JP2006013912A - Stream data distributing method, steam data distributing apparatus, stream data control apparatus, program and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a view interrupting time in a client, when there is abnormality of the stream distributing server itself or the distributing function. <P>SOLUTION: A stream control apparatus 200 monitors to check whether a packet received from a stream distributing server 100A is a packet to be monitored. As a result, if it is detected that a stream packet does not arrive normally when it is the packet to be monitored, the apparatus 200 transmits a rewrite requesting message to a stream distributing server 100B. Upon receiving the message, the server 100B analyzes the rewrite request message, adds the IP address of a rewrite destination to a rewrite list, and rewrites the Source IP Address of the IP header of this packet, in accordance with the rewrite list, if an IP packet to be sent to a client 300 is the packet to be written. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stream distribution network for sending stream packets from one or a plurality of stream distribution servers or stream relay servers to clients or stream relay servers using multicast.

  Conventionally, when performing large-scale stream live broadcasting on the Internet, generally, if the stream distribution server itself or the distribution function stops abnormally and stream packets cannot be transmitted from the stream distribution server, A redundant configuration is adopted in which a stream packet is transmitted from the stream distribution server to shorten the interruption time of the stream live broadcast service.

  As a redundancy method, when a stream distribution server itself or the distribution function abnormally terminates, the client connects to another stream distribution server, so that the stream packet from a stream distribution server different from the stream distribution server that has terminated abnormally There is a way to send. Examples of stream media having the above functions include Windows Media from Microsoft and Real Media from Real Network (see Non-Patent Document 1).

  As another redundancy method, there is a method called clustering in which a plurality of stream distribution servers are connected to each other and virtually behave as one stream distribution server (see Non-Patent Document 2). This clustering will be described with reference to FIG. 5, FIG. 6, and FIG.

  FIG. 5 is a diagram illustrating an operation example when the active stream distribution server fails when clustering is not used. When the client 500 is connected to the active stream distribution server 400A and receives a stream packet from the active stream distribution server 400A, if a failure occurs in the active stream distribution server 400A, the client 500 causes the active stream distribution server 400A to Stream packets cannot be received. Thereafter, the client 500 can receive the stream packet from the switching destination stream distribution server 400B by connecting to the switching destination stream distribution server 400B.

  FIG. 6 is a diagram illustrating an operation example when a working stream server fails when clustering is used. In this case, since the active stream distribution server 400A and the switching destination stream distribution server 400B are recognized as one stream distribution server (cluster node) by the client 500, the client 500 automatically connects to the cluster node. Are connected to the working stream distribution server 400A and receive stream packets from the working stream distribution server 400A. When the client 500 receives a stream packet from the active stream distribution server 400A, if a failure occurs in the active stream distribution server 400A, the client 500 can receive the stream packet from the active stream distribution server 400A. Disappear. At this time, the switching destination stream distribution server 400B automatically recognizes that the working stream distribution server 400A has failed, and automatically switches the switching destination stream distribution server 400B to the current one (failover). Thereafter, the client 500 automatically connects to the switching destination stream distribution server 400B by receiving a stream packet from the switching destination stream distribution server 400B by reconnecting to the cluster node instead of the switching destination stream distribution server 400B. Will be able to.

  FIG. 7 is a diagram illustrating an example of a clustering mechanism. Both the clustered current stream server 400A and the switching destination stream distribution server 400B include a process monitoring unit. The process monitoring unit monitors whether or not the process (application) that distributes the stream packet of the server itself is alive, and the process monitoring unit of the active stream server 400A determines the monitoring state of the switching destination stream distribution server 400B. The process monitoring unit of the switching destination stream delivery server 400B periodically notifies the process monitoring unit of the current stream server 400A. Here, if the process monitoring unit of the switching destination stream distribution server 400B does not receive a status notification (heartbeat) from the process monitoring unit of the active stream server 400A for a certain period of time, the active stream server 400A is down. The switching destination stream distribution server 400B is switched to the current use. In addition, when the status notification (heartbeat) from the process monitoring unit of the active stream server 400A is received as a process down abnormality notification, the process monitoring unit of the switching destination stream distribution server 400B sets the switching destination stream distribution server 400B to be active. Switch.

