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Developing a Holistic Testing Strategy for Ensuring a Successful IPTV Deployment

ContentsAbstract 2

Introduction 2

Current IPTV Market Drivers and Industry Trends 4

Overview of Key IPTV Technologies and Network Infrastructure 6

Transport Network Components 7

IPTV Service Offerings 10

Current IPTV Deployment Challenges 11

Developing a Comprehensive IPTV Testing Strategy 13

Testing the Video Transport Network 16

Testing the Access/Aggregation Network 16

Testing the Customer Premises 17

Testing Other Network Components 18

Testing the End-to-End Service Delivery Network 19

Conclusion 19

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DEVElOPINg A HOlISTIC TESTINg STRATEgy fOR ENSuRINg A SuCCESSful IPTV DEPlOyMENT

AbstrACt

Internet Protocol television, or IPTV, is a term that represents the next generation of digital, IP-based video services being developed by telecommunications service providers. IPTV, including multicast (broadcast) video and unicast (video-on-demand) services, are part of the triple-play bundle of voice, video and broadband data services that are being deployed on a converged, IP-based network infrastructure.

To date, there have been several successful IPTV deployments in various parts of the world. However, one of the key areas that service providers agree requires a more formalized approach is in pre-deployment testing of IPTV and other associated triple play services. Considering that there are many new technologies associated with IPTV deployment, the technical challenge is to integrate several new technologies so that they work well together.

New technologies inherently complicate the overall solution and present unique challenges that must be systematically identified, characterized and resolved – preferably in controlled lab environments. If IPTV service is not executed well, service providers run the serious risk of a failed launch or poor adoption by consumers in the marketplace.

A comprehensive IPTV testing strategy must include not only network-level quality of service, but quality of service from the perspective of application-level delivery. Succeeding in providing consumers the best viewing experience is the ultimate goal in ensuring a successful IPTV deployment.

This paper offers a systematic approach to testing an IPTV transport infrastructure in its early and pre-deployment stages. This paper also highlights several of these challenges, where they occur, how to identify them, and how an overall pre-deployment testing strategy can translate into a successful in-service deployment.

IntroduCtIon

Today’s telecommunications service providers and cable MSOs are currently in a heated race to deploy next-generation networks that are capable of delivering multiple, converged services — including broadband Internet access, voice and video over IP, or Internet Protocol. Particularly for the telcos, this so-called “triple-play” network build out represents a new business paradigm and a new operational strategy that service providers are embracing in order for them to stay relevant in today’s highly competitive marketplace. Indeed, as telcos witness their core telephone revenues decline year after year, they must develop and offer new services to offset these losses, or face eventual extinction.




Central to the telcos’ strategy of service expansion is the addition of digital, IP-based video services to their voice and data (DSl) offerings. This IP-based video offer, and the systems behind it, has come to be known as IPTV.According to Wikipedia, IPTV is defined as follows:

“IPTV (Internet Protocol Television) describes a system where a digital television service is deliv-ered using the Internet Protocol over a network infrastructure, which may include delivery by a broadband connection. for residential users, IPTV is often provided in conjunction with Video on Demand and may be bundled with Internet services such as Web access and VoIP. The com-mercial bundling of IPTV, VoIP and Internet access is referred to as a Triple Play. IPTV is typically supplied by a broadband operator using a closed network infrastructure. This closed network approach is in competition with the delivery of TV content over the public Internet.”

To a layman subscriber however, IPTV service today may simply appear to be an electronic-program-guide (EPg) on their television similar to a rich-media website with a well-designed and user friendly navigation. An EPg allows viewers to browse through broadcast television (BTV) lists and video-on-demand (VoD) content, allowing them to order live events such as concerts, pre-recorded events, or new content such as independent films or new DVD releases.

And while this level of interactive content and service capability has been available from satellite TV operators and cable MSOs for several years now, what makes IPTV different is that it is delivered over an efficient IP network that ultimately has the potential to offer an array of new and exciting services at very competitive price-points.

