JPH11225169A - Communication network controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a service grade by deciding the transmission line of a data packet by a network layer address, dynamically assigning an exclusive transmission line to a terminal in response to the request of the optional terminal and changing the data packet addressed to the assigned terminal to the exclusive transmission line so as to reserve a band on internet. SOLUTION: A subscriber gives a message that the reception of a band- securing-type internet access service is desired to a CATV center 1 by using a switch 14. The center 1 secures a transmission line the subscriber transmitting the message can occupy. When the transmission line is secured, an internet connecting device 21 within the center 1 searches the IP address of a subscriber' s terminal 2 from a routing table entry and changes the value of a corresponding sending port to a port value for the secured transmission line. After then, a pair of the IP address and the multi-cast address of the terminal 2 is added to a table for a resource reservation protocol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cable television (Ca)
The present invention relates to communication network control suitable for a system for providing an Internet service using a transmission path shared by a large number of subscribers, which is used in ble TeleVision (hereinafter, CATV), digital satellite broadcasting, and the like.

[0002]

2. Description of the Related Art In recent years, personal computers (hereinafter referred to as P
C) PCs for homes and offices with higher functionality and lower prices
The introduction of is becoming active. With the spread of PCs, the number of Internet users has been increasing in recent years. In order to incorporate this fast-growing Internet as part of interactive services, CATV and digital satellite broadcasting, which have been providing services within closed networks, have embarked on the market, and have improved transmission capacity through the development of digital modulation methods. The introduction of Internet access services that make use of it is being promoted.

[0003] Internet access service is CATV
Network and a closed network such as digital satellite broadcasting (CNW), which is realized by installing an interface that relays data packets, and allows Internet access service users in the CNW to transmit data on the Internet. The purpose of the present invention is to provide a high-speed communication path for transferring data and downloading a large amount of data in a short time. Conventionally, a bandwidth guarantee type that allocates a dedicated bandwidth to each service provided within the CNW has been adopted, but for Internet access services, the same best practices as the Internet where all users share the same transmission path are used. Effort type is used.

[0004] The Internet uses the Internet Protocol (hereinafter referred to as IP) for transmission of data packets.
In the header portion of the (IP datagram), a destination IP address, a destination IP address, and the like are described. Here, the IP address is a numerical value composed of a network address part and a host address part, and is an address uniquely given to each terminal on the Internet. IP on the Internet
At the route branch point of the datagram, routing is performed using the destination IP address described in the IP datagram header.

[0005] Therefore, a unique IP address having a specific network address is also given to the Internet access service user in the CNW, and the Internet interface installed in the CNW is used for the IP datagram arriving from the Internet. It has a routing function of sending only IP datagrams addressed to subscribers connected to the CNW to the CNW side, and sending IP datagrams in the CNW to the Internet side. At this time,
The interface performs routing using the network address part of the IP datagram.

FIG. 1 shows an example of a CATV Internet access system. In this example, an Internet access service will be described assuming that one transmission path for data transmission (hereinafter, a data transmission band) shared by users of the Internet access service is reserved in advance. In FIG. 1, 1 is a CATV center, 2 is a subscriber terminal,
3 is CATV transmission line, 4 is Internet, 5 is router, 6 is CA
TV LAN, 7 is an Internet connection device, 8 is a CATV center side transmission / reception device, 9 is a subscriber terminal side transmission / reception device, 10 is a conversion device, 11 is an application processing device, 12 is a display, 13 is a service selection control device, 14 Is a switch.
Here, functions of some devices will be described.

The Internet connection device 7 has the configuration shown in FIG. 2A, and the IP termination unit 7 (i) therein has the configuration shown in FIG. 2B. When an IP datagram arrives from the LAN 6 in the CATV, the IP terminal first searches the routing table as shown in FIG. 3 using the destination IP address described in the header of the IP datagram as a key, and finds the IP address. Specify the carrier and transmission port of the frequency assigned to. Here, a channel is used as an identifier for identifying a carrier.

