KR100750583B1 - Network system of supplying streaming service - Google Patents

Abstract

A network system for providing a streaming service is provided to perform RTSP tunneling for streaming without modifying a system of a mobile terminal and provide the streaming service without affecting the network environment of an NAT(Network Address Translator), thereby satisfying various requirements of the streaming server in an external network. A network system for providing a streaming service comprises the followings: a streaming server(30) for providing the streaming service related to media data; a terminal for receiving the media data transmitted based on the streaming method and reproducing the received media data; a relay server(36) for changing a part of server adaptive information and transmitting the changed information to the other party; and an NAT(Network Address Translator)(34) which is applied between the streaming server and the relay server.

Description

Network system providing streaming service {Network system of supplying streaming service}

1 is a diagram showing the configuration of a streaming service network via a general network address translator (NAT),

2 is a diagram illustrating an operation of a communication service connection using a mobile terminal in a streaming service network via a conventional network address translator (NAT).

3 is a diagram illustrating an operation of a streaming service from a streaming server in a streaming service network via a conventional network address translator (NAT).

4A and 4B are diagrams illustrating a UDP transmission and reception relationship of a terminal in a network to which a public IP address of N: 1 corresponds;

5 is a diagram illustrating a configuration of a communication network to which a streaming relay gateway is applied to provide a streaming service according to the present invention.

6 is a view for explaining the operation of the relay (Describe) method through the relay server when providing a streaming service according to the present invention,

7 is a diagram illustrating a flow of a disk message for RTP / RTCP over TCP (HTTP) mode according to a preferred embodiment of the present invention.

FIG. 8 is a diagram for explaining relay operation of a setup method through a relay server when providing a streaming service according to the present invention;

9 illustrates a setup method for an RTP / RTCP over TCP interface according to a preferred embodiment of the present invention.

FIG. 10 is a diagram illustrating a relay operation of a play method through a relay server when providing a streaming service according to the present invention.

11 is a view for explaining the operation of the RTP relay in the RTP over UDP mode according to a preferred embodiment of the present invention,

12 is a view for explaining the operation of the RTCP relay in the RTP over UDP mode according to a preferred embodiment of the present invention,

13 is a view for explaining the operation of the RTP relay in the RTP over TCP mode according to a preferred embodiment of the present invention,

14 is a view for explaining the operation of the RTCP relay in the RTCP over TCP mode according to a preferred embodiment of the present invention,

15 is a diagram illustrating an interface operation in RTSP over TCP and RTP / RTCP over UDP as an external network side interface of a relay server according to an embodiment of the present invention.

16 is a diagram illustrating an interface operation in RTSP / RTP / RTCP over TCP as an external network side interface of a relay server according to another example of the present invention.

17 is a diagram illustrating an interface operation in RTSP / RTP / RTCP over HTTP as an external network side interface of a relay server according to another embodiment of the present invention.

FIG. 18 illustrates an embodiment of a streaming flow using an MMS protocol at an interface between a relay server and a streaming server.

FIG. 19 illustrates an embodiment of a streaming flow using SIP at an interface between a relay server and a streaming server.

FIG. 20 illustrates an embodiment of a streaming flow using HTTP at an interface between a relay server and a streaming server.

<Description of the symbols for the main parts of the drawings>

30: streaming server 32: firewall

34: network address translator 36: relay server

38,38a-38c: terminal

The present invention relates to a network system for providing a streaming service, and more particularly, to control a streaming service from a streaming server to a terminal in a streaming service network using a network address translator (NAT). It's about things.

In general, a streaming service network has a streaming server having a public IP in a network area, and a multimedia such as a video or a voice on a personal computer (PC) or a mobile terminal to which a video on demand player is applied. It is for streaming data.

In such a streaming service network, a streaming server provides a streaming service to a personal computer or mobile terminal having a public IP address, or via a network address translator (NAT) to a personal computer or mobile terminal having a personal IP address. It is designed to provide a streaming service.

FIG. 1 is a diagram illustrating a configuration of a streaming service network via a general network address translator (NAT). In the figure, a VOD player that receives and plays streaming data in a private IP area 6 over a wired or wireless network is provided. Streaming servers 16 and 18 that provide streaming services with public IP addresses in multiple personal computers 2 and / or multiple mobile terminals 4 and public IP network area 14 And a menu server 20 and a database server 22.

The personal computer 2 operates in a public IP address band or a private IP address band depending on whether NAT is present in the local area network (LAN) 8, but the network address translator (NAT) 10 is shown in FIG. IP address translation is used to operate in the private IP address band.

