JP3640652B2 - Switch, network using the same, and multicast transmission method - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a network in which a multicast transmission path route for transmitting / receiving multicast data by a multicast protocol between a transmission terminal and a reception terminal is formed, a switch used therefor, and a multicast transmission method.
[0002]
Multicast is a form of passing data to a plurality of recipients on an IP (Internet Protocol) network, and only one packet is sent to all recipients on the network. It delivers as many packets as needed. It is distinguished from other so-called unicasts that deliver data to a single recipient, and broadcasts that distribute data throughout the network.
[0003]
[Prior art]
In Internet communication, as one of the methods for transmitting and receiving wide band information such as video, multicast data is transmitted and received using a multicast protocol via a network relay device that connects networks between transmitting and receiving terminals ( For example, refer nonpatent literature 2.). The network relay device is often called a router, and will be described below by the name of the router.
The technique related to the multicast protocol is also described in Non-Patent Document 2 below, and here, a simple technique of multicast according to the present invention and a conventional technique according to the present invention will be described.
[0004]
[Non-Patent Document 1]
W. Fender rfc (Request for Comments): 2236 "Internet Group Management Protocol, Version 2", Network Working Group, November, 1997
[Non-Patent Document 2]
Dave Kosiur Director Yukio Hamada “Mastering TCP / IP IP Multicast”, Ohm Co., Ltd., November 10, 2000, first edition, second edition, p. 46-73
[0005]
In group membership in multicast, IGMP (Internet Group Management Protocol) is used as a protocol for handling communication between a router and a lower network configured in the router.
[0006]
FIG. 10 is a block diagram showing a conventional configuration of a network that performs multicasting.
[0007]
As shown in FIG. 10, the configuration of a conventional network that performs multicasting includes, as one aspect, a router R to which a transmission terminal 31 is connected.₁And this router R₁The switches SW11 to SW18, to which the receiving terminals 21 to 28 are connected, are connected in a ring shape. Here, when transmitting multicast data from the transmission terminal to each reception terminal, an IGMP snooping switch is adopted as the switch.
[0008]
Also, the router R₁Is a router R constituting another network.₂Connected to the router R₂Is connected to a receiving terminal 29. The router R₁And the switches SW11 to SW18, or an annular path connecting the switches SW11 to SW18 is defined as an uplink path 2. (Displayed with double lines in the figure)
[0009]
Further, among the ports of each of the switches SW11 to SW18, the ports connected to the uplink path 2 are p1 and p2, respectively, and the ports to which the receiving terminals 21 to 28 are connected are p3. Further, in the uplink path 2, a block port is set in order to logically prevent an infinite loop of packet data in a ring-shaped network.
[0010]
Next, transmission of multicast data in the conventional network configured as described above will be described.
[0011]
The IGMP snooping switch is a router R₁In response to “IGMP Membership Query” (hereinafter referred to as “Query”) sent to each receiving terminal, the receiving terminal connected to the switch sets “IGMP Membership Report (hereinafter referred to as“ Report ”)” to the router R.₁, The multicast filter is automatically performed based on the port connected to the receiving terminal.
In particular,
(1) First, Router R₁Transmits “Query” to the receiving terminals 21 to 28 provided in the lower network 1 that forms a ring. This "Query" is a predetermined router R₁Inquiry information for confirming whether or not there is a receiving terminal participating in the multicast group belonging to the router R₁Is an IGMP packet periodically transmitted to all receiving terminals.
A multicast group is a cluster of virtual data identified by a multicast address in the network. When the transmitting terminal transfers data to which a multicast address is assigned and the receiving terminal desires to receive the multicast data, it is necessary to desire to join the multicast group.
[0012]
Thus, when the receiving terminal wishes to receive multicast data,
(2) The router R to which the receiving terminal belongs₁"Report" is transmitted to This “Report” is, so to speak, a packet in which the receiving terminal expresses participation in the multicast group in which the transmitting terminal transmits multicast data, and is an intention expressing means that desires to receive the multicast data.
