Cisco Headend System Release 2.7 Design Guide

 

4024319 Rev B 

3 

 

The advent of SDV technology promises to fundamentally change the way the 
industry delivers digital entertainment. With SDV, service providers have the ability 
to offer a wider variety of programming while managing HFC network bandwidth 
in a sustainable way. 

In a manner similar to a telephone system, which switches a smaller number of lines 
upon the demand of a larger number of customers, the SDV architecture switches 
only selected content onto the HFC upon the demand of one or more viewers. Thus, 
content that is not requested by anyone in a service group does not occupy HFC 
bandwidth or require edge modulator resources. 

With SDV, popular content continues to be broadcast continuously, while less 
popular content is held back and transmitted only upon request. Unlike video-on-
demand (VOD), with SDV (after the content is transmitted) that stream is shared by 
any subsequent viewers requesting the same content within the same service group. 

SDV also provides access to broadcast service while VOD is retrieving stored content 
from a server. As a result, SDV still uses the broadcaster's schedule to determine 
when a program airs. 

The following diagram illustrates the typical SDV broadcast flow.