In case of mobile terminal of SKT, KTF, etc., in order to solve the shortage of IP addresses, each mobile carrier operates in the private IP address band within the network of each carrier, and in case of mobile carrier services such as JUNE and FIMM services, the service providing system is all It is in the IP address band and does not require a separate NAT service. However, in order for the mobile terminal 4 to receive a service from a streaming server of an external network, a translation to a public IP address is necessary.

In the figure, when the personal computer 2 or the mobile terminal 4 operates in the private IP address band, it is difficult to receive the User Datagram Protocol (UDP). In order to solve the problem, the network address translator (NAT) 10 has to correspond one to one public IP addresses per one private IP address.

However, since the 1: 1 correspondence method of the private IP address to the public IP address is applied to the network address translator (NAT) 10 to solve the lack of the public IP address, this method is limited. Accordingly, the personal computer 2 or the mobile terminal 4 can establish a connection of the Real-Time Streaming Protocol (RTSP) by using the Transmission Control Protocol (TCP) without limitation via the network address translator (NAT) 10 to the server. It is most realistic to build and stream using that channel, so that the VOD player can be routed to RTP over TCP using the RTSP-compliant Embedded (Interleaved) Binary Data transfer mode rather than Real-Time Transport Protocol (RTP) over UDP. To make it work.

However, since the mobile terminal 4 is not easy to change the RTP protocol, compared to the personal computer 2, in which the VOD player can be freely changed or upgraded by the open system environment, the streaming is possible without modification of the terminal. You need a way to do it.

2 is a diagram illustrating the operation of a communication service connection using a mobile terminal in a streaming service network via a conventional network address translator (NAT).

As shown in FIG. 2, the mobile terminal 4 accesses the menu server 20 via the network address translator 10 and the firewall 24 to select content to be streamed. The server 20 downloads the WAP script for the selected content to the mobile terminal 4.

The mobile terminal 4 checks the script of the downloaded content to obtain a URL to the streaming server 16 and accesses it, and the streaming server 16 streams the content to the mobile terminal 4.

An operation for streaming content from the streaming server 16 to the mobile terminal 4 is as shown in FIG. 3.

In FIG. 3, the mobile terminal 4 requests information about the content from the streaming server 16 (Describe Request), and the streaming server 16 sends information about the content to the mobile terminal 4 by SDP. Will be transmitted using.

The mobile terminal 4 confirms the information on the content and informs the streaming server 16 of the UDP port information for receiving the content data (Setup Request), wherein the mobile terminal 4 For each media, two UDP ports (one for data reception and one for RTCP (RTP Control Protocol) transmission and reception) will be used.

Accordingly, the streaming server 16 checks the information transmitted from the mobile terminal 4 and informs the mobile terminal 4 of the UDP port information for transmitting data (Setup Response). UDP ports (one for data transmission and one for RTCP transmission and reception) will be used.

Meanwhile, after the mobile terminal 4 completes resource allocation and preparation for transmitting and receiving data, the mobile terminal 4 transmits data to the streaming server 16 (PLAY Request), and the streaming server 16 transmits the data to the mobile terminal. Data is streamed to (4) (PLAY Response).

When the streaming transmission of the data is completed, the mobile terminal 4 makes a termination request to the streaming server 16 (Teardown Request), and the streaming server 16 performs a response to the termination request ( Teardown Response).

Meanwhile, in order to receive a service by accessing a streaming server located in an external network in a network environment via a network address translator (NAT), a public IP is allocated to the terminal in a public IP address band managed by the network address translator (NAT). Should be. However, since the public IP address band managed by the network address translator (NAT) is finite, the service is provided in a manner in which private IPs of multiple terminals correspond to one public IP when the public IP is insufficient.

That is, the terminal is assigned one of the modes such that the private IP and the public IP correspond to 1: 1, and the mode such that the private IP and public IP of the terminal correspond to N: 1.

First, in the case where the private IP of the terminal and the public IP correspond to 1: 1, the public IP managed by the network address translator (NAT) has a margin, and the terminal corresponds to the external network 1: 1. With IP, all services on a TCP / IP network are available.

In the structure of the mode where the private IP and the public IP correspond to 1: 1, for example, when three mobile terminals are allocated three private IPs of 10.128.120.234, 10.128.156.10, and 10.100.231.123, respectively, In order to receive services by accessing each streaming server, a public IP address (eg, 211.123.10.23, 213.13.123.44, 211.212.231.20) must be allocated by a network address translator (NAT) of a network to which each mobile terminal belongs.

