Abstract:
In a passive optical network (PON), multiple optical network terminals (ONTS) transmit data to an optical line terminal (OLT) using a common optical wavelength and fiber optical media. Various components of the PON, including the OLT and ONT(s), can malfunction. Centralized techniques for maintaining or diagnosing fault conditions may be ineffective in large networks or in relatively small networks because of vast amounts of information and limited storage capacity for the information. Thus, fault conditions may occur and not be diagnosed due to lost or overwritten information. Therefore, a distributed approach based on information related to ranging of ONTs within the PON is employed in an example embodiment of the invention. This distributed approach can improve monitoring and diagnosis of fault conditions that may lead to instability of the PON.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    In a passive optical network (PON), multiple optical network terminals (ONTS) transmit data to an optical line terminal (OLT) using a common optical wavelength and fiber optic media. Various components of the PON, including the OLT and ONT(s), can malfunction. It has always been very difficult to monitor stability of the ONT and diagnose a source of instability in part because of inherent characteristics of signaling paths within a PON. 
         [0002]    In an event of an alarm condition on the ONT, the ONT may transmit a message autonomously to the OLT, which, in turn, may transmit a message to report the alarm condition to a management system. However, when dealing with a large number of ONTs for a long duration of time, it becomes less feasible to rely on the management system to handle a large number of alarm conditions and diagnose causes of the alarm conditions. 
         [0003]    Some information generated or learned by the ONTs cannot be retrieved from ONTs in certain circumstances. For example, existing methods rely on a management system, such as an Element Management System (EMS), capable of logging alarms that are received from ONTs. However, whenever there is a re-range condition, a Lost of Physical Link—Loss of Signal (LOPL—LOS) alarm is generated by the ONTs and is cleared at the ONTs as soon as the condition clears. Also, the EMS has a limit to the number of alarms it can store, and alarms beyond the limit are lost or overwrite previously stored alarms. Thus, diagnosing faults in a passive optical network is challenging. 
       SUMMARY OF THE INVENTION 
       [0004]    A method and system of enabling diagnosing of faults in a passive optical network (PON) according to an example embodiment of the invention may include identifying a correspondence between the ranging information representative of a length of time since ranging a given optical network terminal (ONT) and state information of the given ONT, or another PON device associated with operation of the given ONT. The example embodiment may further include reporting the correspondence to enable diagnosing faults in the PON. 
         [0005]    A further example embodiment of the invention provides a network management service for a passive optical network (PON). The network management service may include determining stability of at least a first node in the passive optical network as a function of a length of time the first node has remained synchronized with at least one second node in the PON. The network management service may further include identifying a correspondence between the stability of the first node and state information of the first node, another PON device, or the at least one second node associated with operation of the first node. A fee is collected for the service. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention. 
           [0007]      FIG. 1  is a high level network diagram of a communications network with a service to facilitate communications and diagnosis between service provider network equipment and end-user network equipment; 
           [0008]      FIG. 2  is a laboratory test setup diagram with a laboratory database connected to the serial ports of several Optical Network Terminal (ONT) devices; 
           [0009]      FIG. 3  is a communications diagram demonstrating interaction between an Optical Line Terminal (OLT) and an Optical Network Terminal (ONT); 
           [0010]      FIG. 4  is a communications diagram demonstrating interaction between several Optical Line Terminal (OLT) devices and an Element Management System (EMS); 
           [0011]      FIG. 5  is a communications diagram demonstrating the interaction between the EMS devices, a Network Management System (NMS), and a Service Provider; 
           [0012]      FIG. 6  is a flow diagram illustrating a process of retrieving ranging event data from an ONT; 
           [0013]      FIG. 7  is a sample report of ranging event data obtained from the Optical Network Terminal (ONT) devices; 
           [0014]      FIG. 8  is a timeline diagram demonstrating ranging event data; 
           [0015]      FIG. 9  is a sample report containing the ranging event data of each Optical Network Terminal (ONT) device and the information of the ONT, Optical Line Terminal (OLT), and other PON devices associated with the ONT; 
           [0016]      FIG. 10A  is a sample network stability report characterizing a level of attention used to service an unstable PON device; 
           [0017]      FIG. 10B  is a plot of a network metric representing average instability of the PON network, with the plot associating instability of the PON with an event; 
           [0018]      FIGS. 11A-B  are flow diagrams illustrating example embodimenst of the present invention; 
           [0019]      FIG. 12  is a flow diagram illustrating the process of correlating ranging event data with state information of devices in the PON; 
           [0020]      FIG. 13  is a flow diagram illustrating an analysis and categorization of the correlated data of  FIG. 12 ; 
           [0021]      FIG. 14  is a network diagram illustrating typical parties associated with network stability maintenance of a PON; 
           [0022]      FIG. 15  is a network diagram illustrating interaction of a manufacturer, content provider, and advertiser in a context of a Wide Area Network (WAN), PON, and network stability server; 
           [0023]      FIG. 16  is a network diagram illustrating the interaction of a manufacturer, service provider, and third-party auditing service provider in the context of the WAN and PON; and 
           [0024]      FIG. 17  is a flow diagram illustrating the network management service provided within the networks of  FIG. 16  or  17 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    A description of example embodiments of the invention follows. 
