network system for the same - Google Patents

Abstract

PURPOSE: A method for using common VLAN(Virtual Local Area Network) and PON(Passive Optical Network) system for the same are provided to flow only one multicast traffic if a plurality of ONT(Optical Network Terminations) using the same channel exists, thereby effectively using bandwidth between a L3 board and a L2 board of an OLT(Optical Line Termination). CONSTITUTION: A PON system includes a plurality of ONT(200) and OLT(100). The plurality of ONT includes VLAN ID and destination multicast IP address in an IGMP(Internet Group Management Protocol) report message. If IGMP report message is received, the OLT converts the VLAN ID into common VLAN. The OLT transmits the multicast traffic of upper layer to the ONT through common VLAN.

Description

TECHNICAL FOR USING COMMON VIRTUAL LOCAL AREA NETWORK AND PASSIVE OPTICAL NETWORK SYSTEM FOR THE SAME

The present invention relates to a PON system, and more particularly, to a method of using a common virtual local area network (VLAN) for a multicast service, and a PON system therefor.

In general, a passive optical network (PON) system is a system that provides an ultra-high speed broadband service of several tens of Mbps or more to end users, such as homes and small businesses, using an optical cable network. The PON system is located between the subscriber terminal nodes and the network terminals of Fiber To The Home (FTTH), Fiber To The Curb (FTTC), and Fiber To The Building (FTTB), which are classified according to where the PON is processed. With a passive divider or a wavelength division multiplexing device, all nodes are networked in the form of a bus or tree structure.

PON systems can be classified into A-PON (ATM: Asynchronous Transfer Mode PON), E-PON (Ethernet PON), G-PON (Gigabit PON), and WDM-PON. The PON structure using optical media has been proposed as a way to provide subscribers with data, video (broadcast) and telephone services at low cost.

Currently, the most widely used internet subscriber access network includes a DSL (Digital Subscriber Line) network and a hybrid fiber coaxial (HFC) network. While DSL networks cannot provide services such as broadcasting, HFC networks have the advantage of providing broadcasting and data services to subscribers at the same time. The HFC network divides an RF frequency band and transmits up / down data and CATV signals to and from a subscriber. The number of subscribers served by one passive divider or wavelength division multiplexing element can accommodate from 500 up to 2000 subscribers, depending on the uplink bandwidth provided to the subscriber. However, DSL and HFC networks have limited bandwidth available to subscribers and thus lack the ability to cope with the explosion of Internet traffic.

The PON system is a point-to-multipoint structure that consists only of passive elements without active elements in the data path between source and destination, and the placement of optical transceivers and optical fibers can be kept to a minimum compared to other structures. There is this. All data transfer in the PON system is between the Optical Line Terminal (OLT) and the Optical Network Unit (ONU) or Optical Network Termination (ONT). The OLT is located at the distribution center and connects between the optical and METRO backbone networks.

The ONT is located on the subscriber terminal side to provide broadcast, voice and data services to the subscriber. The PON system has a point-to-multipoint structure in the downward direction (OLT to ONT) and a multipoint-to-point network structure in the upward direction (ONT to OLT direction).

In general PON system, different VLANs are used to enhance security for each ONT or to use different IP subnets. Even when watching the same channel in multiple ONTs, multicast traffic must be transmitted for each ONT, which wastes bandwidth. There is a problem that occurs.

The present invention provides a method of using a common virtual local area network (VLAN) for multicast services and a PON system therefor.

The PON system of the present invention comprises: a plurality of optical network terminations (ONTs) including a VLAN ID and a destination multicast IP address in an Internet Group Management Protocol (IGMP) report message; And an optical line termination (OLT) for converting the VLAN ID into a common VLAN upon receiving the IGMP report message and transmitting multicast traffic from an upper layer to the ONT using the common VLAN.

In addition, the method of using a common VLAN of the PON system of the present invention, a) Optical Network Termination (ONT) receiving the Internet Group Management Protocol (IGMP) report message as a user request; b) the ONT sending the IGMP Report message to an Optical Line Termination (OLT) including a VLAN ID and a destination multicast IP address; c) the OLT receives the IGMP report message and converts the VLAN ID into a common VLAN; And d) the OLT sending the multicast traffic from an upper layer to the ONT using the common VLAN.

According to the present invention, when there are a plurality of optical network terminations (ONTs) using the same channel, only one multicast traffic flows, and thus bandwidth between the L3 boards and the L2 boards of the optical line termination (OLT) can be efficiently used. And, if the L3 multicast table of the OLT is set to the VLAN basis, it is possible to save the L3 multicast table.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions will not be described in detail if they obscure the subject matter of the present invention.

1 is a block diagram showing the configuration of a PON system according to an embodiment of the present invention, Figure 2 is a block diagram showing the configuration of an IGMP message according to an embodiment of the present invention, Figures 3 to 5 is an embodiment of the present invention An example diagram illustrating message transmission and reception according to the present invention.

First, the network transmission method is a unicast method in which one sender transmits data to another receiver, a broadcast method in which one sender transmits data to all receivers on the same subnetwork, and the same data. It includes a multicast scheme for transmitting data to one or more receivers simultaneously.