In the streaming flow of FIG. 3, the streaming server transmits RTP data of each media using the RTP / RTCP UDP port of the mobile terminal set in the transport setup process, and the network address translator (NAT) receives the received UDP packet. By converting the public IP to the corresponding private IP and transmitted to each mobile terminal, it is possible to normal service by 1: 1 correspondence between the private IP and the public IP.

On the other hand, in the case where the private IP of the terminal and the public IP correspond to N: 1, the public IP managed by the network address translator (NAT) cannot afford to share the terminal with another terminal in order to access the external network. Since the public IP must be used, only a TCP service requesting a connection from the terminal side can be used, and in the case of UDP, only the side transmitting from the terminal side is possible and cannot be received.

In the case of the RTSP protocol, in the case of the RTSP protocol, a connection request is made through TCP first in the case of the N: 1 public IP address of the network address translator (NAT), and in the case of the TCP connection, multiple terminals share one public IP. Because of this, not only correspondence of private IP to public IP but also correspondence conversion of port through network address translator (NAT) is performed.

As a result, in the case of N: 1 public IP address correspondence, 1: 1 correspondence service becomes possible through IP and port couple matching only for TCP connection, so streaming play using private IP is possible. Terminals can also be streamed by using the RTP over TCP function using the embedded binary data transmission mode of the RTSP standard.

However, since a mobile terminal using a mobile communication network does not support the above function, smooth streaming is difficult, so another method is required.

In the case of UDP transmission, since it is a connectionless protocol, since the destination IP and the port are the only packet transmission means, there is a difference between UDP transmission and reception in a network situation via a network address translator (NAT).

4A and 4B are diagrams illustrating a UDP transmission and reception relationship of a terminal in a network to which a public IP address of N: 1 corresponds.

FIG. 4A shows the UDP transmission operation of the terminal in N: 1 correspondence between the private IP address and the public IP address. In this figure, the destination information does not change even when passing through the network address translator (NAT). Accordingly, the streaming server 16 The UE may receive the RTCP Receiver Report transmitted by the terminal.

4b shows RTP over UDP transmission of a streaming server in N: 1 correspondence between a private IP and a public IP address, wherein the transmitted UDP packet is networked by using a destination IP and port information corresponding by a network address translator (NAT). An address translator (NAT) is received, but no longer decides which terminal to transmit to and is dropped. Therefore, in the case of N: 1 public IP address correspondence, terminals using a private IP cannot receive UDP packets transmitted from an external network.

In general, when there is a large demand for IP addresses, such as a mobile carrier, the number of manageable public IPs is very small compared to the number of terminals being serviced, so that N: 1 public IP address correspondence by a network address translator (NAT) is applied. There are many cases. However, there is a disadvantage that it is difficult to receive a multimedia service from an external network in an environment in which a VOD player is not easily replaced, such as a mobile terminal.

Accordingly, the present invention has been made in view of the above-described conventional situation, and an object thereof is to provide a method for performing a normal streaming service via a network address translator (NAT) without modification of a terminal in a communication network.

A network system for providing a streaming service according to an embodiment of the present invention for achieving the above object, a streaming server for providing a streaming service for media data; A terminal for receiving and playing media data transmitted in a streaming form; And server-adaptive information included in the data transmitted from the streaming server and the terminal when the streaming server and the terminal are connected to each other according to a data flow of the streaming service, which includes preparing a streaming and transmitting actual media data. It is configured to include a relay server for changing a part of, wherein, between the streaming server and the relay server is characterized in that a network address translator (NAT) is applied.

Hereinafter, the present invention configured as described above will be described in detail with reference to the accompanying drawings.

5 is a diagram illustrating a configuration of a communication network to which a streaming relay gateway is applied to provide a streaming service according to the present invention.

As shown in FIG. 5, the communication network to which the streaming relay gateway according to the present invention is applied includes a streaming server 30, a firewall 32, a network address translator (NAT) 34, a relay server 36, and a terminal. 38, including.

The streaming server 30 is located in an external network with respect to the terminal 38 to transmit multimedia data through a streaming service.

The terminal 38 is provided with a VOD player for playing multimedia data streamed from the streaming server 30. Here, the terminal 38 may be a mobile telephone, a set-top box, a telematics terminal, or the like.

The relay server 36 relays a Real Time Streaming Protocol (RTSP) / Real Time Transport Protocol (RTP) / RTP Control Protocol (RTCP) message between the terminal 38 equipped with the VOD player and the streaming server 30. And tunneling (Tunneling) function for the firewall (32).

