Superior quality of experience will determine the widespread adoption of carrier-class Internet video. Internet video quality of experience has become an all-encompassing term. There is IP packet delivery assurance in the last mile. There is intelligent policy management ensuring service level agreements (SLA) can be met before provisioning takes place. Inside the network, video must be monitored to assure quality. These different approaches are complementary, but monitoring today is reactive, slow, and not cost effective. This article addresses these issues and shows how Internet video quality monitoring can be optimized, embedded, and cost reduced.
Internet video continues to grow in unexpected ways. The nature of popular Internet video content is rapidly evolving. Consumers are demanding higher content quality, shifting from YouTube home videos to streaming Internet video of sitcom favorites. With professionally developed programming available for Internet video streaming, higher quality Internet video delivery is now in demand.
In order to maintain customer satisfaction, and to derive revenue from differentiated products and services, network providers are creating an Internet video service-aware network. A service-aware network is one with intelligent provisioning, delivery assurance, and Internet video quality monitoring within the network infrastructure for fault isolation and automated corrective actions. With these three elements, a service provider can create a network delivering end-to-end Quality of Experience.
Differing technologies have surfaced to address Internet video quality assurance, all under a common term of QoE. Most prevalent are intelligent provisioning platforms and IP packet delivery assurance techniques. In addition, monitoring the quality of the Internet video stream is crucial for fault isolation and automated corrective actions. With today's Internet video monitoring technologies, cost-effective delivery assurance is not possible.
Intelligent provisioning uses such protocols as Multicast CAC1 and RSVP2. Dedicated equipment can also assist where current equipment may not be capable of addressing these needs. These protocols are designed to ensure the network infrastructure can handle the bandwidth before adding another flow. These request/reservation policies will also allow a network administrator to monitor network capacity for oversubscription through request denial rates. Typically, this solution involves the transport network, the encoder/content server capabilities, and the broadband access/wireless access network. Although this method checks for availability of bandwidth during initial flow setup, these protocols usually don't reach the end device. There is no control over the resources through the duration of content delivery, so Internet video quality cannot be guaranteed.
Another QoE tool is last mile IP packet delivery assurance. These protocols include missing packet retransmission schemes. These can be quite effective within the last mile. The retransmission delay must be small enough that the retransmitted packet arrives before an end user's device will require the packet. For this reason, these technologies exist at the service edge, either in DSLAM equipment or mobile base stations. However, packet loss occurring before these last mile technologies will not be detected and hence cannot be corrected.
Video Quality Monitoring--Filling the Gap
Monitoring of Internet video quality is crucial to the creation of an Internet video service-aware network. The goal of Internet video quality monitoring is timely fault isolation and rapid cost-effective repair to guarantee end-to-end QoE. To accomplish this in a service-aware network, fault isolation must be possible on an individual Internet video stream, and it must be possible to detect where in the network the fault occurred. Timely fault isolation requires expedient alarm aggregation and reporting.
Video quality is typically measured on a standard scale, Moving Picture Quality Metric (MPQM)3. MPQM sets forth a standard of perceived video quality, ranking video on a scale from 5.0 (no impairments) to 1.0 (completely impaired video). MPQM standard scores are used to create alarms by setting thresholds for High/Medium/Low quality video. Timely reporting of alarms can be used to rapidly isolate issues in an access network supporting video distribution.
Internet video quality monitoring has different requirements at different points in a video distribution network. At a video encoder or transcoder, the input video is compared with the resultant video to ensure data loss is within tolerable limits. These video monitoring devices reside along with encoders and transcoders in a Video Network Operations Center (V-NOC). V-NOCs usually deploy very high capacity video servers; therefore, the additional space and power of discrete rack-mounted video monitoring equipment can be tolerated.
Once the video leaves the V-NOC it traverses a live network before it reaches a user. This network is subjected to widely varying loads, and hence is susceptible to packet loss and jitter. This may be from transient events such as failovers, or from oversubscription and improperly configured QoS policy. Whatever the cause, the end result is poor Internet video delivery, resulting in poor end-user QoE. Today, this is not monitored proactively and the network provider is not even aware of an issue until an end user reports it. The result is a dissatisfied customer who serves as the de facto quality monitor for their service provider. Even after an issue is reported, the lack of automated fault isolation makes it very difficult for the service provider to identify the root cause. Service providers are often left with no choice but to deploy expensive truck rolls of field technicians to manually fault isolate the issue.
The alternative to expensive truck rolls and manual fault isolation is to implement automated fault isolation with video monitoring at the access node, to distinguish last mile and customer-premises equipment (CPE) issues from upstream network issues.
Challenges Facing Video Quality Monitoring in Access Networks
Internet video quality monitoring equipment has now been available for a few years, but several factors have inhibited its use in access nodes for fault isolation. Access equipment deployments are not only large in number, but may be deployed far from network operation centers and often reside in small, non-environmentally controlled areas such as outdoor telecom cabinets, and even basements of large buildings. Current video monitoring equipment is too big, expensive, and power hungry for large-scale deployment in access nodes. These issues facing video monitoring at the access node must be resolved to create a cost-effective Internet video service-aware network.
The only solution that overcomes these challenges is embedding the functionality within the access node itself. Once embedded, the monitoring capability can reside anywhere an access node is deployed. An operator avoids the cost of deploying and maintaining dedicated monitoring equipment, and paying for the additional rack space. With embedded monitoring, service providers avoid the cost and carbon footprint of power consumed by dedicated monitoring hardware.
Companies such as LSI Corp. have created efficient, cost-optimized, power-neutral Internet video monitoring solutions to enable widespread deployment of high quality Internet video services. The LSI eQoE solution pairs the company's network processors, widely deployed in wireless access, broadband access, and enterprise applications, with video quality monitoring technology embedded within the existing network processor family.
The APP3300 network processor family supports a wide range of performance and power ranges. Implemented in a 90-nm process, its power consumption is as low as five watts. The APP network processors are utilized today in many outdoor or space-sensitive deployments, including remote DSLAMs, Node-B, and Small to Medium Business (SMB) gateway applications. In these deployments, the APP implements both the transport and control plane operations, including TR-101 DSLAM, LTE and W-CDMA Node-B, and SMB gateways.
Implementing eQoE on the same processor enables video quality monitoring at no additional silicon or equipment cost, power, and rack space. Further, to expedite design cycle times, application optimized software packages are available to implement the control and data plane functionality required for several access applications. By implementing eQoE within the same network processor and software offering, rapid deployment of Internet video monitoring in access networks is possible.