JP2009194495A - Multicast communication system and multicast communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multicast communication system and method, assigning priority corresponding to a transmission information quantity and processing an object having a larger transmission information quantity preferentially. <P>SOLUTION: According to the multicast communication system and the multicast communication method, a communications device is connected to a content distribution server 11 and a channel information distribution server 12 through a network 14, and a terminal device having a video image display means (video terminal unit 19 or terminal unit 17) is connected to the communications device. The channel information distribution server 12 comprises a means for distributing information containing a group ID and a multicast profile about content distribution. The communications device assigns priority corresponding to the transmission information quantity based on the group ID and the multicast profile of a multicast data frame distributed by a multicast filter 1, and enqueues it in the priority queue 3 to perform priority processing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multicast communication system and a multicast communication method capable of distributing real-time stream data such as live video with high efficiency to a plurality of communication terminal devices connected to a network.

  Various communication methods such as between communication terminal devices via a network or between a server and a communication terminal device are known. For example, a unicast communication method in which a server and a communication terminal device communicate one-to-one, a server and A multicast communication method in which a plurality of specific communication terminal devices communicate one-to-n, a broadcast communication method in a broadcast format between a server and a plurality of unspecified communication terminal devices, and the like are known. Is selected corresponding to. For example, when distributing real-time stream data from a television broadcast or the like to a specific number of users via the Internet or the like, a multicast communication method is applied.

  3A and 3B are explanatory diagrams of a conventional multicast communication system, where FIG. 3A is a main configuration of a multicast communication apparatus, FIG. 3B is an example of table contents of a classification unit, and FIG. 3C is an IGMP / MLD (Internet Group). (Management Protocol / Multicast Listener Discovery) frame, (D) indicates the main part of the multicast communication system, 32 is a classification unit, 33 is a priority queue, 34 is an output control unit, 41 is a content distribution server, 42 is channel information A distribution server 43 is a distribution network (CDN; Content Delivery Network), 44 is a network such as the Internet, 45 is a router, 46 is a multicast communication device, 47 is a terminal device such as a personal computer, 48 is Tsu-top box (STB; Set-Top Box), 49 is a video terminal such as a television receiver, 50 denotes an operation unit such as a remote controller. The multicast communication system has a configuration in which a plurality of other multicast communication devices 46 are connected via the network 44 and the router 45, but only one system is shown for the sake of simplicity.

  The content distribution server 41 has a function of distributing real-time stream data such as live video captured by a TV camera in a predetermined data format using a plurality of channels. The channel information distribution server 42 is distributed by the content distribution server 41. A group ID is distributed as channel information of real-time stream data. The multicast communication device 46 on the user side receives the group ID from the channel information distribution server 42 via the router 5, the network 44, and the distribution network 43. A channel is specified, and an IGMP / MLD frame of a participation request including a group ID corresponding to the channel is transmitted.

  As shown in FIG. 3C, the IGMP / MLD frame includes MAC (MAC header), IP (IP header), IGMP / (IGMP / MLD), Group (group ID), Payload, The field includes an FCS (frame check sequence) field. IGMP / MLD snooping is a group ID port that includes a group ID of a join request IGMP / MLD frame that requests distribution of real-time stream data. And snooping for enabling reception of a multicast data frame corresponding to the group ID.

  Further, as shown in FIG. 3A, the multicast communication device 46 has a main part of the reception function including the classification unit 32, the priority queue 33, and the output control unit 34, and the transmission function part is illustrated. Is omitted. The unicast data frame and the multicast data frame received via the router 45 (see FIG. 3D) are transferred to the classification unit 32. The classification unit 32 determines the priority corresponding to the received data type, and performs queuing for the priority queue 33 according to the priority. The classification unit 32 includes, for example, a table shown in FIG. This table shows the case where there are five levels of priority Priority # 0 to Priority # 4, and the queue number of the priority queue 33 for this priority is Queue # 0 to Queue # 4, for example, shown as VoIP Data, etc. Since the call data transmitted by the IP phone is transmitted by unicast and requires the most real-time property, the highest priority Priority # 4 is set, and SIP (Session Initiation) for connection control applied to this IP phone system is used. Protocol) and the like have the second priority Priority # 3, and the above-described multicast stream data has the medium priority Priority # 2 as a real-time multicast, VOD (Video On Demand), and VPN. (Virtual Private Network) data is the fourth priority Priority # 1, and the best-effort transmission data that does not guarantee the transmission band is the lowest priority Priority # 0.