By the way, when performing stream live broadcasting on the Internet, a stream packet of the same content is transferred from the stream distribution server to a plurality of clients. At this time, the stream distribution server serves as a means for transferring the stream packet to each client. There are a case where unicast for transferring stream packets is used and a case where a stream distribution server uses multicast for transferring stream packets to a plurality of clients. In the case of multicast, the stream distribution server does not need to send stream packets to each of a plurality of clients, so the bandwidth of the network to be used can be greatly reduced compared to unicast.
Real Network, "Helix Universal Server Administration Guide", [online], [Search April 5, 2004], Internet <http://service.real.com/help/library/guides/helixuniversalserver/realsrvr .htm> Microsoft, “Network Load Balancing Technology”, [online], [Search January 8, 2004], Internet <URL: http://download.microsoft.com/download/win2000platform/Utility/1.00/NT5/EN/ nlbtech2.exe>

  In the above-described conventional technology, when the stream distribution server itself or the distribution function is abnormal, the client disconnects the stream distribution server, thereby discarding all stream packets stored in the buffer, and another stream distribution server. Since the stream packet received from the stream distribution server starts to be accumulated again in the buffer by newly connecting to the network, viewing cannot be resumed by the client until the stream packet is accumulated in the buffer.

  Clustering can detect abnormalities in the stream distribution server itself and hardware and processes, but it cannot detect abnormalities in the stream packet sent by the stream distribution server, so the stream packet transmission is rough. Even if it was dropped or dropped, the streaming server did not switch, and the viewing quality of the client continued to deteriorate.

  Further, in the clustering, the connection from the client to the stream distribution server is indispensable when the switching destination stream distribution server starts sending the stream packet. When sending a stream packet from a stream distribution server to a client by multicast, the client does not send a connection request message or a stream control message to the stream distribution server, so there is no opportunity to switch the stream distribution server, and the stream distribution server itself And the client was unable to resume viewing when the distribution function was abnormal.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a stream data distribution method for reducing the viewing interruption time at the client when the multicast is used for transferring the stream packet from the stream distribution server to the client and the stream distribution server itself or the distribution function is abnormal. A stream control device, a stream distribution device, a program, and a recording medium.

In the present invention, a stream control device monitors stream packets received from a stream distribution server or a stream relay server (hereinafter collectively referred to as a stream distribution server) that transmits stream packets using multicast, and the stream packets are normally delivered. When it is detected that there is not, a rewrite request message is transmitted to the stream distribution server and the switching destination stream distribution server. The stream distribution server that sends the stream packet using multicast analyzes the rewrite request message sent from the stream control device, adds the multicast IP address and rewrite destination IP address to the rewrite list, and processes them by the IP processing unit. Before transmitting the IP packet to the client, it is determined from the rewrite list whether the packet is a rewrite target packet. In the case of a rewrite target packet, if the rewrite IP address of the rewrite list is null, the packet is discarded. If the rewrite IP address of the rewrite list is not null, the source IP address of the IP header of the packet is discarded. The field value is rewritten to the rewritten IP address and transmitted to the client.

  When multicast is used for transfer of stream packets from the stream distribution server to the client, when the stream packet is not periodically transmitted from the stream distribution server, the same destination multicast IP as the stream packet transmitted by the stream distribution server Stream packets with the same source IP address as the address can be sent from the destination stream distribution server, so the client does not need to reconnect to the stream distribution server and switches without discarding the stream packets stored in the buffer. Stream packets can be received from the previous stream distribution server. As a result, it is possible to reduce the viewing interruption time at the client when the stream distribution server itself or the distribution function is abnormal.

  According to the present invention, it is not necessary to provide special operations and means on the client side, and it is possible to reduce the viewing quality degradation time and the viewing interruption time in the client when the stream distribution server itself or the distribution function is abnormal. It becomes.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a connection configuration example of each device in the present invention. 100A and 100B are stream delivery servers that send stream packets to the client 300 using multicast. The stream delivery servers that currently send stream packets to the client 300 using multicast are 100A and the stream delivery server 100A. Assume that the stream distribution server that sends a stream packet to the client 300 using multicast is replaced with 100B instead of the stream distribution server 100A when the process ends abnormally. Similar to the client 300, the stream control device 200 has a function of receiving stream packets sent by the stream distribution servers 100A and 100B using multicast.

  FIG. 2 is a diagram illustrating a block configuration example of the stream control apparatus 200. As shown in FIG. 2, the stream control apparatus 200 includes a reception unit 211, a monitoring packet determination unit 212, a monitoring rewrite list 213, a rewrite determination unit 214, a rewrite request unit 215, and a transmission unit 216, and includes a transmission unit 216 and a reception unit. Through 211, packets are transmitted to and received from the stream distribution servers 100A and 100B.

  The reception unit 211 passes the packet received from the stream distribution server 100A to the monitoring packet determination unit 212. The monitoring packet determination unit 212 determines whether or not the packet is a monitoring target packet from the monitoring rewrite list 213, and when it is a monitoring target packet, passes it to the rewriting determination unit 214. An example of the monitoring rewrite list 213 in this embodiment is shown in Table 1.

