Abstract:
A system, for use with a broadband network, includes information means for obtaining information relating to network performance, and parameter means, coupled to the information means, for parameterizing the network performance information, with parameters providing information about network performance over time.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to monitoring network performance and more particularly to monitoring broadband network performance using performance metrics.  
         BACKGROUND OF THE INVENTION  
         [0002]    Communications networks are expanding and becoming faster in response to demand for access by an ever-increasing amount of people and for demand for quicker response times and more data-intensive applications. Examples of such communications networks are for providing computer communications. Many computer users initially used, and many to this day still use (there are an estimated 53 million dial-up subscribers currently), telephone lines to transmit and receive information. To do so, these people convey information through a modem to convert data from computer format to telephone-line format and vice versa. Presently, a multitude of computer users are turning to cable communications. It is estimated that there are 5.5 million users of cable for telecommunications at present, with that number expected to increase rapidly in the next several years.  
           [0003]    In addition to cable, there are other currently-used or anticipated broadband communications network technologies, with others as yet to be created sure to follow. Examples of other presently-used or presently-known broadband technologies are: digital subscriber line (DSL) with approximately 3 million subscribers, satellite, fixed wireless, free-space optical, datacasting, and High-Altitude Long Operation (HALO).  
           [0004]    Broadband networks currently serve millions of subscribers, with millions more to come. These networks use large numbers of network elements, such as Cable Modem Termination Systems (CMTSs) physically distributed over wide areas, and other network elements, such as Cable Modems (CMs) located, e.g., in subscribers&#39; homes. With so many network elements, problems in the networks are a common occurrence. Monitoring networks to assess network performance, and locating and correcting, or even preferably anticipating and preventing, network problems are desirable functions that are potentially affected by the increasing number of subscribers, and corresponding size and complexity of networks.  
         SUMMARY OF THE INVENTION  
         [0005]    In general, in an aspect, the invention provides a system, for use with a broadband network, including information means for obtaining information relating to network performance, and parameter means, coupled to the information means, for parameterizing the network performance information, with parameters providing information about network performance over time.  
           [0006]    Implementations of the invention may include one or more of the following features. The parameters provide information about network performance in levels of network performance degradation. The parameter means is configured to manipulate the network performance information into metrics related to network performance, and to determine the level of network performance degradation associated with each metric by comparing the metrics to thresholds associated with the levels of network performance degradation. The information means obtains substantially real-time raw network data and the parameter means manipulates the raw data and compares the manipulated raw data with thresholds that are dependent upon at least one of network performance, network configuration, computer models related to the network, and empirical evidence related to the network. The information means is configured to manipulate the raw data by normalizing the raw data. The parameter means is distributed within the network. Each parameter is indicative of a length of time that the corresponding metric has been at a designated level of network degradation. Each parameter indicates an amount of hours that the corresponding metric has been at the designated level of network performance degradation within a selected amount of time. The network is a DOCSIS network including cable modems and cable modem termination systems, and the parameters indicate numbers of cable-modem hours at the designated levels of network degradation. The levels include degraded and severely degraded.  
           [0007]    Further implementations of the invention may include one or more of the following features. The system further includes a combiner coupled to the parameter means and configured to combine the parameters according to a topology of the network, and according to which portions of the topology are selected for evaluation. The system further includes a combiner coupled to the parameter means and configured to combine the parameters according to a time period selected for evaluation. The system further includes presentation means coupled to the parameter means and configured to present information of the parameters over time. The parameter means is configured to parameterize the network performance information based upon at least one of a topology of at least a portion of the network, and a time period for evaluation.  
           [0008]    In general, in another aspect, the invention provides a computer program product including computer-executable instructions for causing a computer to accumulate data relating to performance of broadband network elements, and reduce the accumulated data relating to performance of multiple broadband network elements to a single value characterizing an aggregate amount of time that the network elements were at a corresponding quality of network performance during a designated time frame.  
           [0009]    Implementations of the invention may include one or more of the following features. The computer program product further includes instructions for causing the computer to reduce the accumulated data relating to performance of multiple broadband network elements to another single value characterizing another aggregate amount of time that the network elements were at another corresponding quality of network performance during the designated time frame. The single value characterizes the aggregate amount of time that the network elements were at the corresponding quality of network performance for a corresponding network issue during the designated time frame, the computer program product further comprising instructions for causing the computer to combine single values, for a common network issue, associated with multiple sets of network elements according to network topology into a single higher-level value of network performance. The computer program product further includes instructions for causing the computer to combine a plurality of the single higher-level values according to network topology and network issue to determine a single highest value indicative of a total amount of aggregate time of network elements at the corresponding level of network performance associated with the corresponding network issue. The computer program product further includes instructions for causing the computer to combine a plurality of highest values corresponding to network issues into a single summary value indicative of a total amount of aggregate time of all network elements at the corresponding level of network performance, in at least a desired portion of network. The instructions for causing the computer to reduce the accumulated data weights different accumulated data differently to determine the single value. The instructions for causing the computer to accumulate data causes the computer to gather raw data from an associated broadband network. The instructions for causing the computer to accumulate data causes the computer to analyze MIB objects provided by DOCSIS network elements.  
           [0010]    Various aspects of the invention may provide one or more of the following advantages. A wide variety of information from very large, e.g., million-element, networks can be aggregated and presented in a single display instance. What network problems exist, when and where they exist or existed, and which are worse than others, and what issues are causing problems can be identified quickly and easily. Network performance can be provided in terms of both relative quality and absolute value. Information regarding network performance can be aggregated in time and topology, and what time period and/or what portions of a network to aggregate information for can be selected. High-level summarizations of network quality can be provided. Simple mechanisms are provided to quickly determine relative network performance in three dimensions: time, network topology, and network issue. Network-performance-related data can be collected synchronously and/or asynchronously. Operations staff can be informed and corrective measures recommended/applied to individual users/network elements responsible for network (e.g., cable plant) congestion, connectivity and/or abuse. Plant transport failures and choke points can be timely identified. Service slowdowns and outages can be reduced and customer retention and acquisition improved. Cable Operators can offer tiered, delay- and loss-sensitive services (e.g., voice quality services). Management platforms are provided that scales to millions of managed devices. Automatic ticket opening, closing and/or broadband network adaptive improvement (and possibly optimization) can be provided. Outages can be predicted and prevented. Network areas can be targeted for repair based on data space trending &amp; triangulation opportunities. Network service can be kept “up” while targeting and scheduling areas for repair.  
           [0011]    These and other advantages of the invention, along with the invention itself, will be more fully understood after a review of the following figures, detailed description, and claims. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0012]    [0012]FIG. 1 is a simplified diagram of a telecommunications network including a network monitoring system.  
         [0013]    [0013]FIG. 2 is a block diagram of a software architecture of a portion of the network monitoring system shown in FIG. 1.  
         [0014]    FIGS.  3 - 5  are screenshots of a computer display provided by the network monitoring system shown in FIG. 1, showing network performance.  
         [0015]    [0015]FIG. 6 is a screenshot of a computer display provided by the network monitoring system shown in FIG. 1, showing network topology.  
         [0016]    [0016]FIG. 7 is a flowchart of a process of monitoring network activity, and analyzing and reporting network performance.  
         [0017]    [0017]FIG. 8 is a screenshot of a computer display provided by the network monitoring system shown in FIG. 1, showing network performance over time. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0018]    The invention provides techniques for monitoring and evaluating network, especially broadband network, performance. Both absolute and relative values for different areas and aspects of network performance are provided, stemming from raw network data. Raw data are collected from the network and manipulated into metrics (i.e., measurements of network performance based on raw data), that can be manipulated into further metrics. These metrics are compared against thresholds indicative of acceptable, degraded performance, and severely degraded performance. Data collections and metric-to-threshold comparisons are performed over time, e.g., periodically. Using the comparisons, and the times over which the comparisons are made, time-dependent performance values are determined, namely values for degraded and severely-degraded hours. In a broadband network, values for Degraded Modem Hours and Severely-Degraded Modem Hours (DMH and SDMH, respectively) are determined.  
         [0019]    Time-dependent network performance values are combined based upon network impact and network topology. Network impact includes whether the metric is an indication of, e.g., network capacity/traffic versus network connectivity, signal quality (e.g., signal-to-noise ratio), power, or resets. Values related to network impact are determined for the lowest levels of the network, and based upon the topology of the network, the values for lower levels are combined to yield cumulative values for higher and higher levels, until a summary level is achieved, yielding a DMH and an SDMH for the network as a whole. Cumulative values are thus derived, and/or are derivable, and available for various levels of the network.  