In the private network environment using the network address translator (NAT) 34, the relay server 36 adaptively converts and transmits the request of the terminal in a form that satisfies the requirements of various streaming servers 30. Act on receipt of the sent message.

The relay transmission function of the RTP / RTCP in the relay server 36 may not receive RTP / RTCP from a terminal due to a network configuration such as a network address translator (NAT) 34 or a firewall 32. As a relay mode, the RTP / RTCP transmission / reception interface mode is largely divided into RTP / RTCP over UDP mode, RTP / RTCP over TCP (RTSP) mode, and RTP / RTCP over TCP (HTTP) mode. Can be distinguished.

When the relay server 36 is applied to a communication network, it is possible to perform RTSP tunneling for a player that is difficult to modify a system environment, such as a terminal, and affect a network environment such as a firewall or a network address translator (NAT). It is possible to proceed with streaming service regardless of the element, and it is possible to adaptively convert user's demand regardless of the type of streaming server, and even if the network is closed, the streaming service is possible.

The following describes the relay server relaying streaming services. In the case of typical multimedia streaming using the RTSP / RTP / RTCP protocol, there are two stages: a session signaling phase corresponding to preparation before streaming and a data streaming phase in which actual media data is transmitted. Here, the session or multimedia session refers to the originator, the receiver, and the data stream flowing from the sender to the receiver of the multimedia data, wherein the session signaling step corresponds to preparing for such a session.

In addition, in the case of an interface with a streaming server, the relay server may support a relay function for various protocols through the above two steps, in addition to RTSP / RTP / RTCP.

First, a description will be given of a series of flows in which a relay server receives a streaming request from a terminal and relays RTSP / RTP / RTCP. Among the above-mentioned transmission / reception interfaces, the RTP / RTCP over UDP mode is basically described, and other interfaces are explained in detail.

In the RTSP / RTP / RTCP protocol, the session signaling step corresponding to the pre-streaming preparation step may include a write method, a setup method, a play method, and the relay server. For each of these methods, the streaming server and the terminal are relayed.

FIG. 6 is a diagram illustrating a disk-driven relay operation through a relay server when providing a streaming service according to the present invention.

In FIG. 6, the RTP / RTCP over UDP mode will be described mainly among the three modes of the RTP / RTCP transmission / reception interface mode.

First, the terminal 38 describes to obtain media information such as a presentation about a specific multimedia content in the streaming server 30 and description information about an object. You will be sent a request message.

In FIG. 6, the disk drive request message includes a method name (Describe), a URL (RTSP: //10.1.1.226/test.mp4), an RTSP version (RTSP / 1.0), and a command sequence number (CSeq :) indicating a disk drive method. 0) and the like.

When the relay server 36 receives the disk live message, the relay server 36 relays the message to the streaming server 30 of the external network. In this case, the relay server 36 changes the part to be adapted to the server, such as the IP address of the server. do.

The streaming server 30 receiving the disk drive request message generates a disk drive response message and transmits it to the relay server 36. In FIG. 6, the disk drive response message includes a response code (200 OK) indicating that the RTSP version (RTSP / 1.0) disk drive request was well processed, a command sequence number (CSeq: 0), and server information (Server: XXX Streamer / 2.0). .0), information about the Session Description Protocol (SDP) (part starting with 'v = 0' in FIG. 6) body (Content-Type: application / sdp, Content-length: 613, Content-Base: rtsp: / /211.172.251.170/test.mp4), SDP body (v = 0, ~) and the like.

The relay server 30 receives the disk drive response message from the relay server 36, modifies the IP address in the adaptive part of the server, that is, information on the SDP body, and transmits the IP address to the terminal 38.

Meanwhile, an interface between the relay server 36 and a streaming server of an external network becomes important for transmitting and receiving RTP / RTCP under network constraints such as a network address translator (NAT) or a firewall. FIG. 6 shows an RTP / RTCP over UDP or the like. Demonstrates the relay of the disk live method in RTP / RTCP over TCP (RTSP).

FIG. 7 is a diagram illustrating a flow of a disk message for an RTP / RTCP over TCP (HTTP) mode according to a preferred embodiment of the present invention, in which the external streaming server in the case of RTP / RTCP over TCP (HTTP) The flow of the disk drive message between the 30 and the relay server 36 is shown.

In the RTP / RTCP over TCP (HTTP) mode, after the exchange of GET Request, GET Response, and POST Request messages, which are HTTP protocols, the disk drive request message and the disk drive response message are exchanged.