[0013]
Router R like this₁Router R is used to send and receive IGMP packets to and from receiving terminals 1 to 29₁IGMP snooping switches SW11 to SW18 interposed between the receiving terminals 1 to 29 and a multicast filter are set. Specifically, the router R₁The IGMP snooping is performed on the multicast filter information (port list) indicating which port corresponds to a predetermined multicast data (multicast address) by specifying a port that returns “Report” for each “Query” transmitted from Created by the switch.
[0014]
Based on the multicast filter information created in this way, the multicast data transmitted from the transmitting terminal is transmitted to the receiving terminal that desires to receive it.
[0015]
[Problems to be solved by the invention]
However, the configuration of a network that performs multicast using an IGMP snooping switch as the switch has the following problems.
[0016]
When performing multicast using an IGMP snooping switch, the router R₁Multicast filter is performed in a tree form. Therefore, when the transmitting terminal is not installed in the multicast filter, the receiving terminal cannot receive the multicast data.
[0017]
Specifically, as shown in FIG. 11 in which the receiving terminal 24 connected to the switch 14 in FIG. 10 is replaced with the transmitting terminal 31, “Report” is sent from the transmitting terminal 31 to the router R.₁Therefore, the transmission path between the port p1 of the switch SW13 and the port p2 of the switch SW14 is blocked, and the multicast data cannot be transmitted from the transmitting terminal 31 to each receiving terminal.
[0018]
Further, in the conventional network configuration, when the uplink path 2 is disconnected, there is a problem that it takes time to switch when changing the topology such as link disconnection. Specifically, in FIG. 10, when the switch SW11 and the switch SW12 are disconnected ((1)), the block port between the switch SW14 and the switch SW18 is released ((2)), and the router R₁The confirmation procedure is taken when the “Query” issued by the server reaches each receiving terminal ((3)), but the multicast filter of each IGMP snooping switch is not changed until these steps are performed. , It takes time to change the topology by the interval of sending “Query”.
[0019]
As one means for solving such a problem, there is a means for adopting a layer 2 switch instead of an IGMP snooping switch as the switch and manually setting a multicast filter.
[0020]
Here, this multicast filter setting is necessary in order to prevent the multicast data transmitted from the transmitting terminal from being transmitted to the receiving terminal via all the ports of the switch when the layer 2 switch is simply adopted. It is. In other words, if a multicast filter is not set in each layer 2 switch, when a large number of transmitting terminals are installed on the network, multicast data relative to the number of transmitting terminals is transmitted to the receiving terminal via the switch. The Rukoto.
[0021]
Therefore, the receiving terminal cannot handle excessive communication traffic, and the possibility of causing the receiving terminal to become inoperable is not low and has a problem that cannot be ignored. Therefore, a means for manually setting a multicast filter is adopted. It will be.
[0022]
However, even if a means for manually setting a multicast filter is adopted, setting a multicast filter for each layer 2 switch not only requires a great deal of effort, but the effort is in proportion to the number of layer 2 switches. It is not difficult to imagine that it can be enormous.
[0023]
The present invention has been made in view of the above problems in the prior art, and has a simple configuration in a network in which a transmitting terminal and a receiving terminal are mixedly connected via two or more switches below a router. An object of the present invention is to provide a switch capable of efficiently executing multicast, a network using the switch, and a multicast transmission method.
[0024]
Further, the present invention provides a topology change such as link disconnection when an uplink path is disconnected in a network in which a transmitting terminal and a receiving terminal are connected together via two or more switches below a router. It is an object of the present invention to provide a switch capable of reducing the time required for the transmission as much as possible, a network using the switch, and a multicast transmission method.