         [0020]    Network performance values may be provided by a user interface such that relative and absolute values of network performance may be quickly discerned for various, selectable, network levels and for selectable network attributes. Network DMH and SDMH are provided in summary format for the entire network, regardless of size, in a concise format, e.g., a single computer display screen. Preferably, network DMH and SDMH are provided in a table arranged according to network traffic and network connectivity. Factors contributing to traffic and connectivity DMH and SDMH are also provided, and designated as to whether the factors are direct or indirect contributors to the network performance. The network performance values displayed depend on the level or levels of network topology selected by a user. The network performance values displayed depend on the length of historical time selected by a user. Also, a displayed category can be selected, and in response, data contributing to the selected category will be revealed. This revealed data may be further selected and further detail provided. This technique may be used to locate problem areas within the network. Graphs of performance values with respect to time may also be provided.  
         [0021]    Referring to FIG. 1, telecommunication system  10  includes DOCSIS™ (data over cable service interface specification) networks  12 ,  14 ,  16 , a network monitoring system  18  that includes a platform  20  and an applications suite  22 , a packetized data communication network  24  such as an intranet or the global packet-switched network known as the Internet, and network monitors/users  26 . The networks  12 ,  14 ,  16  are configured similarly, with the network  12  including CMTSs  32  and consumer premise equipment (CPE)  29  including a cable modem (CM)  30 , an advanced set-top box (ASTB)  31 , and a multi-media terminal adaptor (MTA)  33 . Users of the DOCSIS networks  12 ,  14 ,  16 , communicate, e.g., through the computer  28  and the cable modem (CM)  30  (or through a monitor  35  and the ASTB  31 , or through a multi-media terminal  37  and the MTA  33 ) to one of the multiple CMTSs  32 .  
         [0022]    Data relating to operation of the networks  12 ,  14 ,  16  are collected by nodes  34 ,  36 ,  38  that can communicate bi-directionally with the networks  12 ,  14 ,  16 . The nodes  34 ,  36 ,  38  collect data regarding the CMTSs  32 , and the CPE  29  and manipulate the collected data to determine metrics of network performance. These metrics can be forwarded, with or without being combined in various ways, to a controller  40  within the platform  20 .  
         [0023]    The controller  40  provides a centralized access/interface to network elements and data, applications, and system administration tasks such as network configuration, user access, and software upgrades. The controller can communicate bi-directionally with the nodes  34 , 36 ,  38 , and with the applications suite  22 . The controller  40  can provide information relating to performance of the networks  12 ,  14 ,  16  to the application suite  22 .  
         [0024]    The application suite  22  is configured to manipulate data relating to network performance and provide data regarding the network performance in a user-friendly format through the network  24  to the network monitors  26 . The monitors  26  can be, e.g., executives, product managers, network engineers, plant operations personnel, billing personnel, call center personnel, or Network Operations Center (NOC) personnel.  
         [0025]    The system  18 , including the platform  20  and the application suite  22 , is preferably comprised of software instructions in a computer-readable and computer-executable format that are designed to control a computer. The software can be written in any of a variety of programming languages such as C++. Due to the nature of software, however, the system  18  may comprise software (in one or more software languages), hardware, firmware, hard wiring or combinations of any of these to provide functionality as described above and below. Software instructions comprising the system  18  may be provided on a variety of storage media including, but not limited to, compact discs, floppy discs, read-only memory, random-access memory, zip drives, hard drives, and any other storage media for storing computer software instructions.  
         [0026]    Referring also to FIG. 2, the node  34  (with other nodes  36 ,  38  configured similarly) includes a data distributor  42 , a data analyzer  44 , a data collector controller  46 , a node administrator  48 , an encryption module  50 , a reporting module  52 , a topology module  54 , an authorization and authentication module  56 , and a database  58 . The elements  44 ,  46 ,  48 ,  50 ,  52 ,  54 , and  56  are software modules designed to be used in conjunction with the database  58  to process information through the node  34 . The node administration module  48  provides for remote administration of node component services such as starting, stopping, configuring, status monitoring, and upgrading node component services. The encryption module  50  provides encrypting and decrypting services for data passing through the node  34 . The reporting module  52  is configured to provide answers to data queries regarding data stored in the database  58 , or other storage areas such as databases located throughout the system  18 . The topology module  54  provides for management of network topology including location of nodes, network elements, and high-frequency coax (HFC) node combining plans. Management includes tracking topology to provide data regarding the network  12  for use in operating the network  12  (e.g., how many of what type of network elements exist and their relationships to each other). The authorization and authentication module  56  enforces access control lists regarding who has access to a network, and confirms that persons attempting to access the system  18  are who they claim to be. The data distributor  42 , e.g., a publish-subscribe bus implemented in JMS, propagates information from the data analyzer  44  and data collector controller  46 , that collect and analyze data regarding network performance from the CMTSs  32  and CPE  29 .  
         [0027]    The data collector controller  46  is configured to collect network data from, preferably all elements of, the network  12 , and in particular the network elements such as the CMTs  32  and any cable modems such as the cable modem  30 . The controller  46  is configured to connect to network elements in the network  12  and to control the configuration to help optimize the network  12 . Thus, the system  18  can automatically adjust error correction and other parameters that affect performance to improve performance based on network conditions. The data collector controller  46  can obtain data from the network  12  synchronously, by polling devices on the network  12 , or asynchronously. The configuration of the controller  46  defines which devices in the network  12  are polled, what data are collected, and what mechanisms of data collection are used. The collector  46  is configured to use SNMP MIB (Simple Network Management Protocol Management Information Base) objects for both cable modems, other CPE, and CMTSs, CM traps and CMTS traps (that provide asynchronous information) and syslog files. The collector  46  synchronously obtains data periodically according to predetermined desired time intervals in accordance with what features of the network activity are reflected by the corresponding data. Whether asynchronous or synchronous, the data obtained by the collector  46  is real-time or near real-time raw data concerning various performance characteristics of the network  12 . For example, the raw data may be indicative of signal to noise ratio (SNR) power, CMTS resets, etc. The controller  46  is configured to pass the collected raw data to the data analyzer  44  for further processing.  
         [0028]    The data analyzer  44  is configured to accept raw data collected by the controller  46  and to manipulate the raw data into metrics indicative of network performance. Raw data from which the SDMH and DMH values are determined may be discarded. The metrics determined by the data analyzer  44  provide both a relative evaluation of network performance for various issues as well as absolute values of network performance. The metrics also provide indicia of network performance as a function of time and are standardized/normalized to compensate for different techniques for determining/providing raw network data from various network element configurations, e.g., from different network element manufacturers. More detail regarding standardizing/normalizing of metrics is provided by co-filed application entitled “DATA NORMALIZATION,” U.S. Ser. No. (to be determined), and incorporated here by reference.  
         [0029]    The data analyzer  44  is configured to evaluate the metrics derived from the raw data against thresholds indicative of various levels of network performance over time. The thresholds used are selected to indicate grades or degrees or levels of network degradation indicative of degraded performance and severely degraded performance. If the derived metric exceeds the threshold for degraded performance, then the network element, such as a cable modem termination station interface corresponding to a cable modem, is considered to be degraded. Likewise, if the metric exceeds a severely degraded threshold, then the corresponding network element is considered to be severely degraded. Alternatively, thresholds and metrics could be configured such that metrics need to be lower than corresponding thresholds to indicate that associated network elements are severely degraded or degraded. Further, more than two gradations or degrees of network degradation may be used. Still further, various criteria could be used in lieu of thresholds to determine degrees of degradation of network performance. Indeed, the multiple thresholds imply ranges of values for the metrics corresponding to the levels of degradation of network performance.  
         [0030]    The degree of network degradation, or lack of degradation (i.e., non-degraded network performance) is calculated by the data analyzer  44  as a function of time. Preferably, degrees of network degradation are reflected in values of degraded modem hours or severely degraded modem hours, or non-degraded modem hours. These various values are calculated by multiplying the number of unique modems at a particular status/degree of degradation by a sample time difference in hours between calculations of the degree of degradation (e.g., degraded modem hours equals number of unique modems times sample time Δ in hours). The number of severely degraded modem hours (SDMH), degraded modem hours (DMH) or non-degraded modem hours (NDMH) is calculated and saved along with a time stamp. This provides a record for degree of degradation of network performance associated with issue and time and network topology.  