When the terminal 38 receives the information for the content presentation of the streaming server 30 through the disc live method, the terminal 38 relays the transport information to receive the media data through a setup request. The setup request for the network transport configuration information has two transmission modes, RTP / AVP / UDP and RTP / AVP / TCP, which are defined in the RTSP specification. Normally, the RTP / AVP / UDP mode is used.

8 is a diagram illustrating a relay operation of a setup method through a relay server when providing a streaming service according to the present invention.

The relay server 36 receives the setup request transmitted from the terminal 38 and sets transport information for transmitting and receiving RTP / RTCP between the terminals 38, and transmits the RTP and the RTCP according to the set transport information. While preparing for transmission and reception, the terminal 38 also prepares for RTP reception and RTCP transmission and reception.

In FIG. 8, the terminal 38 sends a setup request including transport information for which RTP and RTCP ports are 16000 and 16001 ports and SSRC (Synchronization Source) is 29, respectively. The relay server 39, which transmits the data to the terminal 38, sets a transport for transmitting and receiving the RTP / RTCP with the terminal 38 based on the received information.

When the transport information setting operation with the terminal 38 is completed, the relay server 36 provides transport information through a setup request for RTP / RTCP transmission and reception with the streaming server 30 of the external network. In FIG. 8, the relay server 36 makes a setup request including transport information of 34500 and 34501 ports and SSRC of 89 for transmitting and receiving RTP and RTCP, respectively.

When receiving the setup request, the streaming server 30 prepares for RTP transmission and RTCP transmission / reception according to the set transport information, and proceeds with a setup response to the setup request. The terminal 38 In the setup response through the relay server 36 to extract information about the transport to prepare for RTP reception and RTCP transmission and reception.

In FIG. 8, the setup response transmitted from the streaming server 30 to the relay server 36 includes transport information in which server ports for RTP / RTSP transmission and reception are 27800-27801 and SSRC for stream source classification 35 is shown. do. In addition, the setup response transmitted from the relay server 36 to the terminal 38 includes transport information in which a server port for RTP / RTSP transmission and reception is 14800-14801 and an SSRC for stream source classification is 4.

The transport setting using the setup method performed by the relay server 36 can be set in various modes according to the RTP / RTCP transmission / reception interface. In FIG. 8, the streaming server 30 and the relay server are illustrated in FIG. 8. A transport setting process for the RTP / RTCP over UDP interface between 36 is shown, and FIG. 9 shows a transport setting process in the case of RTP / RTCP over TCP (RTSP or HTTP).

The setup request and setup response are performed separately for each media. For example, the setup request and setup response are separately performed for video and audio. In addition, ports for RTP and RTCP transmission and reception may be separately set for each media, or ports for RTP and RTCP transmission and reception may be shared by each media, and different SSRCs may be used for transmission and reception of each media.

Next, FIG. 10 is a diagram illustrating a relay operation of a play method through a relay server when providing a streaming service according to the present invention.

In FIG. 10, when all the settings for media streaming from the streaming server 30 are completed, the terminal 38 transmits a play request to the relay server 36 to request the start of streaming. do.

When the relay server 36 receives the play request, the relay server 36 modifies the server adaptive information to relay the play request to the streaming server 30 of the external network, and the streaming server 30 notifies the play response of the play request. The relay server 36 transmits the result.

When the relay server 36 receives the play response from the streaming server 30, the relay server 36 modifies network adaptive information and relays the play response to the terminal 38 to start streaming from the terminal 38. Be sure to

When the preparation work for streaming through the RTSP signaling is completed, the streaming server 30 starts the RTP transmission as shown in FIG. 11, the relay server according to the transport information set by the setup method. The RTP packet is transmitted to 36).

In FIG. 11, the RTP packet transmitted from the streaming server 30 to the relay server 36 sets the IP address of the streaming server 30 as 211.172.251.170 as a source IP, and relays as 10.1.1.226. Using the IP address of the server 36 as the destination IP, it is transmitted in an RTP Packet over UDP packet having an IP header, a UDP header, an RTP header, and an RTP payload.

The RTP packet transmitted from the relay server 36 to the terminal 38 is transmitted using 10.1.1.226 as the source IP and IP address of the terminal 38 having 10.1.1.128 as the destination IP. That is, the relay server 36 modifies the source IP and the destination IP included in the IP header of the RTP packet.

