Abstract:
The present invention proposes a method for network operators to control traffic between a server and a client so that client-induced traffic preemption may be prevented. The present invention comprises the processes of: an operator determining a network status, the network in which a server is streaming content via a multi-media transmission system; in accordance with the status of the network, determining whether to modify the meta data by considering a set of predetermined conditions; and transmitting to a terminal data reflecting the modification decision.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to a traffic control method and a traffic control apparatus using adaptive streaming in a multimedia content transmission system. 
       BACKGROUND 
       [0002]    In recent years, with an increase in the use of online content, smooth content transmission has become important. Accordingly, an adaptive streaming technology has been actively discussed in which a bit rate of content is adaptively changed according to a usable transmission bandwidth and a change in an apparatus performance of a user. 
         [0003]    A Dynamic Adaptive Streaming over HTTP (DASH) corresponds to a representative scheme of the adaptive streaming, which relates to a method of constituting content and a method of transmitting content. 
         [0004]      FIG. 1  is a block diagram illustrating a broadcasting communication system using DASH content. 
         [0005]    Referring to  FIG. 1 , the DASH content  110  is formed by representations  110   a  which are rows of media segments having several different image qualities, several different resolutions, several different bit rates, etc., AdaptationSets  110   b  obtained by grouping the representations  110   a,  and meta data  110   c  describing a relation between the representations  110   a  and the AdaptationSets  110   b.    
         [0006]    A reproduction device (or a client)  120  identifies the AdaptationSets to be reproduced, by receiving the meta data, selects each representation corresponding a network situation and a capability of the reproduction device among a plurality of representations in each AdaptationSet, and downloads and reproduces the selected representation. 
         [0007]      FIG. 2  is a block diagram illustrating an example of a broadcasting communication system using general DASH content. 
         [0008]    The DASH changes server control scheme streaming in a client control scheme. In a server control scheme, a server knows connection with all clients, makes a portion required by each client, and transmits an optical content proper for each network situation. However, as illustrated in a box  210  of  FIG. 2 , there is a disadvantage in that the server is overloaded as the number of clients increases. In the DASH, there is an advantage in that an optimal content can be downloaded and reproduced without a load of the server according to a network situation, by generating a media segment and meta data, by the server, and by reproducing the media segment and the meta data according to a situation, by the client. 
         [0009]    However, there is a disadvantage in that all of the clients attempt a best effort delivery in the range of usable data traffic so that all of the network traffic may be occupied only by a small number of clients. Further, implementation of a DASH client logic of the client is in a region of the reproduction device, and there is no control method which a network provider can perform in order to decrease the network traffic. Further, the server just provides the content, so that it is difficult that the server configures content specific to a network provider in order to solve a problem of the network provider such as an intermediate communication network. Since several different network providers may exist between the server and the client, there is a problem in that the content may not be configured for a specific provider and also reconfiguring of the content according to the network situation does not accord with an initial introduction purpose of the DASH. 
       DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem  
       [0010]    An aspect of the present disclosure is to provide a method and an apparatus for preventing traffic reduction generated due to an excessive connection increase of clients in a multimedia content transmission system using a DASH technology. 
         [0011]    Another aspect of the present disclosure is to provide a method and an apparatus for controlling traffic between content provider server and a client, by a communication provider, in a multimedia content transmission system using a DASH technology. 
       Technical Solution 
       [0012]    An aspect of the present disclosure is to provide a method of streaming content by a server in a multimedia content transmission system, the method including: determining a network situation by a provider; determining whether meta data is modulated, in consideration of a predetermined condition obtained from the determining; and transmitting data which reflects whether the meta data is modulated or not, to a terminal. 
         [0013]    A method of streaming content by a server in a multimedia content transmission system, the method including: dynamically determining a network situation by a provider; transmitting a command to a terminal when it is determined that traffic of the terminal is overloaded. 
       Advantageous Effects  
       [0014]    The present disclosure can prevent traffic reduction generated due to an excessive connection increase of clients in a multimedia content transmission system using a DASH technology. 