Next, the IP datagram is converted into a signal by the CATV channelization section, and the signal is loaded on a carrier of the frequency specified by the IP termination section and transmitted from a specific transmission port. Also, the Internet connection device 7 transmits the signal transmitted from the transmission / reception device 8.
Terminate at the CATV transmission path termination unit, and convert to IP datagram at the IP datagram conversion unit. In the routing table of FIG. 3 held by the Internet connection device 7, the IP addresses of all the users of the Internet access service are entered, and the output port and the carrier of the frequency can be searched.

The transmission / reception devices 8 and 9 have a function of mixing the channels sent from the Internet connection device 7 and the conversion device 10 with other service channels and putting them on the CATV transmission line, and a function of separating the data transmission channel from the CATV transmission line. It has a function to do. The conversion device 10 has a configuration similar to that of FIG. 2, and has a function of transmitting an IP datagram transmitted from the application processing device 11 on a carrier of an assigned frequency and transmitting the IP datagram from a transmission port, and the transmission and reception device 9 transmits the IP datagram. It has a function to convert the signal into an IP datagram. The application processing device 11 has a function of converting an IP datagram into data that can be displayed on the display 12 and a switch 14.
Converts IP datagram specified by subscriber by
Has the function of sending to 10.

The Internet access service is started when the subscriber operates the switch 14 to send a command to the service selection control device 13 and selects an Internet access service from a service selection menu called on the display 12.

First, a procedure for transferring an IP datagram sent from the subscriber terminal 2 to the Internet 4 will be described. The subscriber operates the switch 14 to instruct the application processing device 11 via the service selection control device 13 to transmit the IP datagram designated by the subscriber to a terminal on the Internet. In response, the application processing device 11 sends the instructed IP datagram to the conversion device 10. Upon receiving the transmitted IP datagram, the conversion device 10 specifies a frequency carrier from the destination IP address described in the header of the IP datagram, converts the IP datagram into a signal, and places the signal on the frequency carrier. Send from the sending port.

The transmission / reception device 9 which has received the signal multiplexes the channel on the upstream part of the data transmission band of the CATV transmission line. The transmitting / receiving device 8 on the side of the CATV center cuts out the upstream channel of the data transmission band from the received multiplex channel and sends it to the Internet connection device 7. The Internet connection device 7 converts the signal in the channel into an IP datagram and sends it to the LAN 6 in CATV. The router 5 receiving the IP datagram sends it to the Internet 4.

The IP datagram transmitted from the subscriber terminal 2 is transmitted to the Internet 4 by the above procedure.

Next, a procedure for transferring an IP datagram reaching the router 5 from the Internet 4 to the subscriber terminal 2 will be described. Router 5 is the IP received from Internet 4
With reference to the destination IP address of the datagram, only the IP datagram having the same network address as the terminal in the CNW is transferred to the Internet connection device 7. The Internet connection device 7 compares the destination IP address of the IP datagram with the IP address in the routing table, and determines an IP datagram having a destination IP address not in the routing table, that is, an IP datagram not addressed to the Internet access service user. Discard. In addition, an IP datagram having a destination IP address registered in the routing table, that is, an IP datagram addressed to the Internet access service user is transmitted to a carrier of a specific frequency corresponding to the port number determined according to the routing table. The data is converted, loaded, and sent from the transmission port to the transmission / reception device 8.

The transmission / reception device 8 multiplexes the channel to the downstream part of the data transmission band of the CATV transmission line. The transmission / reception device 9 on the subscriber terminal side cuts out the downstream channel of the data transmission band from the multiplexed CATV transmission line 3, and
Send to 10. Upon receiving the data, the conversion device 10 converts the signal in the channel into an IP datagram, and sends the IP datagram addressed to the subscriber terminal 2 to the application processing device 11. In response, the application processing device 11 converts the IP datagram so that it can be displayed on the display 12 and
Send to The subscriber can view information on the Internet through the display 12.

In the Internet access system illustrated in FIG. 1, the IP datagram on the Internet and the IP datagram of the subscriber terminal are transferred according to the above procedure.