In the multicast method, in order to limit the data transmission to the physical network with hosts belonging to the multicast group, the multicast router needs to know which multicast group exists in the physical network to which it is directly connected.

The multicast router stores a multicast table of groups containing at least one member. When a router receives a packet with a destination address that matches one of the multicast address lists, it converts the IP multicast address contained in that packet into a physical address.

IGMP (Internet Group Management Protocol) is a protocol that operates between hosts and routers and is used to manage and control multicast groups. The IGMP message is divided into a report message sent from the host to the router and a query message sent from the router to the host. An IGMP message consists of 8 bytes, a 4 bit field, a version (Ver.) Field indicating the current version of the protocol, and a 4 bit field, which defines the type of message. Field 220, a 16-bit field, a checksum field 230 for detecting an error in a message, and a group address field 240 for defining a multicast group address of the message. It includes.

The PON system of the present invention includes an optical line termination (OLT) 100 and a plurality of optical network termination (ONT) 200 connected to the OLT 100. The OLT 100 is a device corresponding to a Datalink Layer of an Open Systems Interconnection (OSI) 7 layer, and includes a plurality of L2 boards 110 and a plurality of L2 boards 110 connected to a plurality of ONTs 200 to perform a switching function. L3 board 120 for concentration from 110. The user terminal (host) is connected with each of the plurality of ONT 200. In addition, the L3 board 120 and the L2 board 110 are VLAN setting units 112 and 122 that operate to set specific VLANs in ports included in each board, and a message processing unit 114 for converting VLANs of IGMP messages into specific VLANs. , 124). For the multicast service using the multicast method, both the L3 board 120 and the L2 board 110 should support the multicast service. In the present invention, the OLT 100 serves as a multicaster router, and the ONT 200 serves as a multicast switch.

The PON system separates and uses separate wavelengths for uplink and downlink data transmission, and wavelength division is performed by an optical module (not shown) of the OLT 100 and the ONT 200. In the downlink data transmission, data transmitted from the OLT 100 is received by the plurality of ONTs 200 in 1: n. N, which represents the splitting ratio, has a value ranging from 4 to 64, and this operation is similar to that of the shared media network. In the uplink data transmission, the data transmitted from the ONT 200 is transmitted only to the OLT 100 and is not transmitted to the other ONT 200. The data transmission is similar to the point-to-point structure, but since the collision occurs between the data transmitted from the plurality of ONTs 200, the ONTs 200 must share the optical resources.

In the PON system, multicast transmission method provides a multicast service to the user by adding a separate wavelength in the downward direction in addition to the two wavelengths for transmitting and receiving data, and using only two wavelengths for transmitting and receiving data. There is a method of providing a user in the form of a data transmission frame by using a multicast traffic. The method of providing a multicast service to subscribers using a separate wavelength in the PON system uses the basic characteristic that the downlink data transmission of the PON system is a broadcast method. The advantage is that analog wavelengths can be easily transmitted to all subscribers of a PON system. PON systems using these separate wavelengths transmit relatively large amounts of data to multiple users in real time. In terms of efficiently utilizing a network, a multicast service that performs point-to-multipoint communication is suitable for applications such as broadcast services.

Using IGMP to implement multicast services, multicast routers periodically send query messages to the host indicating processing requests. The host receiving this query message sends a report message to the multicast router. The report message includes the host's multicast IP address in the group address field 240. The multicast router that receives the report message recognizes the host that has declared its intention to participate in the multicast group, and distributes the multicast traffic to multiple hosts included in the multicast group by reflecting the information contained in the report message in the routing process. do. On the other hand, when the host wants to leave the multicast group that includes it, it sends a leave message to the multicast router. The multicast router receiving the exit message stops sending multicast traffic to the host that declared the exit intent. In the above embodiment, the multicast service is provided according to the protocol procedure. In addition, multicast services can be realized by snooping (monitoring) each protocol message when multicasting and performing logical link control in combination with the snooped results, without providing a functional block of routing to the host. have.

In order to implement multicast in the PON system, the VLAN setting units 112 and 122 of the L3 board and the L2 board set the VLANs of all ports included in each board as a preset common VLAN (for example, VLAN 4094). . When the host selects a multicast channel, a report message is entered into the ONT 200, which ONT 200 sends the report message including the virtual local area network (VLAN) ID information and the host's multicast IP address. To send. When the OLT 100 receives the report message including the VLAN ID information and the destination multicast IP address, the OLT 100 adds the information to the multicast table. The OLT 100 transmits multicast traffic to the host using the multicast table. More specifically, assume that VLAN 10 is set as the VLAN ID in the ONT1 200, VLAN 20 is set as the VLAN ID in the ONT2 200, and VLAN 4094 is set as the common VLAN ID. When a report message is input to the ONT1 200 due to the multicast channel selection of the host, the ONT1 200 transmits the report message to the OLT 100 using VLAN 10. When the L2 board 110 of the OLT 100 receives the report message, the L2 board 110 adds information included in the report message to the L2 multicast table for multicast traffic transmission and converts the VLAN into a common VLAN ID 4094. The L2 board 110 stores the destination multicast mac address converted from the destination multicast IP address included in the report message, the port number received from the report message, and the converted VLAN ID information in the L2 multicast table.

