Patent Application
20080198754
The present disclosure is generally related to testing communications networks.
Broadband service providers have gradually transformed from pure data service providers to Internet Protocol (IP)-based content providers (e.g. data, voice and video service providers). Providing IP-based video delivery services has attracted interest because of its inherent flexibility in providing both a large number of channels and advanced features.
However, video delivery via an IP network poses challenges to service providers. Video services have higher quality-of-service (QoS) requirements than data and voice services. For example, video services can tolerate less packet loss, smaller end-to-end jitter and latencies than data and voice services. Guaranteeing the end-to-end QoS desired for providing video services in an IP network is more difficult than for providing the video services via either a circuit-switch based network, an asynchronous transfer mode (ATM) network, or a cable television (CATV) network. Potential causes of video service degradation include network congestion, routing disruption, misconfiguration, and video digital subscriber line (VDSL) loop performance degradation.
Disclosed herein are embodiments of methods and systems for a video service provider to perform video impairment root-cause analyses and trouble isolation. The embodiments include a method to select an appropriate probe type and location for IP-based probe placement, a self-learning method to optimize IP-based probes, and a systematic method to perform trouble isolation and correlation. The embodiments can be used by Internet Protocol (IP)-based video service providers, such as IP-television (IPTV) providers, to efficiently deploy, utilize and correlate a network-based probing mechanism to quickly locate and identify network segments having an undesired performance. The embodiments can reduce a cost to operate an IP-based video service, and can improve video subscribers' quality of experience.
Degradation of video delivery path performance may cause an impairment of video service quality. For example, packet loss can cause any combination of: unavailable video frames to display, video service glitches and/or pixilation. Further for example, large latency and jitter values can cause video decoder buffer overflow or underflow, which in turn can cause time synchronization issues or other issues. Video service quality impairments may be caused by encoder network issues, long distance link failures, routing disruptions, traffic congestions, router/switch mis-configurations, impairment of a very-high-data-rate digital subscriber line (VDSL) network and/or a home network, overloading issues with routers or residential gateways, set-top box (STB) operation issues, or any combination thereof.
A computer 24 cooperates with the IP-based probes 22 to detect network impairments in the IP network 20, isolate troubles in the IP network 20, and act to mitigate the impairments in the IP network 20. In an embodiment, the computer 24 is programmed to: (a) infer IP-layer performance and correlate the performance with video/voice delivery performance, (b) isolate a network segment with a detected impairment, and (c) estimate an overall video/voice delivery performance. Detecting network impairments, performing trouble isolation, and quickly mitigating the impairments is of particular interest when the video delivery network, such as the IP network 20, comprises many network elements (e.g. thousands or tens of thousands of network elements).
The probes 30, 32, 34, 36 and 38 are used to perform various probing tests. The probing tests may include IP-based multicast tests and/or unicast tests. Examples of the unicast tests include, but are not limited to, user datagram protocol (UDP) tests and packet internet groper (PING) tests. The IP-based multicast tests, which provide a lightweight approach to measure most IP network segment performance, are used to monitor the linear programming delivery performance of the IP network 20. If IP-based video delivery is on top of IP-based multicast, the multicast-based probe test can be set up with a similar QoS level to best monitor linear programming video delivery performance. The unicast tests (e.g. UDP and/or PING tests) can be set up at selected locations and segments at selected times to confirm results of the multicast tests and to perform trouble isolation and segmentation.
For example, consider a scenario in which both of the probes 36 and 38 receive multicast traffic based on probing traffic originated from the VHO 42, but the probe 38 captures significant packet loss while the probe 36 does not capture significant packet loss. In the aforementioned scenario, a conclusion can be drawn that a home network segment between the RG 46 and the home networking adaptor 48 is contributing to the packet loss. To further confirm the aforementioned conclusion, two-way UDP-based tests can be performed between the probes 36 and 38 to monitor the home network performance. If the two-way UDP-based tests detect a packet loss between the RG 46 and the home networking adaptor 48, an impairment of the home network segment is inferred.
As indicated by block 60, the method comprises performing a multicast test with an initial multicast packet probing frequency. The initial multicast packet probing frequency is a relatively low value. As indicated by block 62, the method comprises gradually increasing the multicast probing frequency of the multicast test.
As indicated by block 64, the method comprises detecting a potential network impairment based on the multicast test. Based on detecting the potential network impairment, the method comprises decreasing the multicast probing frequency (as indicated by block 66) and performing one or more unicast-based tests at one or more network segments whose impairment may be causing the potential network impairment (as indicated by block 70). Regarding block 66, the multicast probing frequency may be decreased back to the initial multicast packet probing frequency. Regarding block 70, the one or more unicast-based tests may comprise UDP and/or PING tests performed between various network elements. For example, a unicast-based test may be performed between the home networking adaptor 48 and the RG 46, or between the RG 46 and the CO 44, or between the CO 44 and the VHO 42. The one or more segments selected for performing the unicast tests may be based on historical network data, such from a historical trouble tickets and solutions database. The one or more unicast-based tests are performed at an initial unicast probing frequency. As indicated by block 72, the method comprises gradually increasing the unicast probing frequency.