         [0031]    The analyzer  44  determines the thresholds for the various issues using a combination of parameterization of non-real-time complex computer models, non-real-time empirically controlled experiments, real-time information about network equipment configuration, real-time performance data and historical trends such as moving averages, interpolation, extrapolation, distribution calculations and other statistical methods based on data being collected by the node  34 . Parameterizing provides simplified results of complex calculations, e.g., noise distribution integration, or packet size analysis of a distribution of packet sizes. Thresholds can be determined in a variety of other manners. The thresholds provide breaking points for what is determined to be, for that issue, an indication that a modem is degraded or severely degraded. The thresholds are parameterized such that comparison to the thresholds is a computationally efficient procedure.  
         [0032]    The network issue thresholds vary depending upon whether the issues are contributing to network traffic or network connectivity. For example, network traffic is affected by CMTS processor performance, upstream traffic and downstream traffic, which are indirectly affected by outbound network-side interface (NSI) traffic and inbound network-side interface traffic, respectively. Connectivity is affected by upstream and downstream errors, CMTS resets and CM resets. Upstream errors are affected by upstream SNR, upstream receive power (UpRxPwr), and upstream transmit power (UpTxPwr). Downstream errors are affected by downstream SNR and downstream receive DnRxPwr. Other indirect and direct issues obtained from the network  19  can also be used.  
         [0033]    The calculations performed by the data analyzer  44  yield values for DMH and SDMH for each CMTS interface associated with the node  34 . Each node such as the node  34  has a unique set of CMTSs  32  associated with the node. The manipulations by the analyzer  44  yield the metric for SDMH and DMH for the CMTS interfaces of this unique set of CMTSs  32  associated with the node  34 . The metrics determined by the analyzer  44  are conveyed through the data distributor  42  to the controller  40 . The data analyzer  44  further aggregates the metric in time. Raw data may be sampled frequently, e.g., every one minute or every 15 minutes, but not reported by the data analyzer  44  to the controller  40  except every hour. Thus, the data analyzer  44  aggregates the metric determined throughout an hour, and provides an aggregated metric to the controller  40 . The aggregated metric is indicative of the SDMH or DMH, based upon the metric that was determined more frequently than by the hour.  
       EXAMPLES OF STATUS RULES FOR CALCULATING SDMH AND DMH  
       [0034]    Connectivity  
         [0035]    The following status rules describe the calculation of the performance metrics for a set of network issues related to connectivity. Status rules are also applied for traffic issues and examples of these are described below, after connectivity. The following are examples of computationally efficient techniques to determine whether the performance of a particular network issue is severely degraded, degraded, or non-degraded. Many of these rules are based on parameterization of complex computer models containing calculations that would be difficult to perform in real time. Status value judgments are based on the predetermined thresholds. These rules provide information related to overall health of an HFC plant and why the system  18  has determined that various CMTS interfaces have degraded connectivity status.  
         [0036]    SDMH and DMH values are aggregated in time per the aggregation rules given with each contributor below. Using this aggregation, once the higher resolution of recent history has expired, the higher resolution for that data no longer exists in the system  18 . This resolution bounds information available for reporting.  
         [0037]    Table 1 lists direct and indirect contributors applicable to network connectivity. The thresholds for calculation of severely degraded modems and degraded modems are given for each contributor. For each sample time the number of severely degraded, degraded, or non-degraded modems are determined by the node  34  and stored by the node  34  along with the sample interval. As the samples are aggregated by the node  34  up to each resolution bin, the node  34  sums the total degraded hours and aggregates the degraded modem samples by the functions listed in the table. The node  34  performs the detailed logic shown for each sample interval for each CMTS interface. The node  34  applies the following algorithm in classifying modems as degraded, severely degraded, or non-degraded:  
         [0038]    IF Threshold A=TRUE  
         [0039]    Then modems applied to Severely Degraded bin  
         [0040]    ElseIF B=TRUE  
         [0041]    Then modems applied to Degraded bin  
         [0042]    Else modems applied to non-degraded bin.  
         [0043]    The sample intervals apply to the intervals for which the data are collected. Some of the data for the calculation may be collected at slower rates than other data. Non-degraded hours and modems are retained to provide context for percentage-of-network calculations.  
         [0044]    Several of the thresholds are based on theoretical calculations with adjustments for empirical performance. These thresholds have been parameterized for easy lookup to reduce and/or avoid real-time complex calculations.  
                                         TABLE 1                           Degraded modem status thresholds.                                Aggregator               Severely       Sample   (poll               Degraded   Degraded   int.   interval       Contributor   Type   Threshold   Threshold   (minutes)   to 1 hour)               CM resets   Direct   &gt;=15 CM resets   &gt;=10 CM resets &lt;   Trap   The               per 15 minutes per   15 per 15 minutes       number               cable interface   per cable interface       of traps is                           summed                           per CM       CMTS resets   Direct    &gt;=1   NA    1   Note 1       Downstream   Direct   CER &gt;= 5%   5% &gt; CER &gt;= 1%   60   Polled       Codeword                   and       Error Ratio                   calculated       (CER)                   once                           per hour,                           1 SDMH/                           DMH is                           added per                           CM                           exceeding                           threshold       Downstream   Indirect   Note 2   Note 2   60   Polled       RX Power                   and                           calculated                           once                           per hour       Downstream   Indirect   Note 3   Note 3   60   Polled       SNR                   and                           calculated                           once                           per hour       Upstream   Direct   CER &gt; 5%   CER &gt; 1%   15   MAX       Codeword                   over hour       Error Ratio       Upstream Rx   Indirect   Note 4   Note 4   15   AVG       Power                   over hour       Upstream   Indirect   Note 5   Note 5   15   MIN over       SNR                   hour       Upstream Tx   Indirect   Note 6   Note 6   60   AVG       Power                   over hour                  
 
         [0045]    The aggregation listed is for derived data, not SDMH and DMH, and operations indicated in Table 1 may be performed more often, or less often, than every hour.  
         [0046]    Some of the contributors may have calculations to identify fluctuations over time. Additionally, indicia such as T timers indicating signaling or noise problems impacting connectivity may be used, as well as statistics relating to physical layer problems such as ranging attempts and adjustment timing offsets, etc.  
         [0047]    Note 1:  
         [0048]    If there is any reset of a CMTS within an hour, then SDMH=# of unique modems associated with the CMTS times one hour.  
         [0049]    Note 2:  
         [0050]    The number of modems added to the CMTS interfaces as SDM (severely-degraded modems) or DM (degraded modems) is the number that exceed the threshold. In addition to Min and Max, spectral or trend qualities may be used in conjunction with a higher sample rate.  
                                                                                               64 QAM   256 QAM                SDM   DM   SDM   DM                            −16 dBmV &gt;=   −12 dBmV &gt;=                   RxPwr OR   RxPwr &gt; −16           RxPwr &gt; 20   dBmV           dBmV   OR                20 dBmV &gt;=               RxPwr &gt; 15               dBmV       SNR &lt;= 33.6            −7 dBmV &gt;=    −4 dBmV &gt;=       dB           RxPwr OR   RxPwr &gt; −7                   RxPwr &gt;= 20   dBmV                   dB   Or                       RxPwr &gt; 15                       dBmV       SNR &gt; 33.6 dB           −15 dBmV &gt;   −11 dBmV &gt;                   RxPwr OR   RxPwr =&gt; −15                   RxPwr &gt;= 20   dBmV                   dB   Or                       RxPwr &gt; 15                       dBmV                  
 
         [0051]    Where QAM stands for Quadrature Amplitude Modulation, and dBmV stands for decibel-millivolts.  
         [0052]    Note 3:  
         [0053]    The number of modems added to the interfaces as SDM or DM is the number that exceeds the threshold. Some spectral qualities may be used in conjunction with a higher sample rate.  
