JP2012147212A - Communication terminal, transmitting/receiving method of the same, and communication system including terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication terminal capable of carrying out communications exceeding a limit of the number of media streams in a communication network.SOLUTION: Communication terminals 1 and 2 in a communication system, in which a plurality of communication terminals 1 and 2 transmit and receive media streams via a network having an upper limit in the number of media streams, sets, when transmitting and receiving media streams, a reception port number of the media stream, a transmission source port number of the media stream, and information for associating a transmission source port number with what kind of thing the media stream is.

Description

  The present invention relates to a communication terminal, a transmission / reception method thereof, and a communication system including the terminal, and more particularly, a communication terminal that transmits / receives a media stream via a network having an upper limit on the number of media streams, a transmission / reception method thereof, and a communication system including the terminal. About.

  In the bandwidth reservation type communication provided by NGN (Next Generation Network) related to the present invention, the capacity and desired communication contents are exchanged between terminals by SIP (Session Initiation Protocol), and a server installed in the NGN network Only authorized media streams can be communicated. Here, the media stream refers to a series of packet groups obtained by packetizing video and audio.

  On the other hand, as an example of a media stream transmission / reception device related to the present invention, a media distribution device that transmits a packet of a media stream to a network by a real-time transfer protocol, and a media stream connected to the network and transmitting the media stream to a communication link with a large delay A media stream distribution system including a relay device and a packet analysis unit that monitors the packet arriving at the relay device and transmits feedback information indicating the state of the network to the media distribution device is disclosed (Patent Document) 1).

  This technology obtains the transmission rate from the media distribution device to the relay device and the transmission rate from the relay device to the terminal device based on the feedback from both the relay device and the terminal device of the media stream. Communication quality is improved by using the surplus bandwidth for retransmission or forward error correction.

  In this technique, a series of packets of a media stream is specified by a pair of a source address and a destination address included in the IP header, and a pair of a source port number and a destination port number included in the UDP header.

  As another example of related technology, a relay device that relays communication between a plurality of wireless terminals and a wired network records a priority data recording unit that records communication identification data and necessary bandwidth data, and a priority data recording unit. A priority relay unit that preferentially relays received communication, a request reception unit that receives communication identification data and media type data from a communication control device, a selection unit that selects a media type to be preferentially relayed, and a selected The update unit for recording data indicating the bandwidth required for relaying the media type stream and the communication identification data in addition to the priority data recording unit, and the response unit for transmitting a response, and the selection unit indicates the necessary bandwidth data An invention for selecting a media type so that the sum of bands does not exceed a predetermined upper limit value is disclosed (see Patent Document 2).

  Furthermore, as an example of another related technology, a communication system having a first server, a device for setting a connection with the first server using the SIP protocol, and a first terminal that communicates with the first server, An interface that receives the connection request message, a processing unit that performs connection setting for the device in accordance with the received connection request message, and data received from the first terminal after connection setting of the processing unit Has been disclosed (see Patent Document 3).

JP 2003-333577 A JP 2007-274577 A JP 2010-213027 A

  However, the NGN related to the present invention has a problem that the number of media streams per SIP session is limited, and the number of media streams exceeding the limit is rejected by the communication network. For example, in a case where it is assumed that a TV (Television) telephone communication is performed in a network in which the number of media streams per SIP session is limited to two, one audio media stream and one video media stream 1 However, if you want to send multiple video and audio streams or send a shared document stream, the third and subsequent streams will be rejected by the network. It was not possible to realize it.

  On the other hand, the invention described in Patent Document 1 aims to reduce a phenomenon in which the influence of packet loss spreads, and the object is completely different from the present invention. As will be described later, an object of the present invention is to realize communication exceeding the limit of the number of media streams in a communication network. Therefore, the configuration for making “a plurality of media streams appear as one media stream from the network”, which is a feature of the present invention, is not disclosed in the present invention. Therefore, the present invention has the same effect as the present invention. Can not play.

  In addition, the invention described in Patent Document 2 is intended to perform band control of relayed communication in consideration of the media type, and the object is completely different from the present invention. Therefore, the configuration for making “a plurality of media streams appear as one media stream from the network”, which is a feature of the present invention, is not disclosed in the present invention. Therefore, the present invention has the same effect as the present invention. Can not play.

  Furthermore, the invention described in Patent Document 3 is intended to transfer data between two parties that communicate with each other in an NGN with guaranteed communication quality, and the object is completely different from the present invention. Therefore, the configuration for making “a plurality of media streams appear as one media stream from the network”, which is a feature of the present invention, is not disclosed in the present invention. Therefore, the present invention has the same effect as the present invention. Can not play.

