JP2004247931A - Multi-cast tunneling communication system, method for generating multi-cast program identifier, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method by which a transmitter uniquely decides a multi-cast address and a port number of a program identifier without overlapping on other programs when using one-to-many broadcasting application by using multi-cast tunneling communication over a wide area IP network. <P>SOLUTION: A transmission host is fixed for only one program each. By using a static conversion rule by which one-to-one inter-conversion is possible from its own uni-cast address, a transmission side packet conversion device Pa generates a set of the multi-cast address and the port number and uses it as a multi-cast program identifier. By generating the multi-cast program identifier by using the same static conversion rule from the uni-cast address of a transmission origin, a reception side packet conversion device Pc is made to allocate a multi-cast transmission host Ha and a receiving host Hc connected to different packet conversion devices Pa and Pc with a shared multi-cast program identifier and does not allow the multi-cast program identifiers collide with each other among different programs. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a plurality of one-to-many communication protocols compatible with a one-to-many communication protocol are transmitted from a transmission host (sending terminal) supporting one-to-many communication protocols via an existing wide area IP network in which only one-to-one communication (unicast) is provided. The present invention relates to a multicast tunneling communication system for broadcasting data to a receiving host (receiving terminal) and a multicast program identifier generating method.
[0002]
[Prior art]
There are two services to which broadcast communication in a communication network is applied, a one-to-many broadcast application and a many-to-many conference application. The present invention assumes a broadcast type application. As an example of a broadcast type application, Patent Literature 1 discloses an embodiment of a broadcast communication system. As shown in this example, a service in which a specific sender broadcasts stream data such as a video program to a very large number of recipients is one of the effective uses of a communication network. This is a promising technical field.
[0003]
2. Description of the Related Art Conventionally, as a method of implementing multicast communication for broadcasting data to a plurality of reception posts in an IP network, there is a method of performing communication using a predetermined multicast IP address (IP multicast). In this method, when a sending host (sending terminal) sends data to a multicast IP address as a destination, a multicast router (relay device) provided on the Internet copies all the data as needed during the delivery, so that all of the data is received. The same data is delivered to the host.
[0004]
In order to realize the above-described IP multicast, all routers need to support IP multicast. However, under the current situation where most routers do not support IP multicast, it is difficult to make all routers support IP multicast.
[0005]
As a method of realizing IP multicast communication between a transmitting terminal and a receiving terminal via an IP multicast non-compliant network, there is a tunneling communication method such as that performed in a virtual multicast experimental network called MBONE (Multicast backBONE). For example, page 224 of the document "Nikkei BP Digital Encyclopedia 1998" has a description of MBONE. MBONE provides a method for constructing a virtual wide-area multicast backbone network between the two LANs by encapsulating and connecting the two LANs corresponding to the IP multicast with unicast, and performing IP multicast communication therethrough. ing.
[0006]
As a technique similar to the above, Patent Document 2 discloses a method of configuring a system that performs multicast tunneling via a network that does not support multicast and a method of implementing a packet conversion device that is a component thereof. This specification describes a method of tunneling by simply connecting a plurality of packet converters by one-to-one unicast communication without using a virtual multicast experimental network such as MBONE.
[0007]
The communication method using the multicast tunneling described above is a technique for making the IP multicast distribution available in a pseudo-wide area network, and contributes to the spread of the Internet broadcast distribution service. In IP multicast, a program is identified by a multicast IP address. In order to use IP multicast in a wide area network, it is necessary to obtain a globally unique multicast address. The multicast address is managed by the Internet address management organization (IANA), and it is necessary to apply here by writing or the like to have the address assigned.
[0008]
In the MBONE experimental network described above, a plurality of multicast addresses usable for MBONE are assigned from the Internet address management organization (IANA) to the MBONE experimental organization. The applicant for the multicast distribution obtains the multicast address by obtaining an agreement in the MBONE experimental organization by a written application or the like. Therefore, there is no mechanism that allows anyone to immediately perform multicast distribution when necessary.
