JP3668130B2 - Multicast communication apparatus and multicast communication method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multicast communication device having a first network interface that can only receive data and a second network interface that can at least transmit, a communication device that supports multicast communication by the multicast communication device, and multicast communication. Regarding the method.
[0002]
[Prior art]
Focusing on the fact that many multimedia services that use networks download data from the network to the terminal, in recent years, the bandwidth of input to the terminal is extremely wide compared to the bandwidth of output from the terminal. Asymmetric access networks have been developed. In particular, when such an access network is wireless, a first wireless transmission path capable of transmitting data only from the network to the client terminal direction (downward direction) and at least data transmission from the terminal to the network direction (upstream direction) A network (hybrid network) in which a second wireless transmission path is combined has been proposed. Here, the first wireless transmission path is high speed, and the second wireless transmission path is relatively low speed. In this case, the terminal transmits the information to the first wireless interface for receiving information on the first wireless transmission path and at least the second wireless transmission path (for transmission only or for transmission / reception). For a second wireless interface. Such a wireless terminal is called a hybrid terminal. In this configuration, since a high-speed wireless transmission device is omitted from the wireless terminal, it is expected that the wireless terminal is reduced in size, power consumption, and price.
[0003]
On the other hand, on the Internet and the like, a multicast technique for efficiently transmitting the same data to a plurality of terminals has been developed. When multicast routing technology is used, a tree-structured information transmission path is configured from a transmission terminal to a plurality of reception terminals. A multicast router exists in the part where the tree branches. Each terminal corresponds to a leaf portion. When the multicast router of the branching tree receives the data packet from the transmitting terminal, it copies the necessary number of data packets and forwards them to each outgoing route. Multicast operating in this way is more efficient in use of the transmission path than unicast in which the transmitting terminal must repeatedly transmit the same data to each receiving terminal by the number of receiving terminals.
[0004]
In the Internet, in order to realize such multicast routing, protocols such as DVMRP (RFC-1075 “DistanceVector Multicast Routing Protocol”), MOSPF (RFC-1584 “Multicast Extensions to OSPF”), PIM (Protocol Independent) Multicast) is used as a protocol between the terminal (host) and the router, such as RFC-1112 “Host Extensions for IP Multicasting” and RFC-2236 “Internet Group Management Protocol ver.2”. A protocol between multicast routers such as DVMRP is mainly used to form a tree structure with a terminal belonging to a multicast group as a leaf on the network. On the other hand, the protocol between a terminal such as IGMP and a multicast router is used to notify the nearest multicast router of the terminal of joining or leaving the multicast group, or the multicast router is closest to the multicast router. Used to make an inquiry about a multicast group that is subscribed to a terminal in a subnet.
[0005]
[Problems to be solved by the invention]
Protocols such as IGMP and their implementation often assume that the network interface of the terminal can be used for both transmission and reception implicitly. However, this assumption does not hold because the first network interface of the hybrid terminal can only receive and cannot transmit. This creates several problems.
[0006]
Here, a situation is considered in which the hybrid terminal desires to receive multicast information from the first network interface capable of high-speed reception. The terminal needs to send an IGMP report / leave message to indicate joining / leaving the multicast group, but the hybrid terminal can use only the second network interface for data transmission. In general, the first network interface and the second network interface belong to different subnets (referred to as the first subnet and the second subnet, respectively), and the IGMP message is not routed outside the subnet. The multicast router in the first subnet connected to the first network interface cannot recognize that the hybrid terminal is requesting to join the multicast group. For this reason, unless other terminals in the first subnet belong to the same multicast group, a multicast routing tree that reaches the first subnet is not configured. A typical application joins a multicast group at the second network interface that is the default route. The IP layer of a typical terminal is implemented so that even if a multicast packet is received from an interface, if the packet is addressed to a multicast group to which the packet is not joined, it is discarded without being passed to the application. That is, even if the second network interface joins the multicast group, the packet addressed to the multicast group cannot be received by the first network interface.
[0007]
For this reason, the hybrid terminal proposed so far has not been able to receive multicast information from the first network interface capable of high-speed reception.
[0008]
On the other hand, if a method of joining a multicast group with a home network defined in Mobile IP (RFC2002) is used, it is possible to transfer multicast packets to the first network interface. Since packets are encapsulated and transferred into unicast packets, there is a problem in that transmission efficiency which is an advantage of multicast is sacrificed.