  Accordingly, an object of the present invention is to provide a communication terminal capable of communication exceeding the limit of the number of media streams in a communication network, a transmission / reception method thereof, and a communication system including the terminal.

  In order to solve the above-mentioned problem, a communication terminal according to the present invention is a communication terminal in a communication system in which a plurality of communication terminals transmit and receive media streams via a network having an upper limit on the number of media streams. In this case, the receiving port number of the media stream, the transmission source port number of the media stream, and information associating the media stream with the transmission source port number are set. To do.

  A communication terminal transmission / reception method according to the present invention is a communication terminal transmission / reception method in a communication system in which a plurality of communication terminals transmit / receive a media stream via a network having an upper limit on the number of media streams. In this case, a receiving port number of the media stream, a transmission source port number of the media stream, and information associating the media stream with the transmission source port number are set. .

  A communication system according to the present invention includes the plurality of communication terminals.

  According to the present invention, communication exceeding the limit of the number of media streams in a communication network is possible.

It is a block diagram of an example of the communication system which concerns on this invention. It is a figure which shows an example of the sequence at the time of the telephone call start of the communication system which concerns on this invention. It is a figure which shows an example of what modeled the software structure in the communication terminals 1 and 2 which concern on this invention. It is a figure which shows an example of a structure of the UDP header in the communication system which concerns on this invention. It is a figure which shows an example of the normal SIP INVITE message (1). It is a figure which shows an example of the SIP INVITE message (2) of the communication system which concerns on this invention. It is a figure which shows an example of the SIP INVITE message (3) of the communication system which concerns on this invention. It is a figure which shows an example of the 200OK message of SIP of the communication system which concerns on this invention.

  First, the outline of the present invention will be described before the description of the embodiments. In a network in which the number of media streams that can be communicated is limited and the media stream is identified by a packet destination port number, communication exceeding the upper limit of the number of media streams in the network is enabled.

  In the capability exchange before the start of communication using the SIP protocol, the message is extended, and not only the reception port number of the media stream but also the source port number can be exchanged. As a result, packets having the same destination port number but different source port numbers can be correctly separated on the receiving side and a desired operation can be performed, and a plurality of media streams can be transmitted from the network to one medium. It becomes possible to make it look like a stream.

  Usually, in a communication network such as NGN, a stream is identified by a port number of a transport protocol in the fourth layer of OSI (Open Systems Interconnection). Here, as an example, a case where communication using UDP (User Data Protocol) is desired between two terminals will be described.

  Prior to communication, the terminals exchange the SIP protocol via the SIP server to inform each other of the capabilities of the terminal and the information of the stream to be transmitted / received. At the same time, the SIP server determines whether or not to allow the stream to pass through the communication network.

  The stream information is described in SDP (Session Description Protocol) included in the SIP protocol, and the port number for the communication network to identify the stream describes the reception port number. Normally, in the communication network, it is monitored whether the destination port number of the transport protocol of the packet included in the stream matches the reception port number described in the SDP of the permitted communication. Is not monitoring.

  Therefore, even if the source port numbers are different, communication is possible if the destination port number matches the permitted port number. By distinguishing the streams by the transmission source port number at the receiving terminal, it is possible to divide the stream recognized as one in the communication network into a plurality of streams. However, since the transmission side port number is arbitrarily assigned by the transmission side, the reception side cannot determine what each of the separated streams is.

  Accordingly, in the present invention, a plurality of media streams are added to the description of the SDP included in the SIP message by adding the source port number of the media stream and information relating to what the media is. The communication network provides a means to make it appear as one stream.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, a first embodiment of the present invention will be described. FIG. 1 is a configuration diagram of an example of a communication system according to the present invention. Referring to the figure, an example of a communication system according to the present invention includes communication terminals 1 and 2, an NGN network 11, a SIP server 12 provided in the NGN network 11, and edge nodes 13 and 14. Is done.

  In the example shown in the figure, the communication terminals 1 and 2 exchange data with each other via the NGN network 11. Specifically, data transmitted from the communication terminal 1 is transmitted to the communication terminal 2 via the edge node 13 provided on the communication terminal 1 side, the SIP server 12, and the edge node 14 provided on the communication terminal 2 side. Received. Similarly, data transmitted from the communication terminal 2 is received by the communication terminal 1 via the edge node 14 provided on the communication terminal 2 side, the SIP server 12, and the edge node 13 provided on the communication terminal 1 side. The

  Further, in the example shown in the figure, a case is shown in which two communication terminals 1 and 2 perform bandwidth reservation type UDP communication via the NGN network. Further, it is assumed that communication starts from the communication terminal 1 toward the communication terminal 2.