[0025]
[Means for Solving the Problems]
  Provided to solve the above problemsFirst toThe switch according to the invention ofMulticast dataAt least one of a transmission terminal that transmits the multicast data and a reception terminal that receives the multicast dataIt is a switch to be connected, and is connected to the other switches through one router (R1) and connected to each other.A switch constituting the network of
Connected to the router or other switchPort, andAt least one of the transmitting terminal and the receiving terminal is connectedRuA group of ports including ports;
A transmission route between predetermined ports of the port group is formed.forSwitch means;
Connected to the router or other switchRuSet the port in advance as a port that always transmits multicast dataIncludingBased on inquiry information about the multicast data periodically received from the router and a port that has received a participation message for receiving the multicast dataupdateTo beRepresents a transmission route between the ports for distributing the multicast dataA multicast filter table,
  Update the multicast filter table,A packet management means for transmitting the inquiry information to the receiving terminal and transmitting the participation message to the router according to the inquiry information when a participation message is received from the receiving terminal for the inquiry information;
  The packet management meansFor the switch means with reference to the multicast filter table,The transmission route between the portsFormIt is characterized by that.
[0026]
With this configuration, the path connecting the router and the switch, that is, the uplink path is set so that it can be transmitted at all times, so the transmitting terminal and the receiving terminal are mixedly connected via two or more switches below the router. Even in networks with various configurations, effective and efficient multicast can be realized using a simple switch.
[0027]
  Provided to solve the above problemsSecond toThe network according to the invention ofAt least one router;A plurality of switches including at least a switch to which a transmitting terminal is connected and a switch to which a receiving terminal is connected;And at least two of the plurality of switches are connected via the router, and the other switch is arranged next to one of the two switches.A connected network,
Each of the switches
Port connected to the router or other switch, AndA port to which at least one of the transmitting terminal and the receiving terminal is connected;IncludePorts and
A transmission route between predetermined ports of the port group is formed.forSwitch means;
Connected to the router or other switchRuSet the port in advance as a port that always transmits multicast dataIncludingBased on inquiry information about the multicast data periodically received from the router and a port that has received a participation message for receiving the multicast dataupdateTo beRepresents a transmission route between the ports for distributing the multicast dataA multicast filter table,
  Update the multicast filter table,A packet management means for transmitting the inquiry information to the receiving terminal and transmitting the participation message to the router according to the inquiry information when a participation message is received from the receiving terminal for the inquiry information;
  The packet management meansFor the switch means with reference to the multicast filter table,The transmission route between the portsFormIt is characterized by that.
[0028]
With this configuration, the uplink path is set so that it can always be transmitted. Therefore, in a network having various configurations in which a transmitting terminal and a receiving terminal are mixedly connected via two or more switches below the router. However, effective and efficient multicast can be realized using a simple switch.
[0029]
  The network according to the third invention of the present application provided to solve the above problem is the invention according to claim 2,The always-transmitted ports of the other switches at the end of each of the two switches arranged in sequence are connected to form a ring network.It is characterized by that.
[0030]
By adopting such a configuration, the uplink path, which is the main transmission path of the network that is made to be a ring, can be transmitted at all times. Since the time required to receive the information “Query” can be omitted, the time required for topology change such as link disconnection can be shortened as much as possible. Specifically, in the prior art, there are three processes: (1) disconnecting the uplink path, (2) releasing the block port, and (3) issuing “Query” from the router to the switch and taking a confirmation procedure. However, since the multicast data reaches the switch via the uplink path simultaneously with the release of the block port (2), the receiving terminal connected to the switch can immediately receive the multicast data. . That is, the process (3) is not necessary.
[0031]
  A multicast transmission method according to a fourth invention of the present application provided to solve the above-described problem is that a plurality of switches including at least a switch to which a transmitting terminal is connected and a switch to which a receiving terminal is connectedAcross one routerLined up and connected to form one network,Indicates the transmission route between ports of multicast data that each switch hasA multicast transmission method for selectively transmitting multicast data from the transmitting terminal to the receiving terminal based on a multicast filter table,
For each switch,
  A port of a switch directly connected to the router or indirectly connected to the router via another switch is set so as to be included in the multicast filter table in advance as a port where multicast data is always transmitted,
  Referring to the inquiry information regarding the multicast data periodically received from the router and the port connected to the receiving terminal that has received the participation message for receiving the multicast data, the transmission route between the ports of the multicast filter table is determined. Updated,
  The multicast data is selectively transmitted from the transmitting terminal to the receiving terminal by causing the switch means to form a transmission route between the ports based on the multicast filter table.It is characterized by that.
