Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Korean Patent Application No. 10-2006-0120729 filed on Dec. 1, 2006, in the Korean Intellectual Property Office and Korean Patent Application No. 10-2007-0089327 filed on Sep. 4, 2007, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an Internet protocol television (IPTV) service system, and more particularly, to a channel control method for an IPTV service capable of searching and selecting a channel according to a user&#39;s program viewing preference and an apparatus thereof. 
         [0004]    This work was supported by the IT R&amp;D program of MIC/IITA [2005-S-058-01, Development of Network/Service Control Technology in All-IP based Converged network] 
         [0005]    2. Description of the Related Art 
         [0006]    In a conventional channel control method for an IPTV service, an electronic program guide (EPG), that is, a menu-based method has been used. 
         [0007]    The conventional channel control method may be used suitably for a small number of IPTV channels. However, in case of a large number (hundreds or thousands) of IPTV channels, the conventional method is very inefficient. Users need to search for program information one by one inconveniently. 
         [0008]    Generally, in case of broadcast programs, user&#39;s viewing preference for specific programs is specified according to days of the week. However, in the conventional channel control method, the user&#39;s viewing preference is not suitably considered, so that the user needs to search for a desired program by excessively changing channels inconveniently. 
         [0009]    In addition, in the IPTV service network, load caused from excessive channel change requests is increased, so that performance thereof may be deteriorated. In addition, since a response time for the channel change requests is increased, a degree of service satisfaction of the user may be lowered. 
       SUMMARY OF THE INVENTION 
       [0010]    In a conventional channel control method for an IPTV service, since a user&#39;s viewing preference is not suitably considered, channel change requests are unnecessarily increased. Since a response time for the channel change requests is increased, a degree of service satisfaction of the user may be lowered. 
         [0011]    According to a first aspect of the present invention, the re is provided a channel control method for an IPTV service, comprising: a mode setting step setting a favorite channel mode and a basic channel mode by analyzing channel change; a favorite channel control step selecting a channel for favorite programs by searching for only favorite programs in the favorite channel mode; a basic channel control step selecting the channel by searching for all programs in a sequential order in the basic channel mode; and a stream providing step providing stream of the selected channel. 
         [0012]    According to the second aspect of the present invention, the re is provided a favorite program profile managing method in an IPTV service system, comprising: an analyzing step analyzing a request of an IPTV session management apparatus; a registration step, if the request is a registration request of a specific program, acquiring a favorite program profile corresponding to a registration-requested day of the week and registering the specific program; a searching step, if the request is a favorite program searching request, acquiring a favorite program profile corresponding to a search-requested day of the week and acquiring favorite programs according to program preference in a search-requested time period; a reservation step, if the request is a favorite program reservation request, reserving and registering a to-be-reserved program in a favorite program profile corresponding to a reservation-request day of the week. 
         [0013]    According to a third aspect of the present invention, the re is provided an IPTV service system comprising: a IPTV service controller searching for only favorite programs in an order of time-based preferences at the time of a channel change request according to a favorite channel mode to select channels, sequentially searching for all the programs of all the channels to select channels, and, after that, configuring multicast forwarding information; an IPTV application server transmitting channel streams to provide an IPTV service; and an IPTV transmission network performing channel branching based on the multicast forwarding information. 
         [0014]    According to a fourth aspect of the present invention, the re is provided an IPTV terminal comprising: a channel control apparatus searching for all programs of all channels to select channels or searching for only favorite programs in an order of time-based preferences to select the channels; an IPTV set-top box accessing an IPTV service system and receiving steams of the selected channels from the IPTV service system; and a reproduction apparatus reproducing the streams of the selected channels. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0016]      FIG. 1  is a view illustrating a configuration of an IPTV service system according to an embodiment of the present invention; 
           [0017]      FIGS. 2A to 2E  are views illustrating structures of profiles and information according to an embodiment of the present invention; 
           [0018]      FIGS. 3A to 3E  are flowcharts illustrating a channel control method for an IPTV service according to an embodiment of the present invention; 
           [0019]      FIG. 4  is a flowchart illustrating a favorite program profile managing method according to an embodiment of the present invention; 
           [0020]      FIG. 5  is a flowchart illustrating a favorite program searching method according to an embodiment of the present invention; and 
           [0021]      FIG. 6  is a flowchart illustrating a multicast channel branching method according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    Hereinafter, exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The embodiments of the present invention may be modified in various forms, and the scope of the present invention is not limited to the embodiments. The embodiments of the present invention are provided in order that the ordinarily skilled in the art can have the better understanding of the present invention. 