  FIG. 2 is a diagram showing an example of a sequence at the start of a call in the communication system according to the present invention. As shown in the figure, at the start of communication in the communication system according to the present invention, a SIP message is transmitted from the own communication terminal to the partner communication terminal via the SIP server. The SIP message includes SDP, and the reception port number of the stream desired to be received is described in the SDP.

  Both communication terminals exchange each other's communication capability and media information desired to be transmitted / received using SIP messages and SDP, and the SIP server refers to the description of the SIP message and SDP. The edge node is set to pass a packet having the described UDP port number.

  The own communication terminal transmits the reception port number described in the SDP received from the partner terminal as the destination transmission port number of the UDP packet to be transmitted. The edge node of the NGN network checks whether the destination transmission port number of the UDP packet is the same as the port number set by the SIP server, and if it matches, relays the packet, and if it does not match, discards the packet To refuse. In this embodiment, to simplify the description, it is assumed that this NGN network allows only two media streams per session (SIP transaction).

  FIG. 3 is a diagram showing an example of a schematic software configuration in the communication terminals 1 and 2 according to the present invention. Referring to the figure, software including an application 31, an application 32, a UDP protocol 33, and a lower communication protocol 34 is provided in the communication terminals 1 and 2 according to the present invention. The application 31 includes an audio receiving unit 31a and a video receiving unit 31b, and the application 32 includes a video receiving unit 32b.

  As shown in the figure, when a packet is transferred from the UDP protocol 33 to the applications 31 and 32 and modules within the applications 31 and 32, the packet is identified by a normal port number.

  FIG. 4 is a diagram showing an example of the structure of the UDP header in the communication system according to the present invention. The UDP header is added to the UDP data. Referring to the figure, an example of the UDP header 20 in the communication system according to the present invention includes a destination port number 21, a transmission source port number 22, other UDP header information 23, and data 24.

  In the NGN network 11, the destination port number 21 is monitored and used as a stream identifier. Since the source port number 22 is not monitored, if the destination port number 21 matches, the source port number 22 is treated as the same stream even if the source port number 22 is different. Since the stream can be identified if the original port number 22 is different, the packet can be passed to another application or module.

  Next, the operation of the first embodiment will be described. It is assumed that the communication terminal 1 performs a videophone call using the communication terminal 2 and two video streams and one audio stream. At the start of communication, a SIP INVITE message is transmitted as shown in FIG. 2. This INVITE message includes SDP and describes the reception port number of the stream desired to be received.

  FIG. 5 is a diagram showing an example of a normal SIP INVITE message (1). Referring to the figure, normally, in the SDP of the INVITE message (1), two video stream reception port numbers (“10100” and “10200”) and one audio stream reception port number (“10000”) are added. Although described, in this NGN network, since the upper limit of the number of media streams is “2”, communication is rejected.

  FIG. 6 is a view showing an example of the SIP INVITE message (2) of the communication system according to the present invention. Referring to the figure, in order to pass a video stream and an audio stream through the NGN network, the INVITE SDP has one audio reception port number (“10000”) and one video reception port number (“10100”). )) In total.

  In this state, the UDP port of the video media stream transmitted from the communication terminal 2 has the destination port number “10100”. For example, by using “10100” and “10200” as the transmission port numbers, the communication terminal 1 It is possible to separate the two media streams.

  However, since the communication port 2 uniquely assigns the transmission port number of the UDP packet transmitted from the communication terminal 2, for example, when the communication terminal 1 has an internal configuration as shown in FIG. It is not possible to determine whether to pass to 31 or 32.

  Therefore, in the present invention, as shown in FIG. 7 and FIG. 8, the SDP is expanded and a transmission source port number and information associated therewith are added and transmitted. FIG. 7 is a diagram showing an example of a SIP INVITE message (3) in the communication system according to the present invention, and FIG. 8 is a diagram showing an example of a SIP 200 OK message in the communication system according to the present invention.

  The feature of this embodiment is in the description of the line “a = fmtp” shown in FIGS. 7 and 8, and associates the application with the source port number. However, the content of the message is an example, and the present invention is not limited to this. The source port numbers (“20100” and “20200”) of the video media stream shown in FIG. 7 are the source port numbers when UDP is transmitted from the communication terminal 1, and the application 1 (ap1) is the source port number. “20100” indicates that the application 2 (apl) transmits with the transmission source port number “20200”.

  On the other hand, the UDP transmission source port number of the video media stream transmitted from the communication terminal 2 is described in the SDP included in 200 OK of the SIP sequence shown in FIG. 8, and the transmission source port number of the packet addressed to the application 1 (ap1) Is “40100” and the source port number of the packet addressed to application 2 (ap11) is “40200”.

