Patent Publication Number: US-10764651-B1

Title: Service group discovery

Description:
BACKGROUND 
     Field 
     Embodiments generally relate to operation of a cable communication system and including discovering a service group of a subscriber device of the cable communication system. 
     Related Art 
     A cable television (CATV) provider generally provides television, internet data, or other services to a content viewer via radio frequency (RF) signals transmitted to one or more customer premises through, but not limited to, optical fibers or coaxial cables. The content viewer may use a subscriber device, e.g., a set-top box (STB), to receive content, e.g., digital television (DTV) broadcasts, for display on a television. 
     In a CATV system, each subscriber device belongs to an assigned service group, identified by a Service Group ID (SGID). The CATV system assigns various subscriber devices to provide targeted content to groups of content viewers via their subscriber devices. When the content viewer requests access to a video-on-demand (VOD) or digital-video-recorder (DVR) program, the subscriber device transmits the associated SGID in its request to a headend of the CATV system. Upon verifying that the SGID is valid, the headend streams the requested program to the subscriber device via the associated service group. 
     In some conventional CATV systems, the subscriber device is preconfigured to tune to a single well-known frequency, i.e., a golden frequency, to retrieve the SGID identifying the appropriate service group. While this approach may be simple to process, this approach requires that all subscriber devices be pre-configured to tune to the single well-known frequency. Therefore, legacy subscriber devices or differently-configured subscriber devices cannot be readily re-configured to operate on the well-known frequency. Further, the use of a single frequency increases the risk of outages. This is because whenever the single well-known frequency is not in normal operation, the subscriber device can no longer discover the SGID needed in sending content requests. 
     In other conventional CATV systems, the subscriber device is preconfigured to communicate with the headend to obtain the SGID identifying the service group assigned to the subscriber device. This approach requires active communication between the headend and subscriber device, which may increase latency and the load processed of the headend. 
     Further conventional CATV systems may include different types of subscriber devices including those that operate on the single well-known frequency and those that communicate with the headend. There currently exists no efficient process for the subscriber devices to discover their assigned service group regardless of the type of the subscriber devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
       The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments. In the drawings: 
         FIG. 1  illustrates a block diagram of a cable television system according to an example embodiment; 
         FIG. 2  illustrates a service group discovery listing included in a configuration file according to an example embodiment; 
         FIG. 3  illustrates a block diagram of a subscriber device in greater detail according to an example embodiment; 
         FIG. 4  illustrates a flowchart for service group discovery by a subscriber device according to an example embodiment; and 
     
    
    
     The present disclosure will now be described with reference to the accompanying drawings. In the drawings, like reference numbers may indicate identical, functionally similar, or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number. 
     DETAILED DESCRIPTION 
     Methods, systems, and machine-readable mediums disclosed herein enable a subscriber device to flexibly discover an associated service group (SG) regardless of the type of the subscriber device or the network architecture associated with the subscriber device. In an embodiment, the subscriber device receives a configuration file. The configuration file stores a listing of mappings where each association of the listing maps an SG identification (SGID) to network characteristics, a list of transport stream IDs (TSIDs), and a list of radio frequencies (RFs). The subscriber device selects one or more associations, from the listing of mappings, that are associated with a detected network characteristic. Then, the subscriber device tunes to an RF selected from the RF list in the one or more selected associations from the listing of mappings to identify a TSID of the tuned RF. The identified TSID identifies a transport stream received by the subscriber device via the tuned RF. The subscriber device verifies whether the identified TSID matches a TSID from a TSID list within the one or more selected associations from the listing of mappings. Thereafter, the subscriber device determines that the SGID in the one or more selected associations from the listing of mappings identifies the SG associated with the subscriber device. 
       FIG. 1  is a block diagram of a point-to-multipoint communication system  100  according to an example embodiment. Communication system  100  facilitates bi-directional communication of information, such as video, audio, and/or data, between a cable headend system  102  and subscriber devices  104 A through  104 C, simply referred to as subscriber devices  104 , via communication network  106 , such as a hybrid fiber coaxial (HFC) cable network to provide an example. Although  FIG. 1  illustrates subscriber devices  104 A through  104 C, those skilled in the relevant art(s) will recognize that communication system  100  can include any suitable number of subscriber devices  104  without departing from the spirit and scope of the present disclosure. Cable headend system  102  and subscriber devices  104  communicate with each other using a bi-directional transfer of packet-based traffic, such as Internet Protocol (IP) traffic to provide an example. Further, cable headend system  102  operates as an interface between communication network  106  and packet switched network  108  to transfer IP packets received from subscriber devices  104  to packet switched network  108  and to transfer IP packets received from packet switched network  101  to subscriber devices  104 . 