[0009]
The present invention has been made in view of the above circumstances, and a multicast communication device that can receive multicast information from a reception-only network interface, and a communication device that supports multicast communication by this multicast communication device, An object of the present invention is to provide a multicast communication method.
[0010]
[Means for Solving the Problems]
A multicast communication apparatus (for example, a hybrid terminal) according to the present invention includes a first network interface unit that can only receive data, a second network interface unit that can transmit at least data, and the first network. Multicast second control data (for example, an inquiry response) transmitted as a result of the interface means receiving the first control data (for example, an inquiry request) for multicast, or a third multicast data that the device itself transmits autonomously Relay control data (for example, inquiry response) to a predetermined communication device (for example, foreign agent) connected to the subnetwork to which the first network interface unit belongs via the second network interface unit Middle joint Characterized by comprising and.
[0011]
Also, a multicast communication device (for example, a hybrid terminal) according to the present invention includes a first network interface unit that can only receive data, a second network interface unit that can transmit at least data, Proxy joining means for enabling reception of data addressed to the multicast group in the first network interface means when the second network interface means joins the multicast group in the second network interface means. It is provided with.
[0012]
Also, a multicast communication device (for example, a hybrid terminal) according to the present invention includes a first network interface unit that can only receive data, a second network interface unit that can transmit at least data, Multicast user data transmitted by an entity (for example, a multicast application) via the second network interface unit, a relay device (for example, a foreign device) connected to the subnetwork to which the first network interface unit belongs. And a relay means for relaying to the agent).
[0013]
Further, a multicast communication apparatus (for example, a hybrid terminal) according to the present invention includes a first network interface means that can only receive data, a second network interface means that can transmit at least data, A mobility management means for managing movement between sub-networks, and a relay device (for example, a foreign device) serving as a destination to relay information related to multicast to be transmitted by the own device (for example, messages of IGMP protocol, multicast user data) An agent) based on the information obtained from the mobility management means, and information relating to the multicast to be transmitted by the own device via the second network interface means by the determining means Relay means for relaying to the determined relay device; Characterized by comprising.
[0014]
The communication device (for example, a foreign agent) according to the present invention belongs to the same subnetwork as the subnetwork to which the network interface means capable of transmitting and receiving data and the network interface means belongs, and can only receive data. A multicast communication apparatus comprising a first network interface means and a second network interface means belonging to a sub-network different from the sub-network to which the network interface means belongs and capable of transmitting data at least. A request receiving means for receiving a multicast join request transmitted from the interface means, and a multicast group requested to join by the multicast join request received by the request receiving means. The-loop, characterized in that a proxy subscription request means behalf subscription request in behalf of the multicast communication apparatus.
[0015]
The present invention relating to the apparatus is also established as an invention relating to a method, and the present invention relating to a method is also established as an invention relating to an apparatus.
Further, the present invention relating to an apparatus or a method has a function for causing a computer to execute a procedure corresponding to the invention (or for causing a computer to function as a means corresponding to the invention, or for a computer to have a function corresponding to the invention. It is also established as a program (for realizing) and also as a computer-readable recording medium on which the program is recorded.
[0016]
According to the present invention, a multicast application of a hybrid terminal having a network interface that can only receive and a network interface that can transmit at least can receive multicast information via the network interface that can only receive. In addition, there is an advantage that there is no need to change an existing multicast application. Also, the use efficiency of the transmission path is better than the method of encapsulating the multicast packet by unicast.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the invention will be described with reference to the drawings.
[0018]
FIG. 1 shows a configuration example of a network according to an embodiment of the present invention.
[0019]
In the following, an example of network technology that conforms to the Internet protocol will be described. Further, a case where the terminal 101 connected to the network 121 transmits a multicast packet will be described as an example.
[0020]
In the following, the home network is a home network defined by IETF Mobile IP (RFC-2002), and the home agent (HA) and foreign agent (FA) in FIG. It plays a role corresponding to a home agent or a foreign agent defined in Mobile IP.
[0021]
The network 121 is a network in which a plurality of sub-networks (not shown) are interconnected by routers (not shown).
[0022]
Each router (not shown) is a multicast router or is bypassed by a multicast tunnel.