  Therefore, the multicast stream data from the content distribution server 41 is distributed to the queue Queue # 2 of the third priority Priority # 2 of the priority queue 33 by the classification unit 32 of the multicast communication device 46, and this priority queue 33, which are output to the output control unit 34 in the order according to the priority of the queue Queue # 2, are subjected to error correction and decoding processing, and transferred to the video terminal device 49 as real-time stream data, for example, and the display screen Is displayed. As for the TV image included in the real-time multicast data in this case, for example, in the case of a TV image with 525 scanning lines (SD) or a full high-definition TV image with 1080 scanning lines (full HD) Are processed with the same priority as received data of real-time multicast.

  In multicast communication, as the number of users who request distribution of real-time stream data increases, the network system becomes large-scale. For this reason, a configuration for relay transmission is applied. In such a case, the relay device also has a multicast queue and priority control is applied. In that case, the relay transfer route configuration according to the presence or absence of a relay route selection switch or the like in the relay device. There has been proposed a means for avoiding blocking by providing a plurality of queues corresponding to the above and identifying a relay transfer path configuration based on relay transmission destination information and selecting a queue (see, for example, Patent Document 1). When multicast communication is performed via multiple lines with different transmission speeds, data with different priorities is sent in combination in each block, and when the bandwidth of the multicast destination line is narrow, etc. A method has been proposed in which a low-priority block is deleted and a high-priority block is preferentially transmitted to ensure the delivery of multicast data having a high priority (see, for example, Patent Document 2 and Patent Document 3). ).

  In addition, multicast packets and unicast packets transmitted through a common transmission path are restricted by destination and priority, and the transmission amount of the entire multicast packet is restricted with respect to the transmission allowance of the common transmission line to maintain a predetermined transmission quality. Means have been proposed (see, for example, Patent Document 4). Also, in a configuration in which a content server that provides single or multiple quality content is distributed to a multicast proxy device via the Internet, and is distributed from the multicast proxy device to a single or multiple terminal devices. According to the content request, the content server can be selected based on the available bandwidth and the weight or priority of the terminal device. By avoiding congestion on the content transmission path, stable video can be displayed on the display. A means has been proposed (see, for example, Patent Document 5).

In addition, a measurement is performed by connecting a transmission side shaver to which a single or multiple multicast packet transmission terminals are connected and a reception side shaver to which a single or multiple user reception terminals are connected, and transmitting from the transmission side shaver. By transmitting a response packet from the receiving-side shaver to the packet, RTT (Round Trip Time) between the transmitting-side shaver and the receiving-side shaver is measured, and based on the resulting transmission delay time, the transmitting-side shaver is measured. Has proposed means for obtaining an optimum data transmission rate and performing multicast packet communication according to the transmission rate (see, for example, Patent Document 6). A plurality of user side terminals are connected to a content distribution server via a layer 2 switch, a network, and a multicast router, and packets such as participation requests from user side terminals, response reports for participation confirmation, and withdrawal declarations after participation are layered. Transfers to the content distribution server via the transmission buffer of two switches, and when concentrated, discards and records without buffering by the transmission buffer, and priority is given to packets from the terminal on the user side where the number of discards is large Means for buffering and transfer control have been proposed (see, for example, Patent Document 7).
JP 2002-152199 A JP 2002-164925 A JP 2004-260298 A JP-A-2005-244601 JP 2006-246395 A JP 2006-340081 A JP 2007-189512 A

  In video distribution services that apply multicast communication, for example, digital terrestrial broadcasting is full high-definition broadcasting with a large amount of transmission information due to a large number of scanning lines, and the number of scanning lines is smaller and the amount of transmission information is also smaller. Hi-vision broadcasting and 1-segment broadcasting that minimizes the amount of transmission information by broadcasting using one segment in a 13-segment configuration are conventionally used as real-time multicast, for example, as shown in FIG. As shown in FIG. 2, the queue is queued as the same priority. Therefore, when congestion occurs due to a network failure or the like, the ratio of data loss for full high-definition broadcasts with the largest amount of transmission information in real-time multicast data becomes higher. Therefore, the larger the amount of transmission information, the higher the display image quality. There is a problem that the drop of the increase becomes large.

  The present invention aims to solve the above-mentioned conventional problems, and the higher the information transmission amount of a real-time multicast data packet, the higher the priority and the priority reception reception / reproduction processing is performed. Display image quality can be maintained.