         [0026]    An example embodiment of the invention enables diagnosing of faults in a passive optical network (PON). Diagnosis can be difficult due to alarm message storage constraints in large networks and alarm and state information clearing or changing at nodes generating alarm messages after a change in alarm or other state by the nodes generating the alarm messages or by associated nodes. Centralized techniques for maintaining or diagnosing the alarm conditions are thus limited or ineffective. Therefore, a distributed approach based on information related to ranging of optical network terminals (ONTs) within the PON is employed in an example embodiment of the invention. The information related to ranging used by the example embodiment serves to overcome problems previously encountered in diagnosing faults in a PON, as described above. Before presenting details of example embodiments of the invention a description of a PON is presented in reference to  FIG. 1 . 
         [0027]      FIG. 1  is a network diagram of a passive optical network (PON)  100  illustrating aspects of an example embodiment of the invention. The PON  100  includes a service provider  101 , a network management system  102 , at least one content server  103 , a wide area network (WAN)  104 , at least one element management system (EMS)  105 , at least one optical line terminal (OLT)  106 , an optical splitter/combiner (OSC)  107 , at least one optical network terminal (ONT)  108 , and at least one end user  109 . In other network embodiments, optical network units (ONUs) (not shown) may be in optical communication with multiple ONT(s)  108  or directly in electrical communication with end user equipment, such as routers, telephones, home security systems, and so forth (not shown). As presented herein, data communications  114   a - 114   n  may be transmitted to the OLT  106  via the WAN  104 . The data communications are provided by the content server  103 . “Data” as used herein refers to voice, video, analog, or digital data. 
         [0028]    The element management system  105  may provide configuration data  113  to the OLT  106 . The configuration data  113  facilitates communication of downstream data (e.g., content)  110  between the OLT  106  and ONTs  108 . Communications may be performed using standard communications protocols known in the art. For example, downstream data  110  may be broadcast with identification (ID) data to identify intended recipients for transmitting the downstream data  110  from the OLT  106  to the ONT(s)  108 . Time division multiple access (TDMA) may be used for transmitting the upstream data  111  from individual ONT(s)  108  back to the OLT  106 . Note that the downstream data  110  is power divided by the OSC  107  into downstream data  112   a  matching the downstream data  110  “above” the OSC  107 , but with power reduced proportionally to the number of paths onto which the OSC  107  divides the downstream data  120 . It should be understood that, in an optical network environment, the terms “downstream data”  110 ,  112   a  and “upstream data”  111 ,  112   b  refer to optical traffic signals that typically travel via optical communications path(s), such as optical fiber(s). 