     Communication network  106  provides a point-to-multipoint network topology for high speed, reliable, and secure transport of information between cable headend system  102  and subscriber devices  104 . As will be appreciated by persons skilled in the relevant art(s), communication network  106  may include coaxial cable, fiber optic cable, or a combination of coaxial cable and fiber optic cable linked via one or more fiber nodes, and may include frequency translation devices to support a frequency stacking architecture, and may even include wireless links. 
     In an embodiment, communication system  100  may deploy Data Over Cable Service Interface Specification (DOCSIS) compliant equipment and protocols, or portions thereof, to provide the bi-directional (i.e., upstream and downstream) transfer of information, such as video, audio, and/or data, between cable headend system  102  and subscriber devices  104 . As used herein, the term “downstream” refers to the transfer of information in a first direction from cable headend system  102  to the subscriber devices  104 . The term “upstream direction” refers to the transfer of information in a second direction from the subscriber devices  104 A through  104 C to cable headend system  102 . The DOCSIS Specification generally refers to a group of specifications published by CableLabs® that define industry standards for cable headend system  102  and subscriber devices  104 . In part, the DOCSIS specification sets forth requirements and objectives for various aspects of cable modem systems including operations support systems, management, data interfaces, as well as network layer, data link layer, and physical layer transport for data over cable systems. A DOCSIS cable system includes two primary components: one or more subscriber devices  104 , such as one or more set-top boxes to provide an example, at one or more customer premises, and cable headend system  102 . In an embodiment, cable headend system  102  includes one or more cable modem termination system (CMTS) devices that are DOC SIS compliant. Though various embodiments herein are described in the context of using the DOC SIS standard, a person skilled in the art(s) will also appreciate that the embodiments described herein equally apply to other communication standards without departing from the spirit and scope of the present disclosure. 
     In an embodiment, cable headend system  102  may be implemented as a headend, or as a network of headends, that configures received media content, such as television (TV) content, into transport streams broadcasted to subscriber devices  104 . Such media content may include television station&#39;s programming broadcasted from satellites or received via dedicated coaxial, microwave link, the Internet, or fiber-optic line installed between the television station and cable provider system  104 . In an embodiment, the media content may include video on-demand (VOD) content or digital-video recorder (DVR) content received from one or more servers communicatively coupled, e.g. via packet switched network  108 , to cable headend system  102 . 
     In an embodiment, cable headend system  102  multiplexes several sub-streams of media content into a single transport stream for broadcasting on a certain RF. For example, a sub-stream may include encoded audio, encoded video, and/or encapsulated data. In an embodiment, cable headend system  102  configures the transport stream as MPEG transport streams, which is an industry-wide standard digital container format for transmission and storage of audio and video data. In an embodiment, each transport stream, e.g., an MPEG transport stream, also includes one or more listings of mappings that describe the types of information contained in the transport stream as well as information associated with the transport stream. For example, the listings may be in the form of tables where one of the tables includes a transport stream identifier (TSID) which is a unique value that identifies the transport stream. In an embodiment, a transport stream includes information within the one or more listings of mappings that relate to the network such as physical properties of the current network or the network broadcasting the transport stream. For example, these physical properties may include a network name or an associated network ID, which is a value that uniquely identifies the network broadcasting the transport stream. 
     In an embodiment, communication network  106  provides the physical infrastructure for carrying and transmitting transport streams from cable headend system  102 , each transport stream being associated with a corresponding network ID, to subscriber devices  104 . For example, subscriber devices  104 A and  104 B may be part of network “N1” and receive transport streams associated with network “N1.” Further, subscriber device  104 C may be part of network “N2” and receive transport streams associated with network “N2.” In an embodiment, a portion of subscriber devices  104  within a specific network, such as within network “N1,” are further assigned a service group (SG), identified by a service group ID (SGID). In an embodiment, each subscriber device is assigned only one SGID. As described above, a subscriber device such as subscriber device  104 A includes its assigned SGID in its request to cable headend system  102  for content such as VOD or DVR content. Cable headend system  102  may verify the SGID sent by subscriber devices  104  to determine whether to provide the requested content. 