In recent years, a number of applications such as Internet broadcasting and Internet telephony that handle real-time stream data including moving images and audio have appeared on the Internet. Real-time data handled by such an application has a very large transfer amount, and if a certain transmission speed is not maintained, the real-time property is lost and the value of the data itself is lost.

On the other hand, in the Internet where the same line is used by a plurality of users, delays and discarding of IP datagrams are allowed to some extent, and data that can be handled by the Internet and real-time data have different characteristics.
Therefore, to handle real-time data on the Internet, QoS (Quality of Service
A mechanism that provides communication that guarantees ce) is required.

As one means for solving this problem, a protocol RSVP (Resource ReSerVation Protocol) for securing a bandwidth on the Internet for specific stream data.
l) is standardized by IETF (Internet Engineering Task Forc)
e) is proceeding. RSVP is a protocol implemented in nodes (hosts and routers), and enables end-to-end bandwidth reservation by securing a bandwidth for the stream in each node through which stream data passes. Therefore, all nodes through which stream data passes
If VP is not supported, bandwidth reservation is not guaranteed. Hereinafter, a typical procedure for securing, maintaining, and releasing RSVP resources will be described with reference to the RSVP message sequence of FIG.

FIG. 4 shows only one router of the relay node, but it is assumed that there are a plurality of relay nodes (routers) between the server and the receiver. In RSVP, a session having a multicast address or a unicast address is defined, and a bandwidth is reserved for this session. It is also assumed that the session information has been transmitted to all senders (information providing terminals) and receivers (information receiving terminals).

Hereinafter, a case where a session having a multicast address is set as a reservation target will be described.

A Receiver that supports RSVP assigns IGMP (Internet Group Management Protocol) to the multicast group of the session providing the information to be received.
Participate using. Here, IGMP is a protocol used when a host joins a multicast group or informs a router that it has joined.By exchanging IGMP messages, a router belongs to a multicast group to a host under its control. You can know if a host exists.

IGMP is a protocol standardized in RFC1112 of the IETF. For details, published by Takeshi Nishida, "TCP / IP Internetworking", Soft Research Center (199
3) and so on. Normally, stream data addressed to the multicast group reaches the receiver from the time the receiver joins the multicast group. However, since the band has not been reserved at the time of participation, data transmission guaranteeing QoS is not performed.

The Sender supporting RSVP periodically sends a Path message to the multicast address or unicast address of the session providing information, and the message is sent to all terminals subscribing to the session. Can be When joining the multicast group, the Path message is also delivered to Receiver. Pa
In each node through which the th message has passed, information of the Path message, the IP address of the previous node, and the like are described.

The Path message sent by Sender is Receive
receiver, the Receiver sends a Resv message that describes the band you want to secure, your IP address, etc.
Send to er. This Resv message is transferred to the Sender through the reverse path through which the Path message has passed according to the IP address described in each node. Resv message
Only upon arrival at the Sender is the end-to-end bandwidth secured.

The Sender that has received the Resv message transmits data in the transmission band specified by the Resv message. The stream data transmitted from the Sender is transferred through the secured route and delivered to the Receiver. The bandwidth reservation state of each node is maintained by a refresh message (Resv message or Path message) periodically transmitted from Receiver or Sender. Therefore, when the refresh message stops, the node automatically releases the bandwidth. When releasing the reserved band from the Receiver, a TearDown message (ResvTear) is sent to the Sender. Each node receiving this message releases the reserved bandwidth and sends the same message to the Sender node. All bands are released when the ResvTear message reaches the Sender.

As described above, by using the protocol for securing the bandwidth on the Internet, the bandwidth can be guaranteed on the Internet, and real-time data can be handled. See IETF for details on RSVP
It is described in Internet Draft (Jun. 14, 1997).

[0028]

When implementing an Internet access service in a communication network in which a dedicated and shared transmission line such as CATV and satellite communication can coexist, some shared transmission lines are used for the Internet access service. And a transmission method in which one shared transmission line is shared by a plurality of users. In this case, since the same transmission path is shared by multiple users, there is a limit on the bandwidth that can be used per person according to the number of users, and high-speed transmission of large-capacity data such as real-time streams is not possible with a shared transmission path. Have difficulty.

