JP2010045575A - Method and system for monitoring ip multicast communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and system for monitoring IP multicast communication, which monitor communicability of IP multicast channels in units of sender information (S) and of specific group information (G). <P>SOLUTION: When an instruction to start a test is received from a transmission/reception control part 014 by a source node for transferring an IP multicast maintenance packet with an IP multicast packet, packets other than the IP multicast packets for test (S, G) are transferred to a first communication data buffer 011, the IP multicast packets for test (S, G) are transferred to a second communication data buffer 012. When an instruction to complete the test is received from the transmission/reception control part 014, transfer of the IP multicast packets for test (S, G) to the second communication data buffer 012 is canceled, all the received packets are transferred to the first communication data buffer 011, and the transmission/reception control part 014 performs read control in which priority is set on the basis of allowable delay time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a network composed of a plurality of nodes connecting a plurality of distribution servers and a plurality of viewer terminals, and the IP multicast is confirmed when the IP multicast adjacency confirmation is completed between the plurality of nodes. Source information (S) indicating that it is transmitted from a specific distribution server among a plurality of nodes performing IP multicast communication via a route (accepted route) for which a transfer request is accepted IP multicast communication having information on a specific test target (S, G) consisting of the group information (G) is assigned to the test target (S, G) from a specific distribution server to a plurality of viewer terminals to be reached. The present invention relates to an IP multicast communication monitoring method and system for confirming whether or not a usable transfer bandwidth can be transmitted.

  A conventional IP multicast communication monitoring method will be described (for example, see Non-Patent Documents 1 and 2). The first conventional method example based on the technology disclosed in Non-Patent Document 1 is a “block diagram of an example of a conventional IP multicast arrival monitoring method (part 1)” using a PING address for IP multicast. This is shown in FIG. Further, the second conventional method example based on the technology disclosed in Non-Patent Document 2 is a “block diagram of an example of a conventional IP multicast arrival monitoring method (part 2)” using ssmping, as shown in FIG. It shows.

9 and 10,
101-1, 101-2 are distribution servers MS1, MS2,
110-1 and 110-2 are viewer terminals h1 and h2,
115 is its own network area,
116 is a distribution server side,
117 is a user side (that is, viewer terminal side),
118 and 119 are network boundary points,
120 is a source node A;
121 and 122 are relay nodes B, C,
123 and 124 are edge nodes D, E,
Reference numerals 140-1 to 140-6 denote multicast routes addressed to the same group (G) whose transmission source information (S) is MS1 (101-1).

  Here, as a precondition, in this example, a multicast control protocol between nodes is described using PIM-SSM, and a terminal viewing management protocol is described using MLDv2. Further, in the multicast route of 140-1 to 140-6, Neighber is established in the PIM-Hello between adjacent nodes of the source node A (120) to the edge node E (124) (establishment of adjacency confirmation), Furthermore, it is assumed that the confirmation of PIM-Join is completed and the request procedure from the viewer terminal by MLDv2 is completed (establishment of consent route).

  Referring to the sequence shown in FIG. 9, the distribution server MS1 (101-1) transmits the IP multicast group-addressed PING addressed to the group (G). The IP multicast group-addressed PING is copied by the relay node C (122) via the originating node A (120) and arrives at the edge node D (123) and the edge node E (124), respectively. The edge node D (123) transmits a PING addressed to the IP multicast group to the viewer terminal h2 (110-2) that has requested viewing by MLDv2, and the viewer terminal h2 (110-2) is the transmission server of the transmission source. Report the reply of the PING address to the IP multicast group to MS1 (101-1). Also, the edge node E (124) transmits the PING addressed to the IP multicast group to the viewer terminal h1 (110-1) that has requested viewing in MLDv2, and the viewer terminal h1 (110-1) is the transmission source. A reply of the PING addressed to the IP multicast group is reported to the distribution server MS1 (101-1).

  Note that the reply to the IP multicast group-addressed PING returned from the viewer terminal h1 (110-1) is sent to the viewer via the edge node E (124), the relay node C (122), and the source node A (120). Arrives at terminal MS1. In parallel, the reply to the IP multicast group-addressed PING returned from the viewer terminal h2 (110-2) passes through the edge node D (123), the relay node C (122), and the originating node A (120). And arrives at the distribution server MS1. By this procedure, the distribution server MS1 confirms the IP multicast communication (see, for example, Non-Patent Document 1).

  On the other hand, in the case of confirming the communication by the viewer terminal h1 using ssmping, referring to the sequence shown in FIG. 10, the smpmping is performed from the viewer terminal h1 (110-1) to the edge node E (124). Send to. Ssmping arrives at the distribution server MS1 via the edge node E (124), the relay node C (122), and the originating node A (120). The distribution server MS1 (101-1) distributes the IP multicast packet to the group (G) to the viewer terminal h1 (110-1) upon receipt of the ssmping. The IP multicast packet distributed from the distribution server MS1 (101-1) is sent to the viewer terminal h1 (110-1) via the originating node A (120), the relay node C (122), and the edge node E (124). To arrive. Through this procedure, the viewer terminal h1 confirms the IP multicast communication (see, for example, Non-Patent Document 2).

Kamil Sarac and one other, "draft-sarac-mping-00.txt. MPING Protocol Operation", [online], June 2004, IETF, [Search on December 21, 2007], Internet <URL: http /// ietfreport.isoc.org/all-ids/draft-sarac-mping-00.txt> Pavan Namburi and 2 others, “433-059 SSM-PING: A PING UTILITY FOR SOURCE SPECIFIC MULTICAST 4 SSM-Ping”, [online], November 22, 2004, CIIT 2004, [December 21, 2007 Search], Internet <URL: http://www.actapress.com/Content_Of_Proceeding.aspx? ProceedingID = 266 # pages>, <URL: http://imj.gate.edu/papers/CIIT-04b.pdf.gz>

  Here, in the conventional technique described above, when confirming the IP multicast communication, a route for passing an IP multicast packet (hereinafter referred to as multicast tree) is set by a user request, and the network boundary points (118, 119) are set. Since the communication exceeds the limit, there is a problem that it is not possible to confirm the communication closed in the local network area (115). In addition, since it is difficult to check the communication in units of source information (S) and specific group information (G), it is not possible to grasp a timely route for passing an IP multicast packet (that is, multicast tree). There is also a problem that route monitoring is difficult. Furthermore, there is a problem that the IP multicast bandwidth usage status cannot be confirmed in a timely manner.

