The Future of Iptv and Ip-Video

ECE 6613: Broadband Access Networks The Future of IPTV and IP-Video Ji Hwan Kim Georgia Institute of Technology 325050 Georgia Tech Station Atlanta, GA 30332 Abstract— This paper describes the various IPTV architectures and components, which enables large-scale integration of current and future IPTV network. IPTV technologies are transforming how we perceive TV services today and global television industry as whole. However, there is pressing need for improvement on IPTV side to meet the Quality of Experience that is equal to or better than traditional TV services.In recent years, we have seen tremendous growth in Information Technology industry with the emergence of smart phone. Various new technologies are in its development to meet the demand of higher data rate, reliable data transfer, and readily available resources with distributed cloud servers to improve quality of service to the customers. With growing number of smart phone users, IPTV service has become ever more pop ular in telecommunication companies to provide streaming videos through the different new infrastructures.The biggest competitors in IPTV service in the U. S. are Verizon FioS (FTTP) and AT&T U-verse (FTTN) providing triple-play bundle service to the customer. In this paper, we are going to discuss IPTV service architecture difference of Verizon FiOS, AT&T U-verse, Cable Company, and Netflix as well as current IPTV research and development to increase quality of experience through multicast and cloud computing. Also we will analyze some of the emerging IPTV application in the future. Key Words — Internet Protocol Television (IPTV), Verizon FiOS, AT&T U-verse, MulticastIntroduction Today’s IPTV services IPTV technologies are transforming how we perceive TV services today and global television industry as whole. It is a collection of modern technologies in computing, networking, and storage combined to deliver high quality television contents through IP network. It is be coming a platform which changing how we access information and entertainment. In recent years, we have seen tremendous growth in video and networking technologies with the emergence of smart phone.Various new technologies are in its development to meet the demand of higher data rate, reliable data transfer, and readily available resources, distributed cloud servers, to improve quality of service to the customers. The figure below [1] is an example of IPTV broadband network inside a home. [pic] Fig. 1. Diagram of IPTV Broadband Network Inside Home. With IPTV service, video contents are not only limited to the TV but can utilize in multiple platforms to enjoy video content anywhere, anytime, and anydevice.IPTV alter the way the customer consume video content like personal video recorders have done and lets customer have complete control of their entertainment experience to a next level. [pic] Fig. 2. U. S. Multichannel Video Subscriber Census Above is a figure of U. S. Multichannel Vi deo Subscriber Census by SNL Kagan [2]. In 2011, the cable industry lost 1. 8 million video subscribers whereas IPTV providers gained 1. 6 million. This shows that IPTV industry is gaining market share on video content provider and it is expected to grow even more.Cable TV delivers entire line-up of broadcast content channels all the time which requires huge amount of bandwidth being delivered all the time into the home and cable companies are moving toward IPTV delivery services to reduce bandwidth on their infrastructure. IPTV architecture is very different in that it only delivers the single channel that is requested by the consumer’s individual TV. Therefore, IPTV architecture can greatly reduce bandwidth by only providing specific request from the consumer at any given time [4]. [pic] Fig. 3.Expected Growth in IPTV subscribers. However, there is pressing need for improvement on IPTV side to meet the Quality of Experience that is equal to or better than traditional TV ser vices. To provide great quality of experience in IPTV requires almost no packet loss, delay variation of 200ms, and delivery of no more than one perceivable error during a two-hour movie. This constrains and requirements puts heavy burden on service provider to provide reliable and lossless IPTV to customers and requires video admission control. The paper is outlined as follows.In Section II, we overview the different IPTV system and architecture exist today and how service providers are planning to improve their IPTV infrastructure. In Section III we will discuss the multicast protocol in depth and current research from Cisco to deliver IPTV service with multicast protocol. In Section V, we will discuss some of the potential future application that can be seen in near future with IPTV service. IPTV System and architecture IPTV networks generate their video contents for transmission using many clustered components collectively called headends.There are three common types of IPTV hea dends to meet national, regional and local content distribution requirements. Super Headends (SHE) receives and digests content on the national level typically from satellites. After processing and encoding, the SHEs distribute the national content to video hub offices (VHO) over a core IP/MPLS network. VHOs aggregate national, regional, and local content with the on-demand services, and serve metropolitan areas with a population of between 100,000 to 500,000 homes.VHOs are connected to video switching offices (VSO) over metro aggregation networks. VSOs distributed the IPTV streams to the customer premises over access network. The IPTV architecture is shown in Figure. 