Return Path Data Lexicon: Bandwidth

by , Apr 12, 2012, 12:27 PM
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CIMM is taking a pro-active role in advancing new media nomenclature and processes with both its Lexicon (terms and definitions associated with return path data measurement) and Asset Identification Primer (glossary of asset terms). These documents form the basis of this colum,n which offers a common language for RPD nomenclature that can expedite the rollout of the data for its many industry applications.

There is arguably no more important feature of the digital marketplace than bandwidth, which impacts the speed with which we can access and use content. There has been ongoing discussion about how to best package bandwidth --  either through unlimited space, or parsed and priced via tiers of usage. The apportioning of bandwidth can impact return path data measurement because it contributes to latency as well as other usage conditions. Variable bandwidth levels are a challenge to edit rules, algorithm creation and metric standardization.

Bandwidth

CIMM DEFINITION: In computer networks, bandwidth is often used as a synonym for data transfer rate: the amount of data that can be carried from one point to another in a given time period (usually a second). Usually expressed in bits (of data) per second (bps).

A link with a high bandwidth is one that may be able to carry enough information to sustain the succession of images in a video presentation. In electronic communication, bandwidth is the width of the range (or band) of frequencies that an electronic signal uses on a given transmission medium. Here bandwidth is expressed in terms of the difference between the highest-frequency signal component and the lowest-frequency signal component. Since the frequency of a signal is measured in hertz (the number of cycles of change per second), a given bandwidth is the difference in hertz between the highest frequency the signal uses and the lowest frequency it uses. (Source: SearchEnterpriseWAN.com)

NOTES –

1.    Bandwidth impacts latency and therefore dwell time measurement. Restricting or price tiering of bandwidth size impacts measurement too.

2.    It should be remembered that a real communications path usually consists of a succession of links, each with its own bandwidth. If one of these is much slower than the rest, it is said to be a bandwidth bottleneck.

3.    Key constraint determining the amount and type of addressable, interactive applications, which can be run at any one time. (Source: Visible World)

4.    In the digital cable environment there are multiple data paths, each with distinct characteristics. Most obvious is the downstream video path, carrying large volumes of MPEG-2 video data from cable headends to STBs. Non-video data (e.g., EBIF applications) may be embedded within the MPEG-2 data stream at any point in the delivery of video from programmer to headend, and retrieved on the STB. This path provides the most downstream bandwidth, but requires the STB to tune to a specific channel to access it.

A second downstream data path is the out-of-band network, which provides less downstream IP network bandwidth than the video path, but does not require channel tuning, and is thus always available. The out-of-band network also provides a small amount of upstream IP bandwidth (see Back Channel, Return Path). (Source: FourthWall Media)

Please refer to the CIMM Lexicon online at http://www.cimm-us.org/lexicon.htm for additional information on these and other terms.

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