  Therefore, a passing route number that can identify the passing of the own forwarding node is assigned to the IP multicast maintenance packet, forwarded together with the IP multicast packet to one or more viewer terminals, and can be connected to each node in the network. A conservative OpS is a method of monitoring the IP multicast communication by acquiring the information of the path communication from each node (reference document as prior art: Japanese Patent Application No. 2008-43300).

  Here, FIG. 2 shows a block diagram of an example of the IP multicast maintenance packet insertion function of the originating node showing the principle of the prior art described above. 3 to 8 are block diagrams showing an embodiment of the IP multicast communication monitoring method in which the above-described principle of the prior art is applied at the originating node.

2 and 3 to 8,
013 is an IP multicast maintenance packet buffer,
015 is a transmission control unit,
016 is a communication data buffer;
030 is the input packet,
032 is the output packet,
101-1 to 101-2 are distribution servers MS1 to MS2,
110-1 to 110-2 are viewer terminals h1 to h2,
115 is its own network area,
116 is a distribution server side,
117 is a user side (that is, viewer terminal terminal side),
118 and 119 are network boundary points,
120 is a source node A;
121-122 are relay nodes B-C,
123 to 124 are edge nodes D to E,
140-1 to 140-6 are multicast routes addressed to the same group (G) whose source information (S) is MS1 (101-1),
150 is a maintenance OpS,
160 is a breakdown of IP multicast maintenance packet information,
161 represents detailed information in the test mode (TM).

  An embodiment of an IP multicast communication monitoring method in which the principle of the prior art is applied at the originating node will be described with reference to FIG. In the description, the processing for the multicast route (140-1 to 140-6) originating from MS1 is taken as an example.

  The IP multicast packet distributed from the distribution server MS1 (101-1) passes through the source node A (120) according to the multicast route (140-1 to 140-6) of the MS1, and then passes through the relay node C (122). After copying, it is transmitted to the edge node D (123) and the edge node E (124) and distributed to the viewer terminals h1 and h2.

  First, the process of the originating node A (120) will be described as “Process 1”.

[Process 1]
The originating node A (120) performs the following [Processing 1-a] to [Processing 1-c] in a steady state, and [Processing 1-d] is performed when an inquiry from the maintenance OpS is received.

[Process 1-a]
The source information S and group number G (hereinafter referred to as (S, G)) of the passing IP multicast packet are confirmed.

[Process 1-b]
A corresponding (S, G) IP multicast maintenance packet is generated and inserted into the multicast route (140-2). At the time of generation, the test mode (TM), sequence number (SN), and passing route number (RN) are inserted when the packet is inserted. ) Is added to the payload in the packet. In addition, the originating node A (120) gives a test packet identifier (TPM) that can identify an IP multicast maintenance packet to an empty area of the header in the IP multicast maintenance packet (160).

[Process 1-c]
The (S, G), test mode (TM), and sequence number (SN) of the inserted IP multicast maintenance packet are reported to the maintenance OpS.

[Process 1-d]
For (S, G) corresponding to the IP multicast maintenance packet transmitted to the multicast route (140-2), the PIM-Join / Prune transmission state from the multicast route (140-2) is confirmed.

  Next, the processing of the relay node C (122) will be described as “processing 2”.

[Process 2]
In the relay node C (122), the following [Processing 2-a] is performed in a steady state, and [Processing 2-b] to [Processing 2-d] are performed when there is an inquiry from the maintenance OpS.

[Process 2-a]
The relay node C (122) refers to the test packet identifier (TPM), confirms that it is an IP multicast maintenance packet, assigns a passing route number (RN), and sends multicast routes (140-3) and (140- 5) Copy and transfer.

[Process 2-b]
The PIM-Hello is confirmed between the originating node A (120), between the edge nodes E (124) and between the edge nodes D (123).

[Process 2-c]
For (S, G) corresponding to the IP multicast maintenance packet received from the multicast route (140-2), the PIM-Join / Prune reception status from the multicast routes (140-3) and (140-4) is confirmed.

[Process 2-d]
For (S, G) corresponding to the IP multicast maintenance packet received from the multicast route (140-2), the PIM-Join / Prune transmission status to the multicast route (140-2) is confirmed.

  Next, the processing of the edge node D (123) will be described as “processing 3”.

[Process 3]
In the edge node D (123), the following [Processing 3-a] is performed in a steady state, and [Processing 3-b] to [Processing 3-d] are performed when there is an inquiry from the maintenance OpS.

[Process 3-a]
The edge node D (123) refers to the test packet identifier (TPM), extracts only the IP multicast maintenance packet received from the multicast route (140-5), and obtains the sequence number (SN) and transit route number (RN). Confirm and report to maintenance OpS.

[Process 3-b]
Regarding (S, G) corresponding to the IP multicast maintenance packet received from the multicast route (140-5), the transmission state of the MLDv2: Query to the viewer terminal h2 (110-2) is confirmed.

[Process 3-c]
For (S, G) corresponding to the IP multicast maintenance packet received from the multicast route (140-5), the reception status of the MLDv2: Report (Join / Leave) to the viewer terminal h2 (110-2) is confirmed.

[Process 3-d]
For (S, G) corresponding to the IP multicast maintenance packet received from the multicast route (140-5), the PIM-Join / Prune transmission status to the multicast route (140-5) is confirmed.

  In the edge node E (124), the following [Processing 3-a] is performed in a steady state, and [Processing 3-b] to [Processing 3-d] are performed when there is an inquiry from the maintenance OpS.

[Process 3-a]
The edge node D (123) refers to the test packet identifier (TPM), extracts only the IP multicast maintenance packet received from the multicast route (140-3), and obtains the sequence number (SN) and transit route number (RN). Confirm and report to maintenance OpS.

[Process 3-b]
Regarding (S, G) corresponding to the IP multicast maintenance packet received from the multicast route (140-3), the transmission state of the MLDv2: Query to the viewer terminal h1 (110-1) is confirmed.

[Process 3-c]
For (S, G) corresponding to the IP multicast maintenance packet received from the multicast route (140-3), the reception status of the MLDv2: Report (Join / Leave) to the viewer terminal h1 (110-1) is confirmed.

[Process 3-d]
For (S, G) corresponding to the IP multicast maintenance packet received from the multicast route (140-3), the PIM-Join / Prune transmission status to the multicast route (140-3) is confirmed.

  Next, the process of the maintenance OpS (150) will be described as “Process 4”.