         [0015]    The present disclosure can prevent traffic preoccupancy by a client in a multimedia content transmission system using a DASH technology. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a block diagram illustrating a broadcasting communication system using DASH content; 
           [0017]      FIG. 2  is a block diagram illustrating an example of a broadcasting communication system using a general DASH content; 
           [0018]      FIG. 3  is a block diagram illustrating a multimedia content transmission system for describing a traffic control method of a network provider, using DASH metadata modulation, according to an embodiment of the present disclosure; 
           [0019]      FIG. 4  is a block diagram illustrating an example of a broadcasting communication system using DASH content according to an embodiment of the present disclosure; 
           [0020]      FIG. 5  is a flowchart illustrating a method of determining modulation of the metadata according to a first embodiment of the present disclosure; 
           [0021]      FIG. 6  illustrates a network configuration for describing a method of processing metadata using device management according to a fifth embodiment of the present disclosure; and 
           [0022]      FIG. 7  is a flowchart illustrating a method of controlling traffic for an adaptive streaming service using a device management server of a provider. 
       
    
    
     MODE FOR CARRYING OUT THE INVENTION 
       [0023]    In the following description of embodiments of the present invention, a detailed description of known functions or configurations incorporated herein will be omitted when it is determined that the detailed description thereof may unnecessarily obscure the subject matter of the present invention. The terms which will be described below are terms defined in consideration of the functions in the present disclosure, and may be different according to users, intentions of the users, or customs. Therefore, the definitions of the terms should be determined based on the contents throughout the specification. 
         [0024]    The detailed description discussed below will provide representative embodiments of the present invention to solve the technical problems. Further, for the convenience of description of the present invention, the same entity names as those defined in 3GPP (3rd Generation Partnership Project), MPEG (Moving Picture Experts Group), OIPF (Open IPTV Forum), and UPnP (Universal Plug and Play) will be used, but it is apparent that these standards and names do not limit the scope of the present invention, and the present invention may be applied to systems having similar technical backgrounds. 
         [0025]    The present disclosure proposes a method of adjusting traffic between a server and a client by a network provider in order to prevent traffic preoccupancy by the client. 
         [0026]      FIG. 3  is a block diagram illustrating a multimedia content transmission system for describing a traffic control method of a network provider using DASH metadata modulation according to an embodiment of the present disclosure. 
         [0027]    In a right communication network among two communication networks of  FIG. 3 , metadata of the DASH content shows only a part of media segments (the remaining portion other than a dotted line). This right communication network is obtained by diagramming “a part of adaptationset and a part of representation” which will be described below. 
         [0028]    The network provider detects a situation of a provider network, and provides the entirety or a part of a selection width of the AdaptationSet and the Representation which the client can select, by modulating a final network node where traffic is increased, meta data existing in a cache server connected to the final node, or meta data of content providing server provided by a Content Delivery Network (CDN). Since the client connected to the server through the network provider reproduces only a media segment corresponding to the AdaptationSet and the Representation described in the meta data received from the server, while the network provider transmits data received from the server, when the network provider receives meta data to which predetermined modulation is applied, a part of the AdaptationSets and a part of the Representations described in the corresponding meta data are recognized as the entire selection width, and the media segment corresponding to the entire selection width is downloaded and reproduced. 
         [0029]      FIG. 4  is a block diagram illustrating an example of a broadcasting communication system using DASH content according to an embodiment of the present disclosure. 
         [0030]    The meta data can be modulated as long as the server does not require separate integrity, and the modulated meta data should be well formed. Further, compatibility for a DASH standard should be secured. 
         [0031]    Various network nodes exist between the server and the client, and the network nodes are classified into a providing server  410 , a CDN  420 , a Cache server  430 , an End node  440 , and a client  450  according to a function thereof 
         [0032]    The content providing server  410  provides content, and is connected to the network provider through the CDN  420 . 
         [0033]    The CDN  420  is used for allowing the content providing server  410  to smoothly provide the content, and stores the content received from the content providing server  410  in various data servers several times to disperse demands of the network provider so as to more rapidly provide data. 
