Rochester Institute of Technology RIT Scholar Works Articles 2007 Internet protocol television (IPTV): The Killer application for the next-generation internet Yang Xiao Xiaojiang Du Jingyuan Zhang Follow this and additional works at: http://scholarworks.rit.edu/article Recommended Citation IEEE Communications Magazine, November 2007 This Article is brought to you for free and open access by RIT Scholar Works. It has been accepted for inclusion in Articles by an authorized administrator of RIT Scholar Works. For more information, please contact [email protected]. XIAO LAYOUT 10/18/07 2:37 PM Page 126 TOPICS IN INTERNET TECHNOLOGY Internet Protocol Television (IPTV): The Killer Application for the Next-Generation Internet Yang Xiao, University of Alabama Xiaojiang Du, North Dakota State University Jingyuan Zhang, University of Alabama Fei Hu, Rochester Institute of Technology Sghaier Guizani, University of Quebec — Trois Rivières ABSTRACT able on the Internet and can be accessed freely with Internet-connected computers, iPods, and Internet Protocol Television (IPTV) will be cellular phones. The current quality of IPTV in the killer application for the next-generation the United States does not yet approach that of Internet and will provide exciting new revenue cable TV services, but the gap will shrink as opportunities for service providers. However, to bandwidth increases and video codecs improve deploy IPTV services with a full quality of ser- [2]. In 2005, there were about four million homes vice (QoS) guarantee, many underlying tech- in the world that already had IPTV. Minerva has nologies must be further studied. This article about 50 IPTV deployments that cover 150,000 serves as a survey of IPTV services and the users with VCR quality services [2]. Asia has underlying technologies. Technical challenges been at the forefront of IPTV services, launch- also are identified. ing IPTV service tests in eight out of thirteen economies in the Asia-Pacific region [2]. It is an INTRODUCTION appealing consumer application that can use the 20-Mb/s promise of asymmetric digital subscriber Internet Protocol television (IPTV) provides dig- line 2+ (ADSL2+), the 50-Mb/s capability of ital television services over Internet Protocol very high digital subscriber line (VDSL2), and (IP) for residential and business users at a lower the 100-Mb/s potential of fiber to the x (FTTx) cost. These IPTV services include commercial- [2]. Microsoft TV IPTV Edition is a software grade multicasting TV, video on demand (VoD), platform to develop TV services over broadband triple play, voice over IP (VoIP), and Web/email networks including features such as instant chan- access, well beyond traditional cable television nel change (ICC) and multiple picture-in-picture services. IPTV is a convergence of communica- (PIP), VoD, and digital video recorder (DVR). tion, computing, and content [1], as well as an BellSouth, a telecommunication service provider, integration of broadcasting and telecommunica- recently performed trials of Microsoft IPVT [3]. tion. IPTV has a different infrastructure from AT&T and Verizon recently announced signifi- TV services, which use a push metaphor in which cant investments in adopting fiber optic cables to all the content is pushed to the users [1]. IP deliver IPTV channels to residential customers. infrastructure is based on personal choices, com- The challenges of IPTV include integration bining push and pull, depending on people’s of different operators with different infrastruc- needs and interests [1]. Therefore, IPTV has tures and back-office systems, stability of long two-way interactive communications between term, quality of service (QoS) matching cable operators and users, for example, streaming con- providers, and so on [3]. The current systems trol functions such as pause, forward, rewind, won’t be able to keep up with the changes in the and so on, which traditional cable television ser- video distribution model for IPTV [2]. The vices lack. Triple play is a service operator’s Video Networks Ltd. (VNL) rollouts of its package including voice, video, and data. Video HomeChoice video, triple play service over DSL adopting either MPEG-2 or MPEG-4 format is use a Cisco Internet Protocol next-generation delivered via IP multicast. network (IP NGN) solution in the United King- The IPTV service first started in Japan in dom (UK) [4]. HomeChoice offers up to 4 Mb/s 2002, then became available in Korea [2]. IPTV Internet access, IPTV with over 70 channels, and is a convergence of broadcasting and telecom- thousands of movies, videos, and hit TV pro- munication. Many free IPTV services are avail- grams on-demand with up to 10 Gb/s per slot for 126 0163-6804/07/$20.00 © 2007 IEEE IEEE Communications Magazine • November 2007 XIAO LAYOUT 10/18/07 2:37 PM Page 127 next-generation IP multiprotocol label switching (MPLS) [4]. A chicken and egg situation exists: The indus- FTTx try needs IPTV to justify the investment in IPTV broadband, but there is no good IPTV without IPTV content