[Process 4]
In the maintenance OpS (150), the following [Process 4-a] and [Process 4-b] are performed.

[Process 4-a]
The maintenance OpS includes (S, G), test mode (TM), sequence number (SN) of the IP multicast maintenance packet acquired from the originating node A (120) in “Process 1-a”, and “Process 3-a”. The IP multicast maintenance packet acquired from the edge nodes D (123) and E (124) in step 3 is collated with the test mode (TM), sequence number (SN), passage route number (RN), and the arrival status of the IP multicast packet And route monitoring by grasping the IP multicast tree.

[Process 4-b]
The maintenance OpS receives an IP multicast packet as requested from the viewing host h (110) based on information from the edge nodes D (123) and E (124) in "Process 3-b" to "Process 3-d". If the arrival normality is determined and it is determined that there is an abnormality, the information of “processing 1-d” is sent to the originating node A (120) on the multicast route and the relay node C (122) is sent to “ The information of “Process 2-b to 2-d” is inquired, and fault isolation is performed.

  With reference to FIG. 7 and FIG. 8, an example of bandwidth usage status confirmation in an IP multicast arrival monitoring method capable of providing the principle of the prior art will be described.

  FIG. 7 shows information in the IP multicast maintenance packet indicating the principle of the present invention. When confirming whether the IP multicast packet is using the required bandwidth (hereinafter referred to as bandwidth usage status confirmation), the test mode (TM) area is used for identification.

Details of the test mode (TM) (161) show the breakdown of parameters.
MD: Mode identification (normal mode / bandwidth confirmation mode)
PST: Packet status (first packet / intermediate packet / last packet)
T: Monitoring cycle (sending time from the first packet to completion of the last packet: sec)
M: Packet length (bit)
N: Number of packets (number of packets sent within the monitoring period (T): number)

  From this parameter, the transfer bandwidth is expressed by equation (1).

  Next, the operation will be described with reference to FIG.

  In the description, an example of processing in which an IP multicast packet is transferred through the IP multicast route (140) from the MS1 will be described.

  In the case of “confirmation of bandwidth usage”, the bandwidth confirmation mode is set in the mode identification (MD) in the test mode (TM) of the IP multicast maintenance packet to be inserted at the originating node A (120).

  In the band confirmation mode, the packet status (PST), measurement interval (T), packet length (M), and number of packets (N) are set. M allows a variable value for each packet, and T and M must be set when PST = first packet.

  When the originating node A (120) starts sending an IP multicast maintenance packet in which MD = bandwidth confirmation mode and PST = first packet are set to the relay node C, the state of “bandwidth usage confirmation” is started. A (120) transmits the packet set to the number of packets (N) within the measurement interval (T).

  The edge node E (124) and the edge node D (123) confirm the transfer confirmation mode (MD) IP multicast maintenance packet in which the transferred PST is from the first packet to the last packet, and based on the extracted T, M, and N Then, the transfer bandwidth is calculated from the above equation (1), and the bandwidth usage status is confirmed.

  However, when the IP multicast maintenance packet insertion function of the originating node A (120) showing the principle of the prior art is described with reference to FIG. 2, it is possible that traffic different from the traffic sent by the IP multicast maintenance packet may be sent. .

  The input packet (030) composed of the IP multicast packet to be tested (S, G) and other packets (hereinafter referred to as active packets) transferred from the distribution server MS1 (101-1) is one end. It is written in the communication data buffer (016). Upon receiving the test instruction from the outside, the transmission control unit (015) operates the operation packet (030) in the communication data buffer (016) and the IP multicast maintenance packet with N = 1 to 4 in the IP multicast maintenance packet buffer (013). Is sent out as a send packet (032) from both buffers by read control (see FIG. 2). Here, since the IP multicast packet and the IP multicast maintenance packet of the test objects S and G are mixed in the monitoring cycle T in the transmission packet (032), the actual transmission traffic is expressed by the following equation. Traffic different from the traffic transmitted by the IP multicast maintenance packet is transmitted.

  As described above, in the above-described prior art, since the same S, G user-issued IP multicast as the IP multicast maintenance packet is transferred in a mixed manner during the operation, the IP extracted at the receiving edge node is used. When measuring the bandwidth used based on multicast maintenance packets, there are situations where it cannot be accurately grasped. That is, there is a problem that the IP multicast bandwidth usage status cannot be confirmed in a timely manner only when the user-issued IP multicast of the same test target (S, G) does not communicate.

  In view of the above problems, an object of the present invention is to provide an IP multicast communication monitoring method and system for monitoring the IP multicast path communication in units of source information (S) and specific group information (G). It is to provide.

According to the IP multicast communication monitoring method of the present invention, an IP multicast adjacency check is completed between a plurality of nodes in a network composed of a plurality of nodes connecting a plurality of distribution servers and a plurality of viewer terminals. Source information (S) indicating that the IP multicast transmission request has been sent from a specific distribution server among a plurality of nodes performing IP multicast communication via an accepted route through which the IP multicast transfer request has been accepted; An IP multicast communication having information on a test target (S, G) made up of specific group information (G) is sent to the test target (S, G) from the specific distribution server to the plurality of viewer terminals to be reached. In order to confirm whether or not the data amount of the IP multicast packet for the allocated requested bandwidth can be transmitted as the usable transfer bandwidth, After the IP multicast maintenance packet, which is an observation packet, is inserted and forwarded together with the IP multicast packet to the originating node among the nodes located at the boundary between the trust server and the carrier network, the destination node of the plurality of nodes In the IP multicast communication monitoring method for extracting only the IP multicast maintenance packet,
The source node is
A distribution unit, a first communication data buffer, a second communication data buffer, an IP multicast maintenance packet buffer, and a transmission / reception control unit;
The processing of the originating node is as follows:
When the distribution unit receives a test start instruction from the transmission / reception control unit, the packet received from the adjacent distribution server is referred to, and packets other than the IP multicast packet of the test target (S, G) are Transferring to the first communication data buffer and notifying the transmission / reception control unit;
Transferring the IP multicast packet of the test object (S, G) to the second communication data buffer and notifying the transmission / reception control unit by the distribution unit;
When the distribution unit receives a test completion instruction from the transmission / reception control unit, it stops forwarding the IP multicast packet of the test target (S, G) to the second communication data buffer, and Transferring all packets received from the distribution server to the first communication data buffer and notifying the transmission / reception control unit;
The first communication data buffer includes:
It has a buffer capacity that is equal to or larger than the capacity of the IP multicast maintenance packet buffer, and temporarily stores packets other than the IP multicast packet of the test object (S, G) received from the distribution unit, and instructs the transmission / reception control unit To forward the packet to the adjacent relay node,
The second communication data buffer is
A buffer capacity equal to or greater than the capacity of the IP multicast maintenance packet buffer;
The IP multicast packet of the test target (S, G) received from the distribution unit is temporarily stored, and the packet is transferred to an adjacent relay node according to an instruction of the transmission / reception control unit,
The IP multicast packet buffer is
The IP multicast maintenance packet held in advance is transferred to the adjacent relay node according to the instruction of the transmission / reception control unit,
The processing of the transmission / reception control unit is as follows:
A step of confirming a free buffer capacity of the second communication data buffer when receiving an external test instruction, and instructing the distribution unit to start a test when a free space larger than an IP multicast maintenance packet is secured When,
Instructing the distribution unit to end the test when transmission of the IP multicast maintenance packet is completed, or when an allowable delay time that allows waiting for transmission of the IP multicast packet of the test target (S, G) has been reached; ,
Read control for mediation of packet transmission based on the allowable delay time is performed and held in the first communication data buffer, the second communication data buffer, and the IP multicast maintenance packet buffer. And arbitrating transmission of a packet that is present.