[0032]
By adopting such a method, the uplink path is set so that it can always be transmitted. Therefore, even in a network in which a transmitting terminal and a receiving terminal are connected together via two or more switches below the router, it is easy. An effective and efficient multicast can be realized using a simple switch.
[0033]
  The multicast transmission method according to the fifth invention of the present application provided to solve the above problem is the multicast transmission method according to claim 4,The one network is configured as a ring network by connecting the always-transmitting ports of the switch in a ring arrangement via the one router.It is characterized by that.
[0034]
By adopting such a method, it is possible to always transmit the uplink path that is the main transmission path of the network that is in the ring shape, so that when the uplink path is disconnected, the switch is released after the block port is released. Since the time required to receive the inquiry information “Query” can be omitted, the time required for topology change such as link disconnection can be shortened as much as possible. Specifically, in the prior art, there are three processes: (1) disconnecting the uplink path, (2) releasing the block port, and (3) issuing “Query” from the router to the switch and taking a confirmation procedure. However, since the multicast data reaches the switch via the uplink path simultaneously with the release of the block port (2), the receiving terminal connected to the switch can immediately receive the multicast data. . That is, the process (3) is not necessary.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0036]
(Embodiment 1)
FIG. 1 is a block diagram showing the configuration of the first exemplary embodiment of the present invention.
[0037]
As shown in FIG. 1, the network configuration according to the present invention includes a router R.₁And this router R₁The switches SW11 to SW18, to which the transmission terminal 31, the reception terminals 21 to 22, and the reception terminals 24 to 28 are connected, are connected in a ring shape. Here, it is assumed that layer 2 switches are employed as the switches SW11 to SW18.
[0038]
Also, the router R₁Is a router R constituting another network.₂Connected to the router R₂Is connected to a receiving terminal 29.
[0039]
The router R₁And the switch SW11 to SW18 or a path connecting the switches SW11 to SW18 is defined as an uplink path 2. In addition, it is desirable to set the bandwidth of the uplink path 2 to be larger than the bandwidth of other transmission paths (for example, the transmission path connecting the switch and the receiving terminal).
[0040]
Therefore, among the ports of each of the switches SW11 to SW18, the ports connected to the uplink path 2 are p1 and p2, respectively, and the receiving terminals 21 to 22 and the receiving terminals 24 to 28 are connected. Is p3.
[0041]
Further, in the uplink path 2, a block port is set in order to logically prevent an infinite loop of packet data in a ring-shaped network.
[0042]
Next, the configuration of the switch according to the first embodiment of the present invention will be described below with reference to the drawings.
[0043]
FIG. 2A is a block diagram illustrating a configuration of the switch according to the first embodiment of the present invention, and FIG. 2B is a diagram illustrating a multicast filter table.
[0044]
As shown in FIG. 2A, the switch according to the first embodiment of the present invention connects at least one of the two ports 41a to which the uplink path 2 is connected and at least one of the transmitting terminal and the receiving terminal. Port group 41 consisting of ports 41b, switch means 42 for mutually transferring the transmitted IGMP packet between the ports, and detecting the transmitted IGMP packet and extracting the information of the port that received the IGMP packet IGMP packet extracting means 43 for sending, IGMP packet sending means 44 for sending IGMP packets, a multicast filter table 45 for storing information relating to multicast filters, and the type of IGMP packet obtained by the IGMP packet extracting means (“Query”) , "Report", "Lea e "), and updates the multicast filter table based on the identified IGMP packet type and the multicast filter table 45, and the IGMP packet management means 46 always sets the port 41a as a transmission path; , The port information storage means 47 for storing the information of the port that has received “Query”, and the periodic timer 48 for deleting unnecessary multicast. Here, the “Leave” is an IGMP packet transmitted from the receiving terminal, as in the case of the “Report”, and is an indication of intention that the receiving terminal leaves the multicast group. The IGMP packet management means 46 functions in the IGMP protocol and is a kind of the aforementioned packet management means.
