CN1668037A - Access method and equipment for converging IP network and cable TV network - Google Patents

Abstract

This invention disclose an access method for combing IP network and wire TV network including a protocol stack comprising a physical layer, a data link layer, a network layer, a transmission layer and an applied layer to realize forward of IP/DVB multicast data from wire TV network to LAN and help the LAN users to receive the IP/DVB multicast data transferred by the wire TV network and access external IP network and interact with far distance servers to form an interaction loop. A device is disclosed containing a multicast route forward process module and a network address conversion process module and three interfaces, one is connected with the wire TV network receiving downstream IP/DVB multicast data, the other interface is connected with the external IP network and the third one is connected with the internal LAN.

Description

Access method and equipment for converging IP network and cable television network

technical field

The present invention relates to a computer network access method and equipment, in particular to a routing access method combining IP network and cable TV network and equipment for realizing the method.

Background technique

At present, the pure IP network does not support multicast inherently, but multicast has natural advantages for large-capacity multimedia data transmission. The cable TV network is a natural broadcasting network, and it is relatively easy to provide users with multicast services through the cable TV network. From the perspective of broadband, the cable TV network can also meet the needs of multimedia services. Adopting IP Over DVB technology can allow IP to be transmitted through the cable TV network, so the scheme of transmitting large-capacity multimedia data on the cable TV network can be adopted. However, the domestic cable TV network does not support the return line, so if a pure cable TV network is used for broadband transmission, it involves a two-way transformation project of cable TV. As far as the current status of the cable TV network is concerned, the cost is quite high only from the perspective of two-way transformation.

To build a communication platform that meets the requirements, it should be based on the existing network conditions and strive to build a new network that is multicast-based and capable of interaction at a lower cost.

Contents of the invention

In order to allow LAN users to receive IP/DVB multicast data transmitted through the cable TV network, and to enable LAN users to interact with remote server groups that provide such business services, the present invention provides a combination of IP network and cable TV network An access method, which realizes the forwarding of IP/DVB multicast data from a cable TV network to a local area network, and at the same time connects the local area network to an external IP network to realize an interactive loop, thereby better integrating the cable TV network and IP network. This approach is practical and inexpensive.

The present invention also provides an access device implementing the above access method.

An access method for merging an IP network and a cable television network, comprising a protocol stack, wherein the protocol stack is composed of a physical layer, a data link layer, a network layer, a transport layer, and an application layer,

The physical layer of the protocol stack includes an RF interface connected to a cable television network and an ordinary network interface connected to an Ethernet network;

The data link layer includes data streams from multi-protocol encapsulation of the cable television network and Ethernet frames from the Ethernet network;

Described network layer is that the data packet that comes from the multi-protocol encapsulation of the cable TV network is restored to IP packet, and the data packet from Ethernet is also restored to IP packet;

Described transmission layer is TCP/UDP bag, adopts UDP to encapsulate from the data of cable television network, adopts TCP/UDP to encapsulate from the data of Ethernet;

The application layer includes multimedia data streams and common application data streams.

An access device for realizing the access method of merging IP network and cable television network, comprising a multicast routing and forwarding processing module, a network address translation processing module and at least three interfaces: RF interface, external IP network interface, and internal Ethernet interface composition;

The described multicast routing forwarding processing module processes the data input by the RF interface, and restores the data received from the cable television network into IP data packets, and multicasts the multicast data packets, and performs IGMP data monitoring by the IGMP monitoring module , if there are users in the local area network joining this multicast address, the Ethernet interface will forward it to the internal LAN, otherwise the data packet will be discarded;

The described network address translation processing module processes the data input from the external IP network interface and the internal Ethernet interface, adopts network address translation technology to process the received IP packets, if it is data from the external IP network interface, then perform After network address translation, the internal Ethernet interface is forwarded to the internal LAN; the data from the internal Ethernet interface of the internal LAN, selects the network communication interface according to the actual situation, if the target address is an external IP network address, after address translation , forwarded through the external IP network interface.

On the one hand, the access method and equipment of the present invention are connected to the cable television network to receive downlink IP/DVB multicast data; on the other hand, they can be connected to an external IP network, especially to the Internet, through dedicated data lines, dial-up lines or ADSL , so as to establish an end-to-end two-way channel with the information distribution center of the remote server group. This method realizes IP/DVB multicast data forwarding, helps LAN users to receive IP/DVB multicast data transmitted through the cable TV network, and also helps LAN users access the Internet, and can interact with remote servers to realize interaction circuit.

Beneficial effect of the present invention mainly shows as:

1. The access method of the present invention combines the access of the cable TV network and the traditional IP network. The cable TV network uses IP over DVB technology to transmit multicast data that conforms to the IP network standard, and then the device receives the data and forwards the data to the internal LAN users, avoiding that each internal LAN user must pass the DVB data receiving card to Restrictions on receiving IP/DVB data.

2. The equipment of this access method can build a new type of network that is mainly based on multicast data and can interact at the same time by spending a low economic cost, avoiding the high cost of two-way transformation of the cable TV network, and has practical economic benefits.

