Guide to Testing IPTV Technologies and Challenges Part 2


In Part 1 of this series we gave a background to IPTV and explained that the two-way nature of IPTV networks offers many advantages over traditional broadcast technologies, but also presents a number of technical challenges.

In this part we will begin to examine some of the challenges faced by IPTV service providers, and the importance of Quality of Service and Quality of Experience.

Challenges in Delivering IPTV Services: the Importance of QoS and QoE
The first push by telcos into IP was primarily done as an adjunct network to their existing PSTN networks, where voice was offered over PSTN, while data was sent over the IP networks. The ability to offer IP data services came at the expense of managing a host of networks that were driving up operational and maintenance costs. Consequently the focus turned towards creating a system that could offer these services using a single IP network. Initially the primary application was data, but recently voice has been added in the form of Voice over IP (VoIP), and now video over IP services are evolving.

From an “ideal network” perspective, the long-term vision is to have an IP system that can offer converged video, voice and data services over a single network, which will allow network operators to offer bundled services at lower costs. The transition to a converged network presents a number of challenges however, as video, voice and data services each have their own Quality of Service (QoS) requirements when being transported across IP networks. For example, in order to be successfully decoded at the set-top box (STB), the transport stream carrying the video needs to arrive at a known and constant bit rate, in sequence, with minimal jitter or delay. The requirements for the successful delivery of voice or data are just as important but less stringent than those needed by video. The differing characteristics of these services all contribute to the complexity of designing, deploying and maintaining networks required to deliver high quality services to the consumer.

IP networks are, by their very nature “best effort” networks initially developed for the transport of data. As a consequence, these networks are susceptible to lost or dropped packets as bandwidth becomes scarce and jitter increases. In the vast majority of cases this has no significant impact on data services, which can cope with packet resends and packets arriving out of order as they get routed along different paths through networks. Video however is completely intolerant to the vagaries of a best effort network.

Good Quality of Service (QoS) for video requires:

  1. High availability and sufficient guaranteed bandwidth to allow the successful delivery of the service. Without this, video delivery will be “bursty”, causing issues at the STB which expects its data at a constant bit rate and in the correct sequence.

  1. Low transmission delay through the network. This impacts the response time to requests from the user’s remote control, and therefore can have a profound impact on the user’s Quality of Experience (QoE).

  1. Low network jitter. Jitter affects the variability of packet arrival through the network. This variability can lead to buffer under- and overflows at the receiving equipment (STB). Jitter can also impact the way packets are handled at various network elements; if the jitter is too high, packet loss will increase as queuing software tries to load balance traffic at network elements.

  1. Low Packet Loss. Lost packets have the greatest impact on the quality of received video and will generally lead to highly visible blocking errors.


Today’s broadcast systems have established user expectations about the television experience. To be successful, any IPTV service will have to be at least as good as (if not better than) the next best alternative, be that traditional broadcast, cable or satellite services. Quality of Experience (QoE) has therefore become a critical element of IPTV, and needs to consider items such as:

  • Is the subscriber consuming more bandwidth than is provisioned?
  • Are all promised capabilities being delivered (e.g. the Electronic Program Guide, the right program, etc)?
  • What is the subscriber experiencing at this moment (e.g. picture quality, channel change times, etc)?

Quality of Service (which considers whether the network is delivering content adequately) is as important as Quality of Experience because good QoS provides the foundation from which high QoE expectations are more likely to be met. QoS focuses on the performance of the network and its ability to deliver content to the required standard.

Examples of quantifiable QoS measures could be:

  • Where in the network is congestion occurring?
  • Are there adequate VoD content servers in appropriate markets?
  • Are interactions between voice, data and video causing problems within the network?
  • How many IP packets are being lost, and is there excessive jitter on the physical layer?

Given that QoS and QoE are vital pointers to whether subscribers will receive a quality end product, the ability to test, monitor and measure the parameters that impact these is essential. In the next part, we will give an overview of some of the technologies involved in the successful delivery of IPTV services before going on to explore the test and measurement challenges.

Tags: Tektronix | iptv | iss032 | qos | qoe | test and measurement | N/A
Contributing Author N/A

Article Copyright tv-bay limited. All trademarks recognised.
Reproduction of the content strictly prohibited without written consent.