[0045]
In addition, there is means for setting whether or not IGMP snooping is valid, and when IGMP snooping is valid, the setting information of the period timer 48 is transmitted to the IGMP packet management means 46, When the IGMP snooping is invalid, the switch is provided with an IGMP snooping management means 49 that causes the IGMP packet extraction means 43 to send an IGMP packet to the IGMP packet sending means 44. By providing the IGMP snooping management means 49, effective and efficient multicast can be realized using a simple switch even when IGMP snooping is not applicable.
[0046]
Further, as shown in FIG. 2B, in the multicast filter table according to the first embodiment of the present invention, ports that are effective for forming a transmission route for each multicast address are set as a “port list”. ing.
Here, the multicast address is identification information for individually identifying multicast data transmitted from the transmitting terminal. That is, a multicast address is assigned for each multicast data to be transmitted. The port numbers p1 and p2 set in each port list indicate uplink paths, and the other port numbers (p3, p4, p5) are ports to which receiving terminals are connected, that is, ports for transferring multicast data. Is shown. Further, the “Query transmission flag” is a flag for identifying whether or not “Report” has been received for each port, and the “response monitoring flag” and the “discard monitoring flag” are identification flags related to aging.
[0047]
Next, the operation in the first embodiment of the present invention will be described below with reference to the drawings.
[0048]
FIG. 3 is a flowchart showing an operation method of the IGMP packet management means as the first embodiment of the multicast transmission method according to the present invention.
As shown in FIG. 3, it is first determined whether the event is a packet reception or a periodic timer (S1). If the packet is received, a SUM check of the IGMP header is performed (S2). In the event of a failure, “timer event processing” described later is performed.
[0049]
When it is confirmed that the SUM of the IGMP header is normal, the type of the IGMP packet is specified from any one of “Query”, “Report”, and “Leave” (S3).
[0050]
Thereafter, when the type of the IGMP packet is specified as “Query”, the “Query reception process” is performed. When the type of the IGMP packet is specified as “Report”, the “Report reception process” is performed. If the IGMP packet type is identified as “Leave”, “Leave reception processing” is performed.
[0051]
On the other hand, if it is determined in the IGMP header check SUM process that there is an abnormality, the packet is discarded (S4) and the process is terminated.
[0052]
(Query reception processing)
FIG. 4 is a flowchart showing an operation of “Query reception processing” performed when the type of the IGMP packet is specified as “Query”.
[0053]
As shown in FIG. 4, first, the querier port information relating to the port for which “Query” is issued is updated (S11).
[0054]
Next, a response monitoring timer, which is a timer from when "Query" comes from the router to when "Report" comes from the receiving terminal, is initialized and started (S12).
[0055]
Next, "Query" is transferred to ports other than the querier port (S13).
[0056]
Subsequently, the “Query” transmission flag is set (S14), and the process ends.
[0057]
(Report reception processing)
FIG. 5 is a flowchart showing an operation of “Report reception processing” performed when the type of the IGMP packet is specified as “Report”.
[0058]
As shown in FIG. 5, first, it is determined whether or not the received “Report” is registered in the multicast group (S21).
[0059]
If it is determined that the information has been registered, information related to the port that has received “Report” is set in the port list (S22).
[0060]
Here, if this port already exists in the port list, there is no need to set it.
[0061]
Next, the Query transmission flag of the reception port is reset (S23).
[0062]
Subsequently, the discard monitoring timer that performs aging is stopped (S24).
[0063]
Next, it is determined whether or not this report has been transmitted (S25). Here, “whether or not this report has been transmitted” means whether or not “Report” relating to the same multicast data has already been transmitted from another terminal belonging to the connected switch. If it has already been transmitted, “Report” is not transmitted to the Query reception port. If the Report has not been transmitted, “Report” is transmitted to the Query reception port (S25a).
[0064]
When the port list is changed in this way (S26-Yes), the change information is set in the switch means 42, and the “Report” reception process is terminated.