         [0029]    The PON  100  may be deployed for fiber-to-the-premise (FTTP), fiber-to-the-curb (FTTC), fiber-to-the-node (FTTN), and other fiber-to-the-X (FTTX) applications. The optical fiber in the PON  100  may operate at various bandwidths, such as 155 megabits per second (Mbps), 622 Mbps, 1.244 gigabits per second (Gbps), 2.488 Gbps, or other bandwidth implementations. The PON  100  may incorporate asynchronous transfer mode (ATM) communications, broadband services such as Ethernet access and video distribution, Ethernet point-to-multipoint topologies, and native communications of data in time division multiplexing (TDM) formats or other communications formats suitable for a PON  100 . ONT(s)  108  may provide and receive communications to and from the PON  100  and may be connected to standard telephones (e.g., PSTN02 and cellular), Internet Protocol (IP) telephones for Voice-over-IP (VoIP) services, Ethernet units, video devices, computer terminals, digital subscriber lines, wireless access, as well as any other conventional or future customer premise equipment. 
         [0030]    The OLT  106  generates or passes downstream communications  110  to the OSC  107 . After flowing through the OSC  107 , the downstream communications  110  are broadcast as power reduced downstream communications  112   a  to the ONT(s)  108 , where each ONT  108  reads data within received downstream communications  112   a  intended for that particular ONT  108 . The downstream communications  110  may also be broadcast to, for example, another OSC (not shown), where the downstream communications  110  are again split and broadcast to additional ONT(s)  108  and/or ONUs (not shown). 
         [0031]    Data communications  112   a  may be transmitted to an ONT  108  in the form of voice, data, video, and/or telemetry over fiber connection. The ONT(s)  108  transmit upstream communication signals  112   b  back to the OSC  107  via an optical link, such as a fiber connection. The OSC  107 , in turn, combines upstream signals  112   b  from all connected ONTs  108  and transmits a combined signal  111  back to the OLT  106 , which employs, for example, a time division multiplex (TDM) protocol to determine from which ONT  108  portions of the combined signal  111  are received. The OLT  106  may further transmit the communications signals  114   b  to the content server  103  or NMS  102  via the WAN  104 . 
         [0032]    Communications between the OLT  106  and the ONT(s)  108  occur using a downstream wavelength, such as 1490 nanometers (nm), and an upstream wavelength, such as 1310 nm. The downstream communications  110  broadcast from the OLT  106  to the ONT(s)  108  may be provided at 2.488 Gbps, which is shared across all ONT(s). The upstream communications transmitted  112   b  from the ONT(s)  108  to the OLT  106  may be provided at 1.244 Gbps, which is shared among all ONT(s)  108  connected to the OSC  107 . Other communications data rates known in the art may also be employed. 
         [0033]    To ensure upstream communications do not “collide,” a process known as ranging is performed. Results of ranging the ONTs  108  by the OLT  106  include upstream timing offsets, which are provided to the ONTs  108  for use in knowing how long to wait after receipt of a downstream start-of-frame signal (not shown). For example, following receipt of a downstream communications signal  112   a , an ONT waits for its prescribed upstream timing offset before transmitting an upstream communications signal  112   b  to the OLT  106 . Ranging may occur following a power outage, reset, software upgrade, and so forth. 
         [0034]    In an example embodiment of the invention, a method, or corresponding system of enabling diagnosing of faults in a passive optical network (PON) includes monitoring ranging information representative of a length of time since ranging an optical network terminal. The embodiment may include identifying a correspondence between the ranging information and state information of the ONT or another PON device associated with operation of the ONT. The correspondence may be reported to enable diagnosing faults in the PON. 
         [0035]    The example embodiment may include monitoring a counter indicating a number of times over a length of time an encryption key, used to support encrypted communications between the ONT and an optical line terminal (OLT) in communication with the ONT, changed. The encryption key may be a churning key that changes over time, and the churning key and the number of times the churning key changed may be divided by a metric to determine a length of time since the ONT was most recently ranged. 
         [0036]    The example embodiment may also include storing the ranging information. The embodiment may include storing the ranging information in at least one of the following locations: the ONT, an OLT in communication with the ONT, or a management element in communication with the OLT or ONT. 
         [0037]    The example embodiment may include diagnosing the faults as a function of the correspondence between the ranging information and the state information. The information may be the state information of at least the ONT, a Battery Backup Unit (BBU) coupled to the ONT, another ONT in the PON, an OLT in communication with the ONT, or a combination of the OLT and ONT. 