     In an embodiment, communication network  106  includes two or more different network infrastructures with separately configured networks and associated subscriber devices  104 . For example, each network infrastructure and connectivity of subscriber devices  104  to that network infrastructure may be managed and maintained by a separate entity, e.g., cable company. In another example, one of the network infrastructures may be a legacy implementation having different network configurations than that of the other network infrastructure. In either case, because the networks within each network infrastructure may be configured independently, two networks from respective network infrastructures may be assigned the same identifier, i.e., network ID. In an embodiment, to differentiate between two similarly named networks, subscriber device  104  may determine a plant ID for identifying its associated network infrastructure. 
     In an embodiment, to enable subscriber devices  104  to identify their assigned service group, cable headend system  102  generates and manages a configuration file  112 . Configuration file  112  includes information that subscriber devices  104  use to discover their respective assigned service groups. As further described with respect to  FIG. 2 , configuration file  112  may include associations between network characteristics (e.g., a plant ID or a network ID) and an SGID, a list of transport stream IDs (TSIDs), and a list of RFs. In an embodiment, cable headend system  102  continually or periodically broadcasts configuration file  112  to subscriber devices  104  via communication network  106 . In an embodiment, cable headend system  102  broadcasts configuration file  112  via communication network  106  upon request by one or more of subscriber devices  104 . For example, subscriber device  104 A may request configuration file  112  upon start-up. 
     In an embodiment, subscriber devices  104  are clients that communicate with cable headend system  102  to provide content viewers with media content. A person skilled in the art(s) will appreciate that a client may be any computing device or application executing on a computing device that communicates with one or more servers implementing cable headend system  102 . For example, subscriber device  104 A may be a set-top box connected to a cable modem, or a set-top box having cable modem functionalities. A person skilled in the art(s) will also appreciate that a server from cable headend system  102  may be any host computing device, an application executing on a computing device or a hardware/software system that distributes applications or services, e.g., media content within transport streams, to one or more clients. 
     In an embodiment, to discover a service group associated with subscriber devices  104 , each of subscriber devices  104  may include cable interface  114 , processor  116 , and memory  118 . In an embodiment, cable interface  114  may represent a cable modem or a component having cable-modem functionality to enable two-way data communications between its respective subscriber device  104  and cable headend system  102 . In other embodiments, cable interface  114  may represent an interface enabling its respective subscriber device  104  to communicate with a coupled cable modem connected to communication network  106 . 
     In an embodiment, to discover an associated service group, processor  116  retrieves a configuration file  112  from memory  118  which is received via cable modem interface  114 . Then, as further described with respect to  FIG. 4 , processor  116  may perform one or more routines to filter the received and stored configuration file  112  to discover its service group. Upon determining the service group, identified by an SGID, processor  116  may store the SGID to memory  118  for future use. For example, as discussed above, subscriber device  104 A may include the SGID in a content request to cable headend system  102  for VOD or DVR content. 
       FIG. 2  illustrates a service group discovery (SGD) listing  200  included in a configuration file according to an example embodiment. For example, SGD listing  200  may represent information stored in configuration file  112  configured by cable headend system  102  of  FIG. 1 . In an embodiment, to enable subscriber devices  104  from  FIG. 1  to self-discover their associated service groups, each of associations  220 - 232  from SGD listing  200  stores a mapping between network characteristics (e.g., plant ID  202  and network ID  204 ) and an SGID  206 , a list of TSIDs (represented by TSID  208 ), and a list of RFs (represented by RFs  210 ). In an embodiment, as shown in  FIG. 2 , SGD listing  200  is a table data structure with associations  220 - 232  being the rows of the table. In another embodiment, SGD listing  200  may be configured using a different data structure such as a linked list, a tree, or a hash map etc. In the embodiment where SGD listing  200  is a linked list, for example, each of associations  220 - 232  may be stored within a node within the linked list. 