         [0023]    In the accompanying drawings, elements having similar functions and operations are denoted by the same reference numerals. 
         [0024]    For better understanding of the present invention, a data output method of a conventional VoIP (Voice over Internet Protocol) phone is firstly described. 
         [0025]      FIG. 1  is a view illustrating a configuration of an IPTV service system according to an embodiment of the present invention. 
         [0026]    As shown in  FIG. 1 , the IPTV service system  100  includes an IPTV transmission network  110 , an IPTV service controller  120 , and an IPTV application server  130 . An IPTV terminal  200  is connected to the IPTV service system  100 . 
         [0027]    The IPTV transmission network  110  includes an access router  111  for processing switching of broadcasting channels, an edge router  112  and a core router  113  for configuring multicast trees for channels between the IPTV application server  130  and the IPTV terminal  200 . 
         [0028]    Particularly, according to the present invention, the access router  111  process channel branching based on information (for example, multicast forwarding information including multicast IPs, port numbers, user IP addresses, and the like) provided by the IPTV channel controller  125  of the IPTV service controller  120  instead of a conventional group managing message (generated according to a Internet group management protocol (IGMP)). 
         [0029]    The IPTV service controller  120  includes an IPTV session controller (IPTVSCF)  121 , a user profile  122 , a favorite program management unit (PCMF)  123 , a favorite program profile  124 , an IPTV channel controller (CHNCF)  125 , a access right certificating unit (NACF)  126 , and a resources controller (RACF)  127 . 
         [0030]    The IPTVSCF  121  checks user&#39;s requests and service environment by using interaction with IPTV terminal  220  and the user profile  122  and monitors a session state of broadcasting channel access of the user to collect and manage viewing history information. The user profile  122  stores information on the users used for viewing the broadcasting channel. The PCMF  123  checks viewing preference for programs according to time from the viewing history information of the IPTVSF  121  to configure the favorite program profile  124  and searches and notifies the favorite program in response to the request of the IPTVSF  121 . The favorite program profile  124  stores information on the favorite programs according to days of the week and time periods. The CHNCF  125  controls multicast channel branching according to the channels. NACF  126  sets network access environment of the users so as to securely transmit IPTV broadcasting contents with a quality of contents maintained. RACF  127  allocates a bandwidth for transmission of streams according to the channel. 
         [0031]    The IPTV application server  130  includes a contents profile  131  which stores information on broadcasting starting time and broadcasting ending time for contents according to the channel and a broadcasting schedule management unit  132  which selects and transmits to-be-broadcasted contents according to time periods based on the broadcasting schedule. 
         [0032]    The IPTV terminal  200  includes a channel control apparatus  210  which changes the channels in a increment-decrement manner or in an order of program-viewing preferences of a user, an IPTV settop box  220  which performs access to the IPTV service controller  120  and the IPTV transmission network  110 , and a reproduction apparatus  230 . 
         [0033]    The channel control apparatus  210  includes a basic channel controller  212  and a favorite channel controller  211 . The basic channel controller  212  requests for channel change in a conventional increment-decrement manner. 
         [0034]    The favorite channel controller  211  request for channel change according to viewing preferences corresponding to broadcasting time periods (time-based viewing preference). The favorite channel controller  211  includes a reservation button as well as channel increment and decrement buttons to request for reservation of a viewing program in a broadcasting time of the program. At the time on the days of the week of the reserved program, the program is viewed with priority. 
         [0035]      FIGS. 2A to 2E  are views illustrating structures of profiles and information according to an embodiment of the present invention.  FIG. 2A  illustrates a user profile.  FIG. 2B  illustrates multicast session information.  FIG. 2C  illustrates multicast routing information.  FIG. 2D  illustrates multicast forwarding information.  FIG. 2E  illustrates a favorite program profile. 
         [0036]    Referring to  FIG. 2A , the user profile stores user information used for user authentication, service contract information used for notifying a contracted service, QoS contract information used for notifying a contracted quality of service (QoS), access configuration information used for notifying an IP address, IP configuration information used for notifying a user&#39;s IP address, and service mode information used for notifying a default channel mode, a minimum viewing time, and a set available period. 