  In the present embodiment, when the values of the Destination IP Address field and the Source IP Address field of the IP header of the received packet match the multicast IP address and the source IP address in the monitoring rewrite list 213, the monitoring target packet It is judged that. The rewrite determination unit 214 monitors whether the monitoring target packet has arrived normally. If the packet to be monitored does not arrive normally, the rewrite determination unit 214 passes information on the packet to the rewrite request unit 215. In this embodiment, when the monitoring target packet does not arrive for a predetermined time (for example, 5 seconds) or more, it is determined that the monitoring target packet does not normally arrive. In this embodiment, the packet information to be passed to the rewrite request unit 215 is the values of the Destination IP Address field and the Source IP Address field of the IP header of the packet. The rewrite request unit 215 generates two rewrite request messages from the packet information passed from the rewrite determination unit 214, and transmits the messages to the stream distribution server 100A and the switching destination stream distribution server 100B through the transmission unit 216, respectively. . As shown in Table 2, an example of the rewrite request message in this embodiment is that the first 32 bits of the TCP data are the multicast IP address, the subsequent 32 bits are the rewrite destination IP address, and the value of the Destination Port field of the TCP header is 3000.

  In the present embodiment, the rewrite request message to be transmitted to the stream distribution server 100A includes the value of the Destination IP Address field of the IP header passed from the rewrite determination unit 214 as the multicast IP address, the rewrite destination IP address as null, and the rewrite determination unit. The value of the Source IP Address field passed from 214 is set as the transmission destination of the rewrite request message (stream distribution server 100A), and the rewrite request message transmitted to the switching destination stream distribution server 100B is transferred from the rewrite determination unit 214. The value of the Destination IP Address field and the Source IP Address field of the IP header is set as the multicast IP address and the rewrite destination IP address, respectively, and the switching destination at this time The IP address is searched from the monitoring rewrite list 213, and the searched switching destination IP address is set as the transmission destination (stream distribution server 100B) of the rewrite request message.

  FIG. 3 is a diagram illustrating a block configuration example of the stream distribution servers 100A and 100B.

  As shown in FIG. 3, the stream distribution servers 100A and 100B include a receiving unit 111, an IP processing unit 112, a TCP / UDP processing unit 113, a rewrite request analyzing unit 114, a list writing unit 115, a rewriting list 116, and a stream packet processing unit 117. The rewrite unit 118 and the transmission unit 119 are used to transmit and receive packets to and from the stream control device 200 and the client 300 through the transmission unit 119 and the reception unit 111.

  The rewrite request message received from the stream control device 200 through the receiving unit 111 is processed by the IP processing unit 112 in accordance with the IP protocol, and the TCP / UDP processing unit 113 performs TCP protocol and UDP packet respectively on the TCP protocol, The processing defined by the UDP protocol is performed and passed to the rewrite request analysis unit 114. The rewrite request analysis unit 114 passes the multicast IP address and the rewrite destination IP address from the rewrite request message to the list writing unit 115. In the present embodiment, a packet having a Destination Port field value of 3000 in the TCP header is determined to be a rewrite request message, the first 32 bits of the TCP data of the packet are the multicast IP address, and the subsequent 32 bits are the rewrite destination IP address. To do. The list writing unit 115 adds the multicast IP address and the rewriting destination IP address passed from the rewriting request analyzing unit 114 to the rewriting list 116. An example of the rewrite list 116 in the present embodiment is shown in Table 3.

  The stream packet processed by the stream packet processing unit 117 is processed in the order of the TCP / UDP processing unit 113 and the IP processing unit 112, and before being transmitted to the client 300, the rewriting unit 118. Passed to. The rewrite unit 118 determines whether or not the packet is a rewrite target packet from the rewrite list 116, and if it is a rewrite target packet, rewrites the value of the Source IP Address field of the IP header of the packet according to the rewrite list 116. When the value of the Source IP Address field of the IP header of the rewritten packet is null, the packet is discarded, and when the value of the Source IP Address field of the IP header of the rewritten packet is not null, the packet is The data is transmitted to the client 300 through the transmission unit 119. If the packet is not a rewrite target packet, the packet is sent to the transmission unit 119 without any processing and transmitted to the client 300. In the present embodiment, the IP address of the packet passed from the IP processing unit 112 is searched for whether the value of the Destination IP Address field in the IP header matches the multicast IP address in the rewrite list 116. If there is a packet, it is determined that the packet is a rewrite target packet, and the value of the Source IP Address field of the IP header of the packet is rewritten to the rewrite destination IP address of the rewrite list 116 at that time. In the present embodiment, the value of the Source IP Address field in the IP header of the rewritten packet is a value other than null for the stream distribution server 100A and null for the stream distribution server 100B.