                                                                                               64 QAM   256 QAM                SDM   DM   SDM   DM                            SNR &lt;= 24.5   27.7 dB &gt; SNR &gt;=                       24.5       RxPwr &gt; −6           SNR &lt;= 30.5   31 &lt; SNR &lt;       dBmV               33.6       RxPwr &lt;= −6           SNR &lt; 34   SNR &lt; 37 dB       dBmV                  
 
         [0054]    Note 4:  
                                                   Symbol rate                           (ksym/s)   160   320   640   1280   2560                   RxPower   −10 dBmV =&gt;   −10 dBmV =&gt;   −10 dBmV =&gt;   −7 dBmV =&gt;   −4 dBmV =&gt;       SDM   RxPwr   RxPwr   RxPwr   RxPwr   RxPwr       (dBmV)   OR   OR   OR   OR   OR           RxPwr &gt;=   RxPwr &gt;=   RxPwr &gt;=   RxPwr &gt;=   RxPwr &gt;=            14 dBmV    17 dBmV    20 dBmV   23 dBmV   25 dBmV       RxPower    −7 dBmV &gt;    −7 dBmV &gt;    −7 dBmV &gt;   −4 dBmV &gt;   −1 dBmV &gt;       DM (dBmV)   RxPwr &gt;   RxPwr &gt;   RxPwr &gt;   RxPwr &gt;   RxPwr &gt;           −10 dBmV   −10 dBmV   −10 dBmV   −7 dBmV   −4 dBmV           OR   OR   OR   OR   OR            14 dBmV &gt;    17 dBmV &gt;    20 dBmV &gt;   23 dBmV &gt;   25 dBmV &gt;           RxPwr &gt; 11   RxPwr &gt; 14   RxPwr &gt; 17   RxPwr &gt; 20   RxPwr &gt; 22           dBmV   dBmV   dBmV   dBmV   dBmV                  
 
         [0055]    Note 5:  
                                                                                                                                     Protected RS (Reed                   Solomon) symbols           for Max (modulation   Max (modulation for long           for long or short data   or short data grant)                grant)   QPSK       16-QAM                    T =   SDM   DM   SDM   DM                            0   14.5   16   22   23.5           1   13   14   21   22           2   12.5   13.5   20   21           3   12   13   19.5   20.5           4   11.5   12.5   19   20           5   11.5   12   19   20           6   11   12   19   19.5           7   11   11.5   18.5   19.5           8   11   11.5   18.5   19           9   10.5   11.5   18   19           10   10.5   11   18   19                      
 
         [0056]    Where QPSK stands for Quadrature Phase-Shift Keying.  
         [0057]    Note 6:  
         [0058]    Some spectral or trend qualities may be used in conjunction with a higher sample rate. These values could also be parameterized with SNR and/or symbol rate.  
                                                                                 QPSK       16 QAM                    SDM   DM   SDM   DM                       TxPwr &gt; 55   53 dBmV &lt;   TxPwr &gt; 58   56 dBmV &lt;           dBmV   TxPwr &lt; 55   dBmV   TxPwr &lt; 58               dBmV       dBmV                      
 
         [0059]    Traffic  
         [0060]    Table 2 lists direct and indirect contributors applicable to network connectivity.  
                                                                   TABLE 2                           Degraded modem status thresholds.                                Aggregator               Severely       Sample   (poll               Degraded   Degraded   int.   interval       Contributor   Type   Threshold   Threshold   (minutes)   to 1 hour)                    HFC   Direct   Utilization &gt; 71%   Utilization &gt; 59%   15   MAX for       Upstream       AND active   AND active       data,       Traffic       modems &gt;   modems &gt;       SUM for       Capacity       55%*traffic/16e   42%*traffic/16e       time               3   3       HFC   Direct   Utilization &gt; 82%   Utilization &gt; 72%   15   MAX for       Downstream       AND active   AND active       data,       Traffic       modems &gt;   modems &gt;       SUM for       Capacity       82%*traffic/44e   72%*traffic/44e       time               3   3       Processor   Indirect   Utilization &gt; 88%   Utilization &gt; 75%   15   MAX for       Utilization                   data,                           SUM for                           time       Upstream NSI   Indirect   Utilization &gt; 85%   Utilization &gt; 70%    1   MAX for                           data,                           SUM for                           time       Downstream   Indirect   Utilization &gt; 85%   Utilization &gt; 70%    1   MAX for       NSI                   data,                           SUM for                           time                  
 
         [0061]    The aggregation listed is for derived data, not SDMH and DMH, and operations indicated in Table 1 may be performed more often, or less often, than every hour.  
         [0062]    Metric Combining  
         [0063]    Referring again to FIG. 1, the controller  40  is configured to receive metrics from the nodes  34 ,  36 ,  38  and to combine the received metrics by network issue and network topology. The controller  40  aggregates the metrics from the nodes  34 ,  36 ,  38  in accordance with the issues to which each metric relates and in accordance with the topology of the networks  12 ,  14 ,  16 . Data are aggregated by the controller  40  from logically-lower levels relating to the networks  12 ,  14 ,  16  to logically-higher levels, leading to the high-level categories of traffic, connectivity and ultimately summary, incorporating connectivity and traffic. The summary, traffic, and connectivity categories apply to all portions of the networks  12 ,  14 ,  16 , that together form a network  19 , or any portions of the network  19  that are selected by a user  26  of the applications suite  22 . The aggregation by the controller  40  provides the higher-level categories of summary, traffic, and connectivity and contributing issues. The contributing issues (contributors) are grouped into direct contributors and indirect contributors. Direct contributors are considered to be metrics with very high correlation to effect upon one or more of the users of the CPE  29 . An indirect contributor is a metric with correlation to one or more of the CPE users and high correlation with a direct contributor. Calculations performed by the controller  40  can be implemented e.g., using C programming language, Java programming language and/or data base procedures.  
         [0064]    Numerous techniques can be used to combine the metrics from the nodes  34 ,  36 ,  38  to yield aggregated data regarding network performance. How the metrics from the nodes  34 ,  36 ,  38  are combined by the controller  40  depend upon network issues of interest, network topology (including whether a portion of the network  19  has been selected for analysis), and is done in a manner to reflect effects of the issues upon performance of the network  19 . The combined metrics provide categorized information allowing quick analysis of network performance in a convenient, compact format such as a single-screen display of a computer, independent of the number of elements within the network  19 .  
       EXAMPLES OF POSSIBLE COMBINING OPTIONS AND RULES  
       [0065]    The following are examples of different ways in which contributors can be combined. Any of these methods, as well as others, can be used and are within the scope of the invention. Preferably, a weighted average is used where the coefficients are changeable, e.g., in accordance with actual network data. Preferably also, an accurate absolute value of network performance is achieved, while avoiding or reducing double counting of upstream and downstream errors associated with a single cable modem. Preferably also a computationally efficient method is used to combine the network issues. The following background notes describe ideas related to combining logic.  
         [0066]    Background Notes  
         [0067]    Different weightings can be applied to different contributors, e.g., to reflect that some problems are qualitatively worse than others based on their impacts on users of the network  19 . The system  18  provides both relative values and absolute values while also providing a flexible framework to add to or take from or to weight different problems differently as appropriate. The SDMH and DMH metrics indicate relative quality of both the network elements and network problems in a summary fashion of a small set of values for a huge number of devices, while at the same time providing an absolute value of quality.  
         [0068]    Examples of issues that are qualitatively worse than others are CM resets and CMTS resets where it may be desirable to double add modems during the same hour. The system  18  preferably does not (but may) account for this doubling adding, although that is possible. This double counting may be justified in that resets are bad things to have happen to a network, and it is likely that if within an hour period CMTSs reboot and a set of CMs also reboot in an unrelated instance, then they are different bad events. Also, double counting may help simplify metric calculations, including combining calculations.  
         [0069]    If a downstream CMTS interface is degraded for traffic, all associated modems are considered degraded. If not all upstream interfaces in the MAC (Media Access Control) domain are degraded for traffic, however, then an embodiment that divides the number of degraded interfaces by 2 is not absolutely accurate, but may be an acceptable trade-off for calculation efficiency. Similarly, if some upstream interfaces in a MAC domain are degraded, but downstream is not, then dividing by 2 also inaccurately reduces the number of degraded modems, but may be an acceptable trade-off for calculation efficiency. Also, if a downstream on one CMTS is degraded, and an upstream on another CMTS is degraded, these degradations should be added together and not divided by 2, but if the upstream is associated with the downstream on the same MAC interface, then modem errors in both the upstream and downstream direction would be double counted by simply adding. A possible rule is that normalizing may be performed within a MAC domain to not double count within a MAC domain, while not reducing visibility of the amount of degraded modems across multiple CMTS or MAC interfaces when the selection for topology includes multiple CMTS MAC interfaces.  
         [0070]    Issues similar to upstream/downstream traffic surround upstream/downstream codeword errors. Thus, the codeword errors can add in similar fashion as the upstream/downstream traffic errors.  
         [0071]    Also, the metrics of SDM and DM may be calculated more precisely (and possibly exactly) to have a more accurate absolute value by avoiding double counting by tracking each network issue on a per CM basis and weighting each network issue equally.  