         [0038]    The example embodiment may also include monitoring the ranging information, identifying the correspondence, and reporting the correspondence in an environment selected from a group consisting of a laboratory environment and a field operations environment. 
         [0039]    During the identification of a correspondence between the ranging information and state information, another embodiment may include storing the ranging information and state information in a database and associating a start time of the ranging with a state in the state information. The embodiment may further include converting the ranging information, state information, and the correspondence into a human-readable format. 
         [0040]    The example embodiment may also include reporting the correspondence at least locally at the ONT, remotely at an optical line terminal (OLT) in communication with the ONT, or remotely at a management element. Reporting of the correspondence may also include storing the correspondence in a file server in communication with the ONT or an OLT in communication with the ONT. 
         [0041]    The example embodiment may also include monitoring the ranging information in traffic on a Physical Layer Operations, Administration, and Maintenance (PLOAM) channel, an Operations Management and Control Interface (OMCI) channel, or an in-band traffic channel. 
         [0042]    During the reporting of the correspondence process, the example embodiment may include analyzing the correspondence and categorizing the state information of the PON or ONT as a function of the correspondence. The categorization of the state of the PON or ONT may include assigning a priority level for maintenance. 
         [0043]    A network management service for a passive optical network (PON) may also be provided. The network management service may include determining stability of at least a first node in the passive optical network as a function of a length of time the first node has remained synchronized with at least one second node in the PON. The network management service may further include identifying a correspondence between the stability of the first node and state information of the first node, another PON device, or at least the one second node associated with operation of the first node. A fee may be collected for the service. 
         [0044]    The network management service may further include correcting a network fault and reporting information about the network fault to at least a service provider, manufacturer, network stability server, content provider, advertiser, or third-party auditing service provider. 
         [0045]    The fee for the service may be collected on a subscription basis ranging from a one time, weekly, monthly, or annual subscription basis, invoicing the party for the fee, or collecting the fee on a prepayment basis. 
         [0046]    The network management service, in determining the stability of the PON, may further include counting a number of times over a length of time an encryption key, used to support encrypted communications between the first node and at least one second node, changed to determine a length of time the first node has remained synchronized with at least the second node in the PON. The encryption key may be a churning key, and a further method of determining stability of the PON may include dividing the number of times the churning key changed since a most recent ranging by a metric to determine the length of time since the ONT was most recently ranged. 
         [0047]      FIG. 2  is a diagram of a laboratory test setup  200 , which may be an environment in which an embodiment of the invention is employed. The setup  200  may include a laboratory computer  221  connected to a database  222 . The computer  221  is connected to serial ports  209  of several Optical Network Terminal (ONT)  208 - 1  . . . N. An Optical Line Terminal (OLT)  206  is connected to the ONTs  208 - 1  . . . N. Communications between the OLT  206  and ONTs  208 - 1  . . . N may be conducted in a manner similar to that as described in  FIG. 1 . The laboratory database  221  may be connected to the serial port  209  of the ONTs  208 - 1  . . . N and collects ranging event data  220  from the ONTs  208 - 1 . N. The laboratory database  221  then analyzes the ranging event data  220 . This analysis may be monitored by a laboratory technician (not shown). This analysis can be used to improve operational characteristics of the PON devices and diagnose faults, for example. 
         [0048]      FIG. 3  is a communications diagram  300  demonstrating interaction between an Optical Line Terminal (OLT)  306 , Optical Network Terminal (ONT)  308 , and Battery Backup Unit (BBU)  324 . A Battery Backup Unit (BBU)  324  may be coupled to an ONT  308 . The BBU  324  provides actual DC power when the BBU  324  detects the ONT  308  has had a loss of primary power. The BBU  324  also provides status messages  326  periodically or upon detecting, for example, a failure or low-charge. An OLT  306  sends a request for ranging event data  322  to the ONT  308 . This request may be done through, for example, a PLOAM channel  323 . The ONT  308  can store its ranging event data and its ONT state information data locally  321   b . The ONT  308  also stores the status messages  326  provided by the BBU  324 . Once the ONT  308  receives the request  322  from the OLT  306 , the ONT  308  sends the ranging event data, its state information data  320 , and BBU  324  status messages  326  back to the OLT  306 . The OLT  306  can then locally store  321   a  the ONT ranging event data  320  and its OLT state information. 