[0023]
A sub-network 131 connected to the network 121 by the router 111 is a home network to which the hybrid terminal 102 belongs. That is, the hybrid terminal 102 has a home address belonging to the sub-network 131, and the home agent 151 manages the location information of the hybrid terminal 102. If the hybrid terminal 102 is moving, it is transferred to the sub-network 131. The packet addressed to the hybrid terminal 102 is transferred to the current position of the hybrid terminal 102. When the hybrid terminal 102 has moved to the subnetwork 132, the transfer destination is the foreign agent 152, and when the hybrid terminal 102 has moved to the subnetwork 133, the transfer destination is the foreign agent 153. The packet addressed to the hybrid terminal 102 is encapsulated and transferred. Each of the foreign agents 152 and 153 (the FA function 302 (see FIG. 3) thereof) decapsulates the packet addressed to the hybrid terminal 102 and transfers it to the hybrid terminal 102. The hybrid terminal 102 (the mobility control 203 (see FIG. 2)) sends an agent advertisement message (AA (Agent Advertisement) that the foreign agents 152 and 153 (the FA function 302) periodically broadcasts to the subnetworks 132 and 134. )), The current position is grasped and notified to the home agent 151 via the foreign agents 152 and 153 (FA function 302 of the foreign agent). Thereby, the home agent 151 manages the position of the hybrid terminal 102.
[0024]
In the following, a case where a method of determining a relay destination of a multicast group joining request using the Mobile IP function will be described as an example. However, if necessary information such as a relay destination can be obtained, the function of the Mobile IP It is possible to use other methods without being limited to the method of using. Also, here, the case where the hybrid terminal 102 is a mobile terminal is taken as an example, but if the hybrid terminal 102 is a terminal that does not move at all, the necessary information may be given semi-fixed to the hybrid terminal 102. Good.
[0025]
In the following, the base station 141 that supports both uplink and downlink communication is also a router that terminates the PPP connection from the hybrid terminal 102, and the base stations 142 and 143 that support only downlink communication are bridges. A case where it is assumed that
[0026]
A case where the IGMP protocol is used as a protocol between the terminal (host) and the router will be described.
[0027]
FIG. 2 shows a configuration example of the hybrid terminal 102 according to the present embodiment.
[0028]
As shown in FIG. 2, the hybrid terminal 102 includes a hybrid multicast control 202, a movement control 203, a UDP layer 211, an IP layer 221, a packet monitor function 231, a first network interface 241, and a second network interface 242. Have. The IP layer includes a multicast control function 222 and a movement support function 223. In addition, it is assumed that the multicast application 201 is installed.
[0029]
The first network interface 241 can only receive. In the example of FIG. 1, data transmitted by the base station 142 or the base station 143 is received. The second network interface 242 can transmit and receive, and communicates with the base station 141 in the example of FIG. The hybrid multicast control 202, the movement control 203, and the like can use the packet monitor function 231 to appropriately filter and monitor data transmitted and received through these interfaces.
[0030]
The UDP layer 211 realizes a standard UDP function.
[0031]
The IP layer 221 implements a standard IP function. In particular, the multicast control function 222 operates as a multicast terminal that can join and leave a multicast group, send and receive multicast packets, and the like.
[0032]
In addition, the mobility support processing function 223 that performs IP layer processing and the mobility control 203 that performs upper layer processing cooperate to operate as a mobile IP mobile terminal.
[0033]
For example, the hybrid terminal 102 can be configured using a computer, or can be configured as a portable terminal having a software execution function and an Internet access function, and each component shown in FIG. 2), and at least a part of each component shown in FIG. 2 can be realized by hardware such as a semiconductor chip.
[0034]
FIG. 3 shows a configuration example of the foreign agents 152 and 153 according to the present embodiment. As shown in FIG. 3, the foreign agent has a hybrid multicast control 301, an FA (foreign agent) function 302, a UDP layer 311, an IP layer 321, and a network interface 341. The IP layer also includes a multicast control function 322.
[0035]
The network interface 341 can transmit and receive. In the example of FIG. 1, the foreign agent 152 is connected to the subnetwork 132, and the foreign agent 153 is connected to the subnetwork 133.
[0036]
The UDP layer 311 implements a standard UDP function.