In a number of markets around the world, especially in parts of Europe and Asia, new IPTV service has enjoyed great success with many thousands of early adopters who want to engage more interactively with their televisions. Even though these initial rollouts of IPTV services have been generally successful, there have been some mixed feelings about how well some IPTV services compare to what has traditionally been available.

for example, in some cases IPTV rollouts have suffered from a variety of deployment woes, including poor video quality, slow channel changes, service outages and complexity of design. What’s more, these deployment issues have been compounded by slow adoption rates, as customers are generally unwilling to be guinea pigs for a service provider’s new services offering. Additionally, consumers have proven to be very price sensitive, and some providers have fallen short on the promise of competitive pricing and/or fail to truly offer any differentiating services.

But regardless of the current rate of adoption, IPTV technology promises to change the way customers engage with technology in their homes. for telcos, IPTV is one of the first steps to creating a highly engaging home experience where several technologies, services and applications work together in a complete entertainment ecosystem. To achieve this milestone, there are currently several key


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challenges that IPTV deployments face. These challenges encompass a broad array of business dynamics and numerous technological hurdles as IPTV technology itself matures. Such technological problems must be tackled early in the deployment phases, and only then can an IPTV deployment offer a truly differentiating service and be successful in the marketplace.

Current IPtV MArket drIVers And Industry trends

The primary reason for a telco to invest in an IPTV deployment is something that was alluded to in the IPTV definition above: namely, the ability to offer converged network services. from an operators’ point of view, a next-generation IP-based network will offer the most cost-effective and future-proof platform for delivering robust carrier-grade multi-services to their customers. It will also provide significant competitive and technical advantages when compared to building and maintaining parallel and overlay networks to provide multiple services to their customers. The ability to offer voice, data, and video services will ultimately help operators win more market share – but only if they execute well. New telco service offers will initially include triple-play services, with new and premium services brought to market incrementally. Consumers who sign up for these services will enjoy the benefits of getting better programming choices and services at extremely competitive price points. This in turn will increase spending by individual customers thereby increasing the operator’s ARPu (Annual Revenue Per user).

Without a doubt, this is big business. According to a report from Strategy Analytics, over the next five years IPTV subscribers will grow to a staggering 80 million worldwide from just under 6 million IPTV households today. Additionally, the number of households worldwide that pay directly for IPTV service will rise from 3.3 million in late 2006 to 40.9 million in 2011. And according to a study by Infonetics Research, sales of IPTV equipment are expected to skyrocket from $371 million in 200� to $6.8 billion in 2009.

To be sure, telecom operators are deeply committed to this business with an eye to offsetting the video stronghold that cable MSOs and satellite operators have enjoyed for several decades. According to another study by Infonetics, participating service providers spent 40 percent of their capital expenditures (capex) on triple play network equipment in 200� driven by increased broadband revenue per user and new revenue streams. What’s more, these service providers expect up to 48 percent of their revenue to come from triple play services in 2007. The majority of them plan to further increase their capex spending in the next year on IPTV equipment, broadband CPE, broadband aggregation equipment and voice over broadband equipment. VoIP is certainly a big draw, but IPTV is where all the action is.

Consumers are looking for content that resonates with their lifestyle, and operators who deliver such




services will benefit from this venture. Internet video portals like youTube.com have trained today’s Web surfers to expect massive amounts of video-on-demand from their computer screens, and a recent report from Accenture finds that this expectation is shifting to the TV set. Indeed, Isuppli estimates that the worldwide market for video-on-demand services will exceed $13 billion by 2010. Consumers are also looking to consolidate their services currently offered from multiple providers. In effect, bundling multiple services dramatically improves an operators’ competitive advantage. According to a recent study, it was shown that operators offering multiple services generally increase customers’ loyalty and dramatically reduce turnover, or churn. This is something that all telecom operators realize that they can monetize.

yet another study from RBC Capital Markets claims that about 48 percent of Americans who own or want to own a flat screen television would also be interested in buying cable TV from their telecom company. The pollsters informed the respondents that IPTV would allow them to get television, VOD and broadband access all through one telecom provider. Respondents qualified their interest in such a service by giving the top three reasons they would switch to IPTV: cheaper price than existing service, ability to watch what they want when they want, and the ability to watch content more specific to their interests.

Another market trend driving the shift to IPTV is the widespread adoption of broadband access. This broadband growth has provided a pleasant added benefit: customers are much more familiar with what the Internet is and how to best use it. This in effect will allow consumers to easily accept new interactive services into their television viewing experience as well.

