Media Server Technology: Karl Paulsen

Applying the Network Appliance

Could the video file server evolve to become a video network appliance? The question is certainly one to consider as we watch server development continue year after year throughout not only the broadcast industry, but in production, postproduction, cable and corporate business domains, including independent service providers.

A network appliance is fundamentally a dedicated device that has application-specific functionality in a self-contained environment that can be controlled, adjusted or upgraded over a network connection. To understand how the concepts of a network appliance might be applicable, let’s examine what is currently evolving in this arena.

ATTACHED STORAGE

First, we need to review the concept of Network Attached Storage (NAS). NAS is a data-centric storage architecture that leverages existing network infrastructure and network administration skills. Over the past 10 years of development, NAS has gained acceptance from a broad array of companies as a cost-effective means to satisfy general file-serving needs.

NAS is now also becoming a viable option for storage-intensive service providers, such as application, Internet, and storage service providers. When the sharing of files is required, NAS applications become well-suited, especially for imaging, streaming/multimedia and document management.

In the computer-centric world, NAS adheres to the appliance model of computing, as special-purpose servers that store and deliver files over a LAN. NAS architectures provide file and storage services through secure standard network protocols.

TCP/IP is used for data transfer with Ethernet and Gigabyte Ethernet as the network transport. More users are embracing the NAS model, leading vendors to actively address external storage and their communication requirements.

NETWORK NICHE

Video and media file servers may find a niche in the network appliance area. Video servers have now evolved into yet another next-generation system by incorporating many new network-centric concepts. Files can now be delivered via ftp, using TCP/IP, as well as over the higher-speed infrastructures of Gigabit Ethernet, ATM and Fibre Channel.

When looking at concepts for centralized broadcasting, including distributed broadcast hub-and-spoke models, users can make practical sense of file transfer technologies as the exchange of compressed digital images migrates from base line SMPTE 259M (ITU-R-601 video) to packetized transmission of compressed MPEG2 video/audio/data between devices.

A potential direction for a video server approach to NAS might be in the ‘appliance’ configuration. In the computer-centric world, a server appliance is defined as a network-enabled device designed to provide a single dedicated service, such as e-mail, file/print or Internet access. It may contain a predefined suite of services including store and forward of program material, spots or even clips for desktop editorial composition.

Server appliances are intended to come preconfigured for the specific activity they are designed to provide. These sealed systems are generally nonprogrammable and run on functionally optimized and/or streamlined operating systems.

EASY UPGRADE

The server appliance is easily upgradeable, accomplished either locally or in some instances via a remote access operating system. Upgrades can include entire applications or feature sets that enhance that specific application. Such devices would be sold as closed-solution units, designed for ease of deployment and minimal TCO (total cost of ownership).

For broadcast or television news operations, one might find independent news distribution entities providing these appliances to news departments as dedicated servers and storage for daily news feeds. The program syndication delivery industry could place individual server appliances in a facility’s technical operations areas, then extending control hooks into the station automation system for automated recording and timed playback according to the traffic schedule and contract rights allowed on a station by station basis.

In the same fashion that commercials are being delivered to the stations today (i.e., DG and Williams/Vyvx), programs could be delivered with all the necessary elements plus an exact timing schedule that is pre-sent to traffic over the Internet.

Once the program is scheduled for air, it plays out directly from that specific server appliance it was received on, into the air chain – thus eliminating the current practice of transferring the spot to tape, timing it, then ingesting it to the main broadcast server for playout at a later time. In the appliance model, if the program is scheduled to play more than once, it is kept on the server appliance. If not, the material is automatically purged during the next scheduled recording session.

PROGRAM DELIVERY

Program material could be delivered via satellite, dedicated line or network connection. Potentially, the content could be sent at a much lower rate than the playback rate, and "collected" in the server until the entire program is complete. Errors detected in missing or corrupted packets are relayed back (via Internet or dialup backhaul) to the delivery point where an unattended re-send of the bad packets is broadcast to all receivers. Those that don’t need the packets ignore the new data, those that do replace or insert them at the respective server appliance until the program stream is completed.

Program feeds – for example, a half-hour syndicated release – could be dribbled into the server (via the Internet, over ATM or from a slice of a satellite feed) over the entire day. An 8 Mbps feed over a T1 (1.5 Mbps) line would take 5.33 times as long to deliver (30 minutes might take as much as 2-3/4 hours), but probably at less cost than alternatives such as full transponder baseband, digital IRD or dedicated TV1 type circuits.

Once all the program deliveries are complete, an acknowledgment is sent to the delivery agent and to local traffic that the program is "in-house" and ready for scheduling into the log. The entire operation could occur unattended, from the time of order entry (contract) to the moment it airs.

AT YOUR SERVER

Server appliances, envisioned as small, rackable devices designed for specific applications, could change the complexion of the video server to that of a "tapeless-VTR." When the need for storing only a few hours of each program per week arises, the tapeless-VTR cost model versus a large-scale server approach might actually be attractive for applications such as remote insertion of programs, spots or interstitials. Further possibilities, such as multiple server appliances, could make temporary mirroring and/or backup systems a cost effective, scaled down option for the daily or weekly turn around of satellite (or Internet) delivered programs.

Even personal video recorder (PVR) product lines are taking a look at a similar network approach, where the network-PVR takes a server-side alignment, with encoders and disk drives stored at the network headend, reducing the requirements for consumers to purchase, install and configure more-expensive or complicated devices while still enabling VTR-like stunt features.

Like the ease of VTR-technologies we’ve grown to know and understand, any future in server appliances and their applications for video and media industry will need to incorporate the performance, features and functional benefits of servers and storage, while delivering them under a network-centric business model. There must also be an ease-of-deployment and management typical to networking devices and available at a significantly lower cost than current offerings.

Keep your eyes open – these appliances may find their way into the slots in your rack room where legacy VTRs once lived.

Karl Paulsen is VP of Engineering for AZCAR (www.azcar.com). He is the author of the second edition of "Video and Media Servers: Technology and Applications" (published by Focal Press) – a compilation of the early years of this column and its applications to broadcast and industry. Contact him via e-mail at: karl.paulsen@azcar.com.