[0009]
On the other hand, in the case of a simple tunneling method based on one-to-one unicast as represented by Patent Document 2, since a multicast packet is not transferred to an unspecified destination, a globally unique multicast address is assigned. There is no need to obtain it, and any address can be selected from multicast addresses that are allowed to be used locally and used at any time. However, the sender and the receiver need to agree on a multicast address for each program in advance. In the embodiment of the above specification, the multicast address is registered in advance in the address management table in the packet converter on both the transmitting and receiving sides, but the method of allocating the address is not mentioned.
[0010]
As an example of a method of assigning a multicast address, Patent Document 3 discloses a method of accessing a common address management server and registering and referencing the currently used multicast program identifier to the management server, thereby avoiding collision of program identifiers. Is disclosed.
[0011]
[Patent Document 1]
JP 2001-345807 A
[Patent Document 2]
JP 2001-230774 A
[Patent Document 3]
JP-A-1998-154980
[0012]
[Problems to be solved by the invention]
In multicast tunneling communication, a sending host and a receiving host identify a program by a set of a multicast address and a port number (hereinafter, referred to as a multicast program identifier). At both ends of the tunnel, the sending host and the receiving host preferably use the same multicast program identifier. By doing so, it becomes possible to use the transmission / reception application in an environment exactly the same as that connected to the local network.
[0013]
In the broadcast-type application assumed by the present invention, the number of recipients is unspecified and large, and it is assumed that the recipients join or leave during distribution. Therefore, it is natural that the multicast program identifier is determined on the transmitting side, and the receiving side selects a program to be received using the identifier.
[0014]
In the case of a simple tunneling method based on one-to-one unicast, since a multicast packet is not sent over a wide area, a preferred multicast program identifier from a defined range may be used. However, if there are a plurality of senders using tunneling and each sender arbitrarily selects a multicast program identifier and performs communication, identifiers may collide between originally different programs. When the identifiers collide with each other, there is a problem that when hosts receiving different programs accidentally exist on the same local network, packet interference occurs and normal communication cannot be performed.
[0015]
In order to avoid the above-described packet interference, when a new program distribution is started, the distribution must be performed using a multicast program identifier that is not used by anyone. If the network is of a limited scale, there is a method of searching for all the packet converters connected to the network and finding an unused multicast program identifier. It is difficult to grasp.
[0016]
Alternatively, as proposed in Patent Document 3, all packet translators access a common address management server, and register and refer to the currently used multicast program identifier in the management server, thereby causing program identifier collision. However, when the network scale is increased, access to the management server is concentrated and there is a possibility that the identifiers of all programs cannot be managed.
[0017]
The present invention has been made in consideration of the above circumstances, and has as its object no need to search for unused multicast program identifiers, and there is no need to provide a management server or the like for managing multicast program identifiers, and Another object of the present invention is to provide a multicast tunneling communication system and a multicast program identifier generation method that enable a sender to uniquely determine a multicast address and a port number, which are identifiers of a program, without duplication with other programs.
[0018]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and the invention according to claims 1 and 6 is a method for determining a multicast program identifier from a unicast address of a packet converter on the transmitting side in one-to-one correspondence. A unique and unique multicast program identifier shall be generated by using a static conversion rule which can be converted into each other, and all packet converters connected to the network shall use the same static conversion rule to allow the sender Are able to use multicast program identifiers unique to each other without exchanging information with each other.
[0019]
The invention according to claims 2 and 7 is characterized in that the transmission-side packet conversion device has a function of assigning a flow identifier for identifying a plurality of programs to the unicast data. A unique and unique multicast program identifier is generated from a pair of an address and a flow identifier (hereinafter, referred to as a unicast program identifier) using a static conversion rule capable of one-to-one conversion. By using the same static conversion rule for all the packet converters to be connected, senders can use mutually unique multicast program identifiers without exchanging information with each other.
