KR19980047758A - Software structure of CATV system of open distributed processing structure and communication service processing method using this structure - Google Patents

Abstract

The present invention relates to a software structure of an ATM switch, a media server, and a subscriber station device mounted in a CATV network, and a communication service processing method using the structure. Recently, as the communication market is opened to become a free competition system, various types of devices supplied by various vendors are installed in the communication network, and as the communication business is advanced and specialized, many information providers, broadcast providers and There will be a carrier. In addition, as the information society progresses, communication services required by subscribers become diversified, complicated, and multimedia. In addition, the multimedia communication service requires more communication resources when performing services in a network. Therefore, it is important to design a structure that can secure interoperability of devices mounted on a network, easily add / delete / change communication services, and efficiently use network resources in a communication system. . That is, in the present invention, by designing the software structure of each device (media server, ATM switch, subscriber terminal) mounted on the CATV network with an open distributed processing structure to ensure the interoperability (Multi-Vendor) devices Various multimedia services can be easily implemented, and communication resources can be efficiently implemented by separating and implementing control entities performing services in each device into sessions, calls, and connections. It can be used as.

Description

Software structure of CATV system of open distributed processing structure and communication service processing method using this structure

The present invention relates to a software structure of a CATV system of an open distributed processing structure, and more particularly, to a software structure of an ATM switch, a media server, and a subscriber station device mounted in a CATV network.

Recently, as the communication market is opened to become a free competition system, various types of devices supplied by various vendors are installed in the communication network, and as the communication business is advanced and specialized, many information providers, broadcast providers and There will be a carrier. In addition, as the information society progresses, communication services required by subscribers become diversified, complicated, and multimedia. In addition, when performing a service in a communication network, a multimedia communication service requires more communication resources than existing services.

Therefore, it is very important in the communication system to design the structure to secure the interoperability of devices mounted on the network, to easily add / delete / change communication services, and to efficiently use network resources. Do.

Accordingly, since the analog CATV system of the related art generally provides subscribers with only one-way video signal distribution service, research on a CATV system capable of accommodating two-way information and communication services has been conducted in two directions. One is the CATV system of HFC (Hybrid Fiber-Coax) structure, which is connected by optical cable from headend to ONU and coaxial cable from ONU to subscriber premises, and the other is based on optical cable from headend to subscriber premises. It is an optical CATV system. However, until now, the optical CATV system has a problem in economical efficiency, and research and development on the bidirectional CATV system having an HFC structure is actively underway. However, the HFC-based bidirectional CATV system disclosed to date has been introduced to the experimental level products that can provide subscribers with interactive information and communication services by installing a cable modem in the distribution center of the CATV network and the subscriber's home It is true. In other words, the existing technology does not have any research on the structure of CATV system that can accommodate various vendors' devices, implement various kinds of multimedia services, and efficiently use network resources in a communication environment in which many communication providers exist. It is true.

Therefore, the recent communication environment is a free competition system in which a large number of information providers and broadcasters exist, and various types of new multimedia services emerge and multimedia services use a large number of communication resources when performing services unlike the existing communication services. In the CATV system, it is possible to accommodate various products of multi-vendor, add / delete / change various services, and use communication resources efficiently.

1 is a block diagram of a CATV network in which the present invention is mounted.

2 is a software structural diagram of a CATV system of an open distributed processing structure.

3 is a protocol stack of an ATM based media stream channel.

4 is a protocol stack for interaction between users.

5 is a protocol stack for session control.

6 is a call / connection control protocol stack of a broadband general information network;

7 is a session, call / connection control flow diagram of the present system.

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

1 is a configuration diagram of a hybrid fiber-coax (HFC) based CATV system in which the present invention is mounted, and an optical cable-based star is distributed from a distribution center 101 to a distribution center 101 and an ONU (Optical Network Unit) 102 in a CATV broadcasting station. It consists of a star structure and has a coaxial cable-based tree branch structure from the ONU to the subscriber 103. In addition, the present system can provide both subscribers with the bidirectional information communication service required by the subscriber 107 by attaching various media servers 106 to the ATM switcher 105 as well as the existing analog CATV service 104. have.

ATM switch installed in distribution center of CATV network handles subscriber service by PVC (Permanent Virtual Connection) / SVC (Switched Virtual Connection) method, and STM-1 (155 Mbps) or STM-4 between ATM switch and media server. (622 Mbps) via the system.

The service processing software designed in the open distributed processing structure of the present invention is mounted in the ATM switch, the media server, and the subscriber terminal, respectively.