[0037]
The IP layer 321 realizes a standard IP function. In particular, the multicast control function 322 operates as a multicast terminal that can join and leave a multicast group, send and receive multicast packets, and the like.
[0038]
Further, the FA function 302 causes the foreign agent 152 (or 153) to operate as the above-described Mobile IP foreign agent. That is, the FA function 302 transmits a periodic agent advertisement message (AA) to the subnetwork 132 (or 133), relays a location registration request from the hybrid terminal 102 to the home agent 151, and a response to the request. The home agent 151 extracts the packet addressed to the hybrid terminal 102 encapsulated in the packet addressed to the foreign agent 152 (or 153), and transfers the packet to the hybrid terminal 102. When transferring a packet to the hybrid terminal 102, the foreign agent 152 (or 153) needs to know the MAC address of the hybrid terminal 102. In hybrid configurations, the ARP normally used for this purpose does not work. Therefore, the foreign agent 152 (or 153) obtains the MAC address of the hybrid terminal 102 from information included in the location registration request transmitted from the hybrid terminal 102 to the foreign agent 152 (or 153).
[0039]
For example, the foreign agents 152 and 153 can be configured using a computer, and each component shown in FIG. 3 can be realized as a functional module of software (program). 3 can be realized by hardware by forming a semiconductor chip or the like.
[0040]
Now, let us assume a situation where the hybrid terminal 102 is moving to the sub-network 132 by Mobile IP. Further, as described above, it is assumed that the terminal 101 transmits a multicast packet.
[0041]
First, the operation at the time of starting the multicast application will be described with reference to FIGS.
[0042]
Assume that the multicast application 201 is activated in the hybrid terminal 102 (step S11 in FIG. 4). The activated multicast application 201 requests the IP layer multicast control function 222 to join the multicast group G (step S12). The network interface that can be used for transmission by the hybrid terminal 102 is the second network interface 242. Accordingly, the default route of the IP layer routing corresponds to the second network interface 242, and the multicast control function 222 of the IP layer joins the multicast group G in the second network interface 242 (step S13). As a result, an IGMP report message destined for the multicast group G is transmitted from the second network interface 242.
[0043]
On the other hand, the hybrid multicast control 202 monitors the transmission of this IGMP report message using the packet monitor function 231 and recognizes that the multicast application 201 that joins the multicast group G exists in the hybrid terminal 102 (FIG. 5 step S21). Then, the hybrid multicast control 202 requests the IP layer multicast control function 222 to join the multicast group G in the first network interface 241 (step S22). At the same time, the hybrid multicast control 202 obtains the address F of the foreign agent 152, which is the current foreign agent, from the mobility control 203 in order to obtain a destination to which the request for joining the multicast group G is to be relayed (step S23). Then, the monitored IGMP report message is encapsulated in a UDP packet destined for the port number corresponding to the hybrid multicast control 301 of the foreign agent 152 and the address F of the foreign agent 152, and the second network interface 242 is encapsulated. (Step S24).
[0044]
The hybrid multicast control 301 of the foreign agent 152 in FIG. 3 receives this UDP packet and extracts the relayed IGMP report message (step S31 in FIG. 6). Since the source address of the IGMP report message is the address of the second network interface 242 of the hybrid terminal 102 and not the address belonging to the subnetwork 132, the router 112 sends the multicast group to the subnetwork 132 even if it is transmitted as it is. There are cases where it cannot be recognized that there is a terminal that joins G. Therefore, as one method, there is a method in which the hybrid multicast control 301 rewrites the source address of this IGMP report message to the address of the foreign agent 152 and transmits it (step S32). In this method, the IP layer multicast control function 322 does not have a state in which the foreign agent 152 belongs to the multicast group G. As another method, the hybrid multicast control 301 requests the IP layer multicast control function 322 to join the multicast group G. In this method, the multicast control function 322 of the IP layer transmits an IGMP report message destined for the multicast group G (step S32).