devices broadband [2]. However, the investment is a way delivery services CORE networks to survive for some telecommunication compa- (sources, (IP/GMPLS/MPLS and xDSL nies [2]. IPTV is a convergence of IP-based com- database, multicast) programs IPTV munication and broadcasting. devices It is claimed that IPTV is the killer applica- Carrier tion for the next-generation Internet (NGI). In ethernet this article, we provide a survey of IPTV, as well IPTV as a description of its technical support. Some devices technical challenges and research issues also are 802.11n identified. WLAN IPTV The rest of this article is organized as follows. devices We first introduce IPTV and then present access networks and core networks for IPTV. Then, I Figure 1. mobile TV and peer-to-peer (P2P) IPTV are IPTV services. introduced. Finally, we present technical chal- lenges. Successful deployment of IPTV services requires excellent QoS for video, voice, and data. IPTV QoS metrics for video include jitter, number of To bring IPTV to reality requires changes in out-of-sequence packets, packet-loss probability, physical infrastructure. IPTV uses IP protocol to network fault probability, multicast join time, deliver multicasting TV, VoD, triple play, VoIP, delay, and so on. QoS metrics for voice include and so on, to consumers via broadband connec- mean opinion score (MOS), jitter, delay, voice tions, with a QoS guarantee. IPTV has unique packet loss rate, and so on. QoS metrics for features in addition to simply broadcasting ordi- IPTV services include channel availability, chan- nary TV programs over the Internet. IPTV can nel start time, channel change time, channel be incorporated with high-speed DSL access change failure rate, and so on. Before system technologies, such as ADSL2, ADSL2+, and deployment, accurate testing should be per- VDSL, as well as high-speed carrier-grade Eth- formed to test high-quality IPTV services for TV ernet and the emerging high throughput IEEE service, video, voice, as well as interactive service. 802.11n wireless LAN. MPEG-2 and MPEG-4-Part 10 /H.264 are IPTV is an integration of voice, video, and typically used for encoding video with a large data services using high bandwidth and high range of compression rates, allowing a trade-off speed Internet access. IPTV includes several between quality and bandwidth with either a components as shown in Fig. 1: constant bit rate or a variable bit rate [6]. Much • IPTV sources including VoD database and of the compression comes from inter-frame dif- other programs ference encoding instead of intra-frame coding, • High-speed Internet with functions of multi- particularly when there is relatively little change casting, QoS guarantee, and so on, includ- in each scene [6]. For an I frame, with intra- ing an optical backbone network to serve as frame encoding, its image frame consists of an IP multicast core network blocks converted to a set of coefficients using • High-speed access networks such as ADSL, discrete cosine transform (DCT). A group of ADSL2+, VDSL, a combination of fiber- blocks forms a slice carried within one packet. If to-the curb (FTTC) and DSL, fiber-to-the- the first block is damaged, the whole group may home (FTTH) access, carrier-grade be lost, which creates a strip in the image [6]. Ethernet, and the emerging IEEE 802.11n wireless LAN ACCESS NETWORKS • IPTV user devices such as digital televisions In this section, we introduce access networks including high definition televisions such as DSL technologies, carrier-grade Ether- (HDTVs) net, high-speed 802.11n wireless LAN, fiber-to- IPTV features [5] include: the-home (FTTH), and fiber-to-the curb • Selection (users are able to select their TV (FTTC). All these networks can contribute to programs with fast channel selection and the IPTV service deployment. short channel changing time) • Storage (TV programs are stored in local DSL TECHNOLOGIES storage devices so that users can watch DSL technologies, shown in Fig. 2, provide high- them anytime; furthermore, service pro- speed digital data transmissions over a telephone viders should store at least 100 hours of TV local loop from users to end offices. Downlink programs and videos) speed of a typical DSL is about 128 kb/s ~ • QoS (QoS must be guaranteed; a standard 24Mb/s, depending on the service providers. definition TV and a high definition TV ADSL standards can deliver 8 Mb/s over about 2 need bandwidth of 1~4 Mb/s and 4~12 km, and ADSL2+ can deliver up to 24 Mb/s, Mb/s, respectively) depending on the distance between a user and • Low cost (cost to the user must be low; this the nearby end office. ADSL is the most widely is the key to success) deployed DSL technology. IEEE Communications Magazine • November 2007 127 XIAO LAYOUT 10/18/07 2:37 PM Page 128 The high-speed IEEE 802.11n wireless Voice LAN can be one of switch Ethernet/USB the underlying xDSL modem infrastructures to assist IPTV service as Codec the access network Telephone line Splitter with better QoS via N Splitter high data access I D rates.