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IPTV redefines packet processing requirements at the edge
(Electronic Engineering Times Via Thomson Dialog NewsEdge) The rapidly growing momentum behind worldwide broadband deployment and the emerging "triple-play" convergence of voice, video and data services offers network carriers a promising answer to shrinking revenue from traditional landline voice customers. By bundling voice, video and data services in unique and creative ways, carriers hope to differentiate themselves from both traditional and new-entrant competitors. Of particular interest is the move to an all-IP (Internet protocol) network and the deployment of IPTV, which is expected to enable operators to offer a wide range of exciting new services and generate incremental revenue streams.
It is important to note, however, that IPTV is very different from traditional cable/satellite TV services and will place significant new demands on telecom network infrastructure. In a cable/satellite-based system, for example, viewers can only watch those channels offered by the service provider. With IPTV, however, users not only have a much, much wider channel selection, but they also have the opportunity to view what they want, when they want it.
Built around the same transport mechanism subscribers already use for Internet browsing, instant messaging, e-mail and other communications functions, IPTV allows carriers to offer a truly interactive environment for the first time. This interactive environment combines high-definition TV (HDTV), video on demand (VoD), network private video recorder (PVR), video telephony, Internet access and other multiple functions. For the current "lean-forward" generation accustomed to extreme multitasking, the ability to simultaneously text message friends via TV while watching is a powerful draw that neither "PC-over-broadband" nor cable/satellite TV can match.
Opportunity and obstacles
The greatest obstacle that service providers face in the successful implementation of IPTV is the state of the transport network. As currently constructed, the transport network supports Internet traffic, voice-over-IP (VoIP) and video over the Internet, but the quality-of-experience (QoE) for each of these services is limited. Two factors are important in users' QoE: the bandwidth offered by the access network and the mechanisms available to manage traffic at the edge of the network. In particular, any implementation of IPTV today would be forced to share the same IP network with unmanaged traffic such as peer-to-peer (P2P) file sharing, and inevitably this network architecture would lead to bandwidth contention and bottlenecks.
For IPTV to succeed, carriers and service providers must offer a QoE equal to or better than that offered by today's cable/satellite TV. The key to achieving this goal will be the development of "content-aware," network edge devices that are capable of tracking, managing and prioritizing the multiple signal streams flowing through the edge of the network.
A common platform
A second major obstacle to the implementation of IPTV is the development of a common platform to roll out IPTV services. This platform must offer low operating costs, excellent scalability, simple maintenance, guaranteed compatibility with existing infrastructure and a rapid ramp-up to volume production. Since IPTV networks must offer a wide range of constantly evolving features and functions, the platform must also be highly modular in form to ensure operators that their significant capital investment will be "future-proof."
IPTV edge devices must also support multicast streams for regular broadcast channels as well as unicast streams for VoD content. Multicast capabilities will require dedicating resources. For special broadcast channels, IPTV multicast streams may use prereserved resources from head-end to the IP edge. At the IP edge, dynamic resources (media streams) will be required to broadcast these special channels to the digital subscriber line access multiplexers (DSLAMs) and/or the passive optical network (PON) aggregators responsible for sending IPTV streams into subscribers' homes.
The key to managing this increased bandwidth and guaranteeing QoS will be the development of network edge devices capable of extremely rapid packet processing for deep-packet inspection (DPI) at up to 10-Gbit line rates. These capabilities will not only allow service providers to filter bandwidth-intensive applications like P2P file sharing and encapsulated traffic, but they will also play a key role in prioritizing bandwidth associated with premium content such as VoD, HD channels and sporting events.
IP edge devices in the IPTV network will be responsible for aggregation, channel changing, edge routing, congestion management and traffic shaping to provide QoE to IPTV subscribers. These new edge devices must be bandwidth-efficient and able to simultaneously manage both broadcast video (multicast streams) and VoD content (unicast streams). They must also offer faster channel change by giving preference to requests from the access network (via DPI) of the IGMP messages and prioritizing them for processing at the edge device.