This method is suitable for the local area network users to receive multicast data, and at the same time solves the problem of the uplink backhaul interaction line for the local area network users.

Description of drawings

Fig. 1 is a network topology structure diagram implemented by the access method of the present invention;

Fig. 2 is a schematic diagram of the network protocol stack structure of the access method of the present invention;

Fig. 3 is a schematic diagram of the structure and principle of the access device according to the present invention.

Detailed ways

The network topology structure diagram implemented by the access method of the present invention is shown in FIG. 1 . The internal LAN (6) is provided with an access device (3), and the LAN (4) supports multicast transmission. The RF interface of the access device (3) is connected to a cable television network (CATV) (2), and its external IP network interface is connected to an external IP network (such as the Internet) (7). Through the access device (3), the internal local area network user (5) can receive data sent by the remote server group (1), and at the same time realize interaction with the remote server group (1).

The present invention adopts a protocol stack that combines DVB data and IP data through the method shown in FIG. 2 . The structure of the protocol stack is:

1. Physical layer: provide interconnection equipment for data communication. The physical layer includes the RF interface connected to the cable television network and the ordinary network interface connected to the Ethernet network;

2. Data link layer: including the data flow from the multi-protocol encapsulation (MPE) of the cable TV network and the Ethernet frame from the Ethernet network;

3. Network layer: the same as the network layer content of the traditional TCP/IP protocol stack, the data packets from the multi-protocol encapsulation (MPE) of the cable TV network are restored to IP packets, and the data packets from Ethernet are also restored to IP packets;

4. Transport layer: The content of the transport layer is the same as that of the traditional TCP/IP protocol stack. This layer is a TCP/UDP packet. The data from the cable TV network is encapsulated by UDP, and the data from the Ethernet TCP/UDP are all used .

5. Application layer: The content of the application layer is the same as that of the traditional TCP/IP protocol stack, in various forms such as multimedia data streams and files.

As shown in accompanying drawing 3, realize multicast routing forwarding processing module and network address translation (NAT) processing module and at least three interfaces in the access device (3) of the present invention: RF interface 1, external IP network interface 2, Internal Ethernet interface 3; RF interface 1 is connected to the cable TV network, external IP network interface 2 is connected to an external IP network (such as the Internet), and internal Ethernet interface 3 is connected to the LAN.

The RF interface 1 is connected to the TS data packet transmitted by the cable TV network, and then restores the IP packet encapsulated by multi-protocol. At this time, the data has entered the network protocol stack. After analyzing the TS packets from RF interface 1 and restoring them to IP packets, the multicast routing and forwarding module will perform routing analysis on the IP packets to determine whether to forward the IP packets to the local area network connected to the internal Ethernet interface 3. LAN users receive multicast data packets transmitted through the cable TV network through the internal Ethernet interface 3 .

The IP data packets that enter the external IP network interface 2 and the internal Ethernet interface 3 will be processed by the network address translation (NAT) module for simulcast processing to determine whether to perform network address translation to forward the data packets. If it is from the external IP network interface 2, after address translation, the LAN forwarding is done through the internal Ethernet interface 3. For the data from the internal Ethernet interface 3, that is, the data inside the local area network, the network communication interface is selected according to the actual situation. If the destination address is an external IP network address, forwarding is performed through the external IP network interface 2 after address translation. Otherwise, the packet is not forwarded.

The multicast routing follows the Distance Vector Multicast Routing Protocol DVMRP.

Claims (2)

1. a cut-in method that merges IP network and cable TV network comprises a protocol stack, and described protocol stack is made up of physical layer, data link layer, network layer, transport layer, application layer,

Described physical layer comprises RF interface that is connected with the line TV network and the general network interface that is connected Ethernet;

Described data link layer has comprised from the data flow of the multi-protocols of cable TV network encapsulation and from the ethernet frame of Ethernet;

Described network layer is reduced into the IP bag for the packet from the encapsulation of the multi-protocols of cable television network, also is reduced into the IP bag with packet from Ethernet;

Described transport layer is a TCP/UDP bag, encapsulates from the The data UDP of cable television network, from the The data TCP/UDP encapsulation of Ethernet;

Described application layer has comprised multimedia data stream and common application data stream.

2. an access device of realizing merging the cut-in method of IP network and cable TV network comprises multicast routing forwarding processing module and network address translation processing module and at least three interfaces: RF interface, external IP network interface, inner Ethernet interface;

Described multicast routing forwarding processing module is handled the data by the input of RF interface, the data that receive from cable television network, be reduced into the IP packet, multicast packets is carried out the multicast route, carry out the IGMP data decryptor by the igmp snooping module, if this local area network (LAN) has the user to add this multicast address, then be forwarded to internal lan by inner Ethernet interface, otherwise packet discard;

Described network address conversion module is handled by the data from external IP network interface and the input of inner Ethernet interface, adopt NAT technology to handle the IP packet that receives, if from the data of external IP network interface, after then carrying out network address translation, be forwarded to internal lan by inner Ethernet interface; From the data of the internal lan of inner Ethernet interface, select network communication interface voluntarily according to actual conditions, if destination address is the external IP network address, then after carrying out address transition, transmit by the external IP network interface.

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