JPH11252094A - Inter-heterogeneous network fast connection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inter-heterogeneous network fast connection system where a general household, etc., can use the multimedia information on VOD at a low rate. SOLUTION: A VOD server 4 fast sends the multimedia information to an ATM network 3 in the form of ATM cells 11. An ATM switch device 6 puts together the cells 11 to assemble them into the IP packets 13 and sends these packets to a wide-band LAN 2. An HE device 7 modulates the the packets 13 into the analog signals and sends them to a down channel 9 of a CATV network 1. A VOD terminal 5 receives the analog signals to demodulate them into the digital signals of the packets 13 and reproduces these digital signals as the multimedia information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a CATV network, L
The present invention relates to a high-speed connection system between heterogeneous networks in which an AN and an ATM network are interconnected.

[0002]

2. Description of the Related Art Recently, VOD (Video On Demand), in which a user can view a desired video when he / she wants to watch, has recently been used for an exhibition system and an educational system in public facilities. Since this VOD includes moving images, a high-speed, broadband network is required to use the VOD.
M (Asynchronous Transfer M)
mode) is used in companies and public facilities.

On the other hand, in general households, etc., at present,
A telephone network with a transmission rate of 36.6 Kbps or a transmission rate of 6
4Kbps or 128Kbps ISDN (Integ
rated Services Digital Ne
network) has become widespread, and V
It is difficult to receive digital multimedia information services that require high speed and broadband such as OD.

[0004]

At present, using an ATM network to utilize VOD results in high fees. For this reason, there has been a problem that digital multimedia information including high-speed, wide-band moving images, such as VOD, cannot be used at a low payable price in ordinary households and the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a high-speed connection system between heterogeneous networks that can transmit digital multimedia information such as VOD at a low cost in ordinary households. The purpose is to gain.

[0006]

According to the present invention, there is provided a high-speed connection system between heterogeneous networks, comprising: a VOD server having multimedia information such as audio, video, data, etc .; An ATM network for transmitting the ATM cells at high speed, an ATM switch device for assembling the transmitted ATM cells into IP packets, a LAN for transmitting the IP packets assembled by the ATM switch device at a high speed, and an An HE device for modulating an analog signal, a CATV network for transmitting the analog signal modulated by the HE device at a high speed,
A V for demodulating the transmitted analog signal to a digital signal of an IP packet and reproducing the multimedia information
It is connected to an OD terminal.

A high-speed connection system between heterogeneous networks according to the present invention comprises a network band management device for monitoring a transmission band of a CATV network, and when the transmission band of the CATV network is narrower than a predetermined transmission band, the network band management device is provided. , And causes the HE device to discard the erroneous IP packet transmitted by the LAN.

A high-speed connection system between heterogeneous networks according to the present invention includes a network band management device for monitoring a transmission band of reception of a VOD terminal, and when the transmission band of reception of the VOD terminal is narrower than a predetermined transmission band. The bandwidth management device causes the HE device to discard the error-produced IP packet transmitted by the LAN.

A high-speed connection system between heterogeneous networks according to the present invention includes a network bandwidth management device for monitoring an error occurrence rate of an ATM cell transmitted by an ATM network, wherein the error occurrence rate is larger than a predetermined error occurrence rate. In this case, the network bandwidth management device causes the HE device to discard the erroneous IP packet transmitted by the LAN.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a diagram showing a configuration of a high-speed connection system between heterogeneous networks according to the first embodiment. In the figure, reference numeral 1 denotes CATV (Cable Televisio)
n) A network, which is a "broadcast network" using a CATV network communication protocol for simultaneously transmitting continuous information such as video signals, and can be used in ordinary homes at a lower fee than the ATM network 3.

In FIG. 1, reference numeral 2 denotes a LAN (Loc).
al Area Network) and TCP / I
P (Transmission Control Pr)
otocol / Internet Protocol)
It is a "computer network" that mainly uses non-continuous data communication using this communication protocol.
3 is an ATM (Asynchronous Transf)
er Mode) network, which is a “communication network” that uses an ATM network communication protocol for seamlessly transmitting multimedia information such as audio, video, and data.