         [0034]    The cache server  430  is used for smoothly processing the same demand which is repeated several times, and directly provides data without passing through the CDN or the content providing server  410  when different clients require the same content. 
         [0035]    The end node  440  corresponds to a final region of the communication network provider directly connected to the client, and allows the communication network provider to identify a traffic situation of each of the clients connected to each other, and a situation of the entire traffic. 
         [0036]    The meta data is modulated by the cache server  430  which the communication network provider can control, and whether the meta data to be returned to the end node is modulated or not is determined according to the traffic situation of the end node  440  belonging to the communication network provider. 
         [0037]    First embodiment of the present disclosure: Determination on whether the meta data is modulated. 
         [0038]      FIG. 5  is a flowchart illustrating a method of determining modulation of the metadata according to a first embodiment of the present disclosure. 
         [0039]    In step  501 , the network provider recognizes (or determines) a situation of a network and monitors the end node. 
         [0040]    In step  503 , the network provider determines an optimal network level to be owned by each end node, and determines whether DASH content is modulated or not when traffic of the end node exceeds the corresponding level. That is, in step  505 , the network provider determines whether the traffic of the end node is larger than the optimal network level. 
         [0041]    When it is determined that the traffic of the end node exceeds the optical network level, in step  513 , the network provider identifies whether the DASH content is being processed by the cache server connected to the corresponding end node. 
         [0042]    When the DASH content is being processed, in step  515 , the network provider disables pieces of meta data in order from the piece which most largely influences the network. When the DASH content is not being processed, in step  517 , the network provider performs other processes. 
         [0043]    Meanwhile, when it is determined in steps  505  and  507  that the traffic of the end node does not exceed the optimal network level, in step  509 , the network provider determines whether the DASH meta data has been modulated by the cache server connected to the corresponding end node. Meanwhile, when the DASH meta data has been modulated, the process proceeds to step  511 , the network provider enables the disabled pieces of meta data in order from the piece which most slightly influences the network. However, when the DASH meta data has not been modulated, the network provider returns to step  501 . 
         [0044]    As a result, when the network provider examines the traffic and there is no influence on the traffic, the network provider continuously disables the pieces of the meta data in order from the piece having the second largest influence. When the traffic becomes a state similar to the optical network level, the current state is maintained. 
         [0045]    When the traffic becomes lower than the optical network level, the network provider enables the pieces of the meta data in order from the piece having the lowest influence on the network. When the network provider examines the traffic and there is no influence on the traffic, the network provider continuously disables the pieces of the meta data in order from the piece having the second largest influence. When the traffic becomes a state similar to the optical network level, the current state is maintained. 
         [0046]    Second embodiment of the present disclosure: Method of modulating meta data maintaining context 
         [0047]    Various contents of the meta data can be modulated. In the second embodiment of the present disclosure, a method of modulating meta data for traffic control while maintaining the context of the DASH content will be described. 
         [0048]    Items of a Period, an AdaptationSet, and a Representation are written in the meta data. 
         [0049]    Components of the content provided at the same time are written for each AdaptationSet under the Period. 
         [0050]    Media segment rows, having different qualities, of one component of the content provided to the same context are written at the Representation under the AdaptationSet. 
         [0051]    Thus, the Representations written in one AdaptationSet have just different qualities while maintaining the context of the DASH content, so as to modulate the Representation. 
         [0052]    A method of finding an upper Representation influencing on traffic will be described. 
         [0053]    The Representation includes properties of a Bandwidth (items written hereinabove is mandatory), a QualityRanking (items written hereinafter is optional), a Width, a Height, a Framerate, a ScanType, etc. 
         [0054]    The Representation having a larger bandwidth can be determined as the upper Representation which influence traffic, and when the Representations have the same bandwidth, the Representations are sorted in order from the Representation having larger optional properties. 
         [0055]    A method of the modulation includes a method of changing or annotating a name of an element of an XML. 
         [0056]    In this method, an element of &lt;Representation&gt; is found in the meta data, and an end tag portion (&lt;/Representation&gt;) where the corresponding Representation is completed is then found and disabled. 
         [0057]    The disabling method is to change the name of the Representation element to a state which the DASH cannot identify. 