         [0049]    The OLT  306 , when requesting ranging event data  322 , may request a security key, such as a churnkey that changes over time, from the ONT  308 . The OLT  306  requests a new churnkey from the ONT  308  every 30 to 60 seconds. If the ONT  308  chums a churnkey and responds to the OLT  306  every time a request  322  is sent, then the OLT  306  increments a corresponding counter. This counter is used to determine a length of time the ONT  308  has remained ranged with the OLT  306 . If for some reason there is a reset, such as caused by an ONT reboot, the OLT  306  rearranges the ONT  308 , causing the counter to be reset and, thus, resetting the length of time since the ONT  308  was most recently ranged. 
         [0050]      FIG. 4  is a communications diagram demonstrating interaction between several Optical Line Terminals (OLTs)  406  and an Element Management System (EMS)  425 . The EMS  425  may be equipped with a correlator  425 . An OLT device  406  reports ranging event data and OLT/ONT state data  420  to the EMS  405 . The EMS  405  may store the ranging event and state data  420  locally in its database  421 . The EMS  405  may then identify a correspondence between the ranging information and state information of the OLT  406 , ONT  408  or another PON device (not shown) associated with the operation of the ONT  408  (e.g., a Battery Backup Unit, not depicted) using a correlator  425 . The correspondence created by the correlator  425  may also be stored locally in the database  421 . 
         [0051]      FIG. 5  is a communications diagram in an example field deployed network  500  in which example embodiments may be employed. The diagram illustrates interaction between Element Management Systems (EMSs)  505 , a Network Management System (NMS)  502 , and a Service Provider  501 . The EMS  505 , after using a correlator  525  to create a correspondence between ranging information and state information of PON devices  100 , may send a correlation report  526  to a NMS  502 . The NMS  502 , in turn, may send this report to a service provider  501 . The correlation report  526  associates a start time of a re-ranging condition with state information of a PON device at the time of re-ranging. The stored information may be converted into a human-readable format for ease of analysis. In reporting the correspondence, the NMS  502  may also assign a priority level for maintenance if it identifies an error in the PON  100 . 
         [0052]      FIG. 6  is a flow diagram illustrating a process  600  of retrieving ranging event data from an ONT. The process  600  begins by logging into an ONT(x) console and executing a command (e.g., “Vex Pon status”) ( 630 ). A keyswitch value is given ( 631 ). If the value is “0,” then an ONT is not ranged, and this information is reported ( 632 ). The process continues by logging into a next ONT ( 630 ). If the keyswitch value is greater than or less than “0” (i.e., non-zero), then a report is generated with the ONT range time ( 633 ), and the process continues by logging into a next ONT ( 630 ). The process  600  continues until all ONT devices have been accessed. 
         [0053]      FIG. 7  is a sample report of ranging event data obtained from an Optical Network Terminal (ONT) (not shown). The report includes several columns of example data, including: ONT name  727 , type of ONT device  728 , ONT identification  729 , ONT switch  734 , terminal port  735  used, ONT “uptime”  736  (i.e., time duration since most recent ranging), and the ONT range time  737  in minutes corresponding to the uptime  736 . 
         [0054]      FIG. 8  is a timeline diagram demonstrating ranging event data  800 . A time  839  is associated with a loss of signal event  838 . At this time  839 , an ONT re-ranges, and a churnkey is reset to “0”. If data collection  842  occurs before a loss of signal event  838 , the ONT is in a ranged condition, and the churnkey has a value greater then zero, which represents how long the ONT has remained synchronized with the PON. If data collection  842  occurs during a loss of signal event  838 , the churnkey is given a value of zero, which represents a re-ranging condition of the ONT. At this time  839 , the data collection optionally also retrieves state information of PON devices associated with the operation of the ONT. Some or all retrieved information may be analyzed to diagnose faults and, optionally, provide network management services. 