4. [pic] Fig. 4. End-to-End IPTV Network Architecture. The most conventional transport technique for IPTV is to multicast UDP/IP packets with MPEG-2 video compression scheme. The newer standard video architectures use RTP protocol which can provide error repair and stream monitoring unlike UDP protocol.IPTV service hav e slower channel change time compare to CATV service provider since all the TV channels are broadcasted simultaneously whereas IPTV needs to request certain channel from the provider. IPTV zapping time is affected by several factors such as Internet Group Management Protocol (IGMP) signaling delay of leaving and joining multicast group, MPEG decoding delay, program specific information (PSI) including program association table (PAT) and program map table (PMT) acquisition delay, random access point (RAP) delay, conditional access system (CAS) key acquisition delay, and de-jittering buffer delay in the STB [4].More detail of video admission control in IPTV multicast protocol will be discussed in Section III. IPTV service over a packet-switched network demands near zero packet loss and limited jitter. Thus, it is often necessary to enforce traffic management and admission control in IPTV network by sufficient provisioning and resource allocation [4]. More detail on resource allocation through retransmission server to improve IPTV will be discussed in Section III. Telco companies are embracing the IPTV technology since this will open up huge market share with Cable TV companies.Telco companies have been delivering packet-based IP traffic over their xDSL technology for many years and utilizing their existing technology to move to IPTV is a natural choice for them. However, there are great roadblocks to deploy IPTV over DSL which primarily concerned with quality of experience that is equal or better than traditional CATV. Below is the figure of IPTV infrastructure for Telco companies [1]. [pic] Fig. 5. Telco End-to-End IPTV Network Architecture. The primary difference in Telco companies’ architecture can be seen in red cloud shown in Fig. 5.Digital subscriber line access multiplexer (DSLAM) is located in environmentally controlled vaults or huts. It is also called video ready access devices (VRAD), which is placed on lawns or easements or a common space in a partment building. DSLAM often serves 100 to 200 residential gateways (RGs) that are attached to the outside of a residence and various techniques are used to transport signal between DSLAM and RG. Very high-bit-rate DSL (VDSL) for copper and broadband passive optical network (BPON) and gigabit PON (GPON) for giber transport. This metro access segment uses a hub-and-spoke architecture [5].Cable companies have been utilizing Hybrid fiber coaxial (HFC), combine optical fibers and coaxial cables, network since early 1990s to provide broadband internet access over existing cable TV system and its been employed this protocol globally and Data Over Cable Service Interface Specification (DOCSIS) is the international standard for developing equipment for HFC networks. Cable IPTV architecture is able to evolve from the traditional CATV with simple changes by adding few more components: cable modem (CM), cable modem termination system (CMTS), and a PacketCable Multimedia (PCMM).The cable comp anies’ architecture is shown in the figure below. [pic] Fig. 6. Cable Company Network Architecture. The CMTS and CM can provide a bidirectional IP over DOCSIS transport in the HFC network. CMTS can provide media access control (MAC) and physical protocol layer (PHY) in a single device by integrate with DOCSIS however, cable industry is moving toward a modular CMTS (M-CMTS). M-CMTS separates MAC and PHY layers to improve the scalability of DOCSIS transport.The CMTS manages DOCSIS QAM switching and provides QoS over the DOCSIS channel as well as manages residential CMs by dynamically load-balancing CMs among DOCSIS downstream channels to optimize traffic flow. PCMM policy server in DOCSIS networks defines admission control QoS policies by using session managers to request and reserve bandwidth for CMTS to enforce these QoS policies. A. Verizon Fios In 2004, Verizon began deployment of its Fiber to the Premises (FTTP) access network. The initial deployment used the ITU-T G. 983 BPON standard and in 2007, Verizon began using equipment with the ITU-T G. 84 G-PON standard. Fig. 6 below is Verizon’s BPON FTTP architecture diagram describing the connection between Optical Line Terminal (OLT) and Optical Network Terminal (ONT). OLT provides interface between Core network with voice, data, and video signals and Erbium Doped Fiber Amplifier (EDFA) boosts the [pic] Fig. 6. Verizon BPON FTTP architecture optical video signal. ONT performs the optical to electrical signal conversion and provide the data, voice, and video service to the subscriber. Wavelength division multiplexer (WDM) combines the three wavelengths onto a single fiber for transmission to the premises. 