The CATV network 1 is an asymmetric network composed of a downstream channel 9 having a wide band of about 30 Mbps and an upstream channel 10 having a narrow band of about 6 Mbps. The downstream and upstream channels 9 and 10 of the LAN 2 and the ATM network 3 are symmetric.

[0013] Here, the ATM network 3 is a fixed lane or a LAN for which a band is guaranteed after transmitting a band.
Reference numeral 2 denotes a free lane for which transmission is performed without obtaining the permission of use of the band, for which no band is guaranteed, and a down channel 9 of the CATV network 1.
Is a free lane with no guaranteed bandwidth, CATV network 1
The upstream channel 10 is a fixed lane whose bandwidth is guaranteed or a free lane whose bandwidth is not guaranteed depending on the use.

In FIG. 1, reference numeral 4 denotes a VOD server which holds multimedia information such as audio / video / data and operates according to the TCP / IP protocol, and 5 denotes a TCP / IP of a personal computer or the like installed in a general home or the like. A VOD terminal that operates according to the protocol, 6 is an ATM switch device that connects the LAN 2 and the ATM network 3, and 7 is an HE (Headend) device that connects the CATV network 1 and the LAN 2. Also,
11 is an ATM cell on the ATM network 3, 13 is an IP (Internet Protocol) on the LAN 2 and the CATV network 1.
col) packet. Here, the VOD terminal 5
Are connected to the CATV network 1.

As shown in FIG. 1, a VOD server 4 operating according to the TCP / IP protocol and a VOD terminal 5 are basically connected by a LAN 2 using the TCP / IP protocol. , And the VOD terminal 5 is connected via the CATV network 1 which is easy to use.

Next, the operation will be described. The VOD server 4 connects to one channel of the ATM network 3 which is a fixed lane, converts multimedia information such as audio / video / data into an IP packet 13, converts it into an ATM protocol of a 53-byte ATM cell 11, and The data is transmitted to the ATM network 3 at a high speed of about 0.5 Mbps or more. The ATM switch device 6 collects the transmitted ATM cells 11 into about 30 pieces and assembles them into an IP packet 13 of 1.5 Kbytes.
The data is transmitted to the LAN 2 which is a free lane but has a wide band.

The HE device 7 transmits the transmitted IP packet 1
3 is modulated into an analog signal of the protocol of the CATV network 1 and transmitted to the downstream channel 9 which is a free lane of the CATV network 1. The VOD terminal 5 receives the transmitted analog signal, demodulates the digital signal into a digital signal of the IP packet 13, and reproduces the digital signal as multimedia information such as audio, video, and data.

As described above, the digital multimedia information of the VOD server 4 is transmitted at a high speed via the wide band ATM network 3, LAN 2 and downstream channel 9 of the CATV network 1, and reproduced by the VOD terminal 5. You.

When receiving the analog signal, the VOD terminal 5 sends a response signal to the upstream channel 10 of the CATV network 1 which is a free lane or a fixed lane. The response signal is returned to the VOD server 4 via the upstream channel 10, the LAN 2, and the heterogeneous network of the ATM network 3 of the CATV network 1.

As described above, according to the first embodiment, the digital multimedia information of the VOD server 4 which has conventionally been difficult to use in ordinary households is transmitted to the ATM network 3, the LAN 2, and the CATV network 1. VOD of personal computers in general homes via high-speed, broadband heterogeneous networks
The effect of being able to transmit to terminal 5 is obtained.

Further, since the VOD server 4 is connected to the ATM network 3 capable of long-distance high-speed communication, the VOD terminal 5 can receive multimedia information of the VOD server 4 existing at a long distance at high speed. The effect is obtained.