This behavior is a powerful precursor to the choices that customers now expect from in-home entertainment services. They are experiencing better television by interacting with it. The proliferation of PVR time-shifting allows consumers to watch more content whenever they desire, and they feel empowered because they have complete control over their viewing experience. Offering rich and interactive services promotes customer loyalty and ultimately a more long-term and stable business for operators.

Another growing trend in the IPTV industry is recognition that unlike the public Internet, where content is “free,” the model of IPTV deployment is that of a closed system – sometimes referred to as a “walled garden.” The advantage of a closed system is that operators can offer premium content and services that differentiates them from others. for example, the “long tail effect” notes that products that are generally low in demand or that experience a low sales volume can accumulatively outweigh and outpace the small high volume bestsellers in the long term. A perfect example of this is the success of online DVD sales/rentals. Operators acknowledge this new shift and they are engaging with various independent content providers to deliver exclusive content to capitalize on this potentially lucrative business. Take note – this is a stark differentiator between IPTV and Internet TV: the distribution of IPTV is in




a closed system and hence it competes directly with “free” TV content delivered over the public Internet.

In addition to long tail and premium content, new market opportunities include services beyond the video content realm. Consider gaming-on-demand. It will allow operators to leverage their VoD and IPTV infrastructure and bring interactive gaming services to their customers.

Or consider targeted marketing as it presents itself on the Internet. google, yahoo, and AOl come to mind. Content aggregators and channel broadcasters desire this targeted advertising capability in traditional television as well. geo-sensitive and targeted ad-insertion techniques will enable new marketing strategies and product marketing campaigns. This will ultimately drive brand awareness and traffic to websites where transactions can be made, all in the comfort of an IPTV subscriber’s home.

The IPTV value proposition for telco operators is strong and clear: being able to offer such interactive services will increase their bottom-line and provide a long-term strategy for staying competitive in the market.

However, it should be evident that to make an IPTV deployment truly successful requires a deep appreciation of the business dynamics and the many technologies that must be integrated together to make a truly seamless platform hum. As with any advancement in technology, there are considerable challenges associated with an IPTV deployment. Perhaps the most important challenge a telco must undertake is to prevent rather than cure: in essence, to continually measure success in the IPTV pre-deployment stages by adopting comprehensive test and verification procedures. Such testing and service assurance measures will help ensure that a telco’s network and service infrastructure is ready to deliver the most rewarding and highest quality of experience for their customers.

After all, happy customers are loyal customers.

oVerVIew of key IPtV teChnologIes And network InfrAstruCture

In this section, we will review the various technologies and specific network infrastructure that make up a typical IPTV deployment.

The diagram below presents a high-level view of an end-to-end IPTV transport network topology. As is evident in the diagram, as one follows the media flow from the service provider to the subscriber, through the Content Distribution/Digital Head-End, Multicast Transport Network, Access Network, and finally to the Customer Premises – all network infrastructure elements are interconnected. this is an extremely important concept as we examine the need for a comprehensive




testing methodology that not only looks at single network elements but also examines how all network elements interrelate and interwork with each other.

figure 1: Typical IPTV Transport Network Architecture

trAnsPort network CoMPonents

super Video head-end office (sVho)

The SVHO’s job is to take the various video content from many terrestrial sources and process it for delivery on the IP network. This process includes conversion of digital video and analog content into IP packets, and encoder systems that format the various feeds into MPEg2/4/AVC encoded formats, suitable for delivery into the network.

The digital head-end includes video pumps for broadcast TV (BTV) content and VoD servers for on-demand content. It contains large SANs (Storage Area Networks) for content storage and retrieval. Inherent to this platform are several technologies that enable end-to-end communication, and includes




digital rights management (DRM) to secure content that is stored electronically and conditional-access encryption (CA) to secure content while it’s in transmission. In addition, to allow consumers to interact with the content on their TV sets, sophisticated middleware is required to facilitate communication between IP set-top boxes to the Video Head End. Middleware systems provide this glue logic.

Video transport network

The transport network includes national and regional transport networks. This includes optical networks that offer high error-resiliency, high-redundancy and reliability. The transport network provides high-bandwidth connectivity between the SVHO and the access networks.