In the IP multicast communication monitoring method of the present invention,
The processing of the transmission / reception control unit is as read control for mediation of transmission of the packet,
The first communication data buffer, the IP multicast packet buffer, and the second communication data buffer are prioritized until the allowable delay time in which the transmission of the IP multicast packet of the test target (S, G) can be queued. When the transmission arbitration is performed in order and the transmission of the IP multicast packet of the test object (S, G) reaches the allowable delay time or when the transmission of the IP multicast maintenance packet is completed, the second communication data Transmission arbitration is performed in the priority order of the buffer and the first communication data buffer.

Furthermore, the IP multicast communication monitoring system of the present invention is a network composed of a plurality of nodes connecting a plurality of distribution servers and a plurality of viewer terminals, and the IP multicast adjacency confirmation is completed between the plurality of nodes. Source information (S) indicating that the IP multicast transfer request is sent from a specific distribution server among a plurality of nodes performing IP multicast communication via an accepted route through which the IP multicast transfer request has been accepted. ) And test group (S, G) information consisting of specific group information (G) is transmitted to the plurality of viewer terminals to be reached from the specific distribution server to the test target (S, G). To check whether the amount of IP multicast packet data for the requested bandwidth allocated to Then, an IP multicast maintenance packet, which is an observation packet, is inserted and forwarded together with an IP multicast packet to the originating node among the nodes located at the boundary between the distribution server and the carrier network. In the IP multicast communication monitoring system that extracts only the IP multicast maintenance packet at the destination node,
The source node is
A distribution unit, a first communication data buffer, a second communication data buffer, an IP multicast maintenance packet buffer, and a transmission / reception control unit;
The sorting unit is
When the transmission / reception control unit receives a test start instruction, the packet received from the adjacent distribution server is referred to, and packets other than the IP multicast packet of the test target (S, G) are referred to as the first communication data. A function of transferring to the buffer and notifying the transmission / reception control unit; and a function of transferring the IP multicast packet of the test target (S, G) to the second communication data buffer and notifying the transmission / reception control unit Have and
When receiving the test completion instruction from the transmission / reception control unit, the transfer of the IP multicast packet of the test target (S, G) to the second communication data buffer is stopped and received from the adjacent distribution server A function of transferring all packets to the first communication data buffer and notifying the transmission / reception control unit;
The first communication data buffer includes:
A buffer capacity equal to or greater than the capacity of the IP multicast maintenance packet buffer; and
The packet other than the IP multicast packet of the test target (S, G) received from the distribution unit is temporarily stored, and has a function of transferring the packet to an adjacent relay node according to an instruction of the transmission / reception control unit,
The second communication data buffer is
A buffer capacity equal to or greater than the capacity of the IP multicast maintenance packet buffer; and
A function of temporarily storing the IP multicast packet of the test target (S, G) received from the distribution unit and transferring the packet to an adjacent relay node according to an instruction of the transmission / reception control unit,
The IP multicast packet buffer is
A function of forwarding a packet to an adjacent relay node in accordance with an instruction of a transmission / reception control unit for an IP multicast maintenance packet held in advance;
The transmission / reception control unit includes:
A function for checking the free buffer capacity of the second communication data buffer when receiving an external test instruction, and instructing the distribution unit to start a test when a free space larger than the IP multicast maintenance packet is secured When,
A function for instructing the distribution unit to end the test when the transmission of the IP multicast maintenance packet is completed, or when the allowable delay time for enabling the transmission of the IP multicast packet of the test target (S, G) has been reached; ,
Read control for mediation of packet transmission based on the allowable delay time is performed and held in the first communication data buffer, the second communication data buffer, and the IP multicast maintenance packet buffer. And a function of mediating transmission of a packet to be transmitted.

In the IP multicast communication monitoring system of the present invention,
The transmission / reception control unit, as read control for arbitration of the packet transmission,
The first communication data buffer, the IP multicast packet buffer, and the second communication data buffer are prioritized until the allowable delay time in which the transmission of the IP multicast packet of the test target (S, G) can be queued. When the transmission arbitration is performed in order and the transmission of the IP multicast packet of the test object (S, G) reaches the allowable delay time or when the transmission of the IP multicast maintenance packet is completed, the second communication data Transmission arbitration is performed in the priority order of the buffer and the first communication data buffer.

  According to the present invention, according to the IP multicast communication monitoring method and system of the present invention, IP multicast communication closed in its own network area becomes possible. In addition, it is possible to check whether IP multicast has reached all terminals that should be reached in units of specific source information (S) and specific group information (G) in a timely manner, and to understand multicast trees in a timely manner. The route can be confirmed. This facilitates fault monitoring and fault isolation in the multicast communication path.

  In addition, according to the present invention, since the test mode has a function of the bandwidth confirmation mode, it is possible to confirm the bandwidth usage status of the IP multicast in a timely manner on the premise of bandwidth guarantee.

  In particular, according to the present invention, since the IP multicast maintenance packet can be transferred without mixing the same S, G user-issued IP multicast as the IP multicast maintenance packet only when transiting to the test state, it can be timely even during operation. It is possible to accurately check the bandwidth usage status.