310nm wavelength is used for upstream traffic and for downstream, 1550nm (broadcast video) and 1490nm (data and voice) are being utilized. Fiber Distribution Hub (FDH) cabinet contains 1Ãâ€"32 passive optical splitters. Each subscriber is connected to a dedicated fiber between FHD and the premis es. BPON delivers 622 Mbps downstream and 155 Mbps upstream per PON for voice and data through ATM. FiOS provide over 600 channels between 50 to 870 MHz RF signal transmitted over the 1550nm wavelength. [pic] Fig. 7. Verizon FiOS RF spectrumGPON physical architecture is same as BPON however it provides significant improvements over BPON in bandwidth. GPON can provide 2. 5 Gbps downstream and 1. 2 Gbps upstream for data and voice and in addition, GPON have different transport by implementing Ethernet based protocol to transfer data instead of ATM. The comparison of BPON and GPON is shown in Table 1 below. [pic] Verizon uses Multimedia over Coax Alliance (MoCA) technology to provide data communication inside the resident. MoCA is installed in the ONT, Broadband Home Router, and set-top boxes and permits two-way IP data transmission over coax.By using MoCA, Verizon can reduce installation cost by using existing coax cable instead providing Ethernet cables to connect devices in the resi dent. [pic] Fig. 7. Verizon FiOS MoCA Verizon is using two main FTTP deployment schemes, the FTTP Overlay architecture and the FTTP Full Build. The [pic] Fig. 8. FTTP Overlay and Full Build Deployment Choice between two deployment scenarios is dependent on the specific deployment area and the likely take rates. In the FullBuild architecture, the fiber is deployed to each house and each subscriber gets an ONT together.In Overlay architecture, fiber is available to pass all homes and business in a distributed area but only a small percentage of homes and businesses are connected to and served with FTTP [7]. B. AT&T U-Verse In 2006, AT&T launched its U-Verse IPTV service (project lightspeed), comprising a national head-end and regional video-serving offices. AT&T offered over 300 channels in 11 cities through FTTN technology. AT&T utilizes copper pair to connect VRAD to Residential Gateway (RG) using xDSL technology. With U-verse, it can provide 25Mbps to home approximately 2500~4000 f eet away.By using MPEG-4 H. 264 compression technique, U-verse can provide 4 simultaneous TV stream (2HD and 2 SD TV), 2 VoIP and POTS service to the resident. Figure below is U-verse architecture. [pic] Fig. 9. U-verse FTTN Architecture The DSL technology at its beginning stages could only deliver 6 Mbps but now with ADSL2+ and VDSL, it can provide much higher bandwidth over a single copper pair. [pic] Fig. 10. xDSL technology. The various techniques are being implemented to improve the bandwidth and physical loop length capabilities of different DSL technologies.Bonding copper cable pairs can provide higher bandwidth by terminating 2 copper cable pairs together to act as 1 larger copper pair. ADSL2+ and VDSL is bonded together to provide higher bandwidth. VDSL can provide higher throughput than ADSL2+ however, it can only support short loop length. There is newest xDSL technology standard VHDSL2, which approved in February 2006, can provide bandwidth of 200 Mbit/s but maximum dist ance of 300 meters. xDSL technology goal is to provide VDSL speed with longer loop length [4]. The various different xDSL technology characteristics are shown in table below. TABLE 2. xDSL SELECTED CHARACTERISTICS. pic] AT&T typically uses mix of xDSL technologies to deliver broadband service to subscribers. Mainly ADSL2+ from the central office and VDSL2 from the VRAD through FTTN fiber based technology. C) Cable TV to IPTV Transition Cable companies are the largest subscription television service provider in the world and can easily integrate IPTV services to their existing infrastructure. In cable TV infrastructure, there are two main categories of digital video services: broadcast and on-demand Broadcast service defined as a service in which one copy of a program is sent to all subscriber in a broadcast manner.Broadcast services include : – Digital broadcast- Encoded/compressed programs are sent to a subscriber’s STB, where they are decoded/uncompressed for playbac k on a TV. All programs are transmitted regardless of which programs are currently watched by the customer – Switched digital video (SDV) – SDV is similar to digital broadcast but only requested programs are sent to a subscriber group. This group typically consists of all the