     In an embodiment, by associating an SGID  206  with multiple RFs  210 , each of subscriber devices  104  may tune to more than one RF to discover its associated service group. This approach reduces the effect that outages have on subscriber devices  104 . As described above with respect to  FIG. 1 , SGD listing  200  may include plant ID  202  and network ID  204  to enable subscriber devices  104  operating within different network infrastructures to discover respective service groups based on the same SGD listing  200 . For example, a subscriber device  104 A configured to operate with plant ID  2  and network ID  30  may tune to one or more RFs  210  in association  230  to determine an associated SGID. In this example, if subscriber device  104 A extracts a TSID from a tuned RF, from association  230 , that matches one of the TSIDs in association  230 , then subscriber device  104 A determines that SGID “3” identifies the service group in which subscriber device  104 A belongs. 
     In an embodiment, to prevent mapping overlaps or conflicts, SGD listing  200  is generated such that for each service group, i.e., each SGID, the TSID and RF mapping is unique. As shown in SGD listing  200 , a specific set of network characteristics may be associated with multiple service groups. For example, the Plant ID “1” and Network ID “30” pair is associated with associations  220  and  222  representing SGID  400  and  401 , respectively. 
       FIG. 3  illustrates a block diagram of subscriber device  302  according to an example embodiment. In an embodiment, subscriber device  302 , e.g., a set-top box, may be an example implementation of one or more of subscriber devices  104  from  FIG. 1 . Subscriber device  302  includes cable interface  308 , channel decoder  316 , multi-media interface  318 , user interface  310 , processor  320 , and memory  330 . For ease of explanation, reference may be made to SGD listing  200  of  FIG. 2 . 
     Memory  330  includes service group discovery (SGD) routine  332 , configuration file  334 , and service group (SG) information  336 . In an embodiment, SGD routine  332  includes stored instructions that processor  320  performs to discover a service group assigned to subscriber device  302 . In an embodiment, SGD routine  332  is retrieved from memory  330  and executed by processor  320  whenever subscriber device  302  needs to determine the SGID that identifies its assigned service group. For example, SGD routine  332  may be stored in a boot loader and is executed by processor  320  upon startup of subscriber device  302  within a particular network. In another example, processor  320  may execute SGD routine  332  when a previously determined SGID changes due to an outage on the frequency in use. In another example, processor  320  may run SGD routine  332  upon request by cable headend system  102  to adapt to changes implemented by cable headend system  102 . For example, cable headend system  102  may update which service group is assigned to subscriber device  302 . 
     Configuration file  334  may be a configuration file stored in memory and that is received by subscriber device  302  from a cable headend system, such as cable headend system  102  in  FIG. 1 . In an embodiment, subscriber device  302  may receive configuration file  334  upon startup of subscriber device  302 . In an embodiment, subscriber device  302  may receive an updated configuration file from the cable headend system while in operation. As described above with respect to  FIG. 1 , configuration file  334  includes an SGD listing, such as SGD listing  200  from  FIG. 2 , that maps network characteristics to an SGID, a list of TSIDs, and a list of RFs. 
     Service group (SG) information  336  may include information related to an SGID identified by processor  320  while running SGD routine  332 . In an embodiment, SG information  336  includes detected network characteristics, the identified SGID, and the identified corresponding TSID and tuned RF. In an embodiment, since processor  320  determines the SGID using the stored configuration file  334 , SG information  336  includes only information obtainable from configuration file  334 . In subsequent operations, subscriber device  302  may query service group information  336  for the SGID to include in a content request to a content source, such as cable headend system  102  of  FIG. 1 . 
     Cable interface  308  enables subscriber device  302  to communicate with a cable headend system such as cable headend system  102  of  FIG. 1 . In an embodiment, cable interface  308  includes receiver  310  for performing tuning and demodulating operations. For example, receiver  310  may include a tuner that tunes to an RF and extracts a transport stream from the tuned RF. In an embodiment, cable interface  308  includes multiple tuners for concurrently tuning to multiple RFs and extracting the corresponding transport streams. Further, for each tuned RF, subscriber device  202  identifies the TSID from the extracted transport stream that identifies the transport stream. In an embodiment, receiver  312  is controlled by processor  320  to select and tune to a specific RF. 