         [0037]    The user profile is maintained and managed by IPTVSCF  121 . When the IPTV terminal  200  logs in, the user profile is loaded on the IPTVSCF  121 . 
         [0038]    Referring to  FIG. 2B , the multicast session information includes user lists of users accessing the currently-serviced IPTV channels. The multicast session information is managed by IPTVSCF  121 . 
         [0039]    Referring to  FIG. 2C , the multicast routing information includes multicast IP address information corresponding to currently-serviced IPTV channels. The multicast routing information is managed by the CHNCF  125 . 
         [0040]    Referring to  FIG. 2D , the multicast forwarding information includes port information on the ports allocated to the multicast IP addresses and the IP addresses of the user accessing the ports. Namely, the multicast forwarding information includes information on branching of the multicast streams to the users accessing the ports. 
         [0041]    The multicast forwarding information is managed by the CHNCF  125 . The multicast forwarding information is provided to the access router  111 . The access router  111  performs channel branching based on the multicast forwarding information. 
         [0042]    Referring to  FIG. 2E , a plurality of the favorite program profiles  310  to  370  corresponding to the users and the days of the week are provided. Each of the favorite program profiles  310  to  370  stores a program name  311 , a channel number  312 , a latest broadcasting time  313 , a next broadcasting time  314 , a latest viewing time  315 , a number of viewing times  316 , and a reservation flag  317  in a mapping manner. 
         [0043]    The program name  311  stores identification information of the favorite programs. The channel number  312  stores identification information for the channel of broadcasting each of the programs. The latest broadcasting time  313  stores starting time and ending time of the most recent broadcasting of each of the programs. The next broadcasting time  314  stores starting and ending time of the next broadcasting of each of reservation-activated programs. The information  311  to  314  is provided by the IPTV application server  130 . 
         [0044]    The latest viewing time  315  stores the latest viewing date and a total viewing time corresponding to the IPTV terminal  200 . The number of viewing times  316  stores the number of viewing times for the program within the set available period. The reservation flag  317  stores reservation status of the program. The information  315  to  317  is provided from the IPTVSCF  121 . 
         [0045]    In the present invention, the preference for the programs is determined in an order of reserved programs, a most frequently viewed program, an earliest starting program among the reserved programs, and an earliest starting program among non-reserved programs. 
         [0046]    The PCMF  123  searches and selects a favorite program from the favorite program profile according to the preference and provides information on the selected favorite program to the IPTVSCF  121 . 
         [0047]    The IPTVSCF  121  does not register a program of which a total viewing time is shorter than a minimum viewing time (for example, five minutes) as the favorite program, so that it is possible to prevent a temporarily-viewed program at the time of channel zapping from being registered as the favorite program. In addition, the IPTVSCF  121  clears a program of which latest viewing data is beyond a set available period (for example, one month) from the favorite program profile. 
         [0048]      FIGS. 3A to 3E  are flowcharts illustrating a channel control method for an IPTV service according to an embodiment of the present invention. 
         [0049]    Firstly, an IPTV service access initializing method is described with reference to  FIG. 3A . 
         [0050]    When the IPTV terminal  200  is powered on (S 101 ), subscriber authentication is performed based on the user ID and the user password (S 102 ). When the authenticated succeeds, the user profile  132  of the authenticated user is loaded on the IPTVSCF  121  (S 103 ). 
         [0051]    The service access configuration for the IPTV service is set and initialized based on the user profile  132  (S 104 ). The favorite program profile  124  is loaded on the PCMF  123  (S 105 ). 
         [0052]    Next, a channel mode of the IPTV terminal  200  is set to a default channel mode determined at the time of service contract (S 106 ). 
         [0053]    If the default channel mode is a basic channel mode (S 107 ), an electronic program guide (EPG) screen is accessed (S 107 ), and the method proceeds to a step A for channel change in the increment-decrement manner. 
         [0054]    If the default channel mode is a favorite program mode (S 107 ), the method proceeds to a step B for channel change according to channel preference. 
         [0055]    Now, a channel control method in the step A for searching and selection channels in the increment-decrement manner is described with reference to  FIG. 3B . 
         [0056]    In the A step, if a channel selection signal is input from the IPTV terminal  200 , the channel selection signal is analyzed to determine whether the channel of the basic channel controller  212  or the channel of the favorite channel controller  211  is selected. 