  On the other hand, from the communication terminal 2, the destination port number of the UDP packet of the video media stream addressed to either application is “10200” described in the SDP of INVITE from the communication terminal 1, and from the NGN network 11 Looks like a single media stream.

  As described above, according to the first embodiment of the present invention, even if the upper limit of the number of media streams in the NGN network is determined, it is possible to transmit / receive media streams exceeding the upper limit.

  Next, a second embodiment of the present invention will be described. In the first embodiment, the SDP is not expanded, the SIP message is transmitted as shown in FIG. 6, and the relationship between the transmission source port number and the application can be set in advance.

  As described above, according to the second embodiment of the present invention, a media stream exceeding the upper limit can be transmitted and received using a normal SIP message.

  Next, a third embodiment of the present invention will be described. The transmission message is the same as in the second embodiment, but the relationship between the transmission source port number and the application is not fixed, and the stream with the smallest transmission source port number is determined as application 1, and the next smallest stream is determined as application 2. For example, it is possible to associate the relative size of the transmission source port number with the application.

  As described above, according to the third embodiment of the present invention, a normal SIP message can be used to transmit / receive a media stream exceeding the upper limit, and the relationship between the source port number and the application is fixedly set. It is possible to save time and effort.

  Next, a fourth embodiment of the present invention will be described. The present invention is not limited to the NGN network, but is effective when the communication content is applied to the network in advance and the permission of communication is requested, and the media stream has an upper limit number. Also, the message is not limited to SIP or SDP.

  As described above, according to the fourth embodiment of the present invention, the present invention can be applied to networks other than the NGN network.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Supplementary note 1) A communication terminal transmission / reception method in a communication system in which a plurality of communication terminals transmit / receive media streams via a network having an upper limit on the number of media streams, and the media stream reception port when transmitting / receiving the media streams A number, a transmission source port number of the media stream, and information associating the media stream with the transmission source port number, and applying for communication contents in advance to permit communication. A transmission / reception method for a communication terminal, which is applied to a desired network.

  The present invention is not limited to NGN, and can be applied to any network with a limited number of streams.

1, 2 Communication terminal
11 NGN network
12 SIP server 13, 14 Edge node
21 Destination port number
22 Source port number
23 Other UDP header information
24 Data 31, 32 Application
31a Audio receiver 31b, 32b Video receiver
33 UDP protocol
34 Lower communication protocol

Claims (10)

A communication terminal in a communication system in which a plurality of communication terminals transmit and receive media streams via a network having an upper limit on the number of media streams;
Upon transmission / reception of the media stream, a reception port number of the media stream, a transmission source port number of the media stream, and information associating the media stream with the transmission source port number are set. A communication terminal.   What is the reception port number of the media stream, the transmission source port number of the media stream, and the media stream in a message for exchanging capability and desired communication content with the opposite communication terminal 2. The communication terminal according to claim 1, wherein information for associating the source port number with the source port number is added.   A receiving port number of the media stream is added to a message for exchanging capabilities and desired communication contents with an opposing communication terminal, and separately from the message, a transmission source port number of a media stream to be transmitted and received, 2. The communication terminal according to claim 1, wherein information relating to what the media stream is and the source port number is set.   The receiving port number of the media stream is added to a message for exchanging the capability and desired communication content with the opposite communication terminal, and the source port number of the media stream to be transmitted / received is relative to the message. The communication terminal according to claim 1, wherein the size and the application are associated with each other.   The communication terminal according to any one of claims 1 to 4, wherein the communication terminal is applied to a network that requests communication permission in advance and requests communication permission. A communication terminal transmission / reception method in a communication system in which a plurality of communication terminals transmit and receive media streams via a network having an upper limit on the number of media streams.
Upon transmission / reception of the media stream, a receiving port number of the media stream, a transmission source port number of the media stream, and information that associates what the media stream is with the transmission source port number are set. A transmission / reception method for a communication terminal.   What is the reception port number of the media stream, the transmission source port number of the media stream, and the media stream in a message for exchanging capability and desired communication content with the opposite communication terminal 7. The transmission / reception method of a communication terminal according to claim 6, wherein information for associating the source port number with the transmission source port number is added.   In addition to the media stream receiving port number added to a message for exchanging capabilities and desired communication contents with the opposing communication terminal, and separately from the message, the source port number of the media stream to be transmitted and received, 7. The transmission / reception method of a communication terminal according to claim 6, wherein information associating the media stream with the transmission source port number is set.   A receiving port number of the media stream is added to a message for exchanging capability and desired communication contents with an opposing communication terminal, and the source port number of the media stream to be transmitted / received is relative to the message. 7. The communication terminal transmission / reception method according to claim 6, wherein the size and the application are associated with each other.   A communication system comprising a plurality of communication terminals according to claim 1.

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