As indicated by block 74, the method comprises identifying which one or more segments in the IP network 20 are impaired based on the one or more unicast-based tests. As indicated by block 76, the method comprises stopping the one or more unicast-based tests after either an impaired segment is identified or enough information is gathered to identify the impaired segment. As indicated by block 80, the method comprises identifying a root cause of the impairment. The root cause can be identified by correlating historical network events and/or physical events to the information gathered from the multicast and/or unicast tests. As indicated by block 82, the method comprises storing the root cause as root cause data in a database such as a database of historical trouble tickets and solutions.
Flow of the method is directed back to block 60 to repeat the aforementioned acts to detect subsequent network impairments. The previously-stored root cause data can be used to identify a subsequent root cause of a subsequently-detected impairment of the IP network 20.
The computer 24 in
As indicated by block 130, the method comprises receiving a video service trouble ticket or an alternative report of an end user (e.g. a subscriber) of a video service reporting an issue with the video service. The video service trouble ticket is generated in response to a subscriber reporting that video service and/or the IP network 20 is impaired. After the video service trouble ticket is received (or after a service impairment is otherwise reported), a database 132 of historical trouble tickets and solutions is accessed to check whether similar issues were previously reported. Based on statistical estimation, common root causes are analyzed and examined to determine whether any issue needs to be resolved based on previous knowledge.
The statistical estimation may be based on both a space dimension and a time dimension. For the space dimension, the statistical estimation is performed for multiple subscribers (e.g. including subscribers other than the reporting subscriber, such as across all subscribers) and also for a single subscriber (e.g. the reporting subscriber). For the time dimension, the statistical estimation is performed across different time intervals such as daytime/nighttime, and recent/old events. By correlating the historical data, e.g. correlating trouble tickets reported for similar times by different subscribers, troubles in the IP network 20 can be isolated and particular network segment(s) which are the root cause can be determined. Examples of root causes for the event indicated by the trouble ticket include, but are not limited to, impairments of an encoder network, the SHO, the VHO, the IO, the VDSL loop, the home network, or the STB. An embodiment of a process to gradually segment potential problems and perform a root cause analysis is as follows.
As indicated by block 134, the method comprises determining if any similar trouble ticket was previously reported by any subscriber. If yes, the database 132 is accessed to determine what was the root cause and solution for the previous trouble ticket. The IP network 20 is examined to determine if the root cause for the previous trouble ticket is also the root cause for the current trouble ticket.
As indicated by block 136, the method comprises determining if any similar trouble ticket was previously reported by the reporting subscriber. If yes, the database 132 is accessed to determine what was the root cause and solution for the previous trouble ticket. The IP network 20 is examined to determine if the root cause for the previous trouble ticket is also the root cause for the current trouble ticket.
As indicated by block 140, the method comprises determining if the same issue was reported by several subscribers from different VHOs. The same issue is deemed to be reported by several subscribers from different VHOs if the number of subscribers from different VHOs who reported the same issue is greater than or equal to a first threshold. If yes, the method comprises testing or otherwise checking a performance of an IP path between an encoder and an outgoing interface of the SHO.
As indicated by block 142, the method comprises determining if the same issue was reported by several subscribers from the same VHO as the reporting subscriber. The same issue is deemed to be reported by several subscribers from the same VHO if the number of subscribers from the same VHO who reported the same issue is greater than or equal to a second threshold. If yes, the method comprises testing or otherwise checking a performance of an IP path between the SHO and the VHO, and an internal performance of the VHO.
As indicated by block 144, the method comprises determining if the same issue was reported by several subscribers from the same IO as the reporting subscriber. The same issue is deemed to be reported by several subscribers from the same IO if the number of subscribers from the same IO who reported the same issue is greater than or equal to a third threshold. If yes, method comprises testing or otherwise checking the current and historical IP path performance between the VHO and the IO, and the IO router configuration. A database 146 stores the historical IP path performance between the VHO and the IO and other historical performance information. The current and historical performances can be compared to determine if the path between the VHO and the IO is impaired.
As indicated by block 150, the method comprises determining if the same issue was reported by several subscribers from the same digital subscriber line access multiplexer (DSLAM) as the reporting subscriber. The same issue is deemed to be reported by several subscribers from the same DSLAM if the number of subscribers from the same DSLAM who reported the same issue is greater than or equal to a fourth threshold. If yes, the method comprises testing or otherwise checking current and historical IP path performance between the IO and the DSLAM, the IO router, the CO switch, and the DSLAM configuration. The database 146 stores the historical IP path performance between the IO and the DSLAM and other historical performance information. The current and historical performances can be compared to determine if the path between the IO and the DSLAM is impaired.