One of the distinguishing features of IPTV will be "time-shift" viewing, which allows the viewer to "shift" the timing of the broadcast of an entire channel lineup. This will give service providers an opportunity to insert time-sensitive and content-relevant advertisements into a broadcast. Furthermore, operators will be able to offer both demographic-specific and variable-length advertising based on users' preferences. This functionality will be implemented using content-insertion software, based on DPI functionality embedded in IP edge devices, where local broadcast channels and advertisements are fed into the IPTV network.
Distributing content
Telecommunications companies have not yet determined how they will handle clients and suppliers of content such as P2P video traffic (such as YouTube), which will require a different strategy that can apply to a business environment as well as to recreational consumption. Service providers will need to use DPI to determine what content is flowing across their IP network; they can then use that information to modify their delivery strategy and potentially create new revenue streams from P2P TV. IP edge devices need to have highly flexible and scalable storage capabilities to address changing user tastes and fluctuations in content popularity.
Frequently used features such as an electronic programming guide (EPG), digital rights management (DRM) servers and subscriber e-mails will also be kept at the edge of the network. To deliver these services, operators will need to integrate application servers, which will be upgraded into the IP edge platform.
Additionally, to support the coming convergence of IMS services into the IPTV network, telcos will need IP edge platforms with enough scalability to adapt to advancements in hardware and software. Service providers will probably need IP edge devices built into a field-proven, standardized hardware architecture such as advanced telecommunication computing architecture (ATCA), which is widely regarded as the next generation of carrier-grade, standards-based telecommunications infrastructure.
To reach broadcast-TV-quality levels, these IP edge devices must also offer bandwidth-prioritization capabilities for providing guaranteed QoS. HD VoD servers will require multiple high-capacity unicast streams to DSLAMs. To deliver this level of service, the edge device will need to combine the general processing power found today in an ATCA multiprocessor computing blade, with the high-speed packet processing power available in an ATCA packet-processor blade. By basing their platforms on the ATCA standard, IPTV providers can scale their nodes with plug-and-play, ATCA-compliant blades as their subscriber base grows. Pre-integrated platforms will help service providers meet demand for increasingly complex systems in short development windows and will reduce integration and compliance risk.
Managing security
Network security will also be a major concern for IPTV operators. Intruders can use unprotected nodes to spoof, or masquerade, data in various ways, such as unauthorized channel-change requests, NPVR requests, VoD requests and so forth. As these Internet security threats evolve, a robust security mechanism needs to be in place, because network providers cannot rely on simple firewalls or other traditional security measures that are easily overcome by determined and sophisticated hackers.
In an IPTV network, providers will need equipment capable of performing 10-Gbits/second line rate DPI at Layers 4 through 7 to analyze complex patterns for threat signatures. Over time, these complex patterns will also likely evolve, and the only way to combat these threats will be through network edge platforms capable of combining hardware- and software-based DPI at line rates to not only block DDOS (distributed-denial-of-service) attacks but also quarantine and block the latest worms and viruses at the edge of the network. The ideal solution is to combine a high-speed packet-processing blade with traffic-engineering capabilities on an ATCA-based platform.
To support several channels using SDV technology, IPTV networks will also require high-speed switching in the range of 10 Gbits/s to support a fast (and hence) satisfactory channel-change experience. To connect the high-speed core network to DSLAMs/PONs in the access network, service providers will also need Ethernet-switching capability at the edge; an ATCA-based 10-Gigabit Ethernet (GbE) switch can meet this switching requirement.
Software requirements for IPTV edge devices will be critical as well. These nodes will require unicast stream handling, multicast stream handling, SLA-based QoS and subscriber-management capabilities. Ideally, these applications should be hosted on flexible, open standards-based platforms to simplify functional integration and drive down costs.
In addition, such platforms should be scalable, highly reliable and fully integrated with software, so that service providers can focus exclusively on their unique applications expertise.
Nitin Tomar (nitin.tomar@ccpu.com) is technical marketing engineer at Continuous Computing (San Diego). He has a bachelor of engineering degree in computer science and engineering.
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Copyright 2007 CMP Media LLC. All rights reserved.
Copyright ? 2007 CMP Media LLC
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