  The multicast communication system of the present invention is a multicast communication system in which a content distribution server and a channel information distribution server are connected to a communication device via a network, and a terminal device having video display means is connected to the communication device, The information distribution server has means for distributing information including a group ID indicating a content distribution channel and a multicast profile indicating a transmission information amount of the content distribution channel, and whether the communication apparatus is a multicast data frame or not. Multicast filter that identifies and performs distribution processing, and for multicast data frames distributed by this multicast filter, the group ID and multicast profile of this multicast data frame A prioritization matrix unit for performing prioritized based on, and has a configuration including a priority queue for queuing multicast data frames prioritized by the prioritization matrix unit.

  The prioritization matrix unit identifies a transmission information amount based on a group ID and a multicast profile of a multicast data frame, and a plurality of steps for setting a higher priority as the transmission information amount increases. The prioritization matrix unit and means for transferring the multicast data frame whose priority is selected by the prioritization matrix unit to the queue area of the priority queue corresponding to the priority.

  In the multicast communication method of the present invention, a multicast is performed in which a content distribution server and a channel information distribution server are connected to a communication device via a network and a terminal device having video display means is connected to the communication device. A communication method, a process of performing information distribution including a group ID indicating a content distribution channel from a channel information distribution server and a multicast profile indicating a transmission information amount of the content distribution channel, and multicast data from the content distribution server The process of delivering content by frame and the multicast filter of the communication device received via the network identify whether it is a multicast data frame and Transfer to the prioritization matrix part, and this prioritization matrix part identifies the transmission information amount based on the group ID and the multicast profile, and the higher the transmission information amount, the higher the priority, A process of queuing data frames into a priority queue.

  Further, the amount of transmission information is identified based on the group ID and multicast profile of the multicast data frame received by the communication device via the network, and the higher the transmission information amount, the higher the priority. It includes a process of assigning priorities, and a process of queuing in a priority queue according to the priorities given by this process.

  Multicast data frames received by a communication device via a network include, for example, a large amount of transmission information such as Full Hi-Vision and a small amount of transmission information such as One Seg. Are identified based on the group ID and the multicast profile, and the higher the amount of transmission information, the higher the priority and the higher priority is processed by queuing. The display image quality of a video terminal device such as a television receiver can be maintained.

  The multicast communication system of the present invention will be described with reference to FIG. 1. The content distribution server 11 and the channel information distribution server 12 are connected to a communication device (priority multicast communication device 16) via a network 14, and this communication is performed. A multicast communication system in which a terminal device having a video display means (video terminal device 19 or terminal device 17) is connected to the device, the channel information distribution server 12 includes a group ID indicating a content distribution channel and the content distribution channel Means for distributing information including a multicast profile indicating the amount of transmission information, and the communication device identifies a multicast data frame, a unicast data frame, and a broadcast data frame, and performs a distribution process. A prioritization matrix unit 5 that prioritizes the filter 1 and the multicast data frame distributed by the multicast filter 1 based on the group ID and multicast profile of the multicast data frame; This configuration includes a priority queue 3 for queuing multicast data frames prioritized by the prioritization matrix unit 5.

  In the multicast communication method of the present invention, the content distribution server 11 and the channel information distribution server 12 are connected to the communication device (priority multicast communication device 16) via the network 14, and the communication device has a video display means. A multicast communication method in which multicast communication is performed by a configuration in which devices (terminal device 17 and video terminal device 19) are connected, and includes a group ID indicating a content distribution channel from channel information distribution server 12, and an amount of transmission information of the content distribution channel A process of delivering information including a multicast profile indicating the content, a process of delivering content by a multicast data frame from the content delivery server 11, and a multicast filter of a communication device received via the network 14 Thus, it is identified whether or not it is a multicast data frame, and the multicast data frame is transferred to the prioritization matrix unit 5, and this prioritization matrix unit 5 uses the group ID and the multicast profile as a basis. The process includes identifying the amount of transmission information, and increasing the priority as the amount of transmission information increases, and queuing multicast data frames to the priority queue 3.

  1A and 1B are explanatory diagrams of Embodiment 1 of the present invention, where FIG. 1A is a main configuration of a priority multicast communication device, FIG. 1B is an IGMP / MLD (Internet Group Management Protocol / Multicast Listener Discovery) frame, C) indicates a multicast communication system, 1 is a multicast filter, 2 is a classification unit, 3 is a priority queue, 4 is an output control unit, 5 is a prioritization matrix unit, 11 is a content distribution server, and 12 is a channel. Information distribution server, 13 is a content distribution network, 14 is a network such as the Internet, 15 is a router, 16 is a priority multicast communication device as a communication device, 17 is a terminal device such as a personal computer, 18 is a set top box (STB), 19 Denotes a video terminal device such as a television receiver, and 20 denotes an operation unit such as a remote controller. Note that the terminal device 17 such as a personal computer and the video terminal device 19 are terminal devices having video display means, and the multicast communication system is connected to a plurality of routers 15 connected to the network 14 and these routers 15 respectively. The priority multicast communication device 16 is included, but is illustrated as a one-system configuration for simplification.