[0020]
According to the third, eighth and eleventh aspects of the present invention, in the generation of the multicast program identifier, information of an IPv4 unicast address having a space of 32 bits is allowed only to a space of 24 bits or less. By storing the information of 8 bits or more of the difference in a part of the multicast port number having a space of 16 bits in order to convert the information into the multicast address, the multicast address and the port number can be used to store the information. It is characterized in that a one-to-one static conversion rule with a cast address is formed.
[0021]
According to the fourth, ninth, and twelfth aspects of the present invention, in a static address translation rule, a part of unicast address information is stored in a partial area of a multicast port number, and the rest of the port number is stored. The information of the flow identifier is stored in the area.
[0022]
According to a fifth, tenth, and thirteenth aspect of the present invention, in the static address translation rule, the upper 8 bits of the 32-bit multicast address are set to a predetermined constant value, and the other 24 bits are set to 24 bits. The lower 24 bits of the 32-bit unicast address are used as they are, the upper 8 bits of the unicast address are each inverted, and used as the upper 8 bits of the multicast port number having a space of 16 bits. The flow identifier is used as it is for the lower 8 bits of the port number.
According to a fourteenth aspect of the present invention, there is provided a computer-readable recording medium recording the program according to any one of the eleventh to thirteenth aspects.
[0023]
According to the present invention, a transmission host is determined for each program in a broadcast application, and the fact that the unicast IP address of the packet converter on the transmission side has global uniqueness is used. By providing a method in which all packet converters for performing multicast tunneling generate a multicast program identifier according to a common static translation rule, a mechanism is provided for globally unique and unique multicast program identifier for each sender. be able to.
[0024]
ADVANTAGE OF THE INVENTION According to this invention, when performing multicast tunneling, the possibility that packet interference will occur on the receiving side can be eliminated. Further, in the present invention, there is no need for the senders to exchange information with each other in order to guarantee the uniqueness of the multicast program identifier, and the system operates without any problem even if the network scale becomes large. Also, since there is no need to apply to the organization that performs the address assignment and to access an external address management server, anyone can immediately start multicast tunneling distribution when needed.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a multicast tunneling communication system according to an embodiment of the present invention. In the system shown in this figure, three local networks LAN (A), LAN (B), and LAN (C) are connected by a wide area IP network WIP that does not support multicast. The local network LAN (A) is connected to an IP multicast-compatible transmission host Ha and a packet conversion device Pa, and the local network LAN (B) is connected to an IP multicast-compatible transmission host Hb and a packet conversion device Pb. The local network LAN (C) is connected to receiving hosts Hc1 and Hc2 compatible with IP multicast and a packet converter Pc.
[0026]
Each of the packet converters Pa to Pc has a central controller for operating itself autonomously and an input / output interface for transmitting and receiving packets. Further, each of the packet converters Pa to Pc has a program identifier management table Ta1, Tb1, Tc1 for managing a translation address for each program to be distributed. As shown in FIG. 2, the program identifier management tables Ta1 to Tc1 include a multicast program identifier composed of a set of a multicast address and a port number, and a corresponding unicast program identifier composed of a set of a source unicast address and a flow identifier. Is stored. Further, each of the packet conversion devices Pa to Pc has a destination management table Ta2 to Tc2 shown in FIG. 3, and when a transmission host exists in the same LAN, the packet conversion device of the reception side currently desiring to receive the packet is transmitted. A list of unicast addresses is managed.
[0027]
Hereinafter, the operation of the packet converters on the transmitting side and the receiving side when performing multicast tunneling communication with the configuration of the present embodiment will be described. The transmitting side is the packet converter Pa, and one of the receiving sides is the packet converter Pc. The case will be described as an example. Note that this conversion operation is not a new method but one of the methods widely known from the past.