On the other hand, in order to realize real-time data communication that guarantees QoS on the Internet, a bandwidth reservation protocol RSVP (Resource ReSerVation PRS) that secures a certain bandwidth on the Internet for specific stream data is used.
rotocol) has been implemented. By using this RSVP, it is possible to reserve a band from a server on the Internet to a host connected on the Internet, and QoS is guaranteed in real-time data communication.

However, as described above, when an Internet access service such as CATV or satellite communication is used, even if a band on the Internet is secured by a bandwidth reservation protocol such as RSVP, a plurality of networks are not available in the CNW until the Internet is accessed. Since the data transmission is performed using the data transmission band shared by the users, there is a problem that the band is limited and QoS is not guaranteed.

[0031]

SUMMARY OF THE INVENTION A plurality of transmission lines in which two types of transmission lines are mixed, a dedicated transmission line in which one arbitrary terminal occupies one transmission line and a shared transmission line in which a plurality of terminals share one transmission line. Means for determining a transmission path of a data packet by a network layer address in a communication network in which a transmission path is shared by many terminals and can be connected to the Internet using a part of the shared transmission path; Means for dynamically allocating the dedicated transmission path to the terminal in response to a request from any terminal that wants to secure bandwidth on the Internet, and a data packet addressed to the terminal to which the dedicated transmission path is allocated. From the shared transmission line to a dedicated transmission line to which the terminal is assigned. It also has means for reserving a band on the Internet.

[0032]

FIG. 5 shows a CATV Internet access system according to a first embodiment of the present invention.
In this embodiment, DSM-CC is used for communication network management. DSM-CC (Dig
Ital StorageMedia Command and Control (International Organization for Standardization / International Electrotechnical Commission (ISO / IEC))
r-ganization for Standardization / International E
lec-trotechnical Commission), a DSM-CC UU (User-U) that establishes a logical connection (session).
ser) message and DSM-CC UN (User-Network) message that establishes a physical connection (resource). DS
Details of M-CC are ISO / IECJTC1 / SC29 / WG11 MPEG96 / M1806 Sev
illa 17-21 Feb., 1996.

In FIG. 5, 15 is a client session manager (hereinafter abbreviated as CSM), 16 is a session resource manager (hereinafter abbreviated as SRM), 17 is a server session manager (hereinafter abbreviated as SSM), 18 is The CATV center side transmission / reception control device, 19 is a subscriber terminal side transmission / reception control device, 20 is an Internet connection control device, 21 is an Internet connection device, and the rest is the same as FIG. The Internet connection device 21 is a device corresponding to the Internet connection device 7 in the CATV center shown in FIG.
The configuration shown in FIG.

The difference between the Internet connection device 21 and the Internet connection device 7 is that, as can be seen by comparing FIGS. 2A and 6A, the IP datagram addressed to the Internet access service subscriber is used for data transmission. In addition to the transmission port # 1 (for data transmission) for transmission to the band (shared transmission path), a plurality of transmission ports # 2, ..., #n for the exclusive transmission path are retained, and As shown in Fig. 6 (b), it has the function of managing RSVP, and Fig. 2 (b)
In addition to the same transmission port determination unit as above, it has a data copy unit for performing multicast address processing and an IP address determination unit. The IP address determination unit has an RSVP table as illustrated in FIG. 8B. That is the point. Here, it is assumed that a fixed frequency carrier is allocated to the transmission port for each exclusive transmission path.

Hereinafter, a subscriber who has been receiving an Internet access service using a shared transmission line similar to the conventional one has been able to secure a band on the Internet by using RSVP.
The outline of the procedure for switching the service to the bandwidth guaranteed type Internet access service) and receiving the multicast data from the information providing server on the Internet while guaranteeing the bandwidth will be described.

The subscriber uses the switch 14 in FIG. 5 to notify the CATV center 1 via the subscriber terminal 2 that he / she wants to receive the guaranteed bandwidth Internet access service. At that time, the multicast group providing the information you want to receive is
Notify with a message specifying the IP address (multicast address). Upon receiving the message, the CATV center 1 secures a transmission line that can be exclusively used by the subscriber who transmitted the message.