         [0072]    Combining Rule Option 1  
         [0073]    In this option, upstream degradation is assumed to be associated with the same modem as for downstream degradation. Using this option, information of SDMH and DMH is available from analysis plug-ins on a per-CMTS-interface basis, and the MAC layer relationship between upstream and downstream CMTS interfaces is known. Also the SDMH and DMH metrics are presented on a per-CMTS-interface basis for determining SDMH and DMH for the complete network topology selected by the user  26 .  
         [0074]    Rule 1:  
         [0075]    Only direct contributors are summed by the controller  40 . SDMH and DMH are not summed and NDMH (Non-degraded modem hours) are determined and stored for use in calculating percentages of degradation levels as a function of the overall network. The choice of percentage versus absolute degraded modem hour numbers may be selected for display in any display (see below) or combining option.  
         [0076]    Rule 2:  
         [0077]    The numbers are combined in the controller  40  each hour, although combining more frequently or less frequently is acceptable. If a time frame is selected by the user  26 , the number of SDMH and DMH are summed for each time stamp, e.g., one hour time stamp, within the time selected. Combined numbers are updated at the hour, or more frequently while being aggregated to the hour. Thus the combining rules assume calculations are being made from a single time stamp and at every time stamp.  
         [0078]    Rule 3:  
         [0079]    The topology selection is used to filter the specific CMTS interfaces with which the controller  40  works. The topology should not, however, be chosen to be a network element below a CMTS interface, such as a CM or CPE (Customer Premises Equipment such as a computer connected to a CM). The topology can also be selected to be the entire network  19  including millions of elements. If the topology selection is chosen to be a CMTS cable interface for a single direction, then values describing network performance will be 0 for contributors associated with the other data direction. For example, if the topology selected is only an upstream CMTS interface and network connectivity is analyzed, sub-issues contributing to higher-level issues that are associated with downstream interfaces and including downstream errors will be 0 as will be the downstream traffic value. Each network issue metric is calculated for each CMTS interface individually and summed across topology, adding the numbers of SDMH or DMH for each CMTS interface as described below. The weightings of the equations provided below can be chosen to emphasize some network issues at a higher priority than other network issues.  
         [0080]    Rule 4: Up Traffic and Down Traffic:  
         [0081]    For the table that lists single interfaces, the SDMH and DMH are shown as detail contributions to the total value for the complete topology selection.  
         [0082]    If the selected topology is greater than a single interface, then sum all CMTS interfaces&#39; DMH and SDMH values regardless of whether they are upstream or downstream or belong to the same MAC domain, and use that as the number for the degraded traffic contributor at the time stamp.  
         [0083]    u1=d1=0.5  
         [0084]    { 
         [0085]    DMH_cable_interface=u1*DMHutilup+d1*DMHutildn  
         [0086]    SDMH_cable_interface=u1*SDMutilup+d1*SDMHutildn  
         [0087]    } 
         [0088]    Where utilup and utildn stand for upstream and downstream utilization, respectively.  
         [0089]    Rule 5: Degraded Connectivity  
         [0090]    For the table that lists single interfaces, the SDMH and DMH are shown as detail contributions to the total value for the complete topology selection.  
         [0091]    If the selected topology is greater than a single interface, then sum all CMTS interfaces&#39; DMH and SDMH values regardless of whether they are upstream or downstream or belong to the same MAC domain, and use that as the number for the degraded connectivity contributor at the time stamp. The weightings of the equations provided below can be chosen to emphasize some network issues at a higher priority than other network issues.  
         [0092]    { 
         [0093]    u1=d1=0.5  
         [0094]    v1=x1=1  
         [0095]    DMH_cable_interface_CER=u1*DMHCERup+d1*DMHCERdown  
         [0096]    SDMH_cable_interface_CER=u1*SDMHCERup+d1*SDMHCERdown  
         [0097]    } 
         [0098]    Where CERup and CERdown stand for upstream and downstream codeword error ratio, respectively, although the actual calculation may be based on a large set of indicators.  
         [0099]    Additionally, sum values together for each cable interface contained in the topology selection including all upstreams and downstreams.  
         [0100]    { 
         [0101]    u1=d1=0.5  
         [0102]    DMH_cable_interface_CMTS_reset= 
         [0103]    v1*DMHcmtsresetsup+x1*DMHcmtsresetsdown  
         [0104]    SDMH_cable_interface_CMTS_reset=v1*SDMHcmtsresetsup+x1*SDMHcmtsresetsdown  
         [0105]    DMH_cable_interface_CM_reset=v1*DMHcmresetsup+x1*DMHcrnresetsdown  
         [0106]    SDMH_cable_interface_CM_reset=v1*SDMHcmresetsup+x1*SDMHcmresetsdown  
         [0107]    Finally  
         [0108]    z1=z2=z3=0.5  
         [0109]    DMH_cable_interface=z1*DMH_cable_interface_CER+z2*DMH_cable_interface_CMTS_reset+z3*DMH_cable_interface_CM_reset  
         [0110]    SDMH_cable_interface=z1*SDMH_cable_interface_CER+z2*SDMH_cable_interface_CMTS_reset+z3*DMH_cable_interface_CM_reset  
         [0111]    This could be thought of as having two additional sub-issues affecting connectivity, one that sums the resets and one that sums the errors.  
         [0112]    } 
         [0113]    Rule 6: Degraded and Severely Degraded Subscriber Modems  
         [0114]    Perform the following calculation: (the SDMH and DMH number for the time stamp for degraded traffic)+(the SDMH and DMH number for the time stamp for degraded connectivity) and divide by 2 for each interface and sum across all interfaces in topology selection.  
         [0115]    This is the number to be used for the degraded and severely degraded subscriber modems contributor for the time stamp.  
         [0116]    Combining Rule Option 2  
         [0117]    Using this option, the number of modems are only divided by 2 if degraded up and downstream interfaces are in the same MAC domain. In this option, upstream degradation is assumed to be associated with the same modem as for downstream degradation. Using this option, information of SDMH and DMH is available from analysis plug-ins on a per-CMTS-interface basis, and the MAC layer relationship between upstream and downstream CMTS interfaces is known. Also the SDMH and DMH metrics are presented on a per-CMTS-interface basis for determining SDMH and DMH for the complete network topology selected by the user  26 .  
         [0118]    Rules 1-3:  
         [0119]    Similar to Rules 1-3 from Option 1. Each network issue metric is calculated for each CMTS MAC interface individually, applied to the individual cable interfaces based on which modems in the MAC domain are associated with which cable interfaces (see portion  88  in FIG. 3 and description below), and summed across topology adding the numbers of SDMH or DMH for each CMTS interface (see portion  86  of FIG. 3 and description below).  
         [0120]    Rule 4: Up Traffic and Down Traffic  
         [0121]    For each MAC domain, that is a set of upstream and downstream interfaces:  
         [0122]    { 
         [0123]    NU=SUM(Total_upstream interfaces in MAC domain)  
         [0124]    u1=u2=u3= . . . uNU=(0.5)  
         [0125]    d1=0.5  
         [0126]    DMH_MAC_DOMAIN=u1*DMHutilupl+u2*DMHutilup2+ . . . +uNU*DMHutilupNU+d1*DMHutildown 1  
         [0127]    SDMH_MAC DOMAIN=u1*SDMHutilup1+u2*SDMHutilup2+ . . . +uNU*SDMHutilupNU+d1*SDMHutil down1  
         [0128]    } 
         [0129]    Sum SDMH and DMH total for each MAC domain in the topology selection and use that as the number for the Degraded Traffic contributor at the time stamp. If a single cable interface is chosen as the topology, then one of the terms for upstream or downstream is 0 and not the actual number associated with the opposite direction in the MAC domain.  
