TERMINAL

• US 20090257432A1
• Filed: 03/16/2007
• Published: 10/15/2009
• Est. Priority Date: 03/16/2006
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ohmi, Shinichiro, Yano, Junji, Igata, Yuji, Kuroda, Go, Ikeda, Koji, Yasukawa, Toru, Kataoka, Masanori, Yamaguchi, Tsuyoshi, Yokomitsu, Yasushi
• Granted Patent: US 7,978,698 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 47/15 in relation to multipoint traffic arrangements for broadcast or multicast in data networks H04L12/18

Abstract

Provides a terminal for performing multiple access transmission suitable to a transmission path having varied characteristics. The terminal (100) includes a transmission/reception section (201), a control unit (204), a transfer management section (206), and an external interface section (203). The terminal (100) refers to an IGMP (MLD) message received by the transmission/reception section (201) to classify a transmitter host and a relay device of this message based on the characteristic of the transmission path, and performs a multiple access transmission of a multicast packet in a form suitable to the characteristic of the respective transmission path.

Claims

1. A terminal communicable with at least one relay device via a communication medium, comprising:

a transmission parameter setting section for evaluating characteristics of a transmission path up to the relay device and setting a transmission parameter on at least one of a transmittable information amount per a predetermined time length and an error correction strength;

a transfer management section for classifying transmission paths into one or more groups based on similarity of the set transmission parameter, the transmission paths being used for connecting a plurality of relay devices to the communication medium and for transmitting a multicast packet;

a packet replication section for replicating the received packet by a number equal to the number of the groups; and

a transmission section for sending each of the plurality of replicated packets on a unit of a group, based on the transmission parameter set for each group.

2. A terminal according to claim 1, further comprising a transmission time calculation section for calculating a transmission time required for transmitting data to the relay device based on the transmission parameter set for each group;

wherein the transfer management section classifies the transmission paths into one or more groups again based on the calculated transmission time.

3. A terminal according to claim 1, wherein the packet replication section creates a unicast packet when the number of the transmission paths classified into the one or more groups is 1, and creates a multicast packet when the number of the transmission paths classified into the one or more groups is 2 or greater.

4. A terminal according to claim 1, wherein:

the terminal is connected to a first network which is connected to a first communication terminal for transmitting a packet including a multicast address and is also connected to a second network, via the relay device, which is connected to a second communication terminal for receiving the packet transmitted from the first communication terminal; and

the transfer management section creates group management information for each multicast address, the group management information including at least one unit of transmission information in which the group, the transmission path classified into the group, the transmission parameter for each group and information specifying the second communication terminal are associated with one another.

5. A terminal according to claim 4, further comprising a detection section for detecting a group managing message which is included in the received packet based on a group managing protocol defined by layer 3 and defined by the group managing protocol;

wherein when the detection section detects a join message representing a message for notification on joining a group defined by the group managing protocol or a report message representing a message for notification on belonging to a group defined by the group managing protocol, the transfer management section adds, to the group management information, at least one of an identifier specifying the second communication terminal which transmitted the received packet and an identifier specifying the relay device which transferred the received packet.

6. A terminal according to claim 5, wherein when the detection section detects a leave message representing a message for notification on leaving a group defined by the group managing protocol, the transfer management section deletes, from the group management information, at least one of the identifier specifying the second communication terminal which transmitted the received packet and the identifier specifying the relay device which transferred the received packet.

7. A terminal according to claim 1, further comprising an UPnP message detection section for detecting a packet including an UPnP message representing a message conformed to an UPnP protocol,

wherein when the UPnP message detection section detects that the received packet includes the UPnP message, the transmission section transfers the received packet to all the relay devices connected to the second network.

8. A terminal according to claim 5, wherein:

when the group management information corresponding to the multicast address detected by the detection section has already been created, the packet replication section replicates the unicast packets by a number equal to the number of the groups included in the group management information; and

the transmission section sends each of the replicated packets to the second network.