[0028]
The transmission-side packet converter Pa reads the header of the multicast packet sent from the transmission host Ha in the LAN, finds the flow identifier corresponding to the program by referring to the program identifier management table Ta1. Then, the information of the multicast packet including the header portion and the information of the flow identifier are stored in the datagram of the unicast packet and encapsulated. Further, the transmitting-side packet translator Pa copies the unicast packets by the number of receiving-side packet translators desiring reception by referring to the destination management table Ta2, and sends the packets to the respective destinations. I do.
[0029]
On the other hand, the receiving-side packet converter Pc receives the unicast packet sent to itself from the transmitting-side packet converter Pa, extracts and restores the multicast packet stored in the datagram, and restores the receiving host Hc1 in the LAN. , Hc2.
[0030]
The above is the basic mechanism of the multicast tunneling communication. As a method of converting multicast to unicast, in addition to the above-described encapsulation method, there is also a header rewriting type method of rewriting a multicast packet header and transferring it as a unicast packet. The method is also applicable.
[0031]
When the multicast tunneling communication as described above is started, it is necessary to register a program in the program identifier management tables Ta1 and Tc1 in the packet converters Pa and Pc on the transmitting and receiving sides. First, since the sender does not know who wants to receive the program at the start of program distribution, the sender will disclose the program identifier to an unspecified majority in advance. This can be performed by various means such as posting on a web page on the Internet, using a mailing list, posting on a bulletin board or a magazine.
[0032]
When the transmission host Ha is ready for transmission, the program identifier management table Ta1 of the packet conversion device Pa stores a set of a unicast program identifier (a set of a source unicast address and a flow identifier) and a multicast program identifier of the program to be transmitted. Register If both the receiving hosts Hc1 and Hc2 in the LAN (C) desire to receive data, the receiving hosts Hc1 and Hc2 change the packet in the same LAN (C) as the receiving host when they want to start receiving. A set of a unicast program identifier (a set of a source unicast address and a flow identifier) of a program desired to be received and a set of a multicast program identifier are registered in the program identifier management table Tc1 of the device Pc.
[0033]
When performing the registration work, the packet conversion device Pc of the present embodiment compares the unicast program identifier with the multicast program identifier in the central control device in the device, and determines whether the static address conversion rule held in the device is correct. It has a unique function of checking whether or not it is protected, and permitting registration in the management table only if the check is passed. In addition, when one of the unicast program identifier and the multicast program identifier is omitted and is to be registered, the unique function of automatically complementing and registering the other according to the above static address translation rule is provided. Have. Note that the static address translation rule will be described later in detail.
[0034]
When an entry is added to the program identifier management table, the packet translator determines whether it is on the transmitting side or the receiving side of the program, depending on whether or not the source unicast address is its own address. Automatically determine. If it is on the receiving side, it sends a reception request packet including the information of the program identifier to the packet converter of the transmission source. Upon receiving the reception request packet, the transmission-side packet conversion apparatus registers the unicast address of the reception requester in its own destination management table, and starts distribution of the requested program there.
[0035]
Next, a multicast program identifier generation method according to the present embodiment will be described. In FIG. 1, there is a transmission host Ha and a transmission host Hb that distribute different programs on the LAN (A) and the LAN (B), respectively, and two reception hosts Hc1 and Hc2 are located on the LAN (C). It is assumed that the receiving host Hc1 is going to receive the program of the transmitting host Ha, and the receiving host Hc2 is going to receive the program of the transmitting host Hb.
[0036]
At this time, there are the following two problems.
(1) If the sending hosts Ha and Hb determine the multicast program identifier (a set of a multicast address and a port number) without permission, there is a possibility that the same identifier may be accidentally selected. In this case, the receiving hosts Hc1 and Hc2 belong. Packet interference occurs in the LAN (C), and normal reception cannot be performed.