In addition, the relay server 36 changes the port number (RTP / RTCP) included in the UDP header of the RTP packet. In the example of FIG. 8, the UDP header of the RTP packet transmitted from the streaming server 30 to the relay server 36 includes a client port of 34500-34501 and a server port of 27800-27801. The relay server 36 ) Changes the client and server ports in the UDP header to 16000-16001 and 14800-14801, respectively.

In addition, the relay server 36 changes the SSRC included in the RTP header of the RTP packet. In the example of FIG. 8, the RTP header of the RTP packet transmitted from the streaming server 30 to the relay server 36 includes 35 SSRCs, and the relay server 36 changes the SSRC in the RTP header to 4. do.

12 shows transmission of an RTCP packet when the interface between the streaming server 30 and the relay server 36 is RTCP over UDP.

In FIG. 12, the streaming server 30 transmits an RTCP packet having an IP header, a UDP header, an RTCP header, and an RTCP body message to the terminal 38 through the relay server 36. RTCP Sender Report (RTCP Sender Report) to the terminal 38 through the 36, the terminal 38 via the relay server 36, the RTCP Receiver Report (RTCP Receiver Report) ) Will be sent.

Similar to the RTP packet transmission of FIG. 11, the relay server 36 receives an RTCP packet from the streaming server 30 and receives a client IP included in a source IP, a destination IP, and a UDP header included in an IP header of the RTCP packet. The SSRC information included in the port, the server port, and the RTCP header is changed and transmitted to the terminal 38.

FIG. 13 shows a state in which the RTP packet from the streaming server 30 is relayed through the relay server 36 in the RTP over TCP mode, and the TCP is relayed from the streaming server 30 to the relay server 36 through TCP. The transmitted RTP packet has an IP header, a TCP header, a $, an ID, an RTP size, an RTP header, and an RTP payload. However, the RTP packet transmitted through the relay server 36 to the terminal 38 through UDP is It has an IP header, a UDP header, an RTP header, and an RTP payload.

That is, the relay server 36 reconstructs the RTP packet by deleting $, ID indicating the RTP / RTCP, ID indicating the interleaved port, and RTP size from the RTP packet transmitted from the streaming server 30 through TCP. At this time, the relay server 36 changes the source IP and the destination IP included in the IP header, generates a new UDP header based on the TCP header in the received RTP packet, and changes the SSRC information included in the RTP header. The RTP packet is generated through the UDP and transmitted to the terminal 38.

FIG. 14 illustrates a state in which an RTP packet from the streaming server 30 is relayed through the relay server 36 in the RTCP over TCP mode, and is transmitted from the streaming server 30 to the relay server 36. Although Packet over TCP has an IP header, a TCP header, a $, an ID, an RTCP size, an RTCP header, and an RTCP body message, an RTP Packet over UDP transmitted to the terminal 38 through the relay server 36 is IP. It has a header, a UDP header, an RTCP header, and an RTCP payload.

Similar to the RTCP packet transmission of FIG. 13, the relay server 36 receives an RTCP packet from the streaming server 30 through TCP, deletes the $, ID, and RTP sizes, and includes a source IP included in an IP header. And the destination IP is changed, a new UDP header is generated based on the TCP header, and SSRC information included in the RTCP header is changed to generate an RTP Packet over UDP to be transmitted to the terminal 38.

On the other hand, the network interface of the relay server 36 and the external streaming server 30 using RTSP / RTP / RTCP can be classified into three types, RTSP over TCP and RTP / RTCP over UDP, RTSP / RTP / RTCP over TCP In this case, it is desirable to select the most suitable interface according to the limitations of the firewall and the network address translator (NAT).

First, FIG. 15 is a diagram illustrating an interface operation in RTSP over TCP and RTP / RTCP over UDP as an external network side interface of a relay server according to an embodiment of the present invention. Is applied when the relay server 36 has an interface to both the public network and the private network, and there is no restriction in the firewall 32, and the plurality of terminals 38a, 38b, 38c and the streaming server ( 30) There is no restriction on all.

In FIG. 15, the relay server 36 is capable of relaying RTSP requests from the plurality of terminals 38a, 38b, and 38c to the streaming server 30 as it is, and the RTP / RTCP over UDP is directly forwarded to each terminal 38a, 38b, 38c.

Since the RTSP over TCP and the RTP / RTCP over UDP mode interfaces are capable of UDP transmission and reception, the system network interface overhead of the relay server due to the RTP / RTCP transmission and reception using TCP can be reduced. It can be applied immediately without modifying the system of the server and the terminal.

