HEAVY READING | JULY 2006 | WHITE PAPER ASSURING QUALITY OF EXPERIENCE FOR IPTV

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III.    Technical Requirements

Now that we've set up the discussion and outlined the primary challenges involved in achieving a

high-quality IPTV experience, let's examine the technical requirements for congestion avoidance

and service assurance in depth. The following two sections outline the guiding assumptions and

the high-level requirements for achieving these goals. The final section of this white paper out-

lines best practices for implementation and network architecture.

3.1

Guiding Assumptions

Following are the critical guiding assumptions of this white paper. They are listed in no particular

order of priority; they should be considered holistically as a set of interrelated guidelines for meet-

ing service assurance expectations.

 

1.   It is important to differentiate between IPTV and Internet TV. IPTV is a video service sup-

plied by a telecom service provider that owns the network infrastructure and controls con-

tent ingestion and distribution over the broadband network for reliable delivery to the con-

sumer (generally to the TV/IP STB). This is essentially a private/"walled-garden" network

controlled by the service provider. Internet TV, which is rapidly emerging in parallel, con-

sists of content sourced from anywhere on the Internet that can be streamed and/or

downloaded by the user (generally on a PC). Both IPTV and Internet TV are delivered

over a broadband connection, albeit with different levels of bandwidth, control, and QOS.

 

2.   IPTV, when used as a standalone acronym, includes broadcast TV, VOD, and other for-

ward-looking video-integrated data and voice services.

 

3.   IPTV must meet and/or exceed the performance, availability, and QOE metrics currently

being delivered by cable and satellite TV. Anything less will be a non-starter; hence the

enormous importance of service assurance in IPTV networks.

 

4.   Traditional best-effort IP networks are inadequate to support robust and scaleable IPTV

services with an acceptable QOE. Many of the technical requirements discussed below

are enhancements to best-effort IP networks for enabling reliable IPTV service delivery.

 

5.   Formal SLAs must be defined by the service provider. To enforce policies appropriately,

the supporting network architecture and policy-control solution needs to understand ser-

vice priority under different usage scenarios. For example, broadcast TV will likely be as-

signed the highest priority, such that a VOD service competing for network resources

does not disrupt the service contract associated with basic broadcast TV or other VOD

sessions already in progress. The granularity of SLAs goes much deeper, and can differ-

entiate between free and paid VOD, time shifting, and effect on other triple-play services.

 

6.   Frequent "busy signals" and/or service denials are unacceptable and impair customer

loyalty and recurring revenue opportunities for both multicast and unicast IPTV services.

Service denial may be impossible to avoid in extreme peak-usage scenarios, but such

cases should be rare and supported by a graceful message informing the subscriber why

the service is unavailable or offering viable alternatives (e.g., movie content may still be

available in SD format or downloadable for later viewing, if the STB has a hard drive). A

tight coupling between the network layer and IPTV middleware will be important to clearly

present this information and options as defined by provider policies to subscribers.

 

7.   Grossly overprovisioning network bandwidth is not an acceptable solution to support

congestion-free delivery of premium video services. Such a solution will not meet the cost

targets of the service provider nor enable it to achieve a profitable business model. In-

stead, the operator must purpose-build a network that caters to video requirements.