Access/broadband network

The access/broadband network includes multi-purpose devices that are geographically distributed in areas of an operators’ footprint. The access/broadband network often replicates video content that is accessed more frequently, such as prime-time channels or a lineup of channels that are always delivered in all service packages. Some of the devices here include multi-service access nodes (MSANs), Metro transport switches, DSlAMs (Digital Subscriber line Access Multiplexers), BRAS (Broadband Remote Access Server) devices, and PON/OlT (Passive Optical Network/Optical line Termination) devices.

loop/subscriber network

The subscriber network includes physical layer technologies such as fTTH (fiber To The Home) where optical fiber is run directly into the customer premises, fTTN (fiber To The Node) where the fiber plant build-out is to a neighborhood node with copper plant used to extend the network into the home. An fTTH deployment requires an ONT (Optical Network Terminal) device to convert optical into the native interface (such as twisted pair copper wire). for telecom operators, various DSl technologies are used to provide high-speed network access into the home. Customer premises network devices include residential gateways (Rgs) for service separation of data, voice, video and IP Set Top Boxes (STBs) for accessing the content on a TV.

IPtV-related Media Codecs and bandwidth Considerations

The choice of media codecs used in an IPTV deployment has a direct impact on the quality of the video content that is delivered to the customer.

Current satellite and cable television services employ the MPEg-2 codec as the standard codec for encoding, compressing and delivering television content. New IPTV services also use MPEg-2 codecs, primarily because these service providers have experience with it. With MPEg-2, each standard-definition video stream (a typical channel on regular cable service) consumes about 4Mbits/second of bandwidth.




The problem the industry faces is that this approach is simply not sustainable for the next phase of IPTV. first consider that delivering high-definition content with MPEg-2 consumes about 10-20Mbits/second of bandwidth per video stream. Statistically, every home has about 2-3 set-top boxes today, including one with a high definition (HD) channel. And the number of STBs and HD channels per household is expected to grow. In addition, the current DSl services in place provide 2�Mbps of bandwidth -- at best. Based on these statistics, it’s easy to see that the bandwidth required in the near term will easily outpace what is possible today with the current broadband offering.

This forecast has prompted telecom operators to look for the next generation of video codec and MPEg-4-Part-10/H.264 has taken center stage. This new codec is the result of years of work, and it is very powerful in what it offers. MPEg-4 allows HD content to be delivered in several levels of quality which can range from a few kilobits/sec to 10+ Mbps. The result is optimized video that is tuned to the dynamics of the network, always delivering exceptional quality. MPEg-4’s inherent flexibility means that even smaller pipes can deliver consistent quality at lower bit rates.

The following chart provides a comparison of different codecs in use today, and the typical bit rates for standard and high-definition content.

figure 2: Comparison of IPTV Media Codecs

The choice of codec and its bandwidth requirements play a key role in successfully delivering rich media content and providing engaging new services to IPTV customers. Analysts, service providers and vendors agree that MPEg-4-ready set-top boxes are very close to making their mass market debut in North America. In fact, many telcos have delayed their network upgrades while waiting for this next-generation technology to arrive.

With respect to ensuring the optimal quality of experience for a telco’s IPTV service, it’s important to realize that the codec scene is changing rapidly and is very much a moving target – so being able to test MPEg-2 all the way up to MPEg-4 is a critical requirement.

The IPTV network infrastructure described above is responsible for creating the necessary platform on which a variety of IPTV services is provided. These services are described in the next section.




IPtV serVICe offerIngs

broadcast television (btV)

IPTV broadcast television is analogous to what is currently offered by cable and satellite providers, where subscribers are offered several “always-on” channels, such as CNN, fOX, or ABC.