Next, FIG. 16 is a diagram illustrating an interface operation in RTSP / RTP / RTCP over TCP as an external network side interface of a relay server according to another example of the present invention. The RTSP / RTP / RTCP over TCP mode allows the relay server 36 to interface with the streaming server 30 existing in the external network when the relay server 36 does not have an independent public IP address. ) Does not have an independent public IP address, there is no limitation on the interface with each terminal (38a, 38b, 38c). In this case, the relay server 36 supports the streaming protocol with the streaming server 30 by using RTSP / RTP / RTCP over TCP.

Since the relay server 36 does not have an independent public IP address, even though it shares a public IP address such as the other terminals 38a, 38b, and 38c, since the normal TCP service is possible, the RTP, When transmitting and receiving RTCP, it is possible to stably provide a streaming service. Disadvantages include inflexibility in network configuration, and are unlikely to be used when firewall policy changes.

In FIG. 16, when the terminals 38a, 38b, and 38c each having a separate private IP request streaming to the relay server 36, the relay server 36 performs RTSP / RTP / RTCP over in separate sessions. The service is provided to the streaming server 30 using TCP. At this time, the requests from each terminal 38a, 38b, 38c are divided into different TCP ports on the same public IP, and the number of terminals that can be serviced through one relay server can be allocated regardless of system performance. As many TCP ports as possible.

In this case, the RTSP / RTP / RTCP over TCP mode interface can always be used regardless of the network environment to which all kinds of network address translators (NAT) are applied, and the flexibility of the network configuration using the network address translator (NAT) is provided. In addition to being able to provide it, it can also be used to apply restrictive firewall policies.

Disadvantages: Because TCP is used as an interface with the streaming server, the relay server has a higher network interface overhead than UDP, and the streaming server must support the RTSP specification 'Embedded (interleaved) Binary Data', and a strong firewall policy. If applied, use may be restricted.

Next, FIG. 17 is a diagram illustrating an interface operation in RTSP / RTP / RTCP over HTTP as an external network side interface of a relay server according to another example of the present invention. In the RTSP / RTP / RTCP over HTTP mode, Although the relay server 36 does not have an independent public IP address and is used when a policy of a strong firewall 32 is applied to an external network, there is no limitation on an interface with each terminal 38a, 38b, 38c. HTTP interface is possible only with the streaming server 30 existing in the external network.

Thus, in this case, the relay server 36 supports the streaming protocol with the streaming server 30 by using RTSP / RTP / RTCP over HTTP, and this function is implemented by using the HTTP tunneling function.

Here, the RTSP / RTP / RTCP over HTTP mode interface is always available regardless of the network environment to which all kinds of network address translator (NAT) is applied, providing flexibility of network configuration and applying a strong firewall policy. Even if it is possible to use as much as possible.

Disadvantages: Because TCP is used as the interface with the streaming server, the network interface overhead of the relay server is higher than that of UDP, and the streaming server must support the RTSP specification 'Embedded (interleaved) Binary Data' and 'HTTP Tunneling'. And it is not yet standardized.

Meanwhile, as described above, streaming using the RTSP / RTP / RTCP protocol goes through two stages: a session signaling step and a data streaming step. The streaming relay server is connected to the RTSP / RTP / RTCP in connection with an interface with the streaming server. In addition, it can support relay functions for several protocols that go through these two stages. The following describes some representative interfaces among streaming servers.

FIG. 18 illustrates an embodiment of a streaming flow using a Microsoft Media Services (MMS) protocol at an interface between a relay server and a streaming server.

The packet used in the MMS protocol is divided into two types: a command packet corresponding to a signaling packet such as RTSP and a media packet used for media transmission such as RTP. The command packet is used in the session signaling step. As shown in FIG. 18, a streaming service using the MMS protocol performs session signaling using a command packet and then performs data streaming using a media packet.

FIG. 19 illustrates an embodiment of a streaming flow using a Session Initial Protocol (SIP) at an interface between a relay server and a streaming server.

SIP is a widely used protocol in Voice over Internet Protocol (VoIP) and can be used for multimedia streaming. In general, various types of session signaling are possible using various SIP methods, but streaming is also possible in a simple form as shown in FIG. As illustrated in FIG. 19, a streaming service using SIP may perform data signaling using RTP after session signaling using a SIP method.

FIG. 20 illustrates an embodiment of a streaming flow using HTTP at an interface between a relay server and a streaming server.