subscribers served by HFC node which can serve range o 125 to 2000 subscribers. SDV is first two-way communication with subscriber for program selection.The digital broadcast architecture begins with the polling the content in the headend from satellite and terrestrial sources. The acquired content is generally forward to a multifunction media processing device performing following three functions: – Statmux – performs statistical time-devision multiplexing of real-time video content from various sources. – Groomer – adjust rates of content into a maximum bandwidth and limiting the rate of video burst – Splicer – inserts ads into programming breaks as need ed for a regional market. [pic]Fig. 11. CATV Architecture. The content is then forwarded across IP transport network to an IP-enabled quadrature amplitude modulator (QAM), where video content is encrypted and forward to STB for the customer. An out-of-band (OOB) channel provides the STB with basic tuning information, basic tuning information, decryption keys, software upgrade, and other communications. Switched Digital Video (SDV) was designed as a cost-effective method to expand bandwidth capacity in a way different than plant upgrades or better video compression method.Traditional digital broadcast sends all the channels into the HFC network but with SDV, programming terminates at the headend (VHO) or hub (VSO) and does not send channel unless it’s requested. When an SDV program is selected, tuning software in the receiver sends an upstream message and SDV session manager receives the quest and maps the program to a frequency within the allocated pool. If the program is alr eady being viewed within the same subscriber group, the task is as simple as reusing the existing session frequency information. On-Demand service is an interactive service where a requested video program is streamed to one subscriber.All on-demand content is encoded/compressed and stored on server to be received by individual subscriber’s request. On-demand services include following: – Video on demand- Content is stored on a server and subscriber views a list of titles and requests to view a specific title. The VOD system authorizes and streams the requested content to the requested user. – Network-based personal video record (nPVR) – this service is like home PVR except the content is on the service provider network. A subscriber uses the STB to record specific content to record and watches content at a user-chosen time which is same manner as VOD. pic] Fig. 12. Integrated Cable Video Service Architecture Cable IPTV architecture needs three newly added components to enable IPTV to their customers: Cable modem (CM), Cable Modem Termination system (CMTS), and a PacketCable Multimedia (PCMM). [pic] Fig. 13. Cable IPTV Architecture The CMTS and CM provide a two-way IP over DOCSIS transport in the HFC network. Cable Companies are moving toward M-CMTS technology, which can separate, MAC and PHY layer to improve scalability of DOCSIS transport unlike traditional CMTS where both MAC and PHY layer in a single device.In order to utilize IPTV in Cable company network, IP STBs or other IPTV capable devices must be able to receive video over IP transport and remove network delay variation. Major Cable companies are finding hybrid STBs as attractive solution for IPTV. The Hybrid STB with an embedded cable modem can receive video from either IP path or traditional QAM/RF transport path, which is good strategy to migrate from traditional cable architecture to IPTV. Admission control in Cable IPTV can be applied to both the IP network from the vi deo source to the CMTS, and the HFC network between the QAM and the CM through PCMM policy server.Policy server in DOCSIS networks defines QoS policies for CMTS to enforce them. Admission control signaling can be categorized as off-path and on-path. Off-path is when the control path is different from the data path and on-path signaling traverses the data path for bandwidth requests that use the commonly selected Resource Reservation Protocol (RSVP). In order to provide better IPTV services to the customers, Cable industry must improve bandwidth efficiency in the last mile. The biggest recent innovation to optimize available bandwidth is SDV but additional solutions are becoming more important as cable company transition to IPTV service.QAM sharing holds great promise of improving bandwidth efficiency without the need of major change in their current infrastructure. However, there are several factors contribute to the bandwidth efficiency of QAM sharing: †¢ Even if SDV and VOD h ave the same peak hours, a viewer is likely to receive only one service at a time. †¢ The gain of QAM sharing comes from the statistical advantage of a bigger QAM pool, shared by two or more services. †¢ Differing peak hours of DOCSIS and video service contribute additional gains.For instance, the spectrum allocated for DOCSIS commercial services during the day may by reallocated for video services in the evening. Dynamic QAM sharing is being realized