         [0130]    Rule 5: Degraded Connectivity  
         [0131]    For each MAC domain, that is a set of upstream and downstream interfaces:  
         [0132]    { 
         [0133]    NU=SUM(Total_upstream interfaces in MAC domain)  
         [0134]    u1=u2=u3= . . . uNU=(0.5)  
         [0135]    d1=0.5  
         [0136]    DMH_MAC_DOMAIN CER=u1*DMHCERup1+u2*DMHCERup2+ . . . +uNU*DMHCERupNU+d1*DMHCER down1  
         [0137]    SDMH_MAC_DOMAIN_CER=u1*SDMHCERup1+u2*SDMHCERup2+ . . . +uNU*SDMHCERupNU+d1*SDM HCERdown1  
         [0138]    additionally  
         [0139]    u1=u2=u3= . . . uNU=(0.5)  
         [0140]    v1=v2=v3= . . . vNU=(0.5)  
         [0141]    d1=e1=0.5  
         [0142]    DMH_MAC_DOMAIN_CMTS_reset=u1*DMHcmtsresetsup1+u2*DMHcmtsresetsup2+uNU*DMHcmtsresetsupNU+d1*DMHcmtsresetsdown1  
         [0143]    SDMH_MAC_DOMAIN_CMTS_reset=u1*SDMHcmtsresetsup1+u2*SDMHcmtsresetsup2+uNU*SDMHcmtsresetsupNU+d1*SDMHcmtsresetsdown1  
         [0144]    DMH_MAC_DOMAIN_CM_reset=v1*DMHcmresetsup1+v2*DMHcmresetsup2+vNU*DMHcmresetsupNU+e1*DMHcmresetsdown1  
         [0145]    SDMH_MAC_DOMAIN_CM_reset=v1*SDMHcmresetsup1+v2*SDMHcmresetsup2+vNU*SDMHcmresetsupNU+e1*SDMHcmresetsdown1  
         [0146]    Finally  
         [0147]    z1=z2=z3=0.5  
         [0148]    DMH_MAC_DOMAIN=z1*DMH_MAC_DOMAIN_CER+z2* DMH_MAC_DOMAIN_CMTS_reset+z3*DMH_MAC_DOMAIN_CM_reset  
         [0149]    SDMH_MAC DOMAIN=z1*SDMH_MAC_DOMAIN_CER+z2* SDMH_MAC_DOMAIN_CMTS_reset+z3*DMH_MAC_DOMAIN_CM_reset  
         [0150]    This could be thought of as having two additional sub-issues affecting connectivity, one that sums the resets and one that sums the errors.  
         [0151]    } 
         [0152]    Sum SDMH and DMH totals for each MAC domain in the topology selection and use that as the number for the Degraded Connectivity contributor at the time stamp.  
         [0153]    Rule 6: Degraded and Severely Degraded Subscriber Modems  
         [0154]    [SUM (the SDMH and DMH number for the time stamp for degraded Traffic)+(the SDMH and DMH number for the time stamp for degraded Connectivity)] and divide by 2. This is the number to be used for the degraded and severely degraded subscriber modems contributor for the time stamp.  
         [0155]    Combining Rule Option 3  
         [0156]    In this option, all CMTS interface degradations are added, with it assumed that downstream interface typically does not get overutilized due to the asymmetry of traffic, and adding across interfaces occurs without dividing by 2. Using this option, information of SDMH and DMH is available from analysis plug-ins on a per-CMTS-interface basis, and the MAC layer relationship between upstream and downstream CMTS interfaces is known, but not used to affect the counting.  
         [0157]    Rules 1-2:  
         [0158]    Same as Rules 1-2 for Option 2.  
         [0159]    Rule 3:  
         [0160]    Similar to Rule 3 of Option 1, but weightings are 1, resulting in a simple sum.  
         [0161]    Rule 4: Up Traffic and Down Traffic  
         [0162]    Add together upstream and downstream traffic for each cable interface and add across the topology selection for the total number.  
         [0163]    Rule 5: Degraded Connectivity  
         [0164]    Sum of upstream errors and downstream errors based on anticipating that most modems will have primarily upstream errors and when shown as an interface basis the number will not be diluted.  
         [0165]    Sum of CMTS resets and CM resets assuming that these are bad events and this could be weighted heavier even though it is not broken down by upstream and downstream.  
         [0166]    Additionally, sum the total SDMH and DMH for each interface, one number from the resets and one number for the errors, and divide by 2. This could be thought of as having two additional sub-issues affecting connectivity, one that sums the resets and one that sums the errors. This will help prevent some double counting, but may be a summation, e.g., if it appears to be minimizing the number of modems with degraded performance due to few of one issue versus the other.  
         [0167]    Rule 6: Degraded and Severely Degraded Subscriber Modems  
         [0168]    [SUM (the SDMH and DMH number for the time stamp for degraded Traffic)+(the SDMH and DMH number for the time stamp for degraded Connectivity)]. This is the number to be used for the degraded and severely degraded subscriber modems contributor for the time stamp. This is done for each interface. Averaging will help avoid double counting modems.  
         [0169]    Combining Rule Option 4  
         [0170]    This option of combiner adding logic reduces/eliminates double counting of modems, resulting in accurate absolute metrics of degraded modem hours. Using this option, the degraded traffic block, the degraded connectivity block, and the degraded summary block are calculated hourly (or more frequently and aggregated to the hour) for both the cable interface and the MAC interface in the nodes  34 ,  36 ,  38  and distributed from the nodes  34 ,  36 ,  38  to the controller  40 . It requires some more items to be included in a list that has all cable modems per interface that already is cached in memory during the calculation of degradation for each network issue.  
         [0171]    Table 3 lists an example of a set of indicators and some attributes of these based on a possible aggregation rate. These time frames will change based on needs for sampling rate and network quality, but represent a typical example. For example, the NSI interfaces are collected every minute to help avoid counter roll-over.  
                                                                                                         TABLE 3                           Interface, CM, and CMTS contributors            Application   Direct/Indirect   Contributor   Collection                    Per Interface contributors            Traffic   Direct   Up Util   15       Traffic   Direct   Dn util   15       Connectivity   Direct   Up Errors   15       Connectivity   Indirect   Up SNR   15            Per CM contributors rolled up to interface            Connectivity   Indirect   Up RXPwr   15       Connectivity   Indirect   Up TXPWR   60       Connectivity   Direct   Dn Errors   60       Connectivity   Indirect   Dn SNR   60       Connectivity   Indirect   Dn RXPwr   60       Connectivity   Direct   CM Resets   15                   TRAP            Per CMTS contributors rolled down to interface            Traffic   Indirect   CMTS Processor   15       Traffic   Indirect   Out NSI   15       Traffic   Indirect   In NSI   15       Connectivity   Direct   CMTS Resets   60                   TRAP                  
 
         [0172]    Combining into higher-level contributor blocks of Degraded Traffic Status and Degraded Connectivity Status and Degraded Summary only uses direct contributors. Demonstrating only the direct contributors from the example above that are used for these second-level and third-level metric calculations leaves the contributors shown in Table 4. The lists in Table 4 can change as network issues are promoted to direct, or reduced to indirect, or new contributors are added to the combiner.  
                                                                                                                         TABLE 4                           Direct interface, CM, and CMTS contributors                Application   Direct/Indirect   Contributor   Collection                        Per Interface contributors                Traffic   Direct   Up Util   15           Traffic   Direct   Dn util   15           Connectivity   Direct   Up Errors   15            Per CM contributors rolled up to interface                Connectivity   Direct   Dn Errors   60           Connectivity   Direct   CM Resets   15                       TRAP            Per CMTS contributors rolled down to interface                Connectivity   Direct   CMTS Resets   60                       TRAP                      
 
         [0173]    Where collection indicates the number of minutes between data collection, with “trap” indicating asynchronous collection.  
         [0174]    Thus, there are two direct contributors for Degraded Traffic, four direct contributors for Degraded Connectivity, and six direct contributors for Degraded Summary.  
         [0175]    By tracking, for each CM for each interface, a table similar to Table 5 (for the collector) that is cached in memory, the combining mathematics should not (and could even be guaranteed not to) underestimate the number of modem hours and or double count modem hours. Using the logic following Table 5 to build the table and calculate the three higher level contributors for each cable interface, these values could be passed up for each cable interface along with the SDMH, DMH, and NDMH calculated.  
         [0176]    In Table 5, for each column, the fraction of an hour that was used for each per contributor SDMH and DMH calculation is recorded and inserted in the appropriate column as determined by comparison to the respective thresholds. The following rules apply. For each 15-minute sample of a direct contributor including Up Util, Dn Util, Up Errors that is applied to an interface, add 0.25 to each modem on the interface in the column in Table 5 that reflects the degraded modem status as calculated in the status rule. For each of the four 15-minute samples in the hour before distribution, add this 0.25 to the value from the last sample. For CM resets, add 0.25 to each modem that qualifies for severely degraded or degraded status per the status rule based on traps. For the per CM contributor that is currently calculated every 60 minutes for each modem, add 1 to the correct column for each modem. For the CMTS resets, add  1  to each modem on the CMTS for any hour in which the CMTS resets. The summary columns are simple sums of the numbers from the traffic set of columns and the connectivity set of columns. The SDMH Traffic column is added to the SDMH Connectivity column, the DMH column to the DMH column, and the NDMH to the NDMH column. Thus, for each modem, adding across the row in most cases will yield the number of direct contributors, e.g., two for the Degraded Traffic Block, four for the Degraded Connectivity Block, and six for the Degraded Summary Block. The sum across the columns will not add up to the number of direct contributors if data are missed or a modem is added or deleted from the system during the hour.  