  Hereinafter, an IP multicast arrival monitoring method and system according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of an IP multicast communication monitoring method showing the principle of the present invention. 3 to 6 are block diagrams showing not only the above-described prior art but also an embodiment of an IP multicast communication monitoring method in which the principle of the present invention is applied at the originating node. 7 and 8 are examples of bandwidth usage status confirmation that provides the principle of the prior art, but the same applies to the IP multicast communication monitoring method of the embodiment of the present invention. In each figure, the same reference numerals are given to similar components.

  In this description, the multicast control protocol between nodes is described using PIM-SSM, and the terminal viewing management protocol is described using MLDv2. Further, in the multicast routes 140-1 to 140-6, Neighber is established in the PIM-Hello between the adjacent nodes of the source node A (120) to the node E (124) (establishment of adjacency confirmation). , PIM-Join confirmation is completed, and the request procedure from the viewer terminal by MLDv2 is completed (establishment of consent route).

In FIG.
010 is a sorting unit,
011 is a first communication data buffer;
012 is a second communication data buffer;
013 is an IP multicast maintenance packet buffer,
014 is a transmission / reception control unit,
030 is the input packet,
031 is the output packet,
It is.

3 to 8,
101-1 to 101-2 are distribution servers MS1 to MS2, respectively.
116-1 to 110-2 are viewer terminals h1 to h2,
115 is its own network area,
116 is a distribution server,
117 is a user side (that is, viewer terminal side),
118 and 119 are network boundary points,
120 is a source node A;
121-122 are relay nodes B-C,
123 to 124 are edge nodes D to E,
140-1 to 140-6 are multicast routes addressed to the same group (G) whose source information (S) is MS1 (101-1),
150 is a maintenance OpS,
160 is a breakdown of IP multicast maintenance packet information,
161 represents detailed information in the test mode (TM).

  The network in this embodiment includes a plurality of distribution servers MS1, MS2 (101-1, 101-2), a plurality of viewer terminals h1, h2 (110-1, 110-2), and one source node A. (120), a plurality of relay nodes B and C (121, 122), a plurality of edge nodes D and E (123, 124), and one maintenance OpS (150).

  Each of the plurality of distribution servers MS1 and MS2 (101-1, 101-2) has a function of transferring the IP multicast packet to the adjacent originating node A (120) after the route is established.

  Each of the plurality of viewer terminals h1 and h2 has a function of receiving an IP multicast packet transferred from an adjacent edge node.

  The source node A (120) refers to the IP multicast packet received from any of the plurality of adjacent delivery servers MS1, MS2 (101-1, 101-2), and transmits the source information (S) and specific group information. (G) A function for grasping an IP multicast packet, one IP multicast maintenance packet is generated for each grasped source information (S) and specific group information (G), and the referenced IP multicast packet is transferred. A function to transmit to an adjacent relay node of the accepted route, a test mode in which the test mode can be identified when generating an IP multicast maintenance packet (hereinafter referred to as TM), and the order of the IP multicast maintenance packet to be transmitted is determined. Sequence number (SN) and IP multicast maintenance packet pass through And a function of inserting information on a passing route number (RN) that can be grasped by the user into a predetermined storage area, and a source of the IP multicast maintenance packet corresponding to the accepted route after the completion of the transfer of the IP multicast maintenance packet to the accepted route Information (S), specific group information (G), test mode (TM), function to report sequence number (SN) to maintenance OpS (150), source information (S) and specific group information (G) IP multicast transfer from the downstream adjacent relay node by confirming whether or not the PIM-Join and PIM-Prun, which are the routing control protocols for each combination, are received from the adjacent relay node of the downstream acceptance route When there is an inquiry from the maintenance OpS (150) And a function to report IP multicast forwarding requests from de.

  The originating node A (120) generates an IP multicast maintenance packet of the corresponding (S, G) and inserts it into the multicast route (140-2). At the time of generation, when the packet is inserted, the test mode (TM), sequence A number (SN) and a passing route number (RN) are added to the payload in the packet (details are described above with reference to FIG. 7). In addition, the originating node A (120) gives a test packet identifier (TPM) for identifying an IP multicast maintenance packet to an empty area of the header in the IP multicast maintenance packet (160). This test packet identifier (TPM) is used to identify whether the packet is an IP multicast packet or an IP multicast packet in a downstream node (relay node or edge node).

  Each of the plurality of relay nodes B and C (121, 122) has a function of forwarding an IP multicast packet and an IP multicast maintenance packet transferred from an adjacent node to an adjacent node of the acceptance route, and an IP multicast maintenance packet adjacent to the acceptance route. When forwarding to a node, a function of assigning a passing route number (RN) of the own node that can identify passing of the own forwarding node to the predetermined storage area in the IP multicast maintenance packet, and a PIM-Hello based on the routing protocol Confirming the IP multicast adjacency status with neighboring nodes, and downstream consent for PIM-Join and PIM-Prune for each combination of source information (S) and specific group information (G) Whether it is received from the adjacent node of the route By recognizing the IP multicast transfer request from the downstream adjacent node, and the upstream PIM-Join and PIM-Prun for each combination of the source information (S) and the specific group information (G) The function of grasping the IP multicast transfer request to the upstream adjacent node by confirming whether it is transmitting to the node, and when there is an inquiry from the maintenance OpS (150), the IP multicast adjacency status and the downstream adjacency It has a function of reporting an IP multicast transfer request from a node and an IP multicast transfer request to an upstream adjacent node.

  Each of the plurality of edge nodes D and E (123, 124) has a function of extracting only an IP multicast maintenance packet from IP multicast packets arriving from adjacent relay nodes, and transmission source information (S in the extracted IP multicast maintenance packet). ), A specific group information (G), a test mode (TM), a sequence number (SN), a passing route number (RN), and a function for reporting to the maintenance OpS (150), source information (S) and By checking whether the query of the terminal viewing management protocol for each combination of specific group information (G) is transmitted to the viewer terminal corresponding to the consent route, the viewing permission status to the viewer terminal is grasped. R of the terminal viewing management protocol for each combination of source function (S) and specific group information (G) By confirming whether or not the port is received from the viewer terminal corresponding to the acceptance route, the function for grasping the viewing request status from the viewer terminal, the transmission source information (S), and the specific group information ( G) a function for grasping an IP multicast transfer request to an upstream adjacent relay node by confirming whether or not PIM-Join and PIM-Prun for each combination are transmitted to the upstream adjacent relay node, and maintenance OpS When inquired from (150), reports the viewing permission status to the viewer terminal corresponding to the accepted route, the viewing request status from the viewer terminal, and the IP multicast transfer request to the upstream adjacent relay node It has the function to do.