[0065]
If the port list has not been changed (S26-No), the “Report” reception process is terminated.
[0066]
It is determined whether or not the received “Report” is registered in the multicast group (S21). If it is not registered (S21-No), it is newly registered in the multicast filter table, and the uplink path port and the report are received. The port is added to the port list (S27). Next, “Report” is transmitted to the port that has received “Query” (S28). Further, the information is set in the switch means 46 of FIG. 2 (S29), and the Report reception process is terminated.
[0067]
(Leave reception processing)
FIG. 6 is a flowchart illustrating an operation of “Leave reception processing” performed when the type of the IGMP packet is identified as “Leave”.
[0068]
As shown in FIG. 6, first, the IGMP packet management unit deletes information about the port that has received “Leave” from the port list (S31).
[0069]
Next, it is determined whether ports other than the uplink path are in the port list (S32).
[0070]
If the port list is found by this determination, the multicast filter is changed (S33), and the process is terminated.
[0071]
If there is no port other than the uplink path in the port list, “Leave” is transmitted to the port that has received “Query” (S34), and this entry is deleted from the multicast filter table (S35). The multicast filter of the switch means is deleted (S36), and the process ends.
[0072]
(Timer event processing)
FIG. 7 is a flowchart showing an operation of “timer event processing” performed when it is determined whether the event is a packet reception or a periodic timer (S1) and the timer is a periodic timer.
[0073]
As shown in FIG. 7, first, it is “response monitoring processing” in which the time from receiving “Query” to receiving “Report” is monitored, or time-out occurs after receiving “Report” (discard It is determined whether or not “discard monitoring process” is being monitored (S41).
[0074]
If it is "discarding", the timer is decremented (S42), it is determined whether the timer has expired (S43), and if it has expired, the port whose timer has expired is deleted from the port list (S44). . If the timer has not expired, the process ends.
[0075]
Thereafter, it is determined whether or not a port other than the uplink path is in the port list (S45). If there is no port, this entry is deleted from the multicast filter table (S46), and related information in the multicast filter is deleted. (S47), and ends.
[0076]
If there is a port other than the uplink path in the port list, the related information in the multicast filter is changed (S48), and the process ends.
[0077]
Next, if “response monitoring process is in progress”, the timer is decremented (S51), and it is determined whether the timer has expired (S52). If the timer has expired, the “response monitoring process” is terminated (S53). ), The “Query” transmission flag is reset (S54), the discard monitoring process is started for the port for which the Query transmission flag is set (Report not transmitted) (S55), and the process ends. If the timer has not expired, the process ends.
[0078]
As described above, according to the first embodiment of the present invention, an uplink path that always functions as a transmission path is set as a filtering function, so that a transmission terminal is connected via two or more switches below the router. Even in a ring network in which receiving terminals are connected together, an effective and efficient multicast can be realized using a simple switch.
[0079]
In addition, when the uplink path is disconnected, the time required for the switch to receive “Query” after the block port is released can be eliminated, so the time required for topology change such as link disconnection can be minimized. Can be shortened. Specifically, in the prior art, the following three processes were performed: (1) disconnecting the uplink path, (2) releasing the block port, and (3) issuing “Query” from the router to the switch and taking a confirmation procedure. However, since the multicast data reaches the switch via the uplink path simultaneously with the release of the block port (2), the receiving terminal connected to the switch immediately issues a report and sends the multicast data. Can receive. That is, the process (3) is not necessary.
[0080]
(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to the drawings.
In the description of the second embodiment of the present invention, only differences from the first embodiment described above will be described, and redundant descriptions such as descriptions of the configuration and operation of the switches will be omitted.
[0081]
FIG. 8 is a block diagram showing the configuration of the second exemplary embodiment of the present invention.
[0082]
As shown in FIG. 8, the network configuration according to the present invention includes a router R.₁And this router R₁Are received via the switch SW11 to which the receiving terminals 21 to 23 are connected, the switch SW12 to which the receiving terminals 24, 25 and 26 are connected, and the receiving terminal 27 and the switch SW91 (general-purpose layer 2 switch). A so-called tree structure is formed of the switch SW13 to which 28 and the like are connected and the switch SW14 to which the transmission terminal 31 is connected.