  The main parts of the priority multicast communication apparatus shown in FIG. 1A include a multicast filter 1, a classification unit 2, a priority queue 3, an output control unit 4, and a prioritization matrix unit 5. Including, only the main part of the reception function is shown, and the other reception functions and transmission functions are not shown in the figure, but various configurations that are already known can be applied to the configurations that are not shown in the figure. it can. The IGMP / MLD frame shown in FIG. 1B includes a MAC header (MAC Header), an IP header (IP Header), an IGMP / MLD field, a group ID field (Group ID), and a multicast field (Multicast). ), Payload (Payload), and frame check sequence (FCS) fields, and indicates an IGMP / MLD frame in the upstream direction, as indicated by “UP stream” and “For Network”.

  “Enhanced IGMP / MLD snooping” indicates processing by IGMP / MLD frame snooping by the prioritization matrix unit 5 and requests the multicast content distribution server 11 to participate in multicast distribution and to cancel multicast distribution. The group ID (Group) field and the multicast (Multicast) field of the IGMP / MLD frame at the time of the declaration of leaving to be snooped as shown as “IGMP / MLD snooped field”, and at the time of participation request, it corresponds to the group ID Open the port, and when leaving, close the port corresponding to the group ID. Further, the prioritization matrix unit 5 gives priority to the received multicast data frame to the classification unit 2 as shown as “Group ID + Profile → Priority” by the group ID (Group) field and the multicast (Multicast) field. The degree (Priority) is notified.

  Therefore, the prioritization matrix unit 5 identifies the transmission information amount by the multicast data frame based on the group ID and the multicast profile so that the one having a large transmission information has a higher priority. Prioritize and transfer to the classification unit 2. As the priority, for example, as shown in the table format of FIG. 2, a multicast data frame is also set in a plurality of stages. In this case, the priority including the unicast data frame is set to eight priority levels Priority # 0 to Priority # 7, and the IP phone when performing a voice call such as VoIP Data of the data type is multicast. Although it is not data, the highest priority Priority # 7 is set, and the SIP (Session Initiation Protocol) for connection control applied to this IP phone is set to the second priority Priority # 6.

  In the case of the bit rate (transmission information amount) equivalent to the full high-definition (full HD) image quality of the real-time multicast data frame in the aforementioned multicast stream data, the highest priority type of multicast data frame is In the case of a priority Priority # 5 and a bit rate (transmission information amount) equivalent to the next high-definition (HD) image quality, the next priority Priority # 4 is assumed and the bit rate (equivalent to the next DVD (Digital Video Disc) image quality) In the case of (transmission information amount), the fifth priority Priority # 3 is set, and in the case of a bit rate (transmission information amount) equivalent to one seg, the sixth priority Priority # 2 is set. For non-real-time multicast data frames, data such as voice of demand VoD can be set to the seventh priority Priority # 1, and best effort data can be set to the lowest priority Priority # 0. . That is, for a real-time multicast data frame, in response to the transmission information amount, the larger the transmission information amount, the higher the priority is processed. It is possible to further increase the priority level, but since the distribution control becomes complicated while securing the queue area of the priority queue 3, the minimum priority is required as the data type of the real-time multicast data frame. A multi-level setting is desirable. Further, the case where the priority Priority and the queue numbers Queue # 7 to Queue # 0 of the priority queue 3 are associated with each other is shown, but the priority queue 3 is configured to associate the priority Priority with a plurality of queues. You can.

  The multicast communication system shown in FIG. 1C includes a content distribution server 11, a channel information distribution server 12, a content distribution network 13, a network 14 such as the Internet, a router 15, and a priority multicast communication device 16. And a terminal device 17 such as a personal computer, a set top box (STB) 18, a video terminal device 19 such as a television receiver, and an operation unit 20 such as a remote control. As described above, the channel information distribution server 12 includes the reception processing unit shown in FIG. 1A, and the channel information distribution server 12 includes a group ID (channel information) indicating a content type distributed from the content distribution server 11. , A multicast profile indicating the amount of transmission information is sent to the terminal device 17 Video reception software of the set top box 18 in which has the function of pre-notification to recognize.