9. A terminal according to claim 1, wherein when the multicast address included in the packet received from the first communication device does not match any of predetermined at least one multicast address, the transfer management section discards the received packet.

10. A terminal according to claim 1, further comprising a monitoring section for monitoring the number of received multicast packets, the number of transmitted multicast packets, and a transmission data size.

11. A terminal according to claim 8, further comprising a band management section for, when the monitoring section detects a packet including a predetermined multicast address for the first time, assigning a part of resource of the transmission path to the multicast address.

12. A terminal according to claim 11, wherein the band management section adjusts the assignment of the part of the resource of the transmission path to the multicast address based on at least one of the number of received packets, the number of transmitted multicast packets and the transmission data size within a predetermined time length detected by the monitoring section.

13. A terminal according to claim 11, wherein when the monitoring section determines that the multicast packet has not been sent to a transmission path, the band management section releases a part of the resource assigned to the multicast address.

14. A terminal according to claim 11, wherein in the case where a part of resource of a certain transmission path is assigned to a certain multicast address, when the detection section detects the join message or the report message including a new multicast address different from the certain multicast address from the packet received from the second network, the band management section releases a part of resource already assigned and saves again a part of the resource of the transmission path for the new multicast address.

15. A terminal according to claim 5, wherein when the detection section receives a packet including a message different from a non-predetermined message from the second network, the transfer management section discards the received packet.

16. A terminal according to claim 5, wherein when the detection section receives a packet including a message different from a predetermined message from the second network, the transfer management section revises the received packet.

17. A terminal according to claim 3, further comprising a timer section for, when the detection section detects a message included in a packet received from a certain transmission path, counting time on the certain transmission path;

wherein when the timer counts up to a predetermined time, the transfer management section releases the certain transmission path from management.

18. A terminal according to claim 3, wherein the transmission section determines the order of transmission of generated packets based on the transmission time calculated by the transmission time calculation section.

19. A terminal according to claim 1, wherein:

the terminal communicates with at least one relay device using a multiple carrier transmission format;

each of the transmission paths is formed of at least one sub carrier of the multiple carrier transmission format;

the transfer management section classifies at least two sub carriers into at least one sub carrier in advance for each transmission path;

the transmission parameter setting section evaluates a characteristic of each of the transmission paths, and sets the transmission parameter of each of the at least one sub carrier included in each of the transmission paths as a sub carrier group transmission parameter; and

the transfer management section classifies each of the transmission paths into one or more groups based on similarity of among the sub carrier group transmission parameter.

20. A program for communication with at least one relay device via a communication medium, the program causing a computer to realize:

a transmission parameter setting function for evaluating characteristics of a transmission path up to the relay device and setting a transmission parameter on at least one of a transmittable information amount per a predetermined time length and an error correction strength;

a transfer management function for classifying transmission paths into one or more groups based on similarity of the set transmission parameter, the transmission paths being used for connecting a plurality of relay devices to the communication medium, and when a multicast packet is received, for sending the received packet;

a packet replication function for replicating the number of packets which is equal to the number of the groups from the received packet; and

a transmission function for sending each of the plurality of replicated packets on a unit of a group, based on the transmission parameter set for each group.

21. An integrated circuit communicable with at least one relay device via a communication medium, comprising the integration of:

a transmission parameter setting function for evaluating characteristics of a transmission path up to the relay device and setting a transmission parameter on at least one of a transmittable information amount per a predetermined time length and an error correction strength;

a transfer management function for classifying transmission paths into one or more groups based on similarity of the set transmission parameter, the transmission paths being used for connecting a plurality of relay devices to the communication medium, and when a multicast packet is received, for sending the received packet;

a packet replication function for replicating the number of packets which is equal to the number of the groups from the received packet; and

a transmission function for sending each of the plurality of replicated packets on a unit of a group, based on the transmission parameter set for each group.