  The maintenance OpS (150) transmits / receives information to / from the originating node A (120), each of the plurality of relay nodes B and C (121, 122), and each of the plurality of edge nodes D and E (123, 124). , Transmission source information (S), specific group information (G), test mode (TM), sequence number (SN), and information reported from the source node A (120), reported from the edge node By confirming the source information (S), the specific group information (G), the test mode (TM), the sequence number (SN), and the passing route number (RN), which are the transmitted information, the source node A (120 And a function for confirming whether or not the IP multicast maintenance packet transmitted by (1) has arrived at the edge node to arrive.

  The maintenance OpS (150) inquires according to the necessity of information acquisition at each node, and sends an IP address from an adjacent relay node downstream of the source node A (120) to the source node A (120). The multicast transfer request is confirmed, and for each of the plurality of relay nodes B and C (121, 122), an IP multicast adjacency status grasping request, an IP multicast transfer request from a downstream adjacent node, and an upstream The IP multicast transfer request to the adjacent node is confirmed, and for each of the plurality of edge nodes D and E (123, 124), a request for grasping the viewing permission status to each viewer terminal, and the viewer terminal A request for grasping the viewing request status and a request for forwarding an IP multicast to an upstream adjacent relay node.

  That is, the operation of the IP multicast communication monitoring system of the present embodiment related to FIGS. 3 to 8 is the same as that described as the prior art, and the IP multicast communication monitoring system of the present embodiment includes a plurality of distribution servers (MS1, MS1). MS2) and a plurality of nodes (originating node A, relay nodes B and C, and edge nodes D and E) that connect a plurality of viewer terminals h1 and h2 (110-1 and 110-2) The IP multicast adjacency confirmation has been completed between the plurality of nodes, and the IP multicast communication is performed through the acceptance route where the IP multicast transfer request is accepted. , A test object consisting of source information (S) and specific group information (G) indicating that it has been sent from a specific distribution server (MS1, MS2) The IP multicast communication having the information of (S, G) is tested from the specific distribution server (MS1, MS2) to the plurality of viewer terminals h1, h2 (110-1, 110-2) to be tested (S, G). ) Is located at the boundary 118 between these distribution servers (MS1, MS2) and the carrier network in order to confirm whether or not the data amount of the IP multicast packet corresponding to the requested bandwidth allocated to) can be transmitted as the usable transfer bandwidth. After the IP multicast maintenance packet, which is an observation packet, is inserted together with the IP multicast packet and transferred to the originating node A (120) of the nodes, the destination node (preferably the viewer terminal) of the plurality of nodes is transferred. h1, h2 (110-1, 110-2) and an edge node D located at the boundary 119 of the carrier network, Although, the relay node B, and also can) be C, the a IP multicast communication monitoring system for extracting only the IP multicast service packet. Here, the present invention is not limited to the configuration of each embodiment with respect to a specific source node, a plurality of distribution servers, a plurality of relay nodes, a plurality of edge nodes, and a plurality of viewer terminals. Needless to say.

  Hereinafter, in the description, the processing for the multicast route (140-1 to 140-6) from MS1 is taken as an example. The IP multicast packet distributed from the distribution server MS1 (101-1) passes through the source node A (120) according to the multicast route (140-1 to 140-6) of the MS1, and then passes through the relay node C (122). It is assumed that, after being copied, it is transmitted to the edge node D (123) and the edge node E (124) and distributed to the viewer terminals h1 and h2. Therefore, the multicast route in the case of passing through the relay node B (121) will not be described, but the operation of the relay node B (121) in this case is the same as that of the relay node C (122).

  In such an IP multicast communication monitoring system, as described with reference to FIG. 2, the originating node A (120) has the same S and G user-issued IP multicasts as IP multicast maintenance packets mixed in the same brain. Therefore, in the IP multicast communication monitoring system of the present embodiment, the following function is further provided as the following function, since the traffic different from the traffic sent in the IP multicast maintenance packet may occur. 120).

  The originating node A (120) includes a distribution unit (010), a first communication data buffer (011), a second communication data buffer (012), an IP multicast maintenance packet buffer (013), and a transmission / reception control unit. (014).

  When the distribution unit (010) receives a test start instruction from the transmission / reception control unit (014), the distribution unit (010) refers to the packet received from the adjacent distribution server, and receives a packet other than the IP multicast packet to be tested (S, G). The function of transferring the packet to the first communication data buffer (011) and notifying the transmission / reception control unit (014) and the IP multicast packet of the test target (S, G) to the second communication data buffer (012) And a function to notify the transmission / reception control unit (014), and when the test completion instruction is received by the transmission / reception control unit (014), the IP multicast packet of the test target (S, G) is 2 Stops transfer to the communication data buffer and receives the packet received from one of the adjacent distribution servers MS1 and MS2 (101-1, 101-2). The Tsu bets, and forwarded to all the first communication data buffer (011) has a function of notifying the reception control unit (014).

  The first communication data buffer (011) has a buffer capacity equal to or larger than the capacity of the IP multicast maintenance packet buffer (013), and the test target (S, G) IP multicast packet received from the distribution unit (010). 1 is stored, and the packet is transferred to an adjacent relay node according to an instruction from the transmission / reception control unit (014).

  The second communication data buffer (012) has a buffer capacity equal to or larger than the capacity of the IP multicast maintenance packet buffer (013), and the test target (S, G) IP multicast packet received from the distribution unit (010). Is stored, and a packet is transferred to an adjacent relay node according to an instruction from the transmission / reception control unit (014).

  The IP multicast packet buffer (013) has a function of forwarding a packet held in advance to an adjacent relay node according to an instruction from the transmission / reception control unit (014).

  When the transmission / reception control unit (014) receives an external test instruction (preferably, an instruction from the maintenance OpS (150)), it checks the free buffer capacity of the second communication data buffer (012), When a space larger than the IP multicast maintenance packet is secured, a function for instructing the distribution unit (010) to start the test, and when the transmission of the IP multicast maintenance packet is completed, or the IP multicast of the test target (S, G) When the time for which a packet can be waited (referred to as “allowable delay time”) has been reached, a function for instructing the end of the test to the distribution unit (010) and the transmission of a packet based on the aforementioned “allowable delay time” Read control for arbitration is performed, the first communication data buffer (011), the second communication data buffer (012), and the IP multi It has a function of arbitrating the transmission of packets held in Yasuto maintenance packet buffer (013).