In an IPTV deployment, the delivery of the video must be highly efficient in order to distribute hundreds of channels to many thousands of homes at once. This is achieved with an efficient IP multicast network, effectively delivering broadcast service television over the IP network. This is one of the primary areas of transport architecture build-out because multicast traffic offers an order of magnitude better network utilization than other traditional means. This is also an area where significant testing must be done to ensure the IP network is ready to deliver an “always-on” video experience to consumers equal to or better than the service provided by satellite and cable operators.

figure 3: IP Multicast Network Infrastructure

Video-on-demand (Vod)

VoD offers consumers a customized “anytime” video experience by enabling them to request live and pre-recorded video content from a network-based library of content (e.g. new DVD movie releases) and allows them to watch this content immediately or during a set interval of time (usually within 24 hours). There are several technologies associated with delivering this very demanding video traffic, which can be highly unpredictable. Scalability and network congestion issues in broadband access devices and access networks are typically a result of not having sufficient network capacity to support this popular and rapidly growing service.




figure 4: Video on Demand Network Infrastructure

Current IPtV dePloyMent ChAllenges

Telco operators are starting to leverage their experience in packet based networks to enter the new market of IPTV. But because they happen to be the last to enter the market for video services, satellite and cable operators have set the bar pretty high in terms of what services are offered and the quality of video that is delivered.

Telcos face a major challenge – and a huge opportunity -- in building out new IP- based networks to offer converged services as a real alternative to satellite and cable operators dominance in the television market. for network equipment providers, this is an exciting new market as well with tantalizing opportunities for growth. To compete, equipment vendors are building IP-centric devices that excel in delivering triple play traffic with significant quality-of-service mechanisms built-in.

However, telcos wishing to successfully deploy IPTV services faces many technical challenges. One of the key approaches to weeding out problems is to systematically test and verify various network devices in each area of the IPTV transport network architecture. This testing strategy will characterize individual device performance and determine how much of an impact it will have on the overall solution.

following this, system-level tests that incorporate more than one demarcation point of the transport architecture will provide rapid insight into how the systems work together. finally, this approach will extend to testing the end-to-end solution. This process is highly desirable in pre-deployment testing where it is often that development on some of technologies is also ongoing while the service is being readied for small scale deployment. In essence, telcos need to take a systematic approach to testing, and ultimately perform system level tests, not just individual component or feature tests.

the payoff to having a comprehensive pre-deployment testing strategy is the




assurance that the next-generation IP network delivers exceptional service to the customers and is ready for the future.

The technical work then must focus around building a network and service architecture that is future-proof. for example, there must be enough capacity available from the customer to the access network to allow households to have sufficient channel packages, along with video-on-demand content. At the same time, the network platform must allow future growth to meet customer demands of multiple HD channels, multiple STBs with multi-channel capability, multi-angle viewing, and new on-demand services such as gaming.

To this end, billions of dollars are being spent by telcos on building this infrastructure, and it will be several more years before such a network is fully operational. As such, capacity is limited, and strict quality-of-service measures must be observed to deliver reliable IPTV today. Also, contrary to belief, building an infrastructure by simply adding more capacity is neither realistic nor a real solution to offering guarantees of service.

Instead, network resource admission control mechanisms must be used to guarantee that consumers are given access to network resources dynamically. from a service assurance perspective, network utilization must be monitored holistically to check for network congestion, and safeguards must be in place to avoid oversubscription which may hinder already existing video traffic on the network.

from a subscriber’s perspective, telco IPTV performance must be as good as what is offered by cable and satellite operators. Bad news travels fast and consumers will be slow to adopt the new service based on news of sub-par performance. If this occurs, prospective customers will wait on the sidelines until it gets better before subscribing. To raise the stakes even more, with the availability of digital cable and high-definition content, consumers have come to expect a rich television experience already. Perhaps the most important challenge then is to ensure that video quality does not degrade up and until it reaches the customer.

No amount of planning or traffic engineering can truly predict the dynamics of such a complex system. To isolate any issues at the system-level requires monitoring the video quality at critical demarcation points. for example, if video traffic is being impaired by the encoding system at the head-end and this is not identified as part of the system test, such an anomaly may go undetected into the video transport network, making it nearly impossible to locate the source of the problem. What further compounds this problem is the lack of a reference video quality assessment. Service providers must rely on third-parties to provide meaningful measurements. In addition to this sizable challenge is the requirement that key performance indicators (KPI) must be made available under realistic traffic conditions. for example, city-scale traffic must be generated in a controlled lab environment in which to obtain results; only then will the performance indicators truly have meaning on how well the service is delivered.