                                                                                                                   TABLE 5                                       Traffic   Connectivity   Summary                SDMH_cnt   DMH_cnt   NDMH_cnt   SDMH_cnt   DMH_cnt   NDMH_cnt   SDMH_cnt   DMH_cnt   NDMH_cnt                        009083388F23   0.25   0.5   1.25   0.25   0.5   3.25   0.5   1   4.5       0090833095F7   0.25   0.5   1.25   0.25   0.5   3.25   0.5   1   4.5       009083331EBA   0.25   0.5   1.25   0.25   0.5   3.25   0.5   1   4.5       009083325DE9   0   0.5   1.5   2   1   1   2   1.5   2.5       009083325E3F   0   0.5   1.5   2   1   1   2   1.5   2.5       0090833CA5EB   0   0.75   1.25   2   1   1   2   1.75   2.25       00908330AFF5   0   0.75   1.25   2   1   1   2   1.75   2.25       00908338AF43   0.5   0.75   0.75   2   1   1   2.5   1.75   1.75       0090833CF4AB   0.5   0.75   0.75   2   1   1   2.5   1.75   1.75       0090833261BF   0.5   0.75   0.75   2   1   1   2.5   1.75   1.75       00908330B0EF   0.5   0.75   0.75   2   0.75   1.25   2.5   1.5   2       0090833095B1   0.25   0.75   1   2   0.75   1.25   2.25   1.5   2.25       00908338AC1B   0.25   0.25   1.5   0.25   0.25   3.5   0.5   0.5   5       009083326241   0   0   2   0.5   0.5   3   0.5   0.5   5       00908330659C   0   0   2   0.5   0.5   3   0.5   0.5   5                  
 
         [0177]    The following calculations yield the value for each of the contributor blocks. These calculations use the samples that have been evaluated for degraded modem status and can be performed before distribution of the hourly, or higher resolution, data from the nodes  34 ,  36 ,  38  to the controller  40 .  
         [0178]    For each of the three combined blocks:  
         [0179]    { 
         [0180]    X=number of direct contributors i.e. 2 for traffic, 4 for connectivity, and 6 for summary  
         [0181]    For each MAC interface, perform normalization  
         [0182]    { 
         [0183]    For each modem attached to the interface, adjust the number in each column as follows  
                                                                                                                                                                                               {                If SDMH number = X Then           {                SDMH = X           DMH=0           NDMH=0                Else                SDMH=SDMH           If DMH &gt;= X−SDMH Then           {                DMH = X−SDMH           NDMH = 0                Else                DMH=DMH           If NDMH &gt;= X−(SDMH+DMH) Then           {                NDMH = X−(SDMH+DMH)                Else                NDMH = NDMH                }                }                }                }                      
 
         [0184]    Sum the numbers from the columns for all modems on the interface, divide the sum by X, and multiply by MAX(total modems used for each of the per contributor degraded modem hours calculations&#39; 4 samples or more during the hour). This results in 3 numbers for the interface. This calculation should be done for each cable interface and each MAC interface.  
         [0185]    } 
         [0186]    Apply the three indicators (SDMH, DMH, NDMH) to the Block currently under calculation for the specific cable interface to be displayed in the table view (see FIG. 3 and discussion).  
         [0187]    } 
         [0188]    When summing across topology larger than a single cable interface for combiner structure, sum across all MAC domains contained in the topology.  
         [0189]    Hierarchical Display of Network Performance  
         [0190]    Referring to FIG. 1, the application suite  22  is configured to process data from the controller  40  into a user-friendly format. For example, the application suite  22  can take data that is stored in an accessible format and configuration by the controller  40  and arrange and display the data on a display screen of a computer. An example of such a display  50  is shown in FIG. 3. The data can be accessed independently from the display  50  and can be formatted in displays other than the display  50 . The display  50  provides values of SDMH and DMH associated with various network performance categories. While the entries shown are in SDMH and DMH, the entries can be in number of modems, number of modems that are degraded and the number of modems in the network, or percent of the network that is degraded or severely degraded. Numbers provided in the display  50  are preferably periodically, automatically updated.  
         [0191]    Referring to FIGS. 1 and 3, the display  50  provides a hierarchical table indicating network performance. The hierarchical display  50  includes a top level  52  indicating summary performance of the entire network (or a selected portion thereof as discussed further below), network traffic  54 , and network connectivity  56 . Within the indications of traffic  54  and connectivity  56 , there are indications for values associated with direct and indirect contributors to the network traffic  54  and connectivity  56 . The direct and indirect contributors can be distinguished based upon shading, coloring, and/or other visibly distinguishable characteristics such as symbols as shown. As shown, the traffic  54  and the connectivity  56  are direct contributors to the summary category  52 , up traffic  60  and down traffic  62  are direct contributors to the traffic  54 , while CMTS processor  58 , out NSI (network-side interface) traffic  64 , and in NSI traffic  66  are indirect contributors to the traffic  54 . Further, up errors  68 , down errors  70 , CMTS resets  72 , and CM resets  74  are direct contributors to the connectivity  56 , while up SNR  76 , up receive power  78 , up transmit power  80 , down SNR  82 , and down receive power  84  are indirect contributors to the connectivity  56 .  
         [0192]    While direct contributors are the root cause of performance degradation, indirect contributors are factors that result in the root cause degradation. Direct contributors are included in the combining logic when moving up the combining hierarchy. The combining structure of the controller  40  is configured such that new network issues can be added to the structure as research finds that they predict degraded performance of the applications on the network  19 . Contributors can be removed if the opposite is found. Additionally indirect contributors can be “promoted” to direct contributors if it is determined that they provide direct correlation to degraded performance. Direct contributors can likewise be “demoted.” Such alterations can be made automatically by the system  18  or manually by the user  26 .  
         [0193]    The display  50  provides a convenient, single-screen indication of network performance at various levels of refinement. An upper portion  86  of the display  50  provides information at higher levels of the selected portion of the network  19  and a lower portion  88  provides more refined detail regarding a currently-selected category from the upper portion  86 . Using a drop-down menu  90 , or by selecting a particular block of the display  50 , e.g., any of blocks  52  through  80 , the user  26  can select which category, including the summary  52 , traffic  54 , or connectivity  56  categories, and/or any direct or indirect contributors, from the upper portion  86  of the display  50  about which to provide more detail in the lower portion  88 . As shown in FIG. 3, the summary category  52  is currently selected, with the lower portion  88  showing locations of CMTS interfaces affecting the network performance and the SDMH and DMH associated with each of those CMTS interfaces as they affect the summary  52 , connectivity  56 , and traffic/capacity  54  categories. The CMTS interfaces are sorted according to location with highest SDMH initially, with as many locations as space permits being displayed on the display  50 . The categories of the CMTS interface location  91 , summary  53 , connectivity  57 , and traffic/capacity  55  can be selected by the user  26  to sort in accordance with that category or subcategories of SDMH or DMH within the broader categories. A location  92  can also be selected by the user  26  to reveal more detailed information including performance recommendations, historical graphs of SDMH and DMH, and graphs of the actual network values associated with the selected CMTS interface over time. The user  26  may also select a history icon  94 , and in response the application suite  22  will provide history of the displayed metrics. For example, as shown in FIG. 8, a history screenshot  95  shows numbers of cable modems that are severely degraded and degraded over time for indirect contributors  64 ,  66 ,  76 ,  78 ,  80 ,  82 , and  84 .  
         [0194]    Referring to FIG. 4, the display  50  has changed to reflect more detail regarding traffic/capacity  54  performance of the network in response to the user  26  using the drop-down menu  90  select the trafficchoice or by the user  26  selecting either of the capacity/traffic blocks  54  or  55 . In response to this selection, the traffic region  96  is displayed with a more prominent background than regions  98  and  100  for the summary  52  and connectivity  56  categories, respectively. Also, the lower portion  88  of the display  50 , in response to the traffic selection, shows detail regarding the locations of CMTS interfaces affecting the traffic category  54 ,  55 , as well as showing corresponding SDMH and DMH values associated with the CMTS interfaces for the traffic  54 ,  55 , up utilization  60 ,  61 , and down utilization  62 ,  63  contributors.  