[0045]
When the router 112 having the multicast routing function receives an IGMP report message with the address F of the foreign agent 152 transmitted from the foreign agent 152 as the transmission source address and the multicast group G as the destination, the sub-network of the multicast group G Control is performed so that an information transmission path tree up to 132 is constructed. As a result, for example, a packet addressed to the multicast group G transmitted from the terminal 101 reaches the hybrid terminal 102 via the network 121, the router 112, the subnetwork 132, and the base station 142. The hybrid terminal 102 receives this packet at the first network interface 241. As described above, since the hybrid multicast control 202 has joined the multicast group G in the first network interface 241, this packet reaches the multicast application 201 without being discarded in the IP layer.
[0046]
The same functions when the hybrid terminal 102 is moving to the sub-network 133. The hybrid multicast control 202 learns the current foreign agent 153 from the mobility control 203 and relays the IGMP report message there.
[0047]
Now, the router 112 periodically sends an IGMP query message, and checks whether there is a terminal that joins a multicast group in the sub-network 132 depending on whether there is an IGMP report message corresponding to the IGMP query message. When the IGMP report message for a specific multicast group is not within a certain period, the transfer of the packet of the multicast group to the sub-network 132 is stopped.
[0048]
Therefore, the hybrid terminal 102 must respond to the IGMP query message received from the first network interface with an IGMP report message destined for the multicast group G. This response transmitted toward the first network interface 241 is automatically transmitted by the multicast control function 222 of the IP layer. However, since the first network interface 241 is dedicated to reception, the response to the subnetwork 132 is also transmitted. Will not reach. However, the hybrid multicast control 202 can monitor this response using the packet monitor function 231. When this response is detected, the operation is the same as the relay of the IGMP report message to the foreign agent 152 when the multicast application 201 is activated. Also in this case, since the router 112 receives the IGMP report message addressed to the multicast group G from the foreign agent 152, the router 112 continues to transfer the packet addressed to the multicast group G to the subnetwork 132.
[0049]
Next, the operation at the end of the multicast application will be described with reference to FIGS.
[0050]
When the multicast application 201 is terminated, the IP layer multicast control function 222 transmits an IGMP leave message to the multicast group G from the second network 242. The hybrid multicast control 202 monitors this IMGP leave message by the packet monitor function 231 and recognizes that the multicast application 201 leaving the multicast group G exists in the hybrid terminal 102 (step S41 in FIG. 7). Then, the hybrid multicast control 202 requests the IP layer multicast control function 222 to leave the multicast group G in the first network interface 241 (step S42). At the same time, the hybrid multicast control 202 obtains the address F of the foreign agent 152, which is the current foreign agent, from the movement control 203 in order to obtain a destination to relay the request for leaving the multicast group G (step S43). Then, the monitored IGMP leave message is encapsulated in a UDP packet destined for the port number corresponding to the hybrid multicast control 301 of the foreign agent 152 and the address F of the foreign agent 152, and the second network interface 242 is encapsulated. (Step S44).
[0051]
The hybrid multicast control 301 of the foreign agent 152 receives this UDP packet and extracts the relayed IGMP leave message (step S51 in FIG. 8). Since the source address of this IGMP leave message is the address of the second network interface 242 of the hybrid terminal 102 and not the address belonging to the subnetwork 132, the router 112 will send the multicast group G to the subnetwork 132 even if it is transmitted as it is. It may not be recognized that there is a terminal that leaves. Therefore, as one method, there is a method in which the hybrid multicast control 301 rewrites the source address of the IGMP leave message to the address of the foreign agent 152 and transmits it (step S52). In this method, the IP layer multicast control function 322 does not have a state in which the foreign agent 152 belongs to the multicast group G. As another method, the hybrid multicast control 301 requests the IP layer multicast control function 322 to leave the multicast group G. In this method, the multicast control function 322 of the IP layer transmits an IGMP leave message destined for the multicast group G (step S52).
[0052]
When the router 112 having the multicast routing function receives an IGMP leave message with the address F of the foreign agent 152 transmitted from the foreign agent 152 as the transmission source address and the multicast group G as the destination, it transmits an IGMP query message. . If there is no response due to the IGMP report message for a certain period, the router 112 stops forwarding the packet addressed to the multicast group G to the subnetwork 132. Through the above processing, the hybrid terminal 102 is in a state where it does not transmit an IGMP report message. Therefore, if there is no other terminal that joins the multicast group G in the subnetwork 132, the transfer is stopped.