[0083]
Here, it is assumed that layer 2 switches are employed as the switches SW11 to SW14.
[0084]
Also, the router R₁Is a router R constituting another network.₂Connected to the router R₂Is connected to a receiving terminal 29.
[0085]
The router R₁And the switch SW11 to SW14 are defined as an uplink path 2. (Indicated by double lines in the figure) That is, router R₁The switches SW11 to SW14 in the network configured below are connected to the router R by the uplink path 2.₁The configuration is directly connected to.
[0086]
Note that the switch SW91 is not a filter that performs filtering, and therefore it is not particularly necessary to set the uplink path 2.
[0087]
Further, it is desirable to set the bandwidth of the uplink path 2 to be larger than the bandwidth of other transmission paths (for example, the transmission path connecting the switch and the receiving terminal).
[0088]
Next, the configuration of the switch according to the second embodiment of the present invention will be described below with reference to the drawings.
[0089]
FIG. 9 is a block diagram showing a configuration of the switch in the second exemplary embodiment of the present invention.
[0090]
As shown in FIG. 9, the switch according to the second embodiment of the present invention includes at least one port 41a to which the uplink path 2 is connected and a port to which at least one of the transmitting terminal and the receiving terminal is connected. 41b, a port group 41, switch means 42 for mutually transferring the transmitted IGMP packet between the ports, and an IGMP packet for detecting the transmitted IGMP packet and extracting information of the port that has received the IGMP packet Extraction means 43, IGMP packet transmission means 44 for transmitting IGMP packets, multicast filter table 45 for storing information relating to multicast filters, and types of IGMP packets obtained by the IGMP packet extraction means ("Query", "Report" "," Leave " An IGMP packet management means 46 that updates the multicast filter table based on the type of the specified IGMP packet and the multicast filter table 45, and always sets the port 41a as a transmission path; "Port information storage means 47 for storing the information of the port that received" "and a periodic timer 48 for deleting unnecessary multicast.
[0091]
In addition, it has means capable of setting whether or not IGMP snooping is valid, and when IGMP snooping is valid, the setting information of the period timer 48 is transmitted to the packet management means 46, When the IGMP snooping is invalid, the switch is provided with an IGMP snooping management means 49 that causes the IGMP packet extracting means 43 to send an IGMP packet to the IGMP packet sending means 44.
[0092]
Thus, as the uplink path 2, the router R₁And the switch SW11 to SW14 are set, and the ports to which the uplink path is connected in the switch SW11 to SW14 can always be transmitted. Even in a shaped network, it is possible to realize efficient multicast with a simple configuration without excessively affecting traffic.
[0093]
【The invention's effect】
As described above, according to the present invention, the uplink path is set so that it can always be transmitted. Therefore, even in a network in which a transmitting terminal and a receiving terminal are connected together via a switch below a router, The problem that unnecessary multicast data is transmitted to the transmitting terminal and the receiving terminal that occurs when using the layer 2 switch of, and the multicast data from the transmitting terminal that occurs when the IGMP snooping switch is used are not transmitted The problem can be solved and effective and efficient multicast can be realized using a simple switch.
[0094]
In an annular network, when an uplink path is disconnected, the time required for the switch to receive “Query” after the block port is released can be eliminated. The time required for the change can be shortened as much as possible.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a network configuration according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a switch according to the first embodiment of the present invention.
FIG. 3 is a flowchart showing an operation method of the IGMP packet management means in the first embodiment of the present invention.
FIG. 4 is a flowchart illustrating a process of Query reception processing according to the first embodiment of the present invention.
FIG. 5 is a flowchart showing a report reception process according to the first embodiment of the present invention;
FIG. 6 is a flowchart showing a process of Leave reception processing in the first embodiment of the present invention;
FIG. 7 is a flowchart showing a timer event processing process in the first embodiment of the present invention;
FIG. 8 is a block diagram showing a network configuration according to a second embodiment of the present invention.