  In the embodiment, the stream distribution server and the stream control device are separated, but the stream distribution server has the function of the stream control device, and the stream control device 200 of FIG. There may be a configuration in which 100B and the stream control device 200 are one. When the stream distribution server 100B and the stream control device 200 are configured as one, the rewrite information may be directly passed from the rewrite determination unit 214 of the stream control device 200 to the list writing unit 115 of the stream distribution server 100B. In this case, the rewrite list 116 of the stream distribution server 100B may also serve as the monitoring rewrite list 213 of the stream control device 200.

  In the embodiment, information writing means to the monitoring rewrite list 213 is not particularly described, but it is only necessary to include writing means (for example, INI file) according to the system.

  In the above embodiment, the condition for determining that the monitoring target packet does not normally arrive in the rewrite determining unit 214 is a case where the monitoring target packet has not arrived for a predetermined time (for example, 5 seconds). Depending on the conditions, other conditions (for example, when a predetermined number of monitoring target packets arrive within a unit time) may be added or other conditions may be added to be a plurality of conditions.

  Further, in the above-described embodiment, a means for setting a condition threshold for determining that the monitoring target packet does not normally reach in the rewrite determining unit 214 (for example, determining that the monitoring target packet does not normally reach does not reach the monitoring target packet) And means for setting the time) are not particularly described, but it is only necessary to provide writing means according to the system.

  In the above embodiment, the monitoring rewrite list 213 is as shown in Table 1. However, the format is not limited as long as there is a multicast IP address, a rewrite destination IP address, and a transmission destination IP address. In the above embodiment, the rewrite request message is as shown in Table 2. However, the order and the format are not limited as long as the multicast IP address and the rewrite destination IP address are present. Further, the value of the Destination Port field of the TCP header may be other than 3000, and may be UDP instead of TCP.

  In the above-described embodiment, only the value of the Source IP Address field of the IP header is rewritten by the rewriting unit 118, but a multicast IP address may be rewritten.

  In the embodiment, the switching destination stream distribution server has a single configuration, but a plurality of configurations may be used. An embodiment in this case will be described with reference to FIG.

  FIG. 4 is a diagram illustrating an example of a block configuration of the stream control apparatus. The stream control apparatus according to the previous embodiment includes a switching information reading unit 217. The rewrite request unit 215 generates the IP data of the rewrite request message, and then passes the multicast IP address and rewrite destination IP address of the message to the switching information reading unit 217. The switching information reading unit 217 searches for the next switching destination IP address whose next switching destination flag is 1 from the monitoring switching list 213 shown in Table 4 with the multicast IP address and the rewriting destination IP address, and rewrites the switching destination IP address. It passes to the request unit 215. At this time, the switching information reading unit 217 sets the next switching destination flag which is 1 in the monitoring switching list 213 to 0, and changes the next switching destination flag from 0 to 1.

  In the above embodiment, one stream content to be monitored is described as one. However, a configuration in which a plurality of stream contents are monitored and controlled by one stream control device may be possible.

  Moreover, in the said embodiment, although the stream content to deliver is described as one, the structure by which a some stream content is delivered by a stream delivery server can also exist.

  In the embodiment, the packet is rewritten when the value of the IP header Source IP Address field of the packet rewritten by the rewriting unit 118 of the stream distribution servers 100A and 100B is null, but another value (for example, 127) is used instead. 0.0.1).

  In addition to the functions of the stream control device and the stream distribution server realized by dedicated hardware, a program for realizing the functions is recorded on a computer-readable recording medium and recorded on the recording medium. The read program may be read into a computer system and executed. The computer-readable recording medium refers to a recording medium such as a flexible disk, a magneto-optical disk, and a CD-ROM, and a storage device such as a hard disk device built in a computer system. Furthermore, a computer-readable recording medium is a server that dynamically holds a program (transmission medium or transmission wave) for a short period of time, as in the case of transmitting a program via the Internet, and a server in that case. Some of them hold programs for a certain period of time, such as volatile memory inside computer systems.

It is a block diagram of the stream data delivery system of one Embodiment of this invention. It is a block block diagram of the stream control apparatus in FIG. It is a block block diagram of the stream delivery server in FIG. It is another block block diagram of a stream control apparatus. It is a block diagram of the prior art example of a stream data delivery system. It is a block diagram of the other conventional example of a stream data delivery system. It is a block diagram of the stream delivery server in FIG. 5, FIG.