When the transmission path is secured, the Internet connection device 21 in the CATV center 1 searches for the IP address of the subscriber terminal 2 from the routing table entry and changes the value of the corresponding transmission port to the transmission path port value that has been secured. change. Thereafter, a pair of the IP address and the multicast address of the subscriber terminal 2 is added to the RSVP table as an entry. As a result, the IP datagram addressed to the subscriber is transferred not through the shared data transmission band but through the reserved exclusive band. Then, with a terminal on the Internet
Secure bandwidth on the Internet by exchanging RSVP messages. Hereinafter, details of each procedure will be described.

First, a procedure for a subscriber to secure an exclusive band in the CNW will be described. The subscriber uses the switch 14 to send a request message for the bandwidth guaranteed Internet access service to the subscriber terminal 2. At this time, the request message specifies the IP address of the multicast group to which the information desired by the subscriber is transmitted (hereinafter, abbreviated to the subscriber terminal 2 multicast address). The service selection control device 13 in the subscriber terminal 2 that has received the transmitted request message identifies the request as a bandwidth-guaranteed Internet access service request from the message content, and sends a new session opening message to the CSM 15. The message includes the IP address of the subscriber terminal 2 and the multicast address of the subscriber terminal 2.

The time from when the CSM 15 receives a new session establishment message until a new session is set up is shown in FIG.
Explanation will be given according to the DSM-CC UN message sequence. Here, in FIG. 7, Server is SSM 17, Network is SRM 1
6, Client refers to CSM 15. Upon receiving a new session opening request, CSM 15 sends a session opening request to ClientSess
Send an ionSetUpRequest message to SRM 16. At this time, User Data of ClientSessionSetUpRequest message
In the section, it is necessary to establish a session for Internet access service of bandwidth guarantee type and IP of subscriber terminal 2
The address and the multicast address of the subscriber terminal 2 are described.

Upon receiving the request, the SRM 16 checks whether a new session can be opened, and if a session can be opened, a ServerSessionSet to establish the session.
Send an UpIndication message to SSM 17. The User Data portion of this message also indicates that it is a bandwidth guaranteed Internet access service, the IP address of the subscriber terminal 2 and the multicast address of the subscriber terminal 2. Upon receiving the message, the SSM 17 checks the communication network resource information necessary for performing the bandwidth guaranteed Internet access service, and sends the SRM 16 in the ServerAddResourceRequest message.
Request that the required network resources be allocated.

The SRM 16 checks whether the requested communication network resources can be secured, and sends specific information on the secured exclusive bandwidth to the server.
In an AddResourceConfirm message and send it to SSM 17,
Request confirmation of secured network resources. SSM 17 checks the secured network resources, and places the result in SRM 16 as a ServerSessionSet.
Communicate with UpResponse message. Upon receiving this message, the SRM 16 transcribes the same content as the ServerSessionSetUpResponse message into the ClientSessionSetUpConfirm message, and transmits it to the CSM 15 as secured network resource information. This means that the exclusive bandwidth has been secured.

Next, a procedure for changing the transmission path for transferring the IP datagram addressed to the subscriber terminal 2 from the data transmission band, which is a shared band, to the reserved exclusive band will be described. When the occupied bandwidth of the subscriber terminal 2 is secured, the SSM 17 in FIG. 5 transmits a bandwidth change message including the secured network resource information, the IP address of the subscriber terminal 2 and the multicast address of the subscriber terminal 2 to the Internet connection control. Transmit to the device 20.

The Internet connection control device 20 specifies the transmission port of the Internet connection device 21 corresponding to the secured network resource from the correspondence table between the held network resource information and the transmission port of the Internet connection device 21. Then, the Internet connection control device 20 sends a routing table change message specifying the specified sending port, the IP address of the subscriber terminal 2 and the multicast address of the subscriber terminal 2 to the Internet connection device 21.