To address the complex topic of IPTV infrastructure readiness, the next section of this paper will focus




on developing a comprehensive testing strategy that focuses on stressing individual network devices and moving forward to doing system-level testing and verification that will ultimately entail testing the complete end-to-end IPTV service delivery network. The goal of such a strategy is to ensure a successful IPTV deployment from the very start.

deVeloPIng A CoMPrehensIVe IPtV testIng strAtegy

This section provides a use-case approach on how IPTV infrastructure components can be tested in labs and in the early stages of controlled deployment.

The testing strategy follows the IPTV end-to-end architecture model, starting from the video head-end components all the way to the emulation of IP set-top boxes at the customer premises. The recommended approach serves to characterize an individual device’s performance and measure the user’s experience by measuring application level performance.

Telcos are encouraged to extend the testing methodology outlined here and apply them to the specific testing framework of their IPTV deployment strategies.

testing the super Video head-end

In the video head-end, there are several stages that prepare terrestrial content to be delivered over an IP network. Some of the major areas of testing include broadcast TV and VoD server systems, media encoders, middleware systems, and the transport architecture used to deliver the content into the provider’s core network for consumption.

Media encoder Components and Content distribution network Components

At the video super head end, there’s a lot of video analysis that needs to be performed because a lot of encoding and transcoding is performed on the video feeds that are coming into the network. In a nutshell, the quality of the video content that gets delivered depends heavily on the strength of the encoder system. If such equipment isn’t tested, video artifacts can be produced right at the source and propagated to the end users.

It’s important to realize that these things cannot be tested at the network edge – because badly encoded video content will look “good” – with no errors being reported -- at the edge when it’s introduced to the network as a source artifact – and look terrible to the subscriber sitting in front of his TV. So at the super head-end, a lot of emphasis must be placed on sampling the quality of the video content itself to ensure that the encoders are doing a good job.


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Some of the key requirements for testing include:

Characterizing the performance of the various encoders or analog/DVB to IP conversion to ensure that that video stream quality does not degrade as the raw content is transcoded or converted for transmission over IP and as content is distributed into the service provider’s core network for replication and user consumption. Benchmarking the metro switches responsible for this content distribution for delivering very high bandwidth of video traffic. Producing accurate measurements of jitter, latency and loss distribution as video traffic increases.Measuring the performance of the aggregation switches and how well they can deliver real-time video traffic into the network. Such information is critical to knowing that the video being pumped into the network is not being severely impaired at the head-end.

broadcast Components

The broadcast components that require testing include DVB-IP conversion and broadcast video servers

Some of the key requirements for testing include:

Raw throughput performance including maximum stream output capacity. Network-level performance such as latency/jitter and packet loss experienced by video streams.Encoder performance for ensuring consistent video quality.Performance under adverse or failure conditions.Quality of the video based either on network-level or perceived video quality metrics.

Vod Infrastructure Components

The VoD components that require testing include video servers, session and resource managers, and video content allocation equipment.

Some of the key requirements for testing VoD infrastructure include: Maximum and optimal client capacity.Throughput performance that provides the best video output.Success rate of the VoD platform in servicing new requests for content. Network-level performance to ensure that impairments are not hindering the streams.Quality of the video based either on network-level or perceived video quality metrics.

Testing must determine the number of active video clients that a VoD server can handle, whereby the maximum client capacity of a server is the threshold where the server can no longer support any

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additional clients without degradation of quality in media streams.

The video server components must be able to support sudden increases in bandwidth and resource utilization. With a sudden increase of bursty traffic (many on-demand requests from subscribers), the rate of arrival of requests for new content may overwhelm the VoD system. Therefore, tests must measure the ratio of successful video streams delivered over the total number of requests received. This is important for modeling the scalability of a given VoD system so that providers know how to invest in the appropriate infrastructure in order to keep up with the project growth of on-demand content. In addition, testing the network performance of a video server must characterize latency experienced by clients, jitter introduced on the video streams and losses due to oversubscription of resources. Characterizing how well the VoD servers deliver video is important because service providers need this information to ensure they can scale to match the projected user demand. In addition to video servers, video cache devices which replicate frequently accessed content by several thousand users must go through a similar network performance characterization. finally, throughout the individual component testing that is performed, the goal is to ensure that the video delivered into the service provider’s network is of the best possible quality. Therefore an overall requirement is to know the experience of users in watching the VoD content. This includes the effects of the network on the video stream, and also determining a user’s perceived quality of experience based on subjective video analysis. Middleware systems