through new technologies and standards for the following reasons: †¢ The DOCSIS M-CMTS architecture, which separates the DOCSIS MAC and PHY protocol layers. This allows the PHY layer (specifically the QAMs) to be dynamically allocated and de-allocated. †¢ The recent emergence of universal QAMs, which can function as either MPEG video QAMs or DOCSIS QAMs. †¢ Standardization in edge QAM resource management. pic] Fig. 14. Dynamic QAM Sharing with M-CMTS Architecture ERMI specifies several interfaces to an edge res ource manager (ERM). The ERM is a plat- form that manages and leases QAM channel bandwidth for all applications: †¢ ERMI-1 is an interface for edge devices to register QAM channels to the ERM and notify the ERM of any QAM failures or state changes. †¢ ERMI-2 is an interface for the ERM to bind the QAM resources from an edge device to the resource allocation request. †¢ ERMI-3 is an interface for the M-CMTS core to allocate QAM-channel andwidth from the ERM. Variable bit rate (VBR) video provides considerable bit saving compared to constant bit rate (CBR) video. WITH VBR statistical multiplexing, Cable Company can save as much as 30 percent of bandwidth by just varying the output data per time segment. Recently, DOCSIS 3. 0 was release to compete with Telco companies FTTx deployment and it is redefined the communication between cable modem (CM) located at subscriber premises and cable modem termination system (CMTS) at cable service provider’s network headend. D OCSIS 3. are design to allow channel bonding to boost up network throughput and number of bonded channel is usually 4 or 8. With DOCSIS 3. 0 standard, it can provide 300 Mbps download and 100 Mbps upload [8]. TABLE 3. DOCSIS 3. 0 Standards and Characteristics [pic] D) Netflix OTT IPTV System and Architecture Netflix is the leading provider of OTT on-demand internet video streaming in the US and Canada with more than 23 million subscribers. Netflix can stream out HD quality video with average bitrate of 3. 6 Mbps and it is single largest source of Internet traffic in the US by consuming 29. % of peak download traffic. [pic] Fig. 15. Netflix Architecture Designing large-scale network infrastructure to support fast growing video streaming platform with high availability and scalability is technically challenging. The Majority Netflix infrastructure used to be hosted in its own datacenter but recently resorted to the use of cloud services, Content Distribution Networks (CDNs), and other public computing services. Amazon AWS cloud is being utilized by replacing its in house IT infrastructure along with SimpleDB, S3 and Cassandra for file storage.Video streaming is distributed out of multiple content distributed networks (CDNs), UltraDNS, and a public DNS service is used as its authoritative DNS servers. Microsoft Silverlight is employed as the video playback platform for Netflix desktop users and Netflix manages to build its IPTV with little infrastructure of its own. †¢ Netflix data centers – Netflix uses its own IP address space for the host name www. netflix. com. This server primarily handles registration of new user accounts and captures payment information and redirect users to movies. etflix. com or signup. netflix. com. This server does not interact with the client when handling movie request and playback. †¢ Amazon Cloud service – Most of the Netflix servers are served from various Amazon cloud services and key functions are content ingestion, log recording/analysis, DRM, CDN routing, user sign-in, and mobile device support †¢ Content Distribution Networks (CDNs) – Netflix utilize multiple CDNs to deliver the video content to the subscriber. The encoded and DRM protected videos are stored in Amazon cloud and copied to CDNs.The three main CDNS are Akamai, LimeLight, and Level-3. These three servers provide same quality level content to all the subscribers. †¢ Player – Netflix employ Silver light to download, decode and play Netflix movies on desktop web browser. There are different players for mobile phones and other devices such as Wii, PS3, Xbox, Roku, etc. Netflix utilize Dynamic Streaming over HTTP (DASH) protocol for streaming. In DASH, each video is encoded at several different quality levels and is divided into small chunks. The client requests one video chunk at a time via HTTP.With each download, it measures the received bandwidth and runs a rate determination algorithm to deter mine the quality of the next chunk request. It allows the player to freely switch between different quality levels depending on the bandwidth of subscriber. TABLE 4. KEY NETFLIX HOSTNAME [pic] Netflix Client player have many functions to improve its performance and quality of experience (QOE). Netflix video streaming is controlled by instruction in a manifest file, which Silverlight client downloads. This metafile provides the DASH player metadata to conduct the adaptive video streaming capability.It is client-specific and generated according to each client’s playback and bandwidth capability. It is in XML format and contains several