Upon receiving the message, the Internet connection device 21 compares the IP address contained in the message with the IP address entered in the routing table used by the transmission port determination unit in FIG.
Find the entry corresponding to 2. Then, the output port value in the entry is changed to the port value specified in the routing table change message, and a pair of the IP address and the multicast address is added to the RSVP correspondence table used in the IP address determination unit.

For example, the Internet connection device 21 is configured as shown in FIG.
When the Internet connection control device 20 holds the routing table of the subscriber terminal 2, the IP address (152.48.23.2) of the subscriber terminal 2, the multicast address of the subscriber terminal 2 (228.152.36.52), and the changed transmission port value (2 ) Is received. The Internet connection device 21 compares the IP address of the routing table entry with the IP address (152.48.23.2) in the message, and changes the port number (1) corresponding to the IP address (152.48.23.2) of the subscriber terminal 2 to the routing table. Change to the sending port value (2) in the message.

As a result, as shown in FIG.
Only the port number corresponding to the address is changed. Also,
As shown in FIG. 8B, the Internet connection device 21
A pair of the IP address of the subscriber terminal 2 and the multicast address (228.152.36.52) is added to the table for use.

On the other hand, the CSM 15 is a transmission / reception control device on the subscriber side.
At 19, a transmission channel change message including information on the exclusive bandwidth reserved for the subscriber terminal 2 is transmitted. The transmission / reception control device 19 that has received the information knows the new channel to which the IP datagram destined for the subscriber terminal 2 is sent from the correspondence table between the network resource information and the transmission channel that is held, and the transmission / reception device 9 describes the new channel. Send a change message.

The transmission / reception device 9 which has received the request is the subscriber terminal 2
Recognize new channels on which IP datagrams are carried,
It is possible to cut out the downlink channel specified by the channel change message from the multiplexed CATV transmission path 3. As described above, an exclusive band is reserved for the subscriber terminal 2 that has requested the bandwidth guaranteed type Internet access service, and the IP datagram addressed to the subscriber terminal 2 is routed to the exclusive band.

Next, a procedure for securing a band on the Internet will be described. When the bandwidth in the CNW has been secured, the Internet connection control device 20 transmits a multicast join request message to the Internet connection device 21 so as to join the multicast group on behalf of the subscriber terminal 2. The message describes the IP address of the subscriber terminal 2 and the multicast address of the subscriber terminal 2. RS of the Internet connection device 21 that received it
The VP manager creates an IGMP message and sends it to the router 5 to join the multicast group.

At this time, the router 5 adds a set of the IP address of the subscriber terminal 2, the multicast address of the subscriber terminal 2, and the IP address of the Internet connection device 21 corresponding to the next hop to its own routing table. The router 5 determines the IP datagram addressed to the subscriber in the CNW by the network address part of the IP address, and transfers / discards the IP datagram not addressed to the CNW.

The router 5 exchanges a multicast routing protocol with a router on the Internet, and has the router 5 transfer an IP datagram addressed to the multicast group to which the subscriber terminal 2 has joined. When joining a multicast group, this is an RSVP message addressed to the multicast group to which the subscriber terminal 2 has joined.
A Path message arrives at Router 5. The router 5 searches the routing table with the destination IP address (multicast address) described in the header of the arrived IP datagram, specifies the next hop, and transfers the Path message to the Internet connection device 21.

Upon receiving the message, the RSVP management unit of the Internet connection device 21 sends a Resv message, which is a reply of the Path message, to the Internet 4 on behalf of the subscriber terminal 2.
Send to. At this time, the information of the reservable bandwidth specified in the Path message is compared with the bandwidth secured in the CATV center, and a Resv message is created and transmitted with the smaller bandwidth as a reserved bandwidth.

When the Internet 4 is crowded and the band specified by the Resv message cannot be secured, an RSVP error message is sent from the Internet 4 to the Internet connection device 21. Internet connection device that received it
21 sends an error message to the Internet connection control device 20 that the band cannot be reserved.