Middleware provides the glue logic to tie-in customer interaction with their set-top boxes into network actions that deliver the requested video content. Even though every middleware implementation is designed to the specific requirements of each service-provider, it is the most important software system that generates revenue. Middleware ensures that customers have access to what they are authorized to receive, and enables them to request video-on-demand services. In return, middleware systems tie into a service provider’s customer management and billing systems to effect payment and entitlement.

Surprisingly, middleware systems are often not part of a testing cycle. They should be. Proper testing can ensure that the systems can scale to support the service providers’ customer base and coordinate the various video head-end infrastructures to fulfill customer requests and avoid “server full” symptoms that lock out users from getting content they are willing to pay for.




testIng the VIdeo trAnsPort network

A service providers’ core transport network is built with intelligent and scalable architecture. The packet core network provides high-bandwidth, fault-tolerant connections to several geographic regions in the service provider’s network.

As a critical part of an IPTV network, some of the basic requirements of testing this packet core network include:

Measuring the raw performance of unicast (VoD) traffic, Determining the effective multicast distribution of content, and Determining the effectiveness of the various quality-of-service (QoS) mechanisms to forward BTV and VoD traffic.

The packet core network is generally tested end-to-end for network convergence times, packet forwarding switchover times in case of a node failure, and QoS provisioning based on several mechanisms as employed by a service provider.

The ultimate goal is to characterize how well the core network services different flows of traffic based on its QoS markings as the load of different flows of traffic increases linearly or in bursts, or under sustained heavy use. The addition of packet loss, latency and jitter experienced by the BTV and VoD traffic will have an impact on the perceived video quality. As such it must be understood where and under what circumstances the problems occur so that more resources can be provisioned to improve the quality of experience for the subscriber.

testIng the ACCess/AggregAtIon network

The access and aggregation network provides connectivity between the core networks and the edge network devices. Access devices also contain AAA services to give users access to the service provider’s network. Regional networks may also include devices for splicing local content and servers that replicate content that is frequently accessed.

Access and aggregation devices are generally benchmarked for performance as part of an end-to-end solution. This is simply not sufficient. Since access devices are the first demarcation devices that subscriber premises equipment interfaces with, they must be individually benchmarked to ensure that they are able to sustain the expected user and traffic loads under normal and peak usage conditions.

Therefore, access switches that aggregate edge devices must be tested to:Determine support for expected and peak number of subscribers that an edge aggregation device can support, including support for PPP-based subscribers,

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Measure aggregate unicast (VoD) forwarding performance to ensure it is acceptable (by profiling various load conditions and measuring the loss, latency and jitter distribution profiles), Measure multicast (BTV) performance of DSlAMs including IgMP proxy services for multiple channels, Measure channel change performance as experienced by subscribers, Measure the performance of AAA services for user management, including various authentication protocols and mechanisms such as PPP relay tag, and DHCP relay agent options, among others,gauge QoS assurance for the multiple services that the devices must support, including video flow analysis using network quality metrics, Determine that admission control mechanism are effective in reducing network congestionAnalyze the subjective quality of the video content as seen by the subscriber. In addition, there are growing concerns regarding ensuring security and access to provider networks by authorized subscribers and devices only. In addition to current choices of subscriber management, service providers are looking to integrate 802.1X to further supplement subscriber and device management.

In addition to characterizing the performance of subscriber aggregation devices, regional locations also contain video head-end equipment that provide local content aggregation, advertisement insertions, and systems that require adherence to local and regional legislations. It is also desirable to consider testing such devices to ensure that they do not contribute adversely to the quality of video that is seen by subscribers.

testIng the CustoMer PreMIses

Typically not part of the testing cycle, the nature of the customer premises video setup and wiring is proving to play an increasingly large part in determining the quality of the user’s experience. The ultimate goal is to ensure that subscribers are getting a crisp and clear picture, and that impairments in the network are not contributing to failures that cannot be readily known when the content is pushed into the home. As such, IPTV pre-deployment testing must also consider this last demarcation of the service’s delivery.