Further, since a plurality of VOD terminals 5 are connected to the CATV network 1, the VOD server 4 can simultaneously deliver multimedia information to each VOD terminal 5. Can be

Embodiment 2 FIG. FIG. 2 is a diagram showing a configuration of a high-speed connection method between heterogeneous networks according to the second embodiment. In the figure, 8 is the ATM network 3, LAN2 and CA
In order to manage the transmission band of the TV network 1, a network band management device operating by a TCP / IP protocol connected to a predetermined channel on the LAN 2,
The ATM cell in which the error has occurred above is an IP packet 14 in which an error has occurred in the LAN 2. Other symbols are the same as those in FIG. 1 of the first embodiment.

By connecting such heterogeneous networks,
When transmitting digital multimedia information from the VOD server 4, if the number of VOD terminals 5 accommodated in the CATV network 1 increases, the characteristics of each network (for example, CATV
The network 1 is asymmetric, but the LAN 2 and the ATM network 3 are symmetrical, and the quality (for example, the CATV network 1 is the LAN 2 and the AT
(For example, the quality is lower than that of the M network 3), the band of each network cannot be sufficiently secured, and the video / audio may be interrupted or the video noise may occur.

For example, if the transmission path quality of the ATM network 3 is poor or if the processing of the ATM switch device 6 overflows, the 53-byte AT that transmits the ATM network 3
The ATM switch device 6 cannot receive the M cell 11 and the ATM cell 11 is destroyed or lost, so that there is a probability that there is an error.

When the ATM switch device 6 assembles the ATM cell 12 in which the error has occurred into an IP packet 13 of 1.5 Kbytes, the IP packet 14 in which the error of about 30 times has occurred is transmitted over the LAN 2, and the error is transmitted. When the IP packet 14 in which the error occurs flows into the CATV network 1, the bandwidth of the downstream channel 9 of the CATV network 1 which is narrower than that of the LAN 2 is compressed. In this embodiment, the ATM cell 12 in which an error has occurred in the ATM network 3 is stored in the CATV network 1.
, So that the saturation of the band of the CATV network 1 is eliminated.

Next, the operation will be described. The network bandwidth management device 8 monitors the bandwidths on both sides of the ATM switch device 6 via a predetermined channel on the LAN 2 so that the data on the usage status of the VOD server 4, the ATM network 3 and the bandwidth of the LAN 2 can be kept constant. By collecting at time intervals and monitoring the bandwidth on both sides of the HE device 7,
Data on the usage status of the bands of the VOD terminal 5, the CATV network 1 and the LAN 2 is collected at regular time intervals. Next, when the transmission band required for transmitting the multimedia information is not secured, the network bandwidth management device 8 provides a control signal to the HE device 7 to secure the necessary bandwidth.

FIG. 3 is a flowchart showing an operation for securing a necessary band. First, in step ST11,
The network bandwidth management device 8 checks whether the bandwidth of the CATV network 1 is wider than the allowable bandwidth (for example, 1.2 to 1.5 times the bandwidth transmitted by the VOD server 4). The network bandwidth management device 8 notifies the HE device 7 of an instruction to discard the IP packet 14 in which the error has occurred. The IP where the error occurred here
The packet 14 is specified by the IP address added to the IP packet 13. And step ST1
In 5, the HE device 7 discards the IP packet 14 in which the error has occurred and transmitted by the LAN 2.

In step ST11, the CATV
If the band of the network 1 is wider than the allowable band, step ST12
, The network bandwidth management device 8 checks whether the reception bandwidth of the VOD terminal 5 is wider than the permissible bandwidth. If the bandwidth is narrower, the process goes to step ST14, where the network bandwidth management device 8 14
Is notified to the HE device 7, and in step ST <b> 15, the HE device 7 discards the IP packet 14 in which an error has occurred and transmitted through the LAN 2.

In step ST12, if the reception band of the VOD terminal 5 is wider than the allowable band, step S12 is executed.
At T13, the network bandwidth management device 8
It is checked whether the error occurrence rate of the ATM cell 11 of the multimedia information (determined by the ATM address) transmitted to the M network 3 is equal to or more than an allowable value. Management device 8
Sends a discard instruction of the IP packet 14 in which the error has occurred to H.
The E device 7 is notified, and in step ST15, the HE device 7 discards the IP packet 14 in which an error has occurred and transmitted by the LAN 2.