         [0057]    IF the channel of the favorite channel controller  211  is selected, the method proceeds to the step B for channel change in the favorite channel mode. 
         [0058]    If the channel of the basic channel controller  212  is selected, the channel mode is set to the basic channel mode (S 123 ), an access right to the selected channel is verified (S 124 ). 
         [0059]    If the access right to the selected access right is verified to be valid, required resources are checked by analyzing terminal performances, contents features, service contracts, and the like based on the user profile  122  (S 125 ), and a bandwidth is required to the RACF  127  (S 126 ). 
         [0060]    Next, the CHNCF  135  requests the access router  111  to perform a channel switching process so as for the access router  111  to provide the selected channel to the IPTV terminal  200  (S 127  and S 128 ). 
         [0061]    The access router  111  receives the stream of the selected channel and provides the stream to the IPTV terminal  200  (S 129 ), and the method proceeds to a step C. 
         [0062]    Now, a channel control method in the step B for searching and selection channels according to channel preference is described with reference to  FIG. 3C . 
         [0063]    In the step B, the channel mode is set favorite channel mode (S 141 ), channel-change-requested days of the week and time periods are checked (S 142 ). 
         [0064]    The favorite program profile  124  corresponding to the days of the week is searched (S 143 ), and after that, a program of which preference is highest within the time period is selected as the favorite program (S 144 ). 
         [0065]    When the favorite program is selected, the broadcasting time of the program is compared with a broadcasting schedule of the IPTV application server  130  to check whether or not the broadcasting time is changed (S 145 ). 
         [0066]    If the broadcasting time of the program is not changed, a message of notifying the starting of the program is transmitted to the IPTV terminal  200  (S 146 ), and bandwidth acquisition is requested (S 147 ). Next, channel switching is processed (S 148  and S 149 ). 
         [0067]    When the providing of the channel stream to the IPTV terminal  200  starts (S 150 ), the method proceeds to a step C. 
         [0068]    If the broadcasting time of the program is changed or cancelled, a message of notifying program broadcasting change is transmitted to the IPTV terminal  200  (S 152 ). 
         [0069]    Subsequently, the next broadcasting time of the program is modified, or the program is cleared from the favorite program profile (S 153 ). Next, the method proceeds to the step S 144  to search for a program having the next preference. 
         [0070]    If a favorite program corresponding to the day of the week or the time period is not searched from the favorite program profile  124 , an EPG is connected, and the channel mode is switched to the basic channel mode (S 154 ). 
         [0071]    Now, a channel control method in the step C after the providing of the stream of the channel, that is, the channel branching is described with reference to  FIG. 3D . 
         [0072]    In the step C, during the providing of the channel stream (S 161 ), if a new event occurs (S 162 ), the event is analyzed (S 163 ). 
         [0073]    As a result of the analysis of the step S 163 , if the event is an event of notifying starting or ending of the program or reservation of the program, the method proceeds to a step D. In the step D, the event of notifying the starting or ending of the program or the reservation of the program is processed. 
         [0074]    As a result of the analysis of the step S 163 , if the IPTV terminal  200  is powered off, charge information according to a viewing time after log-in for the programs and the channels is collected, and if needed, the charge information is transferred to an application server (not shown) (S 164 ) Next, viewing history information such as a program name, a channel number, and a viewing time for the latest viewing program is updated (S 165 ). 
         [0075]    Next, the favorite program profile  124  is updated based on the updated viewing history information by adding and registering or modifying the program viewed just before the power-off (S 166 ). 
         [0076]    For example, if the program viewed just before the power-off is registered as the favorite program, the program name, the channel number, the latest broadcasting time, the next broadcasting time, the latest viewing time, the number of viewing times (=1), and the reservation flag (NO) of the program are stored in the favorite program profile  124 . 
         [0077]    Next, the resources for transmitting the channel stream allocated by the RACF  127  are returned to the RACF  127  (S 167 ). Next, the favorite program profile clearing is performed to clear programs beyond the set available period from the favorite program profile  124  (S 168 ), and the IPTV service is ended. 
         [0078]    As a result of the analysis of the step S 163 , if the IPTV terminal  200  requests for the channel change, the viewing history information such as a program name, a channel number, and a viewing time of the latest viewing program is updated (S 169 ). Next, the favorite program profile  124  is updated based on the viewing history information (S 170 ). 