         [0058]    Annotation (&lt;!--resentation&gt;. . . &lt;/resentation---&gt;) 
         [0059]    Three front characters of the “Representation” are converted into “!--” 
         [0060]    The string “/Representation” of the End tag is converted into “/resentation---&gt;” 
         [0061]    Substitution (&lt;_epresentation &gt;. . . &lt;/_epresentation&gt;) 
         [0062]    A part of characters of the “Representation” are converted into other Alphabet characters or symbols. 
         [0063]    However, the converted character should be an element which is not used by the existing DASH. 
         [0064]    When performing the enabling, the annotated or substituted name of the element returns to its original name. 
         [0065]    Third embodiment of the present disclosure: Method of modulating meta data which does not maintain context 
         [0066]    The AdaptationSets among the components of the DASH content are configured to instruct a role thereof, while being mixed with Audio and Video through the corresponding value, which is like Main and Alternative, by receiving each media component, for example, the Audio, the Video, and a role descriptor which are provided. 
         [0067]    Thus, when the meta data is modulated, in a case where the Main and the Alternative are provided through the Role, if it is determined that one of the Audio and the Video is modulated, both the Alternative and the Main having the corresponding component type should be disabled. 
         [0068]    The reason is that, when one of the Main and the Alternative is disabled without distinction, the DASH client reproduces only one of the Main and the Alternative, so that there is no effect of the modulation and other contexts are provided from the client, so that a result which the network provider and the client do not want may occur. 
         [0069]    Thus, when all of the Roles of the same media component are identified and modulated, one of the video and the audio is not reproduced. However, due to the characteristic of the DASH, this phenomenon may be generated when the speed of the network is lowered, so that the client may perform the modulated operation without a separate functional problem. 
         [0070]    Fourth embodiment of the present disclosure: Method of determining target to be modulated according to time point 
         [0071]    When different DASH contents are provided, the network provider may determine which DASH content is modulated. 
         [0072]    Although all of the DASH contents used by the end nodes having a problem may be modulated, the traffic is not immediately lowered at the time of the modulation due to the characteristic of the DASH. 
         [0073]    That is, it is proper that the DASH contents to be modulated are selected in order from the DASH content having a low minimumUpdatePeriod value while identifying the minimumUpdatePeriod values within the meta data. 
         [0074]    The reason is that, when the minimumUpdatePeriod is shot, the time during which the DASH client updates the meta data is shortened, so that a probability to influence an operation of the client through the modulation of the meta data is increased by an amount corresponding to the shortened time. 
         [0075]    When there is no minimumUpdatePeriod, the DASH client should update the meta data which is previously downloaded, until reproduction is completed. In this case, even when the meta data is changed within a region of the network provider, the operation of the client is not influenced. 
         [0076]    Fifth embodiment of the present disclosure: Method of applying meta data using device management 
         [0077]      FIG. 6  illustrates a network configuration for describing a method of processing metadata using device management according to a fifth embodiment of the present disclosure. 
         [0078]    The fifth embodiment of the present disclosure is a method in which a terminal previously receives a complete meta data for a service, the network provider dynamically determines a network situation, and if necessary, the terminal receives a command to process the meta data properly with respect to the command. 
         [0079]      FIG. 7  is a flowchart illustrating a method of controlling a traffic for an adaptive streaming service using a device management server of a provider. 
         [0080]    Referring to  FIGS. 6 and 7 , the client selects the contents through a server such as a portal of the provider, etc. Steps  701  to  709  are the same as that of the existing adaptive streaming scheme. When the traffic of the provider network is overloaded while receiving the service, in step  711 , the provider recognizes that traffic reduction is necessary for all of terminals in the network, and determines whether the terminal uses usable maximal bandwidth for the traffic reduction. In step  713 , the provider transmits a message for the usable maximal bandwidth of the terminal, to all of the terminals in the network. In steps  715  to  717 , the terminal receives the corresponding message, and then receives a segment with respect to the Representation having a bandwidth smaller than the corresponding bandwidth. At this time, the terminal may modulate the meta data as in the second embodiment of the present disclosure.