The Internet connection control device 20 again executes Re
internet connection device to send sv message
Send a retry message to 21. The Internet connection device 21 that has received the message reduces the reserved bandwidth and sends out the Resv message again. If the bandwidth on the Internet is not secured and an error message arrives even if the bandwidth is changed three times and the bandwidth is reserved, the Internet connection control device 20 determines that the bandwidth on the Internet cannot be secured. Sends a network resource release message to the SSM 17 stating that the bandwidth on the Internet cannot be secured.

This message describes the IP address of the subscriber terminal 2, the multicast address of the subscriber terminal 2, and the secured network resource information. The SSM 17 receives the message, transmits the same message to the CSM 15 via the SRM 16, and notifies the CSM 15 via the service selection device 13 to the subscriber that the Internet bandwidth could not be secured. At the same time, the shared band secured in the CNW is released. The release procedure will be described later.

When the bandwidth on the Internet is secured,
The stream data is transmitted to the subscriber terminal 2 with the bandwidth secured from the information providing server on the Internet. The transmitted stream data is transferred to the router 5 along the path through which the Parh message has passed, and is delivered to the Internet connection device 21 via the router 5.

The Internet connection device 21 checks whether the destination IP address of the arrived IP datagram is a multicast address or a unicast address. If the destination IP address is a unicast address, it performs ordinary unicast address processing. FIG. 6 (b)
The multicast address processing shown in (1) is performed.

That is, the IP address determination unit searches the RSVP table using the destination IP address (multicast address) of the IP datagram destined for the multicast group that has arrived. If a hit is found, the data copy unit copies the IP datagram. Change the destination IP address to the IP address of the subscriber terminal specified from the RSVP routing table. This process is repeated to copy the IP datagrams that have arrived for the number of terminals that have joined the multicast group and transfer them to the IP processing unit. Thereafter, the transfer is performed in the same manner as in the conventional method. Here, the Internet connection device 21 is RS
Refresh periodically to maintain the bandwidth reserved by the VP
Sends a message and maintains the reserved bandwidth on the Internet on behalf of the subscriber.

Finally, the procedure for releasing the reserved exclusive bandwidth will be described with reference to the message sequence of FIG. Here, in FIG. 9, Server is SSM 1
7, Network is equivalent to SRM 16, Client is equivalent to CSM 15.

First, a case in which the subscriber terminal 2 terminates the bandwidth guaranteed Internet access service will be described. Here, a message sequence exchanged between the SSM 17, the SRM 16, and the CSM 15 is shown in FIG. The subscriber uses the switch 14 to instruct the service selection control device 13 to end the bandwidth guaranteed Internet access service. In response, the service selection control device 13 sends a session end message requesting the CSM 15 to end the session.

The CSM 15 receives the request and sends a ClientReleaseRequest, which is a session disconnection request, to the SRM 16. SR
M 16 sends a ServerReleaseIndication message to SSM 17 to request release of the session. The SSM 17 sends a bandwidth change message to the Internet connection controller 20 to stop using the communication network resources allocated to the subscriber terminal 2. The message describes the IP address of the subscriber terminal 2, the multicast address of the subscriber terminal 2, and the secured network resource information.

Internet connection control device receiving it
20 sends to the Internet connection device 21 a routing table correction message describing the IP address of the subscriber terminal 2 and the multicast address of the subscriber terminal 2. Upon receiving the message, the Internet connection device 21 rewrites the sending port paired with the IP address of the subscriber terminal 2 in the routing table to the data transmission band port # 1, and reads the subscriber terminal 2 and the corresponding multicast from the RSVP table. Delete an address.

On the other hand, the SSM 17 sends a ServerReleaseResponse message to the SRM 16 to request release of network resources. Upon receiving the message, the SRM 16 sends a ClientReleaseComfirm message to the CSM 15. The CSM 15 receives this and transmits a transmission channel correction message to the transmission / reception control device 19. In response, the transmission / reception control device 19 notifies the transmission / reception device 9 that the IP datagram addressed to the subscriber terminal 2 is multiplexed on the channel of the shared band. As a result, the data of the subscriber who has been receiving the band-guaranteed Internet access service is routed to the shared band for data transmission.