As indicated by block 152, the method comprises determining if the issue is reported only by one subscriber, namely the presently-reporting subscriber. If yes, the method comprises testing or otherwise checking current and historical performance of the VDSL loop, the RG, the home network, and the performance and setup of the STB. The database 146 stores the historical performance of the VDSL loop and other historical performance information. The current and historical performances can be compared to determine if the VDSL loop is impaired.
For any of the above acts, various troubleshooting methods can be used to verify a problem. Examples of the troubleshooting methods include, but are not limited to, testing using IP-based probes, checking VDSL/home network noise, checking open shortest path first (OSPF) or border gateway protocol (BGP) configuration, and verifying an IGMP routing configuration.
If an issue is identified based on any of the above acts, the method comprises updating the database 132 of historical trouble tickets and solutions to include the new findings. The new findings, including a root cause, can be used to better identify root causes of subsequently-reported video service issues. As more instances and cases are added to the database 132, the ability to troubleshoot subsequent problems improves.
Any of the above testing acts may comprise automated testing, manual testing, or a combination of automated and manual testing. Any of the above testing acts may be triggered or otherwise initiated by a computer, such as the computer 24. The computer may trigger or otherwise initiate the automated testing and/or manual testing upon determining that an associated condition is met.
Referring to
In a networked deployment, the computer system may operate in the capacity of a server or as a client user computer in a server-client user network environment, or as a peer computer system in a peer-to-peer (or distributed) network environment. The computer system 500 can also be implemented as or incorporated into various devices, such as a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile device, a palmtop computer, a laptop computer, a desktop computer, a communications device, a wireless telephone, a land-line telephone, a control system, a camera, a scanner, a facsimile machine, a printer, a pager, a personal trusted device, a web appliance, a network router, switch or bridge, or any other machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. In a particular embodiment, the computer system 500 can be implemented using electronic devices that provide voice, video or data communication. Further, while a single computer system 500 is illustrated, the term “system” shall also be taken to include any collection of systems or sub-systems that individually or jointly execute a set, or multiple sets, of instructions to perform one or more computer functions.
As illustrated in
In a particular embodiment, as depicted in
In an alternative embodiment, dedicated hardware implementations, such as application specific integrated circuits, programmable logic arrays and other hardware devices, can be constructed to implement one or more of the methods described herein. Applications that may include the apparatus and systems of various embodiments can broadly include a variety of electronic and computer systems. One or more embodiments described herein may implement functions using two or more specific interconnected hardware modules or devices with related control and data signals that can be communicated between and through the modules, or as portions of an application-specific integrated circuit. Accordingly, the present system encompasses software, firmware, and hardware implementations.
In accordance with various embodiments of the present disclosure, the methods described herein may be implemented by software programs executable by a computer system. Further, in an exemplary, non-limited embodiment, implementations can include distributed processing, component/object distributed processing, and parallel processing. Alternatively, virtual computer system processing can be constructed to implement one or more of the methods or functionality as described herein.
The present disclosure contemplates a computer-readable medium that includes instructions 524 or receives and executes instructions 524 responsive to a propagated signal, so that a device connected to a network 526 can communicate voice, video or data over the network 526. Further, the instructions 524 may be transmitted or received over the network 526 via the network interface device 520.
While the computer-readable medium is shown to be a single medium, the term “computer-readable medium” includes a single medium or multiple media, such as a centralized or distributed database, and/or associated caches and servers that store one or more sets of instructions. The term “computer-readable medium” shall also include any medium that is capable of storing, encoding or carrying a set of instructions for execution by a processor or that cause a computer system to perform any one or more of the methods or operations disclosed herein.
In a particular non-limiting, exemplary embodiment, the computer-readable medium can include a solid-state memory such as a memory card or other package that houses one or more non-volatile read-only memories. Further, the computer-readable medium can be a random access memory or other volatile re-writable memory. Additionally, the computer-readable medium can include a magneto-optical or optical medium, such as a disk or tapes or other storage device to capture carrier wave signals such as a signal communicated over a transmission medium. A digital file attachment to an e-mail or other self-contained information archive or set of archives may be considered a distribution medium that is equivalent to a tangible storage medium. Accordingly, the disclosure is considered to include any one or more of a computer-readable medium or a distribution medium and other equivalents and successor media, in which data or instructions may be stored.
Although the present specification describes components and functions that may be implemented in particular embodiments with reference to particular standards and protocols, the invention is not limited to such standards and protocols. For example, standards for Internet and other packet switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) represent examples of the state of the art. Such standards are periodically superseded by faster or more efficient equivalents having essentially the same functions. Accordingly, replacement standards and protocols having the same or similar functions as those disclosed herein are considered equivalents thereof.
The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.
One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description.
The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter.
The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