  In particular, the transmission / reception control unit (014), as read control for mediation of packet transmission based on this allowable delay time, allows an allowable delay that allows the transmission of the IP multicast packet of the test target (S, G) to wait. Up to the time, transmission arbitration is performed in the priority order of the first communication data buffer (011), the IP multicast packet buffer (013), and the second communication data buffer (012), and the test target (S, G) When the transmission of the IP multicast packet reaches the allowable delay time or when the transmission of the IP multicast maintenance packet is completed, the priority order of the second communication data buffer (012) and the first communication data buffer (011) Perform transmission arbitration with.

  The operation of the IP multicast arrival monitoring system using the present invention will be described in detail with reference to FIG. When the transmission / reception control unit (014) receives a test instruction from the outside, the transmission / reception control unit (014) confirms that the free state of the second communication data buffer (012) has a buffer capacity larger than all IP multicast maintenance packets used in the test If the vacancy is confirmed, write control for starting the test is performed on the distribution unit (010).

  Next, the distribution unit (010) that has received the test start write control transfers the active packet of the input packets (030) transferred from the distribution server MS1 (101-1) to the first communication data buffer ( 011) and the IP multicast packet to be tested (S, G) are written once to the second communication data buffer (012).

  As shown in FIG. 1, the transmission / reception control unit (014) sets the first communication data buffer (011) to “A”, the second communication data buffer (012) to “B”, and the IP multicast maintenance packet buffer. When (013) is “C”, read control (that is, arbitration of packet transmission) is performed in the following priority order.

(1) If transmission of the IP multicast packet to be tested (S, G) is within the allowable delay time, read control is performed with priority in the order of “A” → “C” → “B”.
(2) Preferential reading in the order of “B” → “A” after the transmission of the IP multicast packet of the test target (S, G) reaches the allowable delay time or if the transmission of the IP multicast maintenance packet is completed Take control.

  Note that the “allowable delay time” is the test object (S, G) that the IP multicast packet of the test object (S, G) that has been waiting in the second communication data buffer (012) is sent most recently. The allowable delay time between the IP multicast packets.

  Packets read in such a priority order are output as non-mixed transmission packets (031) as shown in FIG. Here, since the IP multicast packet and the IP multicast maintenance packet to be tested (S, G) are not mixed within the monitoring period T in the transmission packet (031), the actual transmission traffic is expressed by the following equation. It becomes like this.

  Traffic equivalent to the traffic sent in the IP multicast maintenance packet is sent.

  As described above, according to the present invention, since the IP multicast maintenance packet can be transferred without being mixed with the same S and G user-issued IP multicast only when transiting to the test state, even during system operation, It becomes possible to accurately check the bandwidth usage status in a timely manner.

  Although specific embodiments have been described in the above-described embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, an IP multicast arrival monitoring method using IP multicast addressed PING or smsping in the prior art may be implemented so as to switch whether or not to perform priority order read-out control at the originating node in response to a test request. it can. Accordingly, the invention is not limited by the embodiments described above, but only by the claims.

  Since it becomes possible to confirm whether or not communication is possible from a specific server to a plurality of viewer terminals, it is useful for multicast communication.

It is a block diagram regarding the IP multicast maintenance packet insertion function of the originating node which shows the principle of this invention. It is a block diagram regarding the IP multicast maintenance packet insertion function of the origination node which shows the principle of the prior art which concerns on this invention. It is a block diagram of the IP multicast arrival monitoring method of the Example which shows the principle of this invention (the 1). It is a block diagram of the IP multicast arrival monitoring method of the Example which shows the principle of this invention (the 2). It is a block diagram of the IP multicast arrival monitoring method of the Example which shows the principle of this invention (the 3). It is a block diagram of the IP multicast arrival monitoring method of the Example which shows the principle of this invention (the 4). It is a figure which shows the information in an IP multicast maintenance packet. It is a figure which shows the Example of the band usage condition confirmation in the IP multicast arrival monitoring method which shows the principle of this invention. It is a block diagram of the conventional IP multicast arrival monitoring system (the 1). It is a block diagram of the conventional IP multicast arrival monitoring system (the 2).

Explanation of symbols

010 Distribution unit 011 First communication data buffer 012 Second communication data buffer 013 IP multicast maintenance packet buffer 014 Transmission / reception control unit 015 Transmission control unit 016 Communication data buffer 030 Input packet 031 Output packet 032 Output packet 101-1 and 101 -2 distribution server MS1, MS2
110-1, 110-2 Viewer terminals h1, h2
115 Local network area 116 Distribution server side 117 User side (ie viewer terminal side)
118,119 Network boundary point 120 Originating node A
121, 122 Relay nodes B, C
123, 124 Edge nodes D, E
140-1 to 140-6 Multicast route addressed to the same group (G) 150 Maintenance OpS
160 Breakdown of IP multicast maintenance packet information 161 Detailed information in test mode (TM) MD mode identification (normal mode / bandwidth confirmation mode)
PST packet status (first packet / intermediate packet / last packet)
T Monitoring cycle (Sending time from the first packet to the completion of the last packet: sec)
M packet length (bit)
N Number of packets (number of packets sent within the monitoring period (T): number)

Claims (4)

