Managing the multi-screen video transformation
Maximizing customer experience through video service assurance.
The multi-screen transformation has taken the video world by storm. Customers now expect the same video services they receive on their set-top box on their video-capable devices (smartphones, computers and tablets). Adoption of multi-screen services is occurring across the spectrum, running the gamut of service providers, content providers and enterprises.
Given the rise in consumer demand, many service providers have been caught back on their heels, trying to quickly adopt and push out desired multi-screen services to meet customer expectations. The largest providers have been able to offer video streaming services relatively quickly because HTTP streaming services leverage existing IP network infrastructure, putting customers right at the providers’ fingertips. In addition, HTTP is a universally accepted transfer protocol in content delivery networks (CDNs) and Internet-connected devices. This provides an excellent way to deliver video to a large number of consumers on a multitude of connected devices.
Though service providers have made significant progress in deploying multi-screen services, in many cases, quality assurance solutions have been partially deployed or altogether overlooked. Needless to say, this has given video providers quite a headache: Industry research has shown that consumers are incredibly sensitive to HTTP video service impairment. In fact, after experiencing a quality impairment, 60 percent of viewers are less likely to return, 25 percent will not return at all and 50 percent go to a competitor’s service (according to Akamai and Jupiter Research’s report “The importance of delivering a great online video experience”). Given the process changes, the complexities of delivering HTTP video services and the volatility of an unmanaged network, there are many areas where video quality is jeopardized. Thus, quality assurance for multi-screen video is a key investment for providers when developing and deploying video streaming services.
For service providers entering the multi-screen marketplace or expanding their multi-screen offerings, developing a CDN – or managing a relationship with a third-party CDN – is an integral piece of the deployment. A CDN is a web of servers that distribute video from the multi-screen headend to the Internet upon customer request. For providers deploying multi-screen, CDNs can be a brave new world. While a CDN is an excellent way to deliver HTTP video to customers, it can also present many challenges for delivering high-quality video. Just like in today’s IPTV networks, providers should assure video quality in the CDN to improve customer experience and reduce churn.
Before entering the CDN, video is prepared in the multi-screen headend, where an incoming video stream is transcoded into different size bit rate files and then chopped into chunks for each of the adaptive bit rate (ABR) protocols (Apple HLS or Microsoft Smooth Streaming). These video files are published to the origin server of the CDN. The origin server’s purpose is to receive and store the video files from the headend, and in turn serve these files out to the cache servers in the CDN upon request. An origin server is provisioned to receive requests from only the cache servers.
Cache servers are the part of the CDN that directly send video to the end-client devices. There can be multiple layers of cache servers, with mid- or shield cache servers positioned between the origin and edge cache servers. These servers cache, or store, video files requested by end-client devices close to the customer. This decreases the distance video files must travel to reach the connected device, thus decreasing the time it takes to receive a video file. It also reduces the amount of bandwidth used within the CDN, as it offloads capacity usage to a specific part of the network, freeing up other cache servers to deliver video services to other customers. Finally, the edge cache server sends out the requested video files to the end-client device.
In ABR networks, there is an added level of complexity. If there is bandwidth congestion in the last mile and the end-client device is unable to receive high-quality video files, it will request lower-bit-rate video during the viewing session. This allows the device to continue to play video, albeit at a lower quality level, rather than pausing for buffering. In turn, the edge cache server will request the corresponding video files from another cache server, or the origin server, and send this new, lower-bit-rate file to the end-client device.
Video service assurance for CDNs
Quality assurance for CDNs is paramount in the multi-screen world. Not only does monitoring quality help improve customer experience by pinpointing network issues, it also helps providers understand the effects of bad quality on the business model. Assuring quality in the CDN can be accomplished at four key monitoring points: pre-origin server, post-origin server, post-cache server and remote monitoring at key geographic locations.
The origin server is the entry point for video in the CDN. Quality impairment at the origin server is replicated downstream as it serves video files to cache servers. Pre-origin server video quality monitoring consists of passively monitoring video traffic to the origin server. Here, providers can monitor quality of service (QoS) of network connection, alarming on packet loss and network congestion. In addition, testing the HTTP connection to the origin server ensures that devices upstream can connect to the origin server and send files downstream. As a final monitoring strategy, providers can actively request the video files being published to the origin server. With these requests, the monitoring device essentially acts as a downstream cache server, ensuring there are no connection issues or HTTP errors.
Assuring origin and cache server communication is a second key monitoring point. By setting monitoring probes post-cache server, a provider can actively request video assets, ensuring that a request can be received by the cache server, which in turn successfully requests, receives and serves a video asset from the origin server to the monitoring probe. Furthermore, passive monitoring post-cache server can provide extensive live session quality, usage and performance statistics for CDN operators. By correlating this quality information with, for example, bandwidth congestion and quality monitoring at the origin server, multi-screen providers gain a comprehensive view of the health of their video services and a clear picture of the customer experience.
A final CDN monitoring strategy is to deploy remote monitoring probes in key geographic locations. By monitoring in areas where customers are requesting video, providers can ensure that after video has left the CDN, it can be accessed in high quality over the last-mile network. These probes should monitor both QoS and quality of experience (QoE) of all bit rate variants of a particular video asset, as well as ensure that the corresponding index/manifest files are not in error.
As a final monitoring strategy, service providers should leverage end-to-end monitoring solutions to aggregate and correlate quality, usage and performance statistics from monitoring points across the CDN. With this centralized view of the network, it is possible to use dashboards, reporting and alarm management capabilities that give providers insight into the entire network and actionable information for fault isolation and resolution. Furthermore, management systems also support integration into OSS/NMS solutions, correlating CDN performance information at a higher level.
SLA compliance in a multi-screen world
Today, many providers are using third-party CDN operators to help expand their multi-screen video coverage. In some instances, a third-party CDN is used exclusively to deliver the video services, while in other cases, providers are both building out their own CDN and hiring out third-party services. For both the service provider and the CDN, service-level agreements (SLA) on video delivery quality are essential to the business.
By monitoring video quality at these key handoff points with independent probe technologies, both providers and CDNs can quickly pinpoint and resolve problems in the network. This empowers all parties involved to uphold their SLAs and provide the necessary objective information about the level of video quality received and delivered.
For example, a service provider can monitor the output of its headend to the third-party CDN provider’s origin server, assuring that the initial feed into the CDN is high quality. CDN providers, in turn, can monitor the input to the CDN, assuring good quality video input and the output of the CDN to assure video is in good quality when it is sent from the CDN. Finally, the provider and/or the CDN can deploy remote monitoring probes at strategic video hubs to actively monitor video quality for SLA compliance.
Managing the multi-screen video transformation
In conclusion, managing the multi-screen video transformation presents many opportunities and challenges for service providers. When deploying these services, the CDN is the essential core of video distribution. Whether providers build out their own CDN or contract services from a third-party CDN, quality assurance solutions for multi-screen video are essential for managing customer experience and SLA. Without video service assurance, multi-screen providers are blind to any quality impairments in the network and will rely on negative customer feedback for isolating network impairment.
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