         [0079]    If the channel requested by the IPTV terminal  200  is not suitable for a currently-set channel mode (S 171 ), the channel mode is changed (for example, the favorite program mode is changed to the basic channel mode, or vise versa) (S 172 ), and after that, the method proceeds to a step E to perform the step  307  of  FIG. 3A . 
         [0080]    As a result of the analysis of the step S 163 , if the IPTV terminal  200  requests for reservation of the currently-viewed program, the program is registered in the favorite program profile  124 , of the next broadcasting time information is modified, and after that, the reservation flag is set to “YES” (S 173 ) Next, the method proceeds to the step C to continue to provide the stream for the currently-viewed channel. 
         [0081]    Now, a channel control method in the step D after the occurrence of the event of notifying the starting or ending of the program or the starting of the reserved program is described with reference to  FIG. 3E . 
         [0082]    In the step D, the event is firstly analyzed (S 181 ). 
         [0083]    If the event is an event of starting the favorite program, a message of notifying starting of the program is transmitted to the IPTV terminal  200  (S 182 ), and the providing of the channel stream starts. Next, the method proceeds to the step C. 
         [0084]    If the event is an event of ending the favorite program, the viewing history information is updated based on a program name, a channel number, and a viewing time of the favorite program (S 183 ), and the favorite program profile  124  is also updated based on the aforementioned information (S 184 ). Next, the method proceeds to the step E to perform the step S 107  of  FIG. 3A . 
         [0085]    If the event is an event of starting a reserved program, the broadcasting time of the reserved program is compared with the broadcasting schedule to check whether or not the broadcasting time is changed (S 185 ). 
         [0086]    If the broadcasting time is not changed, a message of notifying the starting of the program is transmitted to the IPTV terminal  200  (S 186 ), and a band width is acquired (S 187 ). Next, channel switching is processed (S 188  and S 189 ). 
         [0087]    When the providing of the channel stream starts (S 190 ), the method proceeds to the step C to continue to receive the channel stream. 
         [0088]    If the broadcasting time of the reserved program is changed or cancelled, a message of notifying program broadcasting change is transmitted to the IPTV terminal  200  (S 192 ). Subsequently, the next broadcasting time of the program is modified, or the program is cleared from the favorite program profile (S 193 ). Next, the method proceeds to the step B to search for a program having the next preference. 
         [0089]      FIG. 4  is a flowchart illustrating a favorite program profile managing method according to an embodiment of the present invention. The favorite program profile managing method is performed every time when the PCMF  123  receives a favorite program registration request, a favorite program searching request, a favorite program reservation request, or profile clearing request from the IPTVSCF  121 . 
         [0090]    If the IPTVSCF  121  requests for managing and searching for the favorite program (S 201 ), the request of the IPTVSCF  121  is analyzed (S 202 ). 
         [0091]    As a result of the analysis of the step S 202 , if the IPTVSCF  121  requests for registration of the favorite program and provides an user ID, a registration-requested date, and viewing history information, a total viewing time of the registration-requested program is extracted from the viewing history information to check whether or not the total viewing time is longer than a minimum viewing time (for example, five minutes) (S 211 ). 
         [0092]    If the total viewing time is shorter than the minimum viewing time, the registration-requested program is treated as a temporarily-viewed program at the time of the channel change, and the registration operation is not performed. 
         [0093]    If the total viewing time is longer than the minimum viewing time, the favorite program profile  124  corresponding to the day of the week is searched to check whether or not the program is a previously-registered program (S 212 ). If the program is not registered previously, the program is registered as the favorite program (S 213 ). As a result, the program name, the channel number, the latest broadcasting time, the next broadcasting time, the latest viewing time, the number of viewing times (=1), and the reservation flag (NO) of the program are stored in the favorite program profile  124 . 
         [0094]    If the program is a previously-registered program, the information of the program such as the latest broadcasting time, the next broadcasting time, the latest viewing time, and the number of viewing times is updated (S 214 ). 
         [0095]    As a result of the analysis of the step S 202 , if the IPTVSCF  121  requests for searching for the favorite program and provides a user ID and a searching-requested date and time, a program having the highest preference is searched and selected within the days and time period provided from the IPTVSCF  121  by using an searching algorithm according to the present invention (S 221 ). The operation will be described in detail with reference to  FIG. 5 . 
