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HSI access services according to their peak download speed e.g., users could choose between a 2Mb/s, 4 Mb/s or higher speed "download" service.

With the advent of video-rich applications generally and long-form video content specifically, the traffic pattern becomes less bursty and more steady state. When enough subscribers consume video concurrently, as is the case today with OTT video, their combined behavior begins to impact the always present, but seldom felt, engineering rules at the IP service edge: as the demand for higher average bandwidth grows, the over-subscription factor defined at the IP service edge for the HSI service definition is stressed. When this happens, the HSI access service's best effort congestion management system kicks in, resulting in an unpredictable traffic flow. This is how the Internet service is designed to work: a community of users share access to a pool of bandwidth and during periods of congestion all members receive equal treatment. While this "best effort" experience is suitable for many applications, video is not one of them.

Enhanced triple play architectures have introduced significant upgrades from first-generation broadband network solutions - that tunnel "best effort" Internet traffic across the network – by providing distributed, fine-grain enforcement with centralized policy control to deliver multiple services to subscribers. These architectures use every part of the network to deliver and enforce policy, ensuring every service is delivered to subscribers with its required quality of service. Equally important, the policies defined at these multiple and distributed, end-to-end service touch points are managed centrally through a sophisticated subscriber management system.

The phrase "video changes everything" was often heard in 2004 when operators were deciding their IPTV architectures. It is applicable again for today's challenges of OTT video delivery and HSI service delivery over

OTT video by consumers is attempting to change the HSI access service definition. OTT video wants to pull the HSI service bandwidth-usage range upward, increasing the average bandwidth per subscriber. The issue for service providers is that video rich content drives up the average bandwidth per subscriber, thereby stressing the engineering rules defined for HSI at the IP service edge.

For consumers, the statistical nature of HSI service means early adopters of long-form video delivered OTT received more average bandwidth than others, and along with it, a reasonable quality of experience ... but only for a while. Once the majority join in the fun, the Internet's best-effort congestion management system makes its presence known. (That's how it's designed to work.)