     In an embodiment, subscriber device  104  tunes to one or more RFs to extract media content from transport streams transmitted on respective RFs. As described above, the extracted media content may include, for example, a television channel or VOD content requested by a content viewer. Depending on subscriber devices  104  implementation and communication network  106 , one or more of subscriber devices  104  may tune to one or more RFs received from one or more of an Ethernet cable, a satellite dish, a telephone line, a VHF or UHF antenna, or a coaxial cable. 
     In an embodiment, cable interface  308  includes one or more demodulators that transform the transport stream signals from the tuners into a signal that display device  304 , e.g., a television, can use to present the desired content, e.g., TV channel or VOD content, to a content viewer. Digital TV systems often transmit multiple TV channels through a single physical channel of a transport stream. Therefore, a demodulator may be needed to extract the desired TV channel from the single physical channel. Demodulation types may include various formats including, for example, Quadrature Phase Shift Key (QPSK), Quadrature Amplitude Modulation (QAM), and Orthogonal Frequency Division Multiplexing (OFDM) to provide some examples. 
     In an embodiment, cable interface  308  includes cable modem functionality for providing a two-way communication interface between subscriber device  3302  and a cable provider, such as cable headend system  102  of  FIG. 1 . Cable interface  308  may deploy, but is not limited to, a DOCSIS-based standard (e.g., DOCSIS or EuroDOCSIS) for communicating out-of-band requests, commands, and subscriber device information. For example, cable interface  208  may implement QAM demodulators for receiving downstream data and QPSK or QAM modulators for transmitting upstream data. 
     Channel decoder  316  receives, from cable interface  308 , a content signal representative of media content, for example, a TV channel or VOD or DVR content. Channel decoder  316  may be associated with demultiplexers to separate the TV channel into video, audio, or other streams of data. Then, channel decoder  316  may decode or decompress one or more streams of data for processing by display device  304 , such as a television. 
     Multi-media interface  318  may include video and audio interfaces for transmitting the content stream, e.g., TV channel, to display device  304  for broadcast. Example video and audio interfaces may include HDMI or AVI. Therefore, multi-media interface  318  may be coupled to a variety of display device  304  including, for example, a television, a laptop, or a monitor among other display devices. 
     User interface  310  may implement wireless communication protocols such as Wi-Fi or infrared to receive an input from remote control  306  operated by a content viewer. In an embodiment, content user operates remote control  306  to request content provided by a cable headend system such as cable headend system  102 . For example, the requested content may be VOD content or DVR content. In an embodiment, to provide the content viewer with the requested content, subscriber device  302  can send to the headend system the request with its SGID. The headend system may be required to verify the SGID before enabling the subscriber device  302  to receive and process the requested content. In an embodiment, to enable subscriber device  302  to discover its SGID, as described below, processor  320  implements SGD routine  332  stored in memory  330 . 
     Processor  320  may control the functionality of subscriber device  302  and communicate with, for example, cable headend system  102 . In an embodiment, processor  320  retrieves SGD routine  332  from memory  330  to perform operations for discovering the service group of subscriber device  302 , as described below with respect to  FIG. 4 . 
       FIG. 4  is a method  400  for service group discovery by a subscriber device according to an example embodiment of the present disclosure. The disclosure is not limited to this operational description. Rather, it will be apparent to ordinary persons skilled in the relevant art(s) that other operational control flows are within the scope and spirit of the present disclosure. The following discussion describes an exemplary method  400  of a subscriber device, such as subscriber device  302  of  FIG. 3  or subscriber device  104  of  FIG. 1 , for service group discovery. Steps of method  400  need not necessarily be performed in the order shown. For example, step  404  may be performed before step  402 . Method  400  may be performed by processing logic that can comprise hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (e.g., instructions run on a processing device), or a combination thereof. 
     In step  402 , a subscriber device receives a configuration file. In an embodiment, the subscriber device receives the configuration file from a cable headend system, such as cable headend system  102  of  FIG. 1 . The configuration file includes information, such as SGD listing  200  of  FIG. 2 , used by subscriber device to discover its associated service group. In an embodiment, the subscriber device receives the configuration file when the subscriber device detects no associated service group, as identified by an SGID. For example, the subscriber device may receive the configuration file upon startup of the subscriber device or when an outage occurs. 