[0037]
(2) The sender needs to simultaneously notify the receiver of not only the multicast program identifier but also a set of unicast addresses and flow identifiers (unicast program identifiers) used by the transmitting side packet converters Pa and Pb. . This is information necessary for the recipient to notify the transmitting-side packet converters Pa and Pb of the existence of the recipient. However, for the user, it is necessary to handle two types of program identifiers, multicast and unicast, which is troublesome.
[0038]
In order to solve the above two problems, the present invention uses a method of uniquely obtaining a multicast program identifier from a set of unicast program identifiers by a static conversion rule. The following and FIG. 4 show the embodiment.
[0039]
(Conversion rules)
Currently, IPv4 (Internet Protocol version 4), which is generally used, uses a 32-bit IP address and, for convenience, enumerates and describes four decimal numbers separated by periods of 8 bits. The port number has a space of 16 bits. In the present embodiment, when the unicast address of the transmitting-side packet translation device is “ABCDD”, the multicast address to be assigned is “239.BCD”. For the port number to be assigned, the upper 8 bits are "255-A" and the lower 8 bits are a flow identifier.
[0040]
In this conversion rule, the multicast address is allocated from a 24-bit address space starting with 239. According to RFC3171 disclosed by the standardization organization IETF, this space is reserved for local addresses and will not be used for global communication for the time being. In the multicast tunneling communication assumed in the present embodiment, there is no problem since the multicast packet does not flow out of the LAN.
[0041]
Also, the IP address whose lower 24 bits are "0.0.0.0" or ".255.255.255" has a custom of being used for a special purpose, and such a special address is also used for a multicast address. It is safer to avoid using addresses. In this conversion rule, since the lower 24 bits of the unicast address originally possessed by the packet conversion device are allocated to the multicast address, the above-described special address does not appear.
[0042]
On the other hand, when a port number of 1023 or less is used, some computer systems require administrator authority and cannot be used by anyone freely. In order to avoid this problem, “255-A” in which the upper 8 bits of the unicast IP address are inverted is assigned to the upper 8 bits of the port number. Since the upper three bits of the unicast address defined by IPv4 start with one of three types of binary numbers “0”, “10”, and “110”, 0 always exists in some of the upper three bits. Therefore, if the bit is inverted, 1 always exists in some of the upper 3 bits. By embedding the bit-reversed numerical value in the upper bits of the port number, it is guaranteed that the port number will be larger than 8192. Therefore, it has the property that there is no concern that a port number of 1023 or less is allocated. Further, since the lower 8 bits of the port number directly correspond to the flow identifier, if there is an application using a continuous port number, the flow identifier has a property of being a continuous number. Further, the conversion rule is relatively simple, and has a feature that the calculation cost required for the conversion is small.
[0043]
How the two problems related to program identifier assignment are solved by the static conversion rule described above will be described.
First, regarding the first problem of the collision of program identifiers, in a broadcast-type application, the transmission host is determined for each program, and the unicast IP address of the transmitting-side packet converter is originally globally unique. Since all packet converters performing multicast tunneling generate a multicast program identifier according to a common static conversion rule, it is possible to provide a means for giving a globally unique and unique multicast program identifier for each sender. . Therefore, when multicast tunneling is performed, the possibility of packet interference occurring on the receiving side can be eliminated.
[0044]
As for the second problem, in which both the multicast program identifier and the unicast program identifier must be written together, one of them can be designated by using a conversion rule that can be converted one-to-one. If so, the other can be determined automatically. Therefore, if the receiver can know either the multicast program identifier or the unicast program identifier, it only needs to register this in the program identifier management table of the packet converter on the receiving side, and the other identifier is automatically determined by the above conversion rule. And the program identifier management table can be completed. Then, the receiving-side packet translator transmits a program distribution request signal to the unicast address of the transmitting-side packet translating device, so that the transmitting-side packet translating device adds the transmission destination to the transmission destination management table and performs tunneling. It is possible to provide a means for starting communication.
