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Rules changing for the home media server

Posted: 02 Aug 2004 ?? ?Print Version ?Bookmark and Share

Keywords:home network? server? pc? hdtv? lan?

Digital home networks have undergone a rapid evolution that has left the home's traditional PCs and gateway-hub combination in the dust. The emerging network topology is creating an entirely new set of system and performance requirements to efficiently disseminate multimedia content around the home. Instead of a centralized structure, equipment designers are migrating to a more decentralized network where the functions traditionally housed in the PC are distributed across the network.

The enabler for this structure is the media server, which designers must constantly update to meet the ever-changing connectivity, traffic and performance needs of the end user. The key to building high-performance yet cost-effective servers will be the adoption of a highly modular design built around the industry-standard PCI bus and communications processors.

Initial home network deployments coincided roughly with the first widespread deployment of broadband network connectivity. In this first phase, home networks often comprised a PC connected to the WAN via a broadband modem. Usually, these early deployments included little or no LAN connectivity.

Phase two of the digital home network occurred as users began to appreciate the always-on features of their new broadband services. As PC prices dropped and users replaced older models with new systems, users realized the increased bandwidth could be easily shared among multiple users at home by adding an Ethernet routing device to the LAN side of the broadband modem. Eventually, this new commodity status for broadband routers, gateways and Internet Protocol-sharing devices allowed users to build basic home networks at little incremental cost. The rapid decline in the cost of wireless networks also fueled this movement by simplifying the home network deployment process.

The third phase of the digital home network, sparked by the rapid growth of rich multimedia content, is now underway. Users are demanding that their home network be able to share rich content outside the traditional PC network. Whether that is on-demand movies and TV, massive multiplayer online games, streaming music or personal videoconferencing, users want to distribute this data around the home and make it accessible on both their PCs and home entertainment systems. Accordingly, today's home networks must bridge data and consumer electronics networks by interconnecting everything from PCs, laptops and handheld devices to camcorders, DVD players and HDTVs. Over the long term, users can even expect to fold home automation, security and voice telephony devices into this expanding network.

At the heart of the digital home network lies a new system: the media server. It provides a central repository and network distribution center where shared data can be stored and disseminated without PC intervention. Typically, it is able to capture digital content from cameras, MP3 players and other network appliances and provide the means to transcode content into various playback formats. It combines extensive connectivity, via WAN or WLAN or both, with high-performance standardized interfaces to mass-storage devices usually in compliance with the Integrated Device Electronics format.

Designers building home network media servers now face a series of crucial trade-offs. Industry standards are in constant flux, particularly in a new and rapidly changing market. Designers must decide whether to support existing disk drive formats, such as ATA or SCSI, as well as emerging high-performance serial versions including serial ATA and serial-attached SCSI. To interconnect peripheral devices capable of delivering digital content to the home network, the server should also support both USB and IEEE 1394. In both cases, designers must decide whether to support the current generation of the interface in use or its emerging successor.

LAN connectivity poses another dilemma. Should the server support wired or wireless access, or both? What are the cost implications of supporting one connection over another? For example, in the wired arena most networks are based on Fast Ethernet technology. But will users require Gigabit Ethernet in the near future? In the wireless domain the decisions are even more complex as designers must choose among 802.11b/g and the possibility of other, as yet undefined, UWB wireless standards.

A key step in the decision-making process is determining the performance requirements of the network, both in terms of bandwidth and the computation resources needed to manage and distribute the network traffic. One important point designers must consider is how traffic characteristics will change depending upon the use. Applications such as Web surfing or e-mail are moderately bandwidth-intensive and can support some latency. If traffic bottlenecks occur, they are likely to be at the broadband connection or outside the home on the WAN.

On the other hand, home entertainment applications such as HDTV, multiplayer online gaming, streaming music and personal videoconferencing are more real-time in nature and are more sensitive to performance latencies. Still other applications, such as printing, data backup or network file storage, may consume even more bandwidth. Ideally the network media server will be able to support different traffic classification and prioritization capabilities across the network and, at the same time, support low-latency and high-bandwidth applications.

To meet this imposing array of performance requirements, the media server must be built around a highly flexible and highly integrated communications processor. To address the computation needs of these applications the processor should be based on a high-performance 32bit core capable of operating at clock rates in the hundreds of megahertz.

Crucial advantage

An important feature in an integrated communications processor is support for the popular PCI bus. In the dynamic digital home network, flexibility of design and the ability to scale a system to meet changing requirements represent a crucial design advantage. As users demand change and new standards evolve, designers must quickly adopt their design to new hardware and software requirements.

By using the PCI bus as a standard interconnect among system elements, designers can leverage a wide variety of currently available low-cost peripherals and supporting software. They can also use readily available components for network connectivity and multimedia support to develop custom solutions. Most important, they can design a highly modular system that can be modified quickly and inexpensively as market needs change.

Also, the integrated processor should offer a high-performance interface to the DDR memory controller as well as an integrated Fast Ethernet interface with support for the Media Independent Interface (MII) and Reduced MII standards to simplify network connectivity. Going forward, a Gigabit MII should be considered as PCs move toward utilizing this higher-speed interface. To minimize software costs, the processor should run an optimized version of the Linux operating system and include device drivers and application support for popular home-networking applications including hardware-accelerated multimedia codecs, USB host controllers, ATA and serial ATA chipsets.

- Alex Soohoo

Strategic Marketing Manager

Internetworking Products Division

IDT Inc.

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