     In step  404 , the subscriber device detects network characteristics associated with the subscriber device. In an embodiment, the network characteristics include information identifying the network infrastructure and the network assigned to the subscriber device. For example, network infrastructure may be identified as Plant ID  202  from SGD listing  200  and the network may be identified as Network ID  204  from SGD listing  200 . In an embodiment, to detect the network characteristics, the subscriber device extracts Network ID  204  from within a received transport stream, such as from a network information table (NIT) table within an MPEG transport stream. 
     As discussed above, two subscriber devices may be configured to communicate with two differently-configured network infrastructures. And within each network infrastructure, a specific network may be identified according to a convention specific to that network infrastructure. In an embodiment, subscriber devices associated with two differently-configured network infrastructures may be part of the same service group. Therefore, in this embodiment, to discover the same service group for these subscriber devices, the subscriber device operates on the received configuration file of step  402  based on the corresponding detected network characteristics. 
     In step  406 , the subscriber device parses the configuration file of step  402  to select one or more associations from an SGD listing of the configuration file. For example, the SGD listing may be SGD listing  200  of  FIG. 2 . In an embodiment, each association of the SGD listing associates specific network characteristics with an SGID, a list of TSIDs, and a list of RFs. In an embodiment, the subscriber device selects, from the SGD listing, one or more associations having the network characteristics detected in step  404 . For example, the subscriber device may receive SGD listing  200  of  FIG. 2  and detect Plant ID  202  of “1” and a Network ID  204  of “30.” In this example, the subscriber devices parses SGD listing  200  to select associations  220 - 222  matching the detected Plant ID “1” and Network ID “30.” In an embodiment, each identified association, such as associations  220 - 222  for Plant ID “1” and Network ID “30,” is associated with a unique service group, identified as SGID  206 . 
     In an embodiment, to discover an assigned service group, the subscriber device tunes to an RF to extract information from the transport stream transmitted on that tuned RF. In an embodiment, the use of an SGD listing of the configuration file received in step  402  provides the subscriber device with a plurality of RFs to tune to discover the service group. Further, using the SGD listing does not require additional communications between the subscriber device and a headend system. 
     In step  408 , the subscriber device tunes to a RF in a selected association of the selected one or more associations of step  406 . For example, if the selected associations were associations  220 - 222 , then the subscriber device may tune to RF “483” from the list of RFs “465, 471, 483” of selected association  220 . In an embodiment where the subscriber device includes two or more tuners, the subscriber device may currently tune to more than one RF where each tuner may tune to a different RF from the RFs  210  of selected association  220 . By tuning to multiple RFs, the subscriber device may be able to more quickly determine an assigned service group. Similarly, steps  410 ,  412 , and  416 - 420  (as described below) may be performed concurrently for each tuned frequency. 
     In step  410 , the subscriber device identifies a TSID of the tuned RF of step  408 . As discussed above, the identified TSID identifies the transport stream transmitted on the tuned RF. For a received MPEG transport stream, for example, the subscriber device may extract the TSID from a Program Association Table (PAT). 
     In step  412 , the subscriber device verifies whether the identified TSID matches any of the TSIDs within the selected association of step  408 . Upon verification, method  400  proceeds to step  414  if there exists a match or to step  416  if no such match exists. For example, for selected association  220  and a tuned RF “465”, the subscriber device verifies whether the identified TSID is any of TSIDs “103, 51, 1005” within association  220  and associated with RFs “465, 471, 483.” If the identified TSID is, for example, RF “465,” then the subscriber devices finds a matching TSID from the list of TSIDs  208  associated with the selected association  220 . 
     In step  414 , the subscriber device determines the SGID, identifying its service group, based on the matched TSID of step  412 . In an embodiment, the matched TSID and tuned frequency represents a unique paring associated with a specific SGID. In an embodiment, upon determining that the identified TSID matched one of the TSIDs in the selected association, the subscriber device determines the SGID within that selected association. For example, for a selected association  220  from SGD listing  200  and a matched TSID of “103,” the subscriber device determines that SGID “400” identifies the service group associated with the subscriber device. In an embodiment, the subscriber device stores in its memory the determined SGID and the identified unique paring of the matched TSID and tuned RF for future use. From the above example, the subscriber device stores SGID “400” and associated information such as matched TSID “103” and tuned RF “483.” Future use may include a content requests sent by the subscriber device to a headend system such as cable headend system  102  of  FIG. 1 . For example, the subscriber device looks up the stored SGID “400” to include as a parameter in a request to a headend system for VOD or DVR content. 