At step ST13, the ATM cell 1 of the multimedia information transmitted to the ATM network 3
If the error occurrence rate of No. 1 is equal to or less than the allowable value, step S
Returning to T11, the above process is repeated at regular time intervals. Also, in step ST15, even after the HE device 7 discards the IP packet 14 in which the error has occurred, the process returns to step ST11, and the above process is repeated at regular time intervals.

The processes in steps ST11 to ST13 need not be performed in this order, but may be performed in any order.

As described above, according to the second embodiment, the network band management device 8 controls the band of the CATV network 1, the band of the reception of the VOD terminal 5, and the ATM of the multimedia information transmitted to the ATM network 3. The error occurrence rate of the cell 11 is checked. If the error occurrence rate is narrower than the allowable bandwidth or the error occurrence rate is equal to or higher than the allowable error rate, the HE device 7 generates an error based on the instruction from the network bandwidth management device 8.
Since the packet 14 is discarded, the effect of eliminating the saturation of the band of the CATV network 1 can be obtained.

[0034]

As described above, according to the present invention, VO
The multimedia information of the D server can be transferred to a VO of a general personal computer via a high-speed, broadband heterogeneous network.
There is an effect that the data can be transmitted to the D terminal.

According to the present invention, based on an instruction from the network management device, the HE device can determine whether the IP having the error has occurred.
Since the packet is discarded, there is an effect that the saturation of the band of the CATV network can be eliminated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a high-speed connection system between heterogeneous networks according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a high-speed connection system between heterogeneous networks according to a second embodiment of the present invention.

FIG. 3 is a flowchart showing an operation for securing a required band according to the second embodiment of the present invention.

[Explanation of symbols]

1 CATV network, 2 LAN, 3 ATM network, 4 VO
D server, 5 VOD terminal, 6 ATM switch device,
7 HE device, 8 Network bandwidth management device, 11
ATM cell, 12 ATM cell with error, 13
IP packet, 14 IP packet in which an error occurred.

Claims (4)

[Claims] 1. A VOD server having multimedia information such as audio / video / data, an ATM network for transmitting the multimedia information at high speed in the form of an ATM cell, and an ATM network for transmitting the transmitted ATM cell. ATM switch device for assembling into IP packets, LAN for transmitting the IP packets assembled by the ATM switch device at high speed, HE device for modulating the transmitted IP packets into analog signals, and modulation by the HE device A CATV network for transmitting analog signals at high speed; and a V for demodulating the transmitted analog signals into digital signals of IP packets and reproducing the multimedia information.
A high-speed connection method between heterogeneous networks, characterized by being connected to an OD terminal. 2. A network bandwidth management device for monitoring a transmission bandwidth of a CATV network, wherein when the transmission bandwidth of the CATV network is narrower than a predetermined transmission bandwidth, the network bandwidth management device generates an error transmitted by the LAN. 2. The high-speed connection system between heterogeneous networks according to claim 1, wherein the HE device discards the IP packet. 3. A network bandwidth management device for monitoring a transmission bandwidth of a VOD terminal, wherein when the transmission bandwidth of the reception of the VOD terminal is smaller than a predetermined transmission bandwidth, the network bandwidth management device transmits the data over the LAN. 2. The high-speed connection system between heterogeneous networks according to claim 1, wherein the IP packet in which the error has occurred is discarded by the HE device. 4. A network bandwidth management device for monitoring an error occurrence rate of an ATM cell transmitted by an ATM network, wherein when the error occurrence rate is larger than a predetermined error occurrence rate, the network bandwidth management device is connected to the LAN. 2. The high-speed connection system between heterogeneous networks according to claim 1, wherein the HE device discards the transmitted IP packet in which the error has occurred.