         [0096]    As a result of the analysis of the step S 202 , if the IPTVSCF  121  requests for reservation of the favorite program, it is checked based on the favorite program file  124  corresponding to the reservation-requested day of the week provided from the IPTVSCF  121  whether or the program is a previously-registered program (S 231 ). If the program is not a previously-registered program, the program is registered as the favorite program, and the reservation flag is set to “YES” (S 232 ). If the program is a previously-registered program, and the next broadcasting time is set, and the reservation flag is set to “YES” (S 233 ). 
         [0097]    As a result of the analysis of the step S 202 , if the IPTVSCF  121  requests for clearing the favorite program profile, it is checked based on the favorite program file  124  corresponding to the reservation-requested day of the week whether or not the latest viewing time of the program is before an set available period (for example, one month) (S 241 ). If the latest viewing time is before the set available period, the program is cleared from the favorite program profile  124  (S 242 ), so that the favorite program profile can be optimized. 
         [0098]    The aforementioned favorite program profile clearing operation is performed every time when the reproduction apparatus  230  is powered off. 
         [0099]      FIG. 5  is a flowchart illustrating a favorite program searching method according to an embodiment of the present invention. The favorite program searching method is performed every time when the PCMF  123  receives a favorite program searching request. 
         [0100]    If the favorite program searching request including the searching-request date and time and the user ID of the user requesting for the favorite program searching is input (S 301 ), the favorite program profile  124  corresponding to the search-requesting date, that is, the search-requested day of the week is searched (S 302 ). 
         [0101]    Next, a program that is to start in the time period closest to the search-requested time period for the reserved program is searched (S 303 ). The searched program is set to a favorite program having the highest preference (S 304 ). 
         [0102]    Next, a program that is not reserved but is searched among the programs broadcasted in the searching-requested time period (S 305 ), and the searched program is set to a favorite program having the next highest preference (S 304 ). 
         [0103]    Next, the earliest starting program among the programs to be stared after the searching-requested time is searched from the reserved programs (S 306 ) The searched program is set to the favorite program having the next preference (S 304 ). 
         [0104]    Finally, the earliest starting program among the programs to be started after the time period of the log-in of the user is searched from the non-reserved programs (S 307 ) The searched program is set to the favorite program having the lowest preference (S 304 ). 
         [0105]    During the aforementioned operations, if the favorite program is not searched, any favorite program is determined not to be set within the searching-requested day and time period, the basic channel mode is performed (S 308 ). 
         [0106]      FIG. 6  is a flowchart illustrating a multicast channel branching method according to an embodiment of the present invention. 
         [0107]    The IPTV terminal  200  logs in, and an initialization operation for server is performed (S 401 ). Next, the IPTVSCF  121  notifies information on the user ID, the date, and the time to the PCMF  123  based on the user profile  122  and requests for the favorite program searching (S 402 ). 
         [0108]    The PCMF  123  searches for the favorite program based on the received information as shown in  FIG. 5  (S 403 ). The PCMF  123  transmits information on the searched favorite program such as the user ID and the channel number to the IPTVSCF  121  (S 404 ). The IPTVSCF  121  registers the information to the multicast session information configured as shown in  FIG. 2B  (S 405 ) Namely, the IPTVSCF  121  adds the IPTV terminal  200  to the user list of the users accessing the searched channel. 
         [0109]    The IPTVSCF  121  transmits the user ID, the user IP address, the port number, and the channel number to the CHNCF  125  and requests for the multicast channel branching (S 406 ). 
         [0110]    The CHNCF  125  registers the received information to the multicast forwarding information configured as shown in  FIG. 2D  (S 407 ). Next, the CHNCF  125  provides the information to the access router  111  (S 408 ). The information includes the multicast IP, the port number, and the user IP address. 
         [0111]    The access router  111  registers the information received from the CHNCF  125  (S 409 ). Next, the access router  111  performs the channel stream branching based on the information (S 410 ). 
         [0112]    Although the multicast channel branching method for the providing of only the favorite program in the favorite channel mode is shown in  FIG. 6 , the same multicast channel branching method may be applied to the basic channel mode. Namely, when the channels in the basic channel mode is selected by the IPTVSCF  121 , the multicast channel branching for the providing of the channel is performed through the steps S 405  to S 410 . 
         [0113]    While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.

Technology Category: 5