     In an embodiment, the subscriber device re-verifies the stored SGID. For example, the subscriber device may periodically or intermittently verify the SGID as stored in step  414 . In an embodiment, the subscriber device verifies the stored SGID on demand. For example, upon receiving a request from a user for VOD or DVR content, the subscriber device may re-verify the stored SGID. In an embodiment, the subscriber device verifies the SGID by tuning to the stored associated RF to determine whether a TSID of the tuned RF matches the stored TSID associated with the SGID. If verification fails, the subscriber device may reinitiate one or more steps of method  400  to re-discover the SGID. 
     In step  416 , the subscriber device determines whether any RFs within the selected association of step  408  remain for tuning. In an embodiment, by providing more than one RF to associate with an SGID, the possibility for outages is reduced because it is likely that at least one of the multiple transport streams transmitted on a respective RF is in normal operation. If no RF remains for tuning, i.e., each of the RFs associated with the selected association has been tuned to determine an SGID, then method  400  proceeds to step  418 . Otherwise, method  400  proceeds to step  408  where the subscriber device selects the next un-tune RF from the list of RFs associated with the selected association. For example, after tuning to RF “465” and failing to verify a matching TSID in step  412 , the subscriber device may tune to the next RF “471” associated with association  220 . 
     In step  418 , the subscriber device determines whether a remaining association from the selected one or more associations of  406  can be used to determine its service group. For example, the subscriber device may have selected associations  220 - 222  from SGD listing  200 . Upon failing to verify a matching TSID for RFs “465, 471, 483” within association  222 , the subscriber device may select and process information from the next association  222  to determine the service group associated with the subscriber device. In an embodiment, if no more associations remain, then the subscriber device is unable to determine the service group and method  400  proceeds to step  422 . Otherwise, method  400  proceeds to step  420 . 
     In step  420 , the subscriber device selects a remaining association as determined in step  418 . Then, method  400  proceeds to step  408  where the subscriber device tunes to an RF from the selected, remaining association. 
     In step  422 , an error occurs because the service group was not discovered. In an embodiment, the subscriber device provides an output to a content viewer to indicate the error. For example, the error may represent an outage at the headend system providing the subscriber device with media content. 
     The representative functions described herein can be implemented in hardware, software, or some combination thereof. For instance, the representative functions can be implemented using computer processors, computer logic, application specific circuits (ASIC), digital signal processors, etc., as will be understood by those skilled in the art(s)s based on the discussion given herein. Accordingly, any processor that performs the functions described herein is within the scope and spirit of the embodiments presented herein. 
     CONCLUSION 
     The aforementioned description of the specific embodiments will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance. 
     References in the specification to “one embodiment,” “an embodiment,” “an exemplary embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art(s) to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     The exemplary embodiments described herein are provided for illustrative purposes, and are not limiting. Other exemplary embodiments are possible, and modifications may be made to the exemplary embodiments within the spirit and scope of the disclosure. Therefore, the specification is not meant to limit the disclosure. Rather, the scope of the disclosure is defined only in accordance with the following claims and their equivalents. 
     Embodiments may be implemented in hardware (e.g., circuits), firmware, software, or any combination thereof. Embodiments may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any hardware mechanism for storing information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; and other hardware implementations. Further, firmware, software, routines, instructions may be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions in fact results from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc. Further, any of the implementation variations may be carried out by a general-purpose computer. 
     In embodiments having one or more components that include one or more processors, one or more of the processors can include (and/or be configured to access) one or more internal and/or external memories that store instructions and/or code that, when executed by the processor(s), cause the processor(s) to perform one or more functions and/or operations related to the operation of the corresponding component(s) as described herein and/or as would appreciated by those skilled in the relevant art(s). 
     It is to be appreciated that the Detailed Description section, and not Abstract section, is intended to be used to interpret the claims. The Abstract section may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventors, and thus, is not intended to limit the present disclosure and the appended claims in any way. 
     The embodiments presented herein have been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.