Streaming using the HTTP protocol is the simplest method of media delivery. This method is also divided into the above-described session signaling step and data streaming step. Unlike the above-described two examples, it is common to transmit step 2 repeatedly. As shown in FIG. 20, the streaming service using HTTP performs session signaling using HTTP GET Request and Response, and then performs data streaming using a body of Get Response.

On the other hand, the present invention is not limited to the above-described typical preferred embodiments, but can be carried out in various ways without departing from the gist of the present invention, various modifications, alterations, substitutions or additions are common in the art Those who have knowledge will easily understand. If the implementation by such improvement, change, replacement or addition falls within the scope of the appended claims, the technical idea should also be regarded as belonging to the present invention.

As described above, according to the present invention, in a communication network in which a mobile terminal receives a streaming service from an external network via a network address translator (NAT), the mobile terminal generates a streaming service without modifying a VOD player applied to the mobile terminal. By solving the UDP reception problem to enable the streaming service of normal media content, RTSP tunneling for streaming can be performed without modifying the system of the mobile terminal, affecting the network environment of the firewall and network address translator (NAT). As the streaming service becomes available without receiving the service, the streaming service can be performed in a form that satisfies all the various requirements of the streaming server in the external network.

Claims (14)

A streaming server providing a streaming service for media data; A terminal for receiving and playing media data transmitted in a streaming form; And When the streaming server and the terminal are connected to each other according to the data flow of the streaming service, which comprises the steps of preparing the streaming and transmitting the actual media data, it is included in the data transmitted from the streaming server and the terminal to the other party in each step. It is configured to include a relay server for changing a part of the server-adaptive information and forwarding to the other party, Here, a network system for providing a streaming service, characterized in that a network address translator (NAT) is applied between the streaming server and the relay server. The method of claim 1, And the server adaptive information includes at least one or more of a unique number for distinguishing an IP address, a port, and a source. The method according to claim 1 or 2, The interface between the relay server and the streaming server may include a Real-Time Streaming Protocol (RTSP) over Transmission Control Protocol (TCP) and a Real-Time Transport Protocol / RTP Control Protocol (UDP) over User Datagram Protocol (UDP) and RTSP. Network system that provides a streaming service, characterized in that any one of / RTP / RTCP over TCP, or RTSP / RTP / RTCP over HTTP. The method of claim 3, wherein The preparing of the streaming may include requesting and responding to information about media data, requesting and responding to network transport setting information, and requesting and responding to start streaming. Network system that provides streaming services. The method of claim 4, wherein The relay server provides a streaming service, characterized in that for transmitting and changing the IP address included in the message received in the process of requesting and responding to the information on the media data to its own IP address. The method of claim 4, wherein The relay server provides a streaming service, characterized in that for transmitting and changing the IP address, the unique number, and the port for transmitting and receiving RTP / RTCP in the process of requesting and responding to the network transport configuration information. The method of claim 4, wherein The relay server provides a streaming service, characterized in that for transmitting and changing the IP address contained in the message received in the process of requesting and responding to the start of the streaming to its own IP address. The method of claim 3, wherein In the transmitting of the actual media data, the relay server may reconfigure and transfer the header area of the packet transmitted from the streaming server to the terminal based on the information set in the preparing of the streaming. Network system that provides services. The method of claim 8, The relay server provides a streaming service, characterized in that for modifying the RTP and / or RTCP header, UDP or TCP header, and IP header included in the packet transmitted from the streaming server. The method of claim 9, The relay server provides a streaming system for modifying a unique number for distinguishing a source in an RTP and / or RTCP header, a port in a UDP or TCP header, and a source IP and a destination IP in an IP header. . The method of claim 8, When the interface between the relay server and the streaming server is RTP / RTCP over TCP and the interface between the relay server and the terminal is RTP / RTCP over UDP, the relay server is included in a header area of a packet transmitted from the streaming server. Changing the TCP header to a UDP header, and deleting some information included in a header area of a packet transmitted from the streaming server. The method of claim 3, wherein If a firewall is applied between the streaming server and the relay server, but there is no restriction in the firewall, the streaming service characterized in that the RTSP over TCP and RTP / RTCP over UDP is used for the interface between the relay server and the streaming server Providing network system. The method of claim 3, wherein If a firewall is applied between the streaming server and the relay server and a strong firewall policy is applied to the external network, the streaming service is characterized in that RTSP / RTP / RTCP over HTTP is applied to the interface between the relay server and the streaming server. To provide a network system. The method of claim 1, The terminal is a network system for providing a streaming service, characterized in that any one of a mobile phone, a set-top box, a telematics terminal.

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