2 shows a software structure of a media server, an ATM switch and a subscriber station in which the present invention is implemented.

The software configuration of each device mounted in the bidirectional CATV system includes an information provider element 201, an information user element 202, an end-to-end control element 203, a session control element 204, and a connection control element 205. It is designed as a structure in which information is transmitted through standardized interfaces such as S1 (206), S2 (207), S3 (208), and S4 (209). Here, the information provider element 201 corresponds to an information source (eg, MPEG Video Pump) for providing various information to the subscriber, and the information user element 202 represents a video decoder or the like mounted on the subscriber terminal. In addition, the end-to-end control element 203 is an element that performs end-to-end control (eg, control such as pause, fast forward, etc. of the VCR), the session control element 204 manages system resources The session control element, and the connection control element 205 is an element that manages the connection and disconnection of the call / connection. In addition, the information flow S1 206 is used to deliver a large amount of data of high bandwidth, such as a Moving Picture Expert Group-2 (MPEG2) transport stream as a media stream channel, and S2 (207). ) Is the information flow used by the subscriber to control the media server. S3 208 is a signal channel used when establishing a session between a subscriber and a media server, and S4 209 is a signal channel used when establishing a connection between a user and a network.

That is, the software structural feature of the bidirectional CATV system is that the exchange of control information between the subscriber station 201 and the media server 202 is an open distributed processing structure based on the Common Object Request Broker Architecture (COBA) of the Object Management Group (OMG). Designed. The subscriber station can control various media servers using a Digital Storage Media Command and Control (DSM-CC) User-to-User message of ISO / IEC 13818-6. In addition, session establishment between subscriber and media server supports multi server, multi session and multi client by using DSM-CC protocol of ISO / IEC 13818. In addition, through the logical separation of the call control function and the connection control function, the call and the connection are controlled sequentially, and the resources of the system can be efficiently utilized by changing the bandwidth, adding and deleting the connection during communication. In the call control process, it controls the overall call and controls the service acceptance, communication with the connection control function, collection and transfer of billing information, and the connection control processor controls the overall connection and control of network resources. do.

3 shows a protocol stack of information flow S1.

MPEG video / audio information of a bidirectional CATV system is converted into an ATM cell by AAL5 (ATM5) type (AAL5) type and is transmitted to a subscriber network of an HFC structure through a 64/256 quadrature amplitude modulation (QAM) modulation scheme. In the transmission frame structure, the total frame length is 204 bytes, which is composed of 187 bytes of payload, 1 byte (01000111) of frame synchronization, and Reed-Solomon coded 16 parity bytes.

4 is a protocol stack for user-to-user interaction of information flow S2, and data coding of a Use-to-User message uses OMG-CDR (Object Management Group-Common Data Representation) (401). Apply OMG-UNO (Object Management Group-Universal Networked Objects) as a Remote Procedure Call (RPC) (402). The interface between the client and the server is described in IDL (Interface Definition Language), making the system easy to implement and increasing the software reusability.

5 is a protocol stack of information flow S3, using the DSM-CC User-Network message of ISO / IEC 13818-6 (501) to establish a session, release session, and service movement between an information provider, an ATM switch and a subscriber station in a transport network. (Service Transfer), resource addition and resource release procedures.

Figure 6 is a protocol stack of information flow S4 to perform the setup and teardown of a broadband multimedia call using an ITU-T Q.2931 message (601).

7 is a flowchart illustrating a session and call connection between an information provider (media server), an ATM switch and a subscriber station (STU) for performing broadband multimedia service in the CATV system.

First, the session element of the subscriber station transmits a session setup request message (Sess SETUPreq.ind) at the ATM switch (701). When the session element of the ATM exchanger receives the session establishment request message from the subscriber station, it transmits a session establishment request message (Sess SETUPreq.ind) to the server (702). The session element of the server requests the call / connection element of the server to establish a connection (SETUP) for the information flows S1 and S2 from the server to the subscriber terminal (703). Using ITU-T Q.2931 connection control signals, the call / connection elements of the server, ATM switch and subscriber station establish a connection to the information flows S1 and S2 (704, 705). The server's call / connection element informs the server's session element that connection establishment is complete (706). The call / connection control element of the subscriber station notifies the session element that the ATM connection is completed (ResourceADDed.req.ind) (707). The session element of the server informs the ATM exchange that connection establishment is complete (ResourceADDreq.ind) (708). The session element of the ATM exchange sends an acknowledgment (ACK) signal (ResourceADDresp.conf) to the server to complete the connection establishment (709). The session element of the server sends an acknowledgment signal (SessionSETUPresp.conf) to the ATM exchange for the ACK of completion of connection establishment (710). The session element of the ATM exchange notifies the subscriber station that session and connection setup is completed (SessionSETUPresp.conf) (711).