         [0195]    Referring to FIG. 5, the display  50  has changed to reflect more detail regarding connectivity performance  56  of the network in response to the user  26  using the drop-down menu  90  select the connectivity  56  choice or by the user  26  selecting either of the connectivity blocks  56  or  57 . In response to this selection, the connectivity region  100  is displayed with a more prominent background than regions  96  and  98  for the traffic and summary categories, respectively. Also, the lower portion  88  of the display  50 , in response to the connectivity selection, shows detail regarding the locations of CMTS interfaces affecting the connectivity category  56 ,  57 , as well as showing corresponding SDMH and DMH values associated with the CMTS interfaces for the connectivity  56 ,  57 , CMTS resets  74 ,  75 , down errors  70 ,  71  and up errors  68 ,  69  contributors. Referring again to FIGS. 1 and 3, the user  26  may select a portion of the network  19  for display by the application suite  22 , as well as a time period for the display  50 . The application suite  22  is configured to provide the display  50  such that the user  26  can use a drop-down menu  102  to select a portion of the network  19  about which to display information on the display  50 . Likewise, the user  26  can use a drop-down menu  104  to select a time for which the display  50  should reflect information. For the selectable time, the length of time may become coarse the more removed in time the collected data are. For example, data from a month ago may only be able to be displayed by the day while data collected today may be displayed by the hour. To help the user  26  refine the selection for topology to be reflected in the display  50 , the user may select a topology icon  106  in order to be provided with an interface for more flexibly selected desired areas of the topology.  
         [0196]    Referring also to FIG. 6, the application suite  22  is configured to, in response to the user  26  selecting the topology icon  106 , provide a display  110 . The display  110  provides a tree structure  112  that can be expanded by appropriate selections by the user  26  of icons indicating that more detail is available (here, icons with a plus sign in a box). The user  26  can select boxes  114  associated with network elements to indicate a desire to have the topology associated with these boxes  114  displayed. Information for all network elements associated with the selected box  114 , including lower-level elements associated with the selected higher-level element, will be displayed by the application suite  22 . Individual boxes of lower-level network elements can be selected, or deselected as desired. The user  26  can return to the application display  50  by selecting an application icon  116 .  
         [0197]    Referring to FIGS.  1 - 7 , a process  120  for collecting, displaying an analyzing network performance includes the stages shown. The stages shown for the process  120  are exemplary only and not limiting. The process  120  can be altered, e.g., by having stages added, removed, or rearranged.  
         [0198]    At stage  122 , the thresholds for determining whether a modem is degraded or severely degraded are determined. These thresholds are preferably determined in advance to help reduce the processing time used to determine whether a modem is severely degraded or degraded. The calculations for determining the thresholds can be time and processing intensive and based on computer models, empirically controlled experiments, information about network equipment configuration and real-time performance data and historically trending. The thresholdings may be updated based on real-time information about network equipment and performance data.  
         [0199]    At stage  124 , the nodes  34 ,  36 ,  38  collect raw data related to network performance of the network elements in the network  19 . The nodes  34 ,  36 ,  38  use synchronous probing of MIB objects as well as asynchronous information provided from the networks  12 ,  14 ,  16  to gather data regarding performance on the network  19 . Data are gathered for each CMTS interface and CM of the network  19 . Data may also be collected from other network elements using other network protocols such as DHCP, TFTP, HTTP, etc.  
         [0200]    At stage  126 , the real-time and near-real-time raw data collected are manipulated into performance metrics describing network performance. These metrics of network performance are compared at stage  128  to the thresholds, determined at stage  122 , to determine degraded modem hours and severely degraded modem hours metrics. The SDMH and DMH metrics are derived by aggregating, as appropriate, over time the comparisons of the network performance metrics to the thresholds according to the frequencies of sampling of the raw data from the network  19 . The SDMH and DMH metrics are associated with corresponding CMTS interfaces of the network  19 . The SDMH and DMH metrics are provided to the controller  40  for aggregation.  
         [0201]    At stage  130 , the controller  40  combines the SDMH and DMH metrics in accordance with topology selected by the user  26  and by issue affecting network performance. The controller  40  combines the SDMH and DMH metrics in accordance with combining rules associated with a corresponding combining option, such as, but not limited to, the rules discussed above. The combining option used may be predetermined or may be selected by the user  26 . The combined SDMH and DMH metric information, as well as more detailed DMH and SDMH data are available for display by the application suite  22 .  
         [0202]    At stage  132 , the application suite  22  hierarchically displays the SDMH and DMH values by issue in accordance with selected time and topology. In accordance with selections made by the user  26  for a time over which network performance data is desired, and for desired portions of the network  19 , or the entire network  19 , the application suite  20  obtains, massages, and displays appropriate information to the user  26 . The displayed information is in terms of SDMH and DMH values, that incorporate SDMH and DMH data at logically-lower levels of the network.  
         [0203]    At stage  134 , the application suite  22  alters the display  50  in response to input by the user  26 . In response to the user  26  selecting different options on the display  50 , more detail regarding levels of the hierarchical display  50  are provided. The user may select portions of the display  50  to narrow in on problems associated with network performance to thereby determine areas of greatest network problems and possibly options for addressing those problems. As the user  26  selects portions of the display  50  to provide more detail regarding the selected portions, the application suite  22  “bubbles up” more detail regarding the selected information. The user  26  may use this “bubbled up” information to refine the user&#39;s understanding of the network performance, and in particular areas, and causes, of network problems. The application suite  22  may also automatically, using the detail provided by the system  18 , determine areas of concern regarding the network  19  and provide suggestions for correcting or improving network performance. The user  26  may also select the performance metrics to be changed to number of modems, number of degraded and total network modems (at least of the selected topology), or percent of the network (at least of the selected topology) that is degraded.  
         [0204]    Other embodiments are within the scope and spirit of the appended claims. For example, due to the nature of software, functions described above can be implemented using software, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including other than as shown, and including being distributed such that portions of functions are implemented at different physical locations. For example, functions performed by the controller  40  for combining metrics may be performed by the nodes  34 ,  36 ,  38 . In this case, the nodes  34 ,  36 ,  38  may communicate with each other to assist in combining metrics. Parameters shown as individual values in the display  50  may not be individual values. For example, parameters could be ranges of individual values over time (e.g., SNR=12-20 over prior hour). Also, while the discussion focused on modem problems (e.g., SDMH and DMH), problems with other CPE may also be determined and included in displayed metrics, or displayed separately.  
         [0205]    The invention is particularly useful with DOCSIS networks. The DOCSIS 1.1 specifications SP-BPI+, SP-CMCI, SP-OSSIv1.1, SP-RFIv1.1, BPI ATP, CMCI ATP, OSS ATP, RFI ATP, and SP-PICS, and DOCSIS 1.0 specifications SP-BPI, SP-CMTRI, SP-CMCI, SP-CMTS-NSI, SP-OSSI, SP-OSSI-RF, SP-OSSI-TR, SP-OSSI-BPI, SP-RFI, TP-ATP, and SP-PICS are incorporated here by reference. The invention, as embodied in the claims, however, is not limited to these specifications, it being contemplated that the invention embodied in the claims is useful for/with, and the claims cover, other networks/standards such as DOCSIS 2.0, due to be released in December, 2001.  
         [0206]    Additionally, the system  18 , e.g., the data analyzer  44 , may automatically determine network areas of concern and implement actions, e.g., configuring the network  19  through the data collector controller  40 , to correct or improve network performance problems without user input, or with reduced user input compared to that described above, for correcting or mitigating network problems. Based on the SDMH and DMH metric performance, judgments of the network performance are made. Network configuration such as modulation type, Forward Error Correction (FEC) level, codeword size, and/or symbol rate are known. Based on the performance metrics and configuration information, a more optimal solution can be instantiated through the controller  46  into the CMTS through SNMP or the command line interface (cli). This more optimal solution is based on data analysis and real-time calculations along with parameterized CMTS configurations that provide maximum bandwidth efficiency in bits per second per Hz while maintaining packet errors below a level that would hinder (e.g., cause sub-optimal) application performance. As performance, indicated by the metrics, improves or degrades due to the new configuration, changing network properties, and/or changes in traffic capacity, the CMTS will be configured to maintain improved (e.g., optimized) performance.