[0045]
【The invention's effect】
As described above, according to the present invention, when performing multicast tunneling, it is possible to guarantee the uniqueness of a multicast program identifier and eliminate the possibility of packet interference occurring on the receiving side. Further, according to the present invention, the inconvenience of having to write both the multicast program identifier and the unicast program identifier is eliminated, and by using a conversion rule that can be uniquely converted to each other, if either one is specified, the other Can be determined automatically. Further, according to the present invention, there is no need for the senders to exchange program information with each other in order to guarantee the uniqueness of the program identifier, and the system operates without any problem even if the network scale is increased. In addition, since there is no need to apply to the organization that performs the address assignment and no need to access an external address management server, anyone can immediately start multicast tunneling distribution when necessary. The present invention is a technique for solving a problem in multicast tunneling, and contributes to the spread of a multicast service on the Internet.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a multicast tunneling communication system according to an embodiment of the present invention.
FIG. 2 is a diagram showing storage contents of program identifier management tables Ta1 to Tc1 in the same system.
FIG. 3 is a diagram showing storage contents of destination management tables Ta2 to Tc2 in the same system.
FIG. 4 is a diagram for explaining a multicast program identifier generation method in the same system.
[Explanation of symbols]
LAN (A), LAN (B), LAN (C) ... local area network
Pa, Pb, Pc: Packet converter
Ha, Hb ... sending host
Hc1, Hc2 ... receiving host
Ta1, Tb1, Tc1... Program identifier management table
Ta2, Tb2, Tc2 ... destination management table

Claims (14)

A transmitting-side packet converter for converting a multicast packet transmitted from a multicast transmission host into a unicast packet and transmitting the unicast packet to a network that provides IP unicast communication; In a multicast tunneling communication system comprising a receiving-side packet converter for restoring a packet and sending it to a multicast receiving host,
The transmitting-side packet translator generates a multicast program identifier composed of a unique and unique set of a multicast address and a port number using a static translation rule capable of translating one-to-one from its unicast address,
A multicast program identifier generating method, wherein the receiving side packet converter generates a multicast program identifier from a unicast address of a packet converter of a transmission source of a program to be received using the conversion rule. A transmitting-side packet converter for converting a multicast packet transmitted from a multicast transmission host into a unicast packet and transmitting the unicast packet to a network that provides IP unicast communication; In a multicast tunneling communication system comprising a receiving-side packet converter for restoring a packet and sending it to a multicast receiving host,
A unique and unique multicast address and port number using a static translation rule that allows the transmitting-side packet translator to translate one-to-one from its own unicast address and a flow identifier for distinguishing a plurality of programs. Generate a multicast program identifier consisting of
A multicast program identifier generating method, wherein the receiving side packet converter generates a multicast program identifier from the set of a unicast address and a flow identifier of a packet converter of a source of a program to be received using the conversion rule. . The conversion rule stores specific 8-bit or more information of 32-bit unicast address information in a partial area of a multicast port number having a space of 16 bits. 3. The method of generating a multicast program identifier according to claim 1 or claim 2. The method according to claim 2, wherein the conversion rule stores a part of a unicast address in a partial area of a multicast port number, and stores information of the flow identifier in a remaining area of the port number. The described multicast program identifier generation method. According to the conversion rule, the upper 8 bits of the 32-bit multicast address are set to a predetermined constant value, and the other 24 bits are used as they are, and the lower 24 bits of the 32-bit unicast address are used as they are. Each of the 8 bits is inverted to be used as upper 8 bits of a multicast port number having a space of 16 bits, and the flow identifier is used as it is for lower 8 bits of the port number. Item 3. A method for generating a multicast program identifier according to Item 2. A transmitting-side packet converter for converting a multicast packet transmitted from a multicast transmission host into a unicast packet and transmitting the unicast packet to a network that provides IP unicast communication; In a multicast tunneling communication system comprising a receiving-side packet converter for restoring a packet and sending it to a multicast receiving host,