  The priority multicast communication device 16 receives the group ID from the channel information distribution server 12 and the multicast profile, includes the content information that can be distributed from the content distribution server 11 and the video display means. The terminal device 17 or the video terminal device 19 has a function of displaying, and the group ID corresponding to the displayed content distribution content is specified by the terminal device 17 or the operation unit 20 to request participation in the content distribution service As a result, the IGMP / MLD frame (see FIG. 1B) of the participation request is transmitted from the priority multicast communication device 16 to the content distribution server 11, and the group ID is snooping as described above. Open the corresponding port and prioritization matrix section 5 The request IGMP / MLD frame snooping, and notifies the priority corresponding to the group ID to the classification unit 2. It should be noted that already known means for the sequence of transmission of IGMP / MLD frames for participation requests and departure declarations to the content distribution server 11 side, and the transmission of confirmation frames from the content distribution server 11 side, etc. Can be executed.

  When the priority multicast communication device 16 receives data multicast from the content distribution server 11 in accordance with the participation request, the multicast filter 1 of the priority multicast communication device 16 sends the multicast data frame to the prioritization matrix unit 5. The unicast data frame and the broadcast data frame are distributed and transferred to the classification unit 2. The prioritization matrix unit 5 identifies the data type of the multicast data frame by the group ID and the multicast profile, determines the priority by referring to the contents shown in the classification table format shown in FIG. To the queue area of the priority queue 3 corresponding to the priority. The output control unit 4 reads data preferentially from the high priority queue area of the priority queue 3 and transfers the data to a subsequent processing circuit (not shown). The subsequent processing circuit performs error correction and decoding processing, transfers the data to the terminal device 17 or the video terminal device 19, and displays it on the display screen.

  Therefore, for real-time multicast data frames, the amount of transmission information is large, for example, the one corresponding to full high-definition broadcasting is assigned the highest priority among real-time multicast data frames of the data type, Since other low-priority received data is preferentially processed, even if there is a delay due to network congestion, etc., it is possible to avoid deterioration of the image quality of the screen displayed on the terminal device 17 or the video terminal device 19 It becomes possible to do.

It is explanatory drawing of Example 1 of this invention. It is explanatory drawing of the table of the prioritization matrix part of Example 1 of this invention. It is explanatory drawing of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multicast filter 2 Classification part 3 Priority queue 4 Output control part 5 Prioritization matrix part 11 Content distribution server 12 Channel information distribution server 13 Content distribution network 14 Network 15 Router 16 Priority multicast communication apparatus 17 Terminal apparatus 18 Set top Box (STB)
19 Video terminal device 20 Operation unit

Claims (4)

In a multicast communication system in which a content distribution server and a channel information distribution server are connected to a communication device via a network, and a terminal device having video display means is connected to the communication device.
The channel information distribution server has means for distributing information including a group ID indicating a content distribution channel and a multicast profile indicating a transmission information amount of the content distribution channel,
The communication device identifies a multicast data frame and performs distribution processing, and a multicast data frame group ID and multicast for the multicast data frame distributed by the multicast filter A configuration including a prioritization matrix unit that prioritizes based on a profile, and a priority queue that queues the multicast data frames prioritized by the prioritization matrix unit A multicast communication system.   The prioritization matrix unit identifies a transmission information amount based on the group ID of the multicast data frame and the multicast profile, and sets a higher priority as the transmission information amount increases. A prioritization matrix unit for performing prioritization of stages, and a means for transferring the multicast data frame whose priority is selected by the prioritization matrix unit to a queue area of the priority queue corresponding to the priority; The multicast communication system according to claim 1, comprising: In a multicast communication method for performing multicast communication with a configuration in which a content distribution server and a channel information distribution server are connected to a communication device via a network, and a terminal device having video display means is connected to the communication device.
A process of performing information distribution including a group ID indicating a content distribution channel and a multicast profile indicating an amount of transmission information of the content distribution channel from the channel information distribution server;
A process of delivering content by multicast data frames from the content delivery server;
The multicast filter of the communication device received via the network identifies whether the data frame is a multicast data frame, forwards the multicast data frame to the prioritization matrix unit, and the prioritization matrix Identifying the amount of transmission information by the unit based on the group ID and the multicast profile, increasing the priority as the amount of transmission information increases, and queuing the multicast data frame in a priority queue; A multicast communication method comprising:   The transmission information amount is identified based on the group ID and the multicast profile of the multicast data frame received by the communication device via the network, and the higher the transmission information amount, the higher the priority. 4. The multicast communication method according to claim 3, further comprising a step of performing prioritization in a plurality of stages and a step of queuing in a priority queue according to the priority given by the step.

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