Thereafter, the L2 board 110 transmits a report message to the L3 board 120 using the common VLAN 4094. When the L3 board 120 receives the report message, the L3 board 120 adds the information included in the report message to the L3 (or IP) multicast table for multicast traffic transmission, and converts the VLAN into a common VLAN ID 4094. The L3 board 120 stores information on a destination multicast IP address included in the report message, a port number receiving the report message, and a translated VLAN ID in the L3 multicast table.

If the multicast traffic packet is being received up to the OLT 100, the L3 board 120 transmits the multicast traffic to the L2 board 110 using the L3 multicast table to VLAN 4094. The L2 board 110 transmits multicast traffic using VLAN 4094 to all ports registered in the L2 multicast table. If ONT1, ONT2, and ONT3 are all registered in the L2 multicast table, all of the ONT 200 transmits multicast traffic. When the user selects the multicast channel in the ONT2 200, the IGMP message is transmitted to the L2 board 110 using VLAN 20 in the same manner as in the ONT1 200, and the L3 board 120 and the L2 board 110 Multicast traffic will be transmitted using VLAN 4094.

Although the methods have been described through specific embodiments, the methods may also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, flash memory, and the like, as well as carrier waves (for example, transmission over the Internet). It also includes the implementation in the form of. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the above embodiments can be easily deduced by programmers of the present invention.

In addition, while the present invention has been described in connection with some embodiments, it is to be understood that various modifications and changes can be made without departing from the spirit and scope of the invention as will be understood by those skilled in the art. You will need to know It is also contemplated that such variations and modifications are within the scope of the claims appended hereto.

1 is a block diagram showing the configuration of a PON system according to an embodiment of the present invention.

2 is a block diagram showing the configuration of an IGMP message according to an embodiment of the present invention.

3 to 5 are exemplary diagrams illustrating message transmission and reception according to an embodiment of the present invention.

Claims (10)

In a Passive Optical Network (PON) system, A plurality of optical network terminations (ONTs), including a VLAN ID and a destination multicast IP address in an Internet Group Management Protocol (IGMP) report message; And Optical Line Termination (OLT) for converting the VLAN ID to a common VLAN upon receiving the IGMP report message and transmitting multicast traffic from an upper layer to the ONT using the common VLAN. PON system comprising a. The method of claim 1, The OLT is, A plurality of L2 boards connected to the plurality of ONTs to perform a switching function; And L3 board for concentration from the plurality of L2 boards PON system comprising a. The method of claim 2, The L2 board is, An L2 VLAN setting unit operable to convert the VLAN ID of the port included in the L2 board; And An L2 message processing unit operable to convert the VLAN ID of the IGMP report message received by the L2 board PON system comprising a. The method of claim 3, The L2 board is, L2 multicast table for storing information about the destination multicast mac address for the multicast traffic transmission and the port number to transmit the multicast traffic PON system comprising a. The method of claim 4, wherein The L3 board, An L3 VLAN setting unit operable to convert the VLAN ID of the port included in the L3 board; And An L3 message processing unit operable to convert the VLAN ID of the IGMP report message received by the L3 board PON system comprising a. The method of claim 5, The L3 board, L3 multicast table for storing a destination multicast IP address for the multicast traffic transmission, information on the port number to transmit the multicast traffic and information on the VLAN ID PON system comprising a. In the method of using a common VLAN (Virtual LAN) of a PON (Passive Optical Network) system, a) Optical Network Termination (ONT) receives an Internet Group Management Protocol (IGMP) report message as a user request; b) the ONT sending the IGMP Report message to an Optical Line Termination (OLT) including a VLAN ID and a destination multicast IP address; c) the OLT receives the IGMP report message and converts the VLAN ID into a common VLAN; And d) the OLT sending the multicast traffic from an upper layer to the ONT using the common VLAN How to use the common VLAN of the PON system including. The method of claim 7, wherein The OLT is, A plurality of L2 boards connected to the plurality of ONTs to perform a switching function; And L3 board for concentration from the plurality of L2 boards How to use the common VLAN of the PON system including. The method of claim 8, The L2 board is, An L2 VLAN setting unit operable to convert the VLAN ID of the port included in the L2 board; And And an L2 message processing unit operable to convert the VLAN ID of the IGMP report message received by the L2 board. L2 multicast table for storing information about the destination multicast mac address for the multicast traffic transmission and the port number to transmit the multicast traffic How to use the common VLAN of the PON system including. 10. The method of claim 9, The L3 board, An L3 VLAN setting unit operable to convert the VLAN ID of the port included in the L3 board; And An L3 message processing unit operable to convert the VLAN ID of the IGMP report message received by the L3 board; L3 multicast table for storing a destination multicast IP address for the multicast traffic transmission, information on the port number to transmit the multicast traffic and information on the VLAN ID How to use the common VLAN of the PON system including.

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