         [0055]      FIG. 9  is a sample report containing ranging event data of each Optical Network Terminal (ONT) and, optionally, state information of the ONT(s), OLT, and other PON devices associated with the ONT(s). The report  900  contains multiple columns, including, for example, columns with: an ONT number  945  used to identify an ONT in the PON, ranging time (or count)  946  of the ONT, state information  947  of the ONT, state information  948  of an OLT in communication with the ONT, and state information  949  of any other PON device associated with the ONT. This report  900  can be used to diagnose faults in the PON by correlating and analyzing the data. 
         [0056]      FIG. 10A  is a sample network stability report  1000  characterizing a level of attention used to service an unstable PON device. The sample network stability report  1000  contains columns with, for example, information useful for understanding network stability, such as: a PON subnet number  1001  that identifies which network is being analyzed, unstable PON element(s)  1002  (e.g., ONT, OLT), time of instability  1003 , recent PON activity  1004  (e.g., software upgrade), and a characterization of the attention level needed  1005 . Characterization can be determined as a function of the unstable PON elements(s), type(s) of alarms, or other information understood in the art as being useful to characterize the attention level needed to service the PON. 
         [0057]      FIG. 10B  is a plot  1010  of an “instability” metric representing average instability of the PON network. The plot  1010  associates an instability of the PON with an event. The instability metric plot  1010  contains a graphical display of a measure of instability solid-line curve  1011  versus a time  1012 . An average instability dashed-line curve  1013  is illustrated and demonstrates whether the instability of the PON is on average, decreasing or increasing. Events  1014   a - 1014   e  may be indicated on the instability metric plot  1010  to demonstrate potential causes or resolutions of faults in the PON. 
         [0058]      FIG. 11A  is a flow diagram of a process  1100  illustrating an example embodiment of the invention. Using ranging event data and state information of PON devices, a correspondence between the ranging event data and state information of the PON devices is identified ( 1106 ). Subsequently, a report and/or analysis of the correspondence is created ( 1107 ). 
         [0059]      FIG. 11B  is a flow diagram of a process  1150  illustrating a further example embodiment of the invention. The process  1150  begins ( 1119 ) and monitors ( 1120   a ,  1120   b ) ranging event data and state information of PON devices. At any point of data collection a correspondence between ranging event data and state information of PON devices is identified ( 1126 ). Subsequently, a report and/or analysis of the correspondence is created ( 1127 ). This report and/or analysis is used to diagnose faults ( 1128 ) if any are found. If it is determined that any faults are found, the faults may be resolved or fixed ( 1130 ). The process  1100  thereafter may begin ( 1119 ) again. 
         [0060]      FIG. 12  is a flow diagram illustrating an example process  1200  of correlating ranging event data with state information of devices in the PON. The process  1200  may begin by retrieving a churnkey (or other variable from which time or elapsed time can be determined) value ( 1210 ). The value is parsed ( 1211 ) to determine whether it is equal to zero or greater/less than zero. If the value is greater/less than zero, the ONT is determined to be ranged ( 1212 ). The churnkey value may then be converted into minutes ( 1213 ), and the time of last ranging may be calculated ( 1214 ) by taking the current time and subtracting the churnkey value. The ranging time is correlated with PON state information ( 1215 ), and this information may be reported and analyzed ( 1218 ). If the churnkey value is equal to zero, the ONT is re-ranging ( 1216 ), the PON state information is correlated with the current time ( 1217 ), and the results of the correlation are reported and analyzed ( 1218 ). 
         [0061]      FIG. 13  is a flow diagram illustrating an example process  1300  of analyzing and categorizing correlated data. The process  1300  begins by receiving state information of PON devices at a time of ONT ranging ( 1301 ). Each PON device is diagnosed for errors at the time of ONT ranging ( 1302 ). The data is parsed ( 1303 ) and, if there are no problems found in any PON device, a report is given that the error(s) are not caused by a PON device ( 1304 ,  1305 ). If a problem is found, the error is likely caused by an error in a PON device ( 1306 ), and the error may be diagnosed ( 1307 ). A report categorizing the level of attention may be given ( 1305 ,  1308 ). 