Explanation of symbols

100A, 100B Stream distribution server 111 Receiving unit 112 IP processing unit 113 TCP / UDP processing unit 114 Rewrite request analyzing unit 115 List writing unit 116 Rewriting list 117 Stream packet processing unit 118 Rewriting unit 119 Transmitting unit 200 Stream control device 211 Receiving unit 212 Monitoring packet discrimination unit 213 Monitoring rewrite list 214 Rewrite determination unit 215 Rewrite request unit 216 Transmission unit 217 Switching information reading unit 300 Client

Claims (10)

In a stream distribution network that sends stream packets from one or more stream distribution servers or stream relay servers to clients or stream relay servers using multicast,
In the stream control device,
It is determined whether the packet received from the stream distribution server or the stream relay server is a packet to be monitored, and when the packet is the packet to be monitored, the packet is monitored to confirm that the stream packet does not reach normally. If detected, send a rewrite request message to the stream delivery server or stream relay server and the switching destination stream delivery server or stream relay server,
At the stream delivery server or stream relay server,
The rewrite request message sent from the stream control device is analyzed, the multicast IP address and the rewrite destination IP address are added to the rewrite list, and the IP packet processed by the IP processing unit is sent to the client before being sent to the client. Whether the packet is a rewrite target packet is determined from the rewrite list. When the packet is a rewrite target packet, the value of the Source IP Address field of the IP header of the packet is rewritten according to the rewrite list, and the IP header of the rewritten packet is rewritten. A stream data distribution method comprising: discarding the packet when the value of the Source IP Address field of the packet is null, and transmitting the packet to the client when the value is not null.   The stream data delivery method according to claim 1, wherein not only the value of the Source IP Address field of the IP header of the rewrite target packet but also the value of the Destination IP Address field are simultaneously rewritten by the stream delivery server or the stream relay server. In a stream distribution network that sends stream packets from one or more stream distribution servers or stream relay servers to clients or stream relay servers using multicast,
In the stream control device, it is determined whether the packet received from the stream distribution server or the stream relay server is a packet to be monitored, and when the packet is the packet to be monitored, the packet is monitored, and the stream packet A stream control method comprising: transmitting a rewrite request message to the stream distribution server or stream relay server and the switching destination stream distribution server or stream relay server when it is detected that the message does not reach normally. In a stream distribution network that sends stream packets from one or more stream distribution servers or stream relay servers to clients or stream relay servers using multicast,
At the stream delivery server or stream relay server,
Analyzes the rewrite request message sent from the stream controller, adds the multicast IP address and rewrite destination IP address to the rewrite list, and rewrites the packet before sending the IP packet processed by the IP processing unit to the client Whether the packet is a target packet is determined from the rewrite list. If the packet is a rewrite target packet, the value of the Source IP Address field of the IP header of the packet is rewritten according to the rewrite list, and the source IP of the IP header of the rewritten packet is rewritten. A stream data delivery method characterized in that if the value of the Address field is null, the packet is discarded, and if it is not null, the packet is transmitted to the client.   The stream data delivery method according to claim 4, wherein not only the value of the Source IP Address field of the IP header of the rewrite target packet but also the value of the Destination IP Address field are simultaneously rewritten. In a stream distribution network that sends stream packets from one or more stream distribution servers or stream relay servers to clients or stream relay servers using multicast,
Means for determining whether a packet received from a stream distribution server or a stream relay server is a packet to be monitored;
Means for monitoring the packet when the packet is a packet to be monitored and detecting that the stream packet does not normally reach;
And a means for generating a rewrite request message for transmission to the stream delivery server or stream relay server and the switching destination stream delivery server or stream relay server when detected. In a stream distribution network that sends stream packets from one or more stream distribution servers or stream relay servers to clients or stream relay servers using multicast,
Means for analyzing the rewrite request message sent from the stream control device;
Means for adding the multicast IP address and rewrite destination IP address obtained by analysis to the rewrite list;
Before transmitting the IP packet processed by the IP processing unit to the client, it is determined from the rewrite list whether the packet is a rewrite target packet. If the packet is a rewrite target packet, the source IP of the IP header of the packet is determined. Means for rewriting the value of the Address field according to the rewrite list, discarding the packet if the value of the Source IP Address field of the IP header of the packet after rewriting is null, and transmitting the packet to the client if not null A stream distribution apparatus.   The stream delivery apparatus according to claim 7, comprising means for simultaneously rewriting not only the value of the Source IP Address field of the IP header of the rewrite target packet but also the value of the Destination IP Address field.   The program for making a computer perform the stream data delivery method in any one of Claim 3 to 5. A computer-readable recording medium on which the program according to claim 9 is recorded.

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