[0053]
Up to this point, it has been assumed that the base station 141 is a router but not a multicast router. That is, even when the hybrid terminal 102 joins the multicast group G through the second network interface 242, packets addressed to the multicast group G are transmitted from the hybrid terminal 102 via the base station 141 toward the subnetwork 131 (upstream), Conversely, the data is not transferred from the subnetwork 131 via the base station 141 in the direction of the hybrid terminal 102 (downward). The fact that the forward transfer is not performed is not a problem because the network interface 241 can receive packets addressed to the same multicast group. If forward transfer is performed, the bandwidth of the second network interface 242 is generally narrower than the bandwidth of the first network interface 241, and therefore the second network interface may be saturated depending on the characteristics of multicast traffic. Yes, it is better not to transfer. However, the inability to transmit in the upstream direction can be problematic.
[0054]
In this case, the hybrid multicast control 202 of the hybrid terminal 102 monitors the user data packet addressed to the multicast group G transmitted from the multicast application 201 via the second network interface 242 by the packet monitor function 231 (step S61 in FIG. 9). ). The monitored multicast user data packet is encapsulated by, for example, UDP and transmitted to the relay destination obtained from the movement control 203. For example, in order to obtain a destination to which multicast user data is to be relayed, the address of the foreign agent 152 (or 153), which is the current foreign agent, is acquired from the mobility control 203 (step S62), and the foreign agent 152 The second network interface 242 encapsulates the monitored multicast user data packet in a UDP packet destined for the port number corresponding to the hybrid multicast control 301 of (or 153) and the address of the foreign agent 152 (or 153). (Step S63).
[0055]
Upon receiving this, the hybrid multicast control 301 of the foreign agent 152 or the foreign agent 153 extracts the original multicast user data packet from the UDP packet and transmits it as it is. The multicast user data packet is transferred to the network 121 by the router 112 or the router 113, and further transferred along the multicast path tree. As another method, there is a method in which the base station 141 transfers the multicast packet in the upstream direction and does not transfer the multicast packet in the downstream direction.
[0056]
In the above description, the foreign agent serves as both a device that relays a request to join the multicast group G and a device that relays multicast user data. It is also possible that the device that relays user data is a different device.
[0057]
According to the present embodiment, a multicast application of a hybrid terminal having a network interface that can only receive and a network interface that can at least transmit can receive multicast information via the network interface that can only receive. In addition, there is an advantage that there is no need to change an existing multicast application. Also, the use efficiency of the transmission path is better than the method of encapsulating the multicast packet by unicast.
[0058]
Each function described above can be realized as software.
The present embodiment can also be implemented as a program for causing a computer to execute predetermined means (or for causing a computer to function as predetermined means, or for causing a computer to realize predetermined functions), The present invention can also be implemented as a computer-readable recording medium on which the program is recorded.
[0059]
Note that the configuration illustrated in the embodiment of the present invention is an example, and is not intended to exclude other configurations, and a part of the illustrated configuration may be replaced with another or one of the illustrated configurations. Other configurations obtained by omitting a part, adding another function or element to the illustrated configuration, or combining them are also possible. Also, another configuration that is logically equivalent to the exemplified configuration, another configuration that includes a portion that is logically equivalent to the exemplified configuration, another configuration that is logically equivalent to the main part of the illustrated configuration, and the like are possible. is there. Further, another configuration that achieves the same or similar purpose as the illustrated configuration, another configuration that achieves the same or similar effect as the illustrated configuration, and the like are possible.
In addition, various variations of various components illustrated in the embodiment of the present invention can be implemented in appropriate combination.
Further, the embodiment of the present invention is an invention of an invention as an individual device, an invention of two or more related devices, an invention of the entire system, an invention of components within an individual device, or a method corresponding thereto. The invention includes inventions according to various viewpoints, stages, concepts, or categories.
Therefore, the present invention can be extracted from the contents disclosed in the embodiments of the present invention without being limited to the exemplified configuration.
[0060]
The present invention is not limited to the above-described embodiment, and can be implemented with various modifications within the technical scope thereof.
[0061]
【The invention's effect】
According to the present invention, multicast information can be received from a reception-only network interface in a multicast communication device.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a network according to an embodiment of the present invention.