Related Interviews
  • Tektronix at IBC2011

    Tektronix at IBC2011

  • Tektronix at IBC 2016

    Tektronix at IBC 2016

  • Tektronix at IBC 2015

    Tektronix at IBC 2015

  • Tektronix at IBC 2014

    Tektronix at IBC 2014

  • Tektronix at IBC 2013

    Tektronix at IBC 2013

  • VITEC EZTV Lite Platform for IPTV and digital Signage at ISE2020

    VITEC EZTV Lite Platform for IPTV and digital Signage at ISE2020

  • VITEC IPTV Digital Wall and Digital Signage Platform at ISE 2019

    VITEC IPTV Digital Wall and Digital Signage Platform at ISE 2019

  • VITEC EZ TV IPTV and Digital Signage Platform at NAB 2019

    VITEC EZ TV IPTV and Digital Signage Platform at NAB 2019

  • IPTV Digital Signage from VITEC at NAB 2017

    IPTV Digital Signage from VITEC at NAB 2017

  • Bridge Technologies QoE Monitoring with Mobile Videowall Display at IBC 2013

    Bridge Technologies QoE Monitoring with Mobile Videowall Display at IBC 2013

  • Elemental Technologies news at IBC 2015

    Elemental Technologies news at IBC 2015

  • Thomson Video Networks at IBC 2014

    Thomson Video Networks at IBC 2014

  • BBright at IBC 2014

    BBright at IBC 2014

  • Viaccess-Orca at IBC 2014

    Viaccess-Orca at IBC 2014

  • Perception at NAB 2014

    Perception at NAB 2014

  • Elemental Technologies Software-Defined Video at NAB 2014

    Elemental Technologies Software-Defined Video at NAB 2014

  • Elemental Technologies HEVC solutions at NAB 2014

    Elemental Technologies HEVC solutions at NAB 2014

  • Elemental Technologies Multiscreen Solutions at NAB 2014

    Elemental Technologies Multiscreen Solutions at NAB 2014

  • Haivision on BroadcastShow LIVE at IBC 2013

    Haivision on BroadcastShow LIVE at IBC 2013

  • Albis Technologies celebrating ten years at IBC 2013

    Albis Technologies celebrating ten years at IBC 2013

  • Visionary Solutions at NAB 2013

    Visionary Solutions at NAB 2013

  • Telestream Vantage v5 at NAB 2013

    Telestream Vantage v5 at NAB 2013

  • Visionary Solutions at NAB 2012

    Visionary Solutions at NAB 2012

  • Phabrix RX2000 at NAB 2013

    Phabrix RX2000 at NAB 2013

  • Phabrix at BVE 2012

    Phabrix at BVE 2012

  • Sencore at IBC2011

    Sencore at IBC2011

  • Leader at IBC2011

    Leader at IBC2011

  • Murraypro at IBC2011

    Murraypro at IBC2011

  • Hamlet at IBC2011

    Hamlet at IBC2011

  • Phabrix at IBC2011

    Phabrix at IBC2011


Related Shows
  • Kiloview Video Converter Decoder Converter Live Streaming with Digi-Box

    Kiloview Video Converter Decoder Converter Live Streaming with Digi-Box


Articles
Avid and Rohde & Schwarz
Ciaran Doran

Rohde & Schwarz is the perfect ingest partner to build flexible workflows with Avid.

Tags: Rohde and Schwarz | avid | spycernode | editing | asset management | venice | Ciaran Doran
Contributing Author Ciaran Doran Click to read
Sennheiser MKE 400 hands on review and test
KitPlus

Sennheiser have just released two products aimed at simplifying audio on the move, the MKE400 shotgun microphone and the XS Lav Mic, in this review we’re looking at the MKE400.

Tags: sennheiser mke400 | sennheiser mke 400 | sennheiser mke 400 quality | best microphones for youtube | mic for youtube videos | sennheiser mke 400 hands on | microphone review | iphone videography | microphones | sound for video | camera microphone | microphone for iphone | microphone for youtube | video microphone | shotgun mics | smartphone microphone | vlogging mic | best microphone for video | shotgun microphone review | mke 400 | sennheiser mke 400 hands on review | sennheiser mke 400 test | KitPlus
Contributing Author KitPlus Click to read
A Broadcasters Guide to Microservices
Roger Persson

The word “microservices” has been creeping into the conversation about software-centric systems recently. Is it really a different approach, what does it mean, and what are the advantages?

Tags: nxt edition | microservices | modular software | Roger Persson
Contributing Author Roger Persson Click to read
Streaming Technologies Explained
Bruce Devlin - new

The word streaming can relate to different technologies from different manufacturers in different scenarios and in this short article we are going to take a little tour of what it all means. 

Tags: mr mxf | streaming | hls | dash | cmaf | mpeg | Bruce Devlin - new
Contributing Author Bruce Devlin - new Click to read
REVIEW - Hollyland MARS 400S PRO Digital Wireless Transmission System
Phil Vinter

Built by Hollyland and costing around £600 the Mars 400S is an easy-to-use wireless video transmitter/receiver system – it will be right up the alley of anyone who, like me, considers an instruction manual to be nothing more than box padding.

Read Phils Full review here, and link to the video review.

Tags: HOLLYLAND | MARS 400 | wireless | tx | rx | Phil Vinter
Contributing Author Phil Vinter Click to read