The transmitting side packet translator generates a multicast program identifier composed of a unique and unique set of a multicast address and a port number by using a static translation rule capable of translating one-to-one from its own unicast address. ,
The multicast tunneling communication system, wherein the receiving-side packet conversion device generates a multicast program identifier from a unicast address of a packet conversion device that is a transmission source of a program to be received, using the conversion rule. A transmitting-side packet converter for converting a multicast packet transmitted from a multicast transmission host into a unicast packet and transmitting the unicast packet to a network that provides IP unicast communication; In a multicast tunneling communication system comprising a receiving-side packet converter for restoring a packet and sending it to a multicast receiving host,
The transmission-side packet conversion device uses a unicast address of the transmission-side terminal and a flow conversion identifier for distinguishing a plurality of programs from each other, using a static conversion rule capable of performing a one-to-one conversion from one to another. Generate a multicast program identifier consisting of a set of address and port number,
The multicast tunneling communication system, wherein the receiving-side packet conversion device generates a multicast program identifier from a set of a unicast address and a flow identifier of a packet conversion device that is a transmission source of a program to be received, using the conversion rule. The conversion rule stores specific 8-bit or more information of 32-bit unicast address information in a partial area of a multicast port number having a space of 16 bits. The multicast tunneling communication system according to claim 6 or 7. The method according to claim 7, wherein the conversion rule stores a part of a unicast address in a part of a multicast port number and stores information of the flow identifier in a remaining part of a port number. The described multicast tunneling communication system. According to the conversion rule, the upper 8 bits of the 32-bit multicast address are set to a predetermined constant value, and the other 24 bits are used as they are, and the lower 24 bits of the 32-bit unicast address are used as they are. Each of the 8 bits is inverted to be used as upper 8 bits of a multicast port number having a space of 16 bits, and the flow identifier is used as it is for lower 8 bits of the port number. Item 7. A multicast tunneling communication system according to Item 6. A transmitting-side packet converter for converting a multicast packet transmitted from a multicast transmission host into a unicast packet and transmitting the unicast packet to a network that provides IP unicast communication; In a multicast tunneling communication system comprising a receiving-side packet converter for restoring a packet and sending it to a multicast receiving host,
The computer that constitutes the transmitting side or receiving side packet translator is provided with a specific 8-bit or more information of the 32-bit unicast address information in a partial area of the multicast port number having a space of 16 bits. A program for executing a procedure for storing and generating a new multicast port number. A transmitting-side packet converter for converting a multicast packet transmitted from a multicast transmission host into a unicast packet and transmitting the unicast packet to a network that provides IP unicast communication; In a multicast tunneling communication system comprising a receiving-side packet converter for restoring a packet and sending it to a multicast receiving host,
A part of the unicast address is stored in a part of the multicast port number in a computer constituting the transmitting or receiving side packet converter, and the information of the flow identifier is stored in the remaining part of the port number. To execute a procedure for generating a new multicast port number. A transmitting-side packet converter for converting a multicast packet transmitted from a multicast transmission host into a unicast packet and transmitting the unicast packet to a network that provides IP unicast communication; In a multicast tunneling communication system comprising a receiving-side packet converter for restoring a packet and sending it to a multicast receiving host,
In the computer constituting the transmission-side or reception-side packet conversion device,
Storing a fixed value preset as the upper 8 bits of the 32-bit multicast address;
Storing the lower 24 bits of the 32-bit unicast address as the other 24 bits;
A procedure in which each of the upper 8 bits of the unicast address is inverted and stored in the upper 8 bits of the multicast port number having a space of 16 bits;
Storing the flow identifier in the lower 8 bits of the port number;
The program to execute. A computer-readable recording medium on which the program according to any one of claims 11 to 13 is recorded.

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