key pieces of information including list of the CDNs, location of trickplay data, video/audio chunk URLs for multiple quality level, and timing parameters such as time-out interval, polling interval and other data to provide QoE to users. Manifest files ranks CDNs to indicate which CDNS are preferred for content delivery. Trickplay is achieved by downloading a set of thumbnail images for periodic snapshot during network congestion [15]. IPTV multicasting protocolIn early IP networks, a packet could be sent either in unicast (single device) or broadcast (all devices). With multicast, single transmission for a group of devices is possible. Multicast transmissions enable efficient communication between groups of devices by allowing Data to be transmitted to a single multicast IP address and received by the group of interest. Multicast over IPTV network presents many challenges related to reservation of resource and maintaining quality of experience (QoE). Backbone can be built based on IP/MPLS and the routers can be enabled for multicast using IGMP protocols.Before going into detail of multicast protocol in IPTV, we will discuss multicast protocol in detail and how it can help IPTV through multicast mechanism. TABLE 5. IGMPV2 AND IGMPV3 MAJOR DIFFERENCE [pic] The IGMP was defined to allow a host computer to select a stream fro m a group of multicast streams a user request. Following is the basic functions IGMP protocol: †¢ Join: an IGMP host indicates that it wants to receive information from a multicast group to become a member. †¢ Leave: An IGMP host indicates that it no longer wishes to receive information from a multicast group. Query: An IGMP router can ask the hosts which groups they are member of. This is done to verify a JOIN/LEAVE request or to look for error conditions. Queries maybe be: o Specific Query: Asks whether the host is a member of a specific multicast group o General Query: Asks the host to indicate all groups that it belongs to †¢ Membership Report: an IGMP host tells the IGMP host what group it belongs to. This report can be either: o Solicit Membership Report: Sent in response to a QUERY o Unsolicited Membership Report: initiated by the client.In the IPTV network, each broadcast TV channel is an IP multicast group. The subscriber changes the channel by leaving one gr oup and joining a different group. IGMPv1 is not suitable for IPTV because it does not include an explicit â€Å"Leave† capability. The client will continue to receive all requested stream until the multicast router issues next query. The standard for IGMPv2 and IGMPv3 major difference is shown in Table 5. IGMPv2 supports Any Source Multicast (ASM) networks and which allows host to specify which multicast group it wishes to join.Most deployed IPTV clients supports IGMPv2. The Major enhancement in IGMPv3 is that it allows Support Specific Multicast (SSM). Host can specify the source address it wants to listen to. Here’s basic IGMP operation involving two devices: †¢ IGMP host (client or STB) – issues messages to join or leave a multicast group. The client also responds to queries from the multicast router. †¢ IGMP router – responds to the join and leave messages to determine if multicast groups should be forward out an interface. Periodic queries are used to discover from error conditions and verify requests.The IGMP router receives multicast groups either through the use of a multicast protocol such as PIM or static flooding. It is the termination point for IGMP messages and does not send any IGMP information to its upstream neighbors. [pic] Fig. 16. DSL Access Network IPTV Service In xDSL IPTV architecture, the subscriber initiates channel change requests and responds to status inquiries. The Routing Gateway (RG) at the subscriber’s site and DSLAM aggregate traffic from multiple subscribers in order to act on request from the STB.However, IGMP networks were not originally designed to have networking equipment between IGMP client and the IGMP routers. This creates some challenges to the multicast implementation: – Excessive multicast traffic: When delivering high bandwidth IPTV over broadband network, it is important to ensure that IPTV channels are forward only to those subscriber currently viewing them sinc e bandwidth is scarce. If the intermediate devices are unaware of IGMP flows then all multicast traffic is broadcast out all ports – Excessive IGMP traffic: Extra bandwidth is consumed as IGMP flows are broadcast to across the network.A single STB IGMP request can result in responses from thousands of IGMP peer clients. – Excessive time to Leave a group: With small spare bandwidth in broadband networks, Leave request often must be processed before additional join request can be served. To mitigate above challenges, several techniques are proposed and developed in intermediary devices: Local Replication, Proxy routing, Proxy Reporting, and Immediate Leave. Local replication, IGMP snooping from DSLAM, allows DSLAM to inspect incoming IGMP Join and Leave request and take appropriate action.If