VoIP system, VoIP server and client, and multicast packet communication method

• US 20040252691A1
• Filed: 06/10/2004
• Published: 12/16/2004
• Est. Priority Date: 06/11/2003
• Status: Active Grant

• Current Assignee: NEC Platforms, Ltd.
• Original Assignee: NEC Infrontia Corporation (NEC Corporation)
• Inventors: Kobayashi, Yoshikazu, Hori, Masato
• Granted Patent: US 7,801,134 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/403 Arrangements for multi-party communication, e.g. for conferences data switching systems for conference H04L12/18; arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities H04M3/56; television conferencing systems H04N7/15
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04M 15/56 for VoIP communications
• CPC Class Codes: H04M 2215/202 VoIP; Packet switched telephony
• CPC Class Codes: H04M 2215/2073 Multipoint, e.g. messaging, broadcast or group SMS
• CPC Class Codes: H04M 3/4285 Notifying, informing or entertaining a held party while on hold, e.g. Music On Hold
• CPC Class Codes: H04M 3/56 Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities video conference systems H04N7/15
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

A VoIP system has a VoIP server and plural clients. The client transmits paging data as multicast packets addressed at a specific multicast address, to other clients. In response to a request from the client, the VoIP server transmits multicast packets of MOH data to the other clients. At this time, whether the other clients can receive multicast packets is determined. To the clients that are determined to be capable of receiving multicast packets, transmission data is sent in the form of multicast packets. To the client which belongs to a router and is determined to be incapable of receiving multicast packets, the transmission data is sent as unicast packets. It is thus possible for the VoIP system to support paging and MOH in the form of multicast packets, with respect to clients incapable of receiving multicast.

Claims

1. A VoIP system in which voice communication is performed between a source client for transmitting IP packets and a destination client for receiving the IP packets via an IP network, comprising:

a VoIP server connected to the IP network; and

a plurality of clients including the source client and the destination client, and being connected communicably to the VoIP server via the IP network, wherein

each of the clients comprises

a first multicast transmission unit configured to transmit predetermined transmission data, as multicast packets addressed at a specific multicast address, to destination clients via the IP network, and

a multicast transmission request unit configured to send a predetermined request message to the VoIP server so as to request the VoIP server to transmit the multicast packets, and

the VoIP server comprises

a second multicast transmission unit configured to transmit the multicast packets to the destination clients, upon receipt of the request message sent from the clients by the multicast transmission request unit.

2. The VoIP system according to claim 1, wherein the VoIP server further comprises:

a determination unit configured to determine whether the destination clients are capable of receiving the multicast packets when the multicast packets are transmitted by the first or second multicast transmission unit; and

a transmission control unit configured to control the first or second multicast transmission unit to transmit the transmission data as unicast packets to the destination client which are determined to be incapable of receiving the multicast packets, based on a determination result.

3. The VoIP system according to claim 2, wherein the determination unit transmits a predetermined test message as multicast packets to the destination clients and determines whether the destination clients can receive the multicast packets or not.

4. The VoIP system according to claim 2, wherein the transmission control unit comprises

a table in which determination results obtained by the determination unit are registered, and

a unit which makes the transmission control unit operate based on the determination results registered in the table, without using the determination unit.

5. The VoIP system according to claim 1, wherein the transmission data is data broadcasted concurrently by paging.

6. The VoIP system according to claim 1, wherein the transmission data is music-on-hold data to be sent in accordance with a hold operation at the time of the voice communication.

7. The VoIP system according to claim 6, wherein

the VoIP server further comprises a unit which sends a request for reproducing an internal sound source, to the destination clients, if the destination clients each have the internal sound source of the music-on-hold data, and

each of the clients further comprises a unit which reproduces the internal sound source upon receipt of the reproduction request.

8. A VoIP server for use in a VoIP system in which voice communication is performed between a source client for transmitting IP packets and a destination client for receiving the IP packets via an IP network, comprising:

a multicast transmission unit which transmits predetermined data as multicast packets to destination clients, upon receipt of a request message requesting transmission of multicast packets and sent from the source client;

a determination unit which determines whether the destination clients are capable of receiving the multicast packets when the multicast packets are transmitted by the multicast transmission unit or the source client; and

a transmission control unit which controls the multicast transmission unit or the source client to transmit the transmission data as unicast packets to those destination clients which are determined to be incapable of receiving the multicast packets, based on a determination result.

9. The VoIP server according to claim 8, wherein the determination unit transmits a predetermined test message as multicast packets to the destination clients and determines whether the destination clients can receive the multicast packets or not.

10. The VoIP server according to claim 8, wherein the transmission control unit comprises

a table in which determination results obtained by the determination unit are registered, and

a unit which makes the transmission control unit operate based on the determination results registered in the table, without using the determination unit.

11. The VoIP server according to claim 8, wherein

the transmission data is music-on-hold data to be sent in accordance with a hold operation at the time of the voice communication, and

the VoIP server further comprises a unit which sends a request for reproducing the internal sound source, to the destination clients, if the destination clients each have an internal sound source of the music-on-hold data.

12. A client connected communicably to a VoIP server via an IP network, comprising:

a unit which transmits predetermined transmission data, as multicast packets addressed at a specific multicast address, to destination clients; and

a unit which transmits a predetermined request message requesting the VoIP server to transmit the multicast packets, to the VoIP server.

13. The client according to claim 12, wherein

the transmission data is music-on-hold data to be sent in accordance with a hold operation at the time of the voice communication, and

the client further comprises:

an internal sound source of the music-on-hold data; and

a unit which reproduces the internal sound source, upon receipt of a reproduction request requesting reproduction of the internal sound source from the VoIP server.

14. A multicast packet communication method for a VoIP system comprising a VoIP server connected to an IP network, and a plurality of clients connected communicably to the VoIP server via the IP network, enabling voice communication via the IP network between a source client among the clients, which transmits IP packets, and a destination client among the clients, which receives the IP packets, the method comprising:

a step in which the clients transmit predetermined transmission data, as multicast packets addressed at a specific multicast address, to destination clients;

a step in which a predetermined request message is sent from any one of the clients to the VoIP server, to request the VoIP server to transmit the multicast packets;

a step in which upon receipt of the request message sent from any of the clients, the VoIP server transmits the multicast packets to the destination clients;

a step in which when the multicast packets are transmitted by the VoIP server or any one of the clients, whether the destination clients can receive the multicast packets or not is determined; and

a step in which the VoIP server performs control to transmit the transmission data as unicast packets to the destination clients that are determined to be incapable of receiving the multicast packets, based on the determination results.

15. The multicast packet communication method according to claim 14, wherein

the transmission data is music-on-hold data to b sent in accordance with a hold operation at the time of the voice communication, and

the method further comprises:

a step in which if the destination clients have an internal sound source of the music-on-hold data, the VoIP server sends a reproduction request requesting reproduction of the internal sound sources to the destination clients; and

a step in which upon receipt of the reproduction request, the clients reproduce the internal sound source.