FIG. 9 is a block diagram illustrating a configuration of a switch according to a second embodiment of the present invention.
FIG. 10 is a block diagram showing a configuration of a network for performing a conventional multicast.
FIG. 11 is a block diagram showing a configuration of a network for performing a conventional multicast.
[Explanation of symbols]
1 network
2 Uplink path
21-29 receiving terminal
31 Sending terminal
41 port group
42 Switch means
43 IGMP packet extraction means
44 IGMP packet sending means
45 Multicast filter table
46 IGMP packet management means
47 Port information storage means
48 period timer
49 IGMP snooping management means
p1-p3 ports
R₁, R₂  Router
SW11 to SW18, SW91 switch

Claims (5)

A switch at least one of the receiving terminals are connected to receive the transmit terminal and the multicast data and transmits the multicast data, together with the other said switch (SW11~SW18), and the column set via one router (R1) Are connected to each other to form one network,
The router or another switch connected Ru port, and the transmitting terminal and the port group including the port at least one is Ru is connected to the receiving terminal (41),
Switch means (42) for forming a transmission route between predetermined ports of the port group;
Contact information and the multicast data for the multicast data to which the router or other connected Ru port (41a) of the multicast data to the switch includes that is preset as a port to be transmitted continuously, periodically receives from the router A multicast filter table (45) representing a transmission route between the ports for distributing the multicast data , which is updated based on the port that has received the join message for receiving the message;
Update the multicast filter table , send the inquiry information to the receiving terminal, and send the participation message to the router according to the inquiry information when a participation message is received from the receiving terminal in response to the inquiry information A packet management means (46),
The packet management unit refers to a multicast filter table and causes the switch unit to form the transmission route between the ports. And at least one router (R1), a plurality of a switch (SW11~SW18) including a switch at least transmitting terminal connected switch and the receiving terminal is connected, at least two of said routers of the plurality of switches A network in which another switch is connected in series following one of the two switches ,
Each of the switches
Port connected to the router or other switches, as well as the transmitting terminal and the port group including the port at least one is connected to the receiving terminal (41),
Switch means (42) for forming a transmission route between predetermined ports of the port group;
Contact information and the multicast data for the multicast data to which the router or other connected Ru port (41a) of the multicast data to the switch includes that is preset as a port to be transmitted continuously, periodically receives from the router A multicast filter table (45) representing a transmission route between the ports for distributing the multicast data , which is updated based on the port that has received the join message for receiving the message;
Update the multicast filter table , send the inquiry information to the receiving terminal, and send the participation message to the router according to the inquiry information when a participation message is received from the receiving terminal in response to the inquiry information A packet management means (46),
The packet management means refers to a multicast filter table and causes the switch means to form the transmission route between the ports. 3. The network according to claim 2, wherein the constantly transmitted ports of the other switches at the end of each of the two switches arranged in order are connected to form a ring network. 4. . A plurality of switches including at least a switch to which a transmission terminal is connected and a switch to which a reception terminal is connected are arranged in a line with one router interposed therebetween to form one network, and each switch has multicast data A multicast transmission method for selectively transmitting multicast data from the transmitting terminal to a receiving terminal based on a multicast filter table representing a transmission route between ports ,
For each switch,
A port of a switch directly connected to the router or indirectly connected to the router via another switch is set so as to be included in the multicast filter table in advance as a port where multicast data is always transmitted,
Referring to the inquiry information regarding the multicast data periodically received from the router and the port connected to the receiving terminal that has received the participation message for receiving the multicast data, the transmission route between the ports of the multicast filter table is determined. Updated,
A multicast transmission method , wherein the multicast data is selectively transmitted from the transmitting terminal to the receiving terminal by causing the switch means to form a transmission route between the ports based on the multicast filter table . The said one network is comprised as a cyclic | annular network by connecting the said always-transmitted port of the said switch in a ring arrangement via the said 1 router, and connecting. 5. The multicast transmission method according to 4.

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