Next, the procedure for releasing the exclusive band since the RSVP cannot secure the band on the Internet will be described with reference to the message sequence of FIG. 9B. The Internet connection control device 20 that determines that the bandwidth on the Internet cannot be reserved transmits a network resource release message to the SSM 17 to release the bandwidth secured earlier. The message describes the IP address of the subscriber terminal 2, the multicast address of the subscriber terminal 2, and the secured network resource information.

Upon receiving the message, the SSM 17 sends a ServerReleaseRequest message, which is a session disconnection request, to the SR.
Send to M16. The SRM 16 sends a ClientReleaseIndication message to the CSM 15 to notify the release of the session.
The CSM 15 receives the request and controls the transmission / reception control device to stop using the network resources allocated to the session.
A transmission channel correction message is transmitted to 19.

In response, the transmission / reception control device 19 notifies the transmission / reception device 9 that the IP datagram addressed to the subscriber terminal 2 is multiplexed on the channel of the shared band. Also, CSM 15
Sends a ClientReleaseResponse message to SRM 16 and
RM 16 sends a ServerReleaseComfirm message to SSM 17. As a result, the reserved exclusive bandwidth is released,
The IP datagram addressed to the subscriber terminal that has secured the exclusive bandwidth is transferred using the data transmission bandwidth.

According to the present embodiment, it is possible to secure a band on the Internet and a band in the CNW from a terminal in the CNW that uses the band shared by a plurality of users for the Internet access service. This has the effect of realizing real-time communication.

[0068]

According to the present invention, in a system for providing an Internet access service using a shared band,
Bandwidth can be reserved, and Qo of real-time information such as video and audio stored on the Internet
A communication network controller that guarantees S can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional CATV Internet access system.

FIG. 2 is a configuration diagram of an Internet connection device 7;

FIG. 3 is a view showing an example of a routing table of the Internet connection device 7 shown in FIG. 1;

FIG. 4 is a diagram showing an example of a message sequence for securing, maintaining, and releasing a band by RSVP.

FIG. 5 is a diagram showing a CATV Internet access system according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram of the Internet connection device 21.

FIG. 7 is a diagram showing a session setup message sequence by DSM-CC UN in FIG. 5;

FIG. 8 is a diagram showing an example of a routing table of the Internet connection device 21.

FIG. 9 is a diagram showing a session release message sequence by DSM-CC UN.

[Explanation of symbols]

1… CATV center, 2… Subscriber terminal, 3… C
ATV transmission line, 4 ... Internet, 5 ... Router,
6 LAN within the center, 7 Internet connection device, 8 transmission / reception device, 9 transmission / reception device on the subscriber side,
10… Conversion device, 11… Application processing device,
12… Display, 13… Service selection control device,
14 ... Switch, 15 ... Client Session Manager (CSM), 16 ... Session Resource Manager
(SRM), 17… Server Session Manager (SSM), 18… CA
TV center side transmission / reception control device, 19 ... subscriber terminal side transmission / reception control device, 20 ... Internet connection control device, 21 ... R
Internet connection device with SVP, 21 (a)… IP
Terminating device.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukiyoshi Imura 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Japan

Claims (2)

[Claims] An exclusive transmission line in which one terminal occupies one transmission line and a shared transmission line in which a plurality of terminals share one transmission line coexist, and data packets are transmitted using the Internet protocol. Means for determining a data packet transmission path by a table that associates a network layer address with a transmission path in a communication network in which connection with another communication network such as the Internet is possible using a part of the shared transmission path. Means for dynamically allocating the dedicated transmission path to the terminal in response to a request from any terminal, and means for reserving a band on the other communication network. The transmission path of the data packet addressed to the terminal to which the transmission path is allocated is changed from the shared transmission path to the dedicated transmission path allocated by changing the table, and A communication network control device for performing communication with guaranteed service quality by using a band reserved by a unit for reserving a band on another communication network and a dedicated transmission line allocated by the transmission line allocating unit. . 2. The communication network control device according to claim 1, further comprising means for releasing a dedicated band allocated to said terminal when a band on the Internet cannot be secured. .