         [0062]      FIG. 14  is a network diagram  1400  illustrating typical parties and equipment that may be associated with network stability maintenance of a PON. The diagram  1400  includes a manufacturer  1410 , network stability server  1409 , content provider  1408 , advertiser  1407 , Wide Area network (WAN)  1406 , local PON management and OLT  1402 , PON  1401 , manufacturer&#39;s PON equipment  1403   a , end-users  1403   b , third-party auditing service provider  1412 , and service provider  1411 . 
         [0063]    In the example network diagram  1400  a manufacturer  1410  provides service  1414  through a WAN  1406 . The manufacturer  1410  is able to access reports  1413  regarding correspondence between stability of PON node(s) and state information of PON device(s) or node(s) through the WAN  1406 . The local PON management and OLT  1401  receives content  1404 , which is distributed to manufacturer&#39;s PON equipment  1403   a  in the PON  1401 . The end-users  1403   b  ultimately receive the content  1404  via display or otherwise via the manufacturer&#39;s equipment  1403   a . Synchronization (Synch) data  1405  is sent back to the WAN  1406  by the manufacturer&#39;s PON equipment  1403   a.    
         [0064]      FIG. 15  is a network diagram  1500  illustrating interaction of a manufacturer  1510 , content provider  1508 , and advertiser  1507  in a context of a WAN  1506 , PON  1501 , and network stability server  1509 . A PON  1502 , or device therein, sends synchronization (synch) data  1505  through the WAN  1506  to the manufacturer  1510 , a network stability analysis server  1509 , or both. The manufacturer  1510  may send network stability information  1515  to a content provider  1508  or an advertiser  1507  in exchange for a fee  1516 . The content provider  1508  may also obtain the network stability information  1515  from the network stability analysis server  1509 . The content provider  1508  may also provide content  1504  through the use of content servers (not shown) to end-users  1503 . 
         [0065]      FIG. 16  is a network diagram  1600  illustrating interaction of a manufacturer  1610 , service provider  1611 , and third-party auditing service provider  1612  in the context of a WAN  1606  and PON  1601 . A manufacturer  160  receives synchronization data  1605  via the WAN  1606  from a PON  1601 . In an example scenario, the manufacturer  1610 , initially, proved PON equipment  1617  to a service provider  1611 . The manufacturer  1610  is then able to provide network stability data  1615  to the service provider  1611  for a per instance fee  1616 , for example. Similarly, a third-party auditing service provider  1612  may provide similar services through the WAN  1606  for a licensing fee  1616  given to the manufacturer  1610 . In commerce, the third-party auditing service provider  1612  receives synchronization data  1605  from the PON  1601  via the WAN  1606  and provides network stability data  1615  for a fee  1616 . 
         [0066]      FIG. 17  is a flow diagram illustrating an example of the network management service  1700  provided with the network of  FIG. 16  or  17 . The service begins by monitoring nodes in the PON ( 1720 ). The service  1700  determines the stability ( 1721 ) of the PON devices. If there are no errors, the service  1700  continues monitoring nodes ( 1720 ). If an error is found, a service to correlate data and report data is provided ( 1723 ). The network management service also provides an additional service to analyze the data ( 1724 ) and identify or fix any instability based on the correlation ( 1725 ). The service  1700  continues monitoring nodes in the PON ( 1720 ). 
         [0067]    While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. 
         [0068]    For example, any of the flow diagrams described herein may be modified or arranged in any manner to support operation in various network configurations. The flow diagrams may include more or fewer blocks, combined or separated blocks, alternative flow arrangements, or the like. The flow diagrams may also be implemented in the form of hardware, firmware, or software. If implemented in software, the software may be written in any suitable code in accordance with the example embodiments herein or other embodiments. The software may be stored in any form of computer readable medium and loaded and executed by a general purpose or application specific processor suitable to perform the example embodiments described herein or other embodiments.