In a network composed of a plurality of nodes connecting a plurality of distribution servers and a plurality of viewer terminals, the IP multicast adjacency confirmation has been completed between the plurality of nodes, and the IP multicast transfer request has been accepted. A test consisting of source information (S) and specific group information (G) indicating that it has been transmitted from a specific distribution server among a plurality of nodes performing IP multicast communication via the approved route An IP multicast packet corresponding to the requested bandwidth allocated to the test target (S, G) from the specific distribution server to the plurality of viewer terminals, in which the IP multicast communication having the target (S, G) information is performed In order to confirm whether or not the amount of data can be transmitted as an available transfer band, it is positioned at the boundary between the distribution server and the carrier network. After the IP multicast maintenance packet, which is an observation packet, is inserted and forwarded to the originating node of the nodes to be transmitted together with the IP multicast packet, only the IP multicast maintenance packet is extracted at the destination node of the plurality of nodes In the IP multicast communication monitoring method to
The source node is
A distribution unit, a first communication data buffer, a second communication data buffer, an IP multicast maintenance packet buffer, and a transmission / reception control unit;
The processing of the originating node is as follows:
When the distribution unit receives a test start instruction from the transmission / reception control unit, the packet received from the adjacent distribution server is referred to, and packets other than the IP multicast packet of the test target (S, G) are Transferring to the first communication data buffer and notifying the transmission / reception control unit;
Transferring the IP multicast packet of the test object (S, G) to the second communication data buffer and notifying the transmission / reception control unit by the distribution unit;
When the distribution unit receives a test completion instruction from the transmission / reception control unit, it stops forwarding the IP multicast packet of the test target (S, G) to the second communication data buffer, and Transferring all packets received from the distribution server to the first communication data buffer and notifying the transmission / reception control unit;
The first communication data buffer includes:
It has a buffer capacity that is equal to or larger than the capacity of the IP multicast maintenance packet buffer, and temporarily stores packets other than the IP multicast packet of the test object (S, G) received from the distribution unit, and instructs the transmission / reception control unit To forward the packet to the adjacent relay node,
The second communication data buffer is
A buffer capacity equal to or greater than the capacity of the IP multicast maintenance packet buffer;
The IP multicast packet of the test target (S, G) received from the distribution unit is temporarily stored, and the packet is transferred to an adjacent relay node according to an instruction of the transmission / reception control unit,
The IP multicast packet buffer is
The IP multicast maintenance packet held in advance is transferred to the adjacent relay node according to the instruction of the transmission / reception control unit,
The processing of the transmission / reception control unit is as follows:
A step of confirming a free buffer capacity of the second communication data buffer when receiving an external test instruction, and instructing the distribution unit to start a test when a free space larger than an IP multicast maintenance packet is secured When,
Instructing the distribution unit to end the test when transmission of the IP multicast maintenance packet is completed, or when an allowable delay time that allows waiting for transmission of the IP multicast packet of the test target (S, G) has been reached; ,
Read control for mediation of packet transmission based on the allowable delay time is performed and held in the first communication data buffer, the second communication data buffer, and the IP multicast maintenance packet buffer. An IP multicast communication monitoring method comprising the step of: The processing of the transmission / reception control unit is as read control for mediation of transmission of the packet,
The first communication data buffer, the IP multicast packet buffer, and the second communication data buffer are prioritized until the allowable delay time in which the transmission of the IP multicast packet of the test target (S, G) can be queued. When the transmission arbitration is performed in order and the transmission of the IP multicast packet of the test object (S, G) reaches the allowable delay time or when the transmission of the IP multicast maintenance packet is completed, the second communication data 2. The IP multicast communication monitoring method according to claim 1, wherein transmission arbitration is performed in a priority order of a buffer and the first communication data buffer. In a network composed of a plurality of nodes connecting a plurality of distribution servers and a plurality of viewer terminals, the IP multicast adjacency confirmation has been completed between the plurality of nodes, and the IP multicast transfer request has been accepted. A test consisting of source information (S) and specific group information (G) indicating that it has been transmitted from a specific distribution server among a plurality of nodes performing IP multicast communication via the approved route An IP multicast packet corresponding to the requested bandwidth allocated to the test target (S, G) from the specific distribution server to the plurality of viewer terminals, in which the IP multicast communication having the target (S, G) information is performed In order to confirm whether or not the amount of data can be transmitted as an available transfer band, it is positioned at the boundary between the distribution server and the carrier network. After the IP multicast maintenance packet, which is an observation packet, is inserted and forwarded to the originating node of the nodes to be transmitted together with the IP multicast packet, only the IP multicast maintenance packet is extracted at the destination node of the plurality of nodes In the IP multicast communication monitoring system
The source node is
A distribution unit, a first communication data buffer, a second communication data buffer, an IP multicast maintenance packet buffer, and a transmission / reception control unit;
The sorting unit is
When the transmission / reception control unit receives a test start instruction, the packet received from the adjacent distribution server is referred to, and packets other than the IP multicast packet of the test target (S, G) are referred to as the first communication data. A function of transferring to the buffer and notifying the transmission / reception control unit; and a function of transferring the IP multicast packet of the test target (S, G) to the second communication data buffer and notifying the transmission / reception control unit Have and
When receiving the test completion instruction from the transmission / reception control unit, the transfer of the IP multicast packet of the test target (S, G) to the second communication data buffer is stopped and received from the adjacent distribution server A function of transferring all packets to the first communication data buffer and notifying the transmission / reception control unit;
The first communication data buffer includes:
A buffer capacity equal to or greater than the capacity of the IP multicast maintenance packet buffer; and
The packet other than the IP multicast packet of the test target (S, G) received from the distribution unit is temporarily stored, and has a function of transferring the packet to an adjacent relay node according to an instruction of the transmission / reception control unit,
The second communication data buffer is
A buffer capacity equal to or greater than the capacity of the IP multicast maintenance packet buffer; and
A function of temporarily storing the IP multicast packet of the test target (S, G) received from the distribution unit and transferring the packet to an adjacent relay node according to an instruction of the transmission / reception control unit,
The IP multicast packet buffer is
A function of forwarding a packet to an adjacent relay node in accordance with an instruction of a transmission / reception control unit for an IP multicast maintenance packet held in advance;
The transmission / reception control unit includes:
A function for checking the free buffer capacity of the second communication data buffer when receiving an external test instruction, and instructing the distribution unit to start a test when a free space larger than the IP multicast maintenance packet is secured When,
A function for instructing the distribution unit to end the test when the transmission of the IP multicast maintenance packet is completed, or when the allowable delay time for enabling the transmission of the IP multicast packet of the test target (S, G) has been reached; ,
Read control for mediation of packet transmission based on the allowable delay time is performed and held in the first communication data buffer, the second communication data buffer, and the IP multicast maintenance packet buffer. And an IP multicast communication monitoring system characterized by having a function of mediating transmission of a packet. The transmission / reception control unit, as read control for arbitration of the packet transmission,
The first communication data buffer, the IP multicast packet buffer, and the second communication data buffer are prioritized until the allowable delay time in which the transmission of the IP multicast packet of the test target (S, G) can be queued. When the transmission arbitration is performed in order and the transmission of the IP multicast packet of the test object (S, G) reaches the allowable delay time or when the transmission of the IP multicast maintenance packet is completed, the second communication data 4. The IP multicast communication monitoring system according to claim 3, wherein transmission arbitration is performed in a priority order of a buffer and the first communication data buffer. 5.

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