the channel being requested to view is already being received at the DSLAM, it will replicate the stream and forward to the subscriber. The DSLAM builds a table to track which channe l are being forwarded to each port. [pic] Fig. 17. DSLAM with IGMP Snooping Proxy routing works by allowing intermediate device (DSLAM) takes active role of terminating all IGMP flows. This makes DSLAM to act as IGMP host and responds to all incoming requests. DSLAM will recreate the IGMP request and use its own IP address as source.The major benefit of proxy routing is scaling since router is not aware of individual subscribers. [pic] Fig. 18. IGMP Proxy Routing Proxy Reporting reduces the number of IGMP packets flowing across the network by selectively dropping IGMP packets that are not need to be forwarded. The Proxy Reporting can be subdivided to two categories: Query Suppression and Report Suppression. Query Suppression reduces traffic between the DSLAM and the subscriber premises by having the DSLAM intercept and respond to IGMP queries sent by the router.DSLAM will never send a specific query to any clients and forward general queries only to those client receiving at least o ne multicast group. [pic] Fig. 19. Query Suppression. Report Suppression reduces traffic from DSLAM to the router by having DSLAM aggregate the response. The DSLAM can intercept IGMP reports coming from STB and forwards a summarized version to the IGMP router only when it is necessary. There are two categories of reports. Unsolicited membership reports are forward when first subscriber joins a multicast group or last subscriber leaves a multicast group.This tells router to begin or stop sending channel to this DSLAM. Solicited membership reports are forward once per multicast group. The DSLAM will aggregate multiple responses together into a single membership report to save bandwidth. [pic] Fig. 20. Report Suppression Immediate leave alleviate IPTV challenge to change channel rapidly. The standard IGMP Leave operation for channel change is as follow: – The STB sends a request to leave one multicast group – Router responds by issuing Membership Query to confirm the requ est. The STB responds with a Membership Report which does not include the multicast group By implementing immediate leave, STB can leave the multicast group by just simply sending a request to leave one multicast group [16]. [pic] Fig. 21. Standard IGMP Leave and Immediate Leave. The emerging IPTV deployments utilize Real-time Transport Protocol (RTP) in order to deliver media content. Unlike UDP, RTP protocol can provide sequence numbers to maintain packet ordering and detect losses, and timing information to determine network delay and synchronize timing between senders and receivers.RTP control protocol maintains session state between senders and receivers and report sender and receiver statistics bi-directionally [17]. The rapid acquisition is illustrated in the Fig 22 flow diagram below. [pic] Fig. 22. Rapid Acquisition Flow Diagram 1) The RTP receiver sends a Multicast Leave message to its upstream multicast router to leave the current multicast session and end the currently v iewed channel. 2) The RTP receiver sends a feedback message to the feedback target asking for rapid acquisition for the session it wants to join. In this feedback message, the RTP receiver can specify its specific requirements. ) The retransmission server receives the feedback message and decides whether or not to accept the request. If the retransmission server accepts the request, it sends a message to the RTP receiver that describes the burst that the retransmission server will generate and send, including the indication when the RTP receiver should join the new multicast session. The unicast burst stream consists of retransmission of a specific block of packets which will allow the RTP receiver to begin displaying video without waiting for a certain random access point to arrive in the multicast flow.If the retransmission server denies the request, it informs the RTP receiver immediately. 4) If the retransmission server accepts the request, it transmits the unicast burst data an d any additional message(s) needed to carry the key information about the new channel. The key information is used to prime the decoder inside the IPTV STB so that it can start decoding sooner. The unicast burst continues at a higher than natural rate until the unicast burst catches up with the real-time multicast flow. The sustainable burst rate depends on the access network link characteristics. ) At the appropriate moment (as indicated or computed from the burst parameters), the RTP receiver joins the new multicast session by sending a Multicast Join message to its upstream multicast router. 