FIG. 2 is a view showing a configuration example of a hybrid terminal according to the embodiment;
FIG. 3 is a view showing a configuration example of a foreign agent according to the embodiment;
FIG. 4 is a flowchart showing an operation example of the hybrid terminal according to the embodiment;
FIG. 5 is a flowchart showing an operation example of the hybrid terminal according to the embodiment;
FIG. 6 is a flowchart showing an operation example of a foreign agent according to the embodiment;
FIG. 7 is a flowchart showing an operation example of the hybrid terminal according to the embodiment;
FIG. 8 is a flowchart showing an operation example of a foreign agent according to the embodiment;
FIG. 9 is a flowchart showing an operation example of the hybrid terminal according to the embodiment;
[Explanation of symbols]
101 ... terminal
102 ... Hybrid terminal
111-113 ... Router
121, 131-133 ... network
141-143 ... base station
151 ... Home Agent
152,153 ... Foreign Agent
201: Multicast application
202, 301 ... hybrid multicast control
203 ... Movement control
211, 311 ... UDP layer
221, 321 ... IP layer
222, 322 ... Multicast control function
223 ... Mobility support function
231 ... Packet monitor function
241: First network interface
242 ... Second network interface
302 ... FA function
341 ... Network interface

Claims (8)

First network interface means capable of only receiving data;
A second network interface means capable of transmitting at least data;
The second network control data transmitted as a result of the first network interface means receiving the first control data for multicast, or the third control data for multicast transmitted autonomously by the device itself, A multicast communication apparatus comprising: relay means for relaying to a predetermined communication apparatus connected to a subnetwork to which the first network interface means belongs via the network interface means. First network interface means capable of only receiving data;
A second network interface means capable of transmitting at least data;
When the entity in the own apparatus joins the multicast group in the second network interface means, the first network interface means includes a proxy joining means for enabling data reception to the multicast group in the first network interface means. A multicast communication apparatus characterized by the above. First network interface means capable of only receiving data;
A second network interface means capable of transmitting at least data;
Relay means for relaying multicast user data transmitted by an entity in the own apparatus to a relay apparatus connected to a subnetwork to which the first network interface means belongs, via the second network interface means. A multicast communication apparatus characterized by the above. First network interface means capable of only receiving data;
A second network interface means capable of transmitting at least data;
Movement management means for managing movement between sub-networks of the own device;
A determining unit that determines a relay device as a destination to relay information related to multicast to be transmitted by the own device based on information obtained from the mobility management unit;
Multicast communication comprising relay means for relaying information related to multicast to be transmitted by the own apparatus to the relay apparatus determined by the determining means via the second network interface means apparatus. Network interface means capable of transmitting and receiving data;
First network interface means that belongs to the same subnetwork as the subnetwork to which the network interface means belongs, and that can only receive data, and belongs to a subnetwork different from the subnetwork to which the network interface means belongs, and at least transmits data Request receiving means for receiving a multicast subscription request transmitted from the second network interface means by a multicast communication device comprising second network interface means capable of
A communication apparatus, comprising: a proxy joining requesting means for requesting a proxy group to join a multicast group requested to join by the multicast joining request received by the request receiving means. A multicast communication method in a multicast communication device comprising a first network interface means capable of only receiving data and a second network interface means capable of transmitting at least data,
The second network control data transmitted as a result of the first network interface means receiving the first control data for multicast, or the third control data for multicast transmitted autonomously by the device itself, A multicast communication method comprising: relaying to a predetermined communication device connected to a subnetwork to which the first network interface means belongs via the network interface means. A computer-readable recording medium on which a program executed on a multicast communication apparatus having first network interface means capable of only receiving data and at least second network interface means capable of transmitting data is recorded Because
The second network control data transmitted as a result of the first network interface means receiving the first control data for multicast, or the third control data for multicast transmitted autonomously by the device itself, A computer-readable recording medium recording a program having a function of relaying to a predetermined communication device connected to a subnetwork to which the first network interface means belongs via the network interface means. A first network interface means only receive data can be a computer that records up Rogura beam for causing a computer to function as a multicast communication equipment having a second network interface means which can send at least data A readable recording medium ,
The second network control data transmitted as a result of the first network interface means receiving the first control data for multicast, or the third control data for multicast transmitted autonomously by the device itself, of via the network interface means, said first network interface means computer-readable recording medium recording a program having the function of relays to a predetermined communication device connected to the subnetwork belongs.

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