Therefore, there are several technologies being deployed in a home environment – technologies which the operators do not have as much control over as they would like -- that require attention.

These technologies include:Various residential ONT devicesDSl modemsResidential gateways (Rg)

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Wireless routersIPTV set-top boxes, and In-house wiring ranging from HPNA, Cat� to MOCA cabling.

Therefore, service providers must also emulate a subscribers’ home network (and its various permutations) to come up with the best approach to ensure that customers are not inadvertently impairing otherwise exceptional video content within their homes.

“Sanity testing” is recommended since large scale testing of customer premises is next to impossible in order to determine the performance of various devices and combinations of in-home wiring.

testIng other network CoMPonents

Additional infrastructure components constitute the various technologies, components, services and methodologies that allow the service provider to deliver a rich triple-play experience.

This includes:DHCP and AAA services for automatic configuration (ACS) of residential gateways and set top boxes,DNS for name resolutionCPE management (e.g. using the TR-069 specification)Application-aware admission-control (CAC) facilities, andNetwork devices that understand resource allocation like RSVP, among others.

Consider this hypothetical scenario: An affluent neighborhood is expected to experience a 2�% increase in consumer uptake of services over the next 6 months. However, network infrastructure such as DHCP servers that are responsible for address assignment and management are not aligned to manage this rapid growth. This oversight could lead to users experiencing slow startup times, times of service denial when all addresses are exhausted, or a worst case scenario where the rate of arrival of requests for address assignments overwhelm the DHCP servers, causing outright service failure.

This example is not an extreme case. Since DHCP servers are part of the network infrastructure technologies that make delivery of multi-services possible, their performance must be characterized so that new infrastructure components can be provisioned to service new consumer growth and demand for new services. The testing requirements for this additional network infrastructure are to measure client serving capacity, maximum transaction rates, optimal response times, server resiliency in case of failure, and the ability to manage network resources effectively.

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testIng the end-to-end serVICe delIVery network

The complete end-to-end delivery of IPTV includes an array of several different technologies. When rolling out new services, the infrastructure is built incrementally to support new services or align with new business strategies. The end-to-end performance of the IPTV network must therefore be characterized as the network evolves, as it will provide insight into how the various devices and technologies work to deliver the various services.

A customer’s quality of experience must be optimal, and the following general approach is recommended when testing the end-to-end service delivery network:

Create a realistic load conditions on the network, Measure key performance indicators such as (a) Adherence to the quality of service (QoS) provisioned to deliver guaranteed service (b) Acceptable service response times under normal and adverse load conditions, (c) Impact on service based device/component failures or routing instabilities Determine the perceived video quality as experienced by subscribers

ConClusIon

The stakes couldn’t be higher for telcos entering the triple-play/IPTV marketplace, as their very survival depends on them being able to deliver video that is of exceptional quality, free of service hiccups and quality of service issues. furthermore, they need to be able to offer unique on-demand entertainment services that serve to differentiate them from competing satellite operators and cable MSOs.

In order to ensure a successful IPTV deployment, it is critical that telcos understand that IPTV is not a separate function from their existing IP network infrastructure. In order to validate the quality of the service offer, pre-deployment testing is an essential undertaking that involves not only testing specific, individual network components but also testing IPTV service from a systematic, holistic point of view.

There are many test solutions available that test specific network equipment, but the problem is that they don’t test network and application performance in a unified, natural way. What is ultimately required is a single testing solution that is able to support a comprehensive, integrated IPTV testing methodology that includes system-level tests and end-to-end service delivery testing, not just individual component or feature tests.

ultimately, telcos need to test their IPTV deployments according to what happens in the field during real-world scenarios, where they are able to correlate tests of the various services and applications running on their triple-play networks as they relate to real-world network dynamics. It is simply not

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enough for a provider to perform video tests based on the load created by a million users – it is essential that they test these users while other subscribers are making voice calls and downloading music files – in essence during real-world traffic conditions.

finally, telcos need to ensure that an adequate degree of scalability exists in their test network in order to ensure that their new IPTV network can scale for the foreseeable future.

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