6) The RTP receiver starts receiving the multicast flow and completes the rapid acquisition. The STB will not join multicast session immediately with rapid acquisition since there would not be enough available left over on the access link. By utilizing unicast burst sent from the retransmission server o catch up with the multicast flow in a reasonable amount of time before joining to multicas t group allows faster channel switching capability rather than joining multicast group immediately [18]. Cloud Computing service in IPTV IPTV videos can be delivered to subscribers through various different network structures. For many years, Proxy servers have been utilized to decrease network traffic and delays through high speed and robust connection. Telco companies are looking for ways to keep service calls rejections to minimum through cloud service for on-demand IPTV service. Figure below shows on-demand IPTV service for cloud architecture. pic] Fig. 23. On-demand IPTV cloud services Video can be streamed from any of the virtual servers by load balancing among server and handle peak loads by avoid overload to achieve continuous, high utilization levels of servers. Virtual servers can provide low cost computing resources. The Virtual server acts like a dedicated server but it co-reside on a single physical machines acting as multiple physical dedicated server. However, if too many virtual servers reside on the single physical machine, services may face problem due to scarce computing resource per virtual server.Virtual storage through cloud computing allow easy share of resources among themselves. Physical storage is virtualized into virtual disk, which allows storage consolidation across heterogeneous vendors and protocols, enabled by dynamically growing and shrinking of storage through live migration, in the enterprise storage area network to be used by applications [22]. F uture application of IPTV The key to differentiating IPTV from traditional TV service of VOD and Network-based personal video record (nPVR) is the real-time interactive application and social TV.With FTTx or Gigabit Ethernet providing more bandwidth in broadband network allows new killer application to maximize the value of the IPTV service. A) SayUTV SayUTV service allows users’ participation into TV sports, discussion, variety show, and so on. SayUTV allow mixing their vide o and sources into provider’s content to allow maximum interactive and customize IPTV content. The subscriber can click participation button on SayUTV GUI. After service provider or host of the content allows his/her participation, the subscriber’s audio and video content is mixed into program’s content.All the viewer of the content can view the participant’s image and voice. [pic] Fig. 26. SayUTV Service System Architecture SayUTV service divides the role of users into three major roles: †¢ Controller – who creates a service session and has a control over that session. †¢ Participants – who joins the session and contributes his/her own multimedia content. †¢ Simple Viewer – who enjoys this service in a passive way [pic] Fig. 27. SayUTV Implementation. SayUTV is an advanced IPTV service, which combined with bidirectional multimedia communication technologies allowing interactive user-participation [20].B) IPTV Interacti ve Online Shopping In order for IPTV service provider to maximize the profit from IPTV service require smart ad insertion based on customers’ preference. TV series and sports media are well known for effective product advertisement aid. Apparels worn by a main actress of TV series or MVP sports athletes have greater potential for larger sales than conventional display by online shopping website. In order to provide customer’s shopping craving while watching TV series or sports event is to add additional information to the product description field such as TV series name, and character or athletes name.This will allow customers place some tags on that particular product through watching particular TV series or service provider can collect customers’ preference based on content and insert smart ad targeting each subscriber. [pic] Fig. 28. Shopperama Service Screen in Korea Shopperama is OTT provider in Korea providing series, which have broadcasted through a TV st ation, online along with smart ad insertion. The apparels worn by main actors and products inside the episode are displayed in a synchronized manner with video content as shown in Fig 25.This allows customer to shop for products very easily while watching TV series and reduce customer’s burden of trying to find particular product [21]. To improve interactive online shopping with IPTV service still needs many enhancements to fully flourish in E-business model. Behavior targeting content to users is estimate to be 20 billion dollar industry and in order for IPTV interactive online shopping to gain market share requires smart integration of cross layer platforms. C) Final Remarks With IPTV service deployment, Cable Company is afraid of cord-cutting case.The IPTV service is gaining popularity amongst consumer and there are many opportunities for new killer application to integrate with IPTV service. In this paper, we described current IPTV architecture in the market and presented recent efforts to improve IPTV technology. 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