As described above, the present invention provides a media server and an ATM installed in a CATV network in order to accommodate communication devices of various products in a number of communication service provider environments, to accommodate various types of multimedia services, and to efficiently use resources. The software structure of the switch and the subscriber station is designed as an open distributed processing structure. That is, the exchange of control information between the subscriber terminal 201 and the media server 202 is designed as an open distributed processing structure based on the Common Object Request Group (COBA) of the Object Management Group (OMG), and controls the media server of the subscriber terminal. Used ISO / IEC 13818-6 DSM-CC (Digital Storage Media Command and Control) User-to-User message. In addition, by using the DSM-CC protocol of ISO / IEC 13818 for session establishment between subscriber and media server, multi server, multi session and multi client can be supported.

In addition, through the logical separation of the call control function and the connection control function, the call and the connection are sequentially controlled, and the resources of the system can be efficiently utilized by changing the bandwidth during the communication and adding and deleting the connection.

The present invention as described above by implementing the software structure of the CATV system in an open distributed processing structure, it is possible to ensure the interoperability between devices mounted in the system, it is easy to add / delete / change various multimedia services, communication resources The effect that can be utilized efficiently is expected.

The present invention configures the software structure of the ATM switch, the media server, and the subscriber terminal mounted in the CATV network in an open distributed processing structure, thereby ensuring interoperability between multi-vendor devices installed in the network. Various multimedia services can be easily implemented, and communication resources can be efficiently implemented by separating and implementing control entities that perform services in each device into sessions, calls, and connections. The purpose is to make it available.

Claims (3)

An ATM switch installed in a distribution center of a CATV network for subscriber service processing, various media servers attached to the ATM switch, and a subscriber terminal, It is composed of a fiber-based star structure from the distribution center to the ONU (optical network device), and is composed of a coaxial cable-based tree branch from the ONU to the subscriber terminal. In the CATV system of the open distributed processing structure that attaches a server and simultaneously provides bidirectional information and communication services required by subscribers, Mounted on the ATM switch, a media server, and a subscriber station, An information provider element in which the media server provides various information to a subscriber terminal through a media stream channel which is a first information flow; An information user element representing a video decode implemented in the subscriber terminal; An end-to-end control element that performs end-to-end control of each of the media server and the subscriber station, and allows the subscriber to control the media server through a signal channel, which is a second information flow; A session control element for managing system resources through a signaling channel which is a third information flow used in establishing a session between the subscriber and the media server; And A software structure of a CATV system of an open distributed processing structure, comprising a connection control element that manages connection and disconnection of a call / connection through a signal channel, which is a fourth information flow used when establishing a connection between a user and a network. In the open distributed architecture, information provider elements, information user elements, end-to-end control elements, session control elements, and connection control elements, which are mounted on ATM exchangers, media servers, and subscriber terminals, are separated and standardized interfaces are provided. In order to process the communication service of the CATV system required by the subscriber, having a software structure for allowing information to be transmitted, A first step of the session control element of the subscriber station transmitting a session establishment request message to the ATM switch; Receiving, by the subscriber terminal, the session establishment request message transmitted from the subscriber station, and sending a session establishment request message to the media server by the session control element of the ATM switch; A third step of the session control element of the media server requesting the call / connection element of the server to establish a connection for the information flow to the subscriber terminal from the server; A fourth step in which the call / connection elements of the media server, the ATM switch and the subscriber station establish a connection to the information flow; A fifth step in which the call / connection element of the server informs the session control element of the server that the connection establishment is completed; A sixth step of the call / connection control element of the subscriber station notifying the session control element that the ATM connection is completed; A seventh step of sending, by the session control element of the ATM exchange, an acknowledgment (ACK) signal to the server to complete the connection establishment; An eighth step of the session control element of the server sending an acknowledgment signal for the connection establishment completion signal to the ATM switch; And And a ninth step in which the session control element of the ATM switcher notifies the subscriber station that the session and connection establishment is completed, the communication service processing method using the software structure of the CATV system of the open distributed processing structure. The method of claim 2, Deliver large amounts of data with high bandwidth, such as the media stream channel MPEG2 Transport Stream, The subscriber controls the media server and handles the CATV service using a protocol stack for the signal channel used for establishing a session between the subscriber and the media server and the signal channel used for establishing a connection between the user and the network. Communication service processing method using software structure of CATV system of distributed processing structure.