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Focus: FireWire Networks
Streaming Unlimited

Can FireWire supplement Ethernet-based networks as a viable storage and networking system? by Dr Seamus Phan

Are you a home moviemaker who carries a miniDV camcorder wherever you go? If so, you'll know that the best way to archive all those wonderful memories is to convert the miniDV tapes into a digital format such as DVD, or perhaps VideoCD, if you are not too fussy with video quality.

However, the process of converting tape data into digital formats suitable for online non-linear editing (NLE), as well as eventual deployment into multiple data formats including QuickTime, RealMedia, Windows Media or
even MPEG4, can be tedious and complex.

What then, can organizations do to store audio and video information, as well as provide high-speed bandwidth to stream them to users, especially on LANs?

The answer may lie in a combination of IEEE 1394 (commonly referred to as iLink by Sony, or FireWire by Apple Computer) devices, and various digital format conversion software running on alternative FireWire-based networking software.

Short bit on FireWire

IEEE 1394 or better known as FireWire, uses 64-bit fixed addressing derived from the IEEE 1212 standard. Each packet of information carried out contains a 10-bit bus ID (for tagging which FireWire bus the data comes from), a 6-bit physical ID (for identifying which device on the bus initiated the data transmission), and a 48-bit storage zone (that is capable of addressing 256 TB of information for each FireWire node).

FireWire nodes are best kept 4.5m or below from each other to retain data integrity, and the total aggregate distance for a series of daisy-chained nodes should be 72m or less, with no more than 16 hops.

FireWire?
Just what is FireWire and why is it so interesting, especially in a small departmental network that needs to share very large files?

In a nutshell, sheer speed. FireWire can transfer data up to 400 Mbps, which when compared to 100 Base-T Ethernet's 100 Mbps is four times as broad a bandwidth.

FireWire is also a plug-and-play data transfer protocol, which means you can remove storage disks on the fly, and plug them back when you want them. It is a daisy chain system, which means that you link one device to the next. FireWire connections can be powered or unpowered. Computers that have built-in FireWire ports tend to have powered ports, while removable disks tend to require power from another source, such as a host computer or a power supply.

To be able to share information using FireWire between different computers, you cannot simply plug FireWire cables from one computer to another and expect the peering computers to turn up in your network neighborhood. You need software that allows computers to "see" FireWire as a legitimate data sharing protocol. One such software is FireNet Software (www.unibrain.com), which turns the FireWire port into a 400 Mbps data transfer demon, and allows computers to use FireWire much like Ethernet.

With FireNet, FireWire connections operate exactly like Ethernet, allowing all TCP/IP traffic to travel through the FireWire port, including AppleTalkIP, FTP, http, streaming and so on. Using FireNet, coupled with Unibrain's FireNAS, you can easily move hundreds of megabytes of data to and from computers, and easily archive them to the NAS.

FireNet co-exists with Ethernet, and you can operate two completely independent and redundant networks for a small group of computers. For example, Ethernet can still be used for general network and Internet connectivity, while FireNet can be used in place of Ethernet for the transfer of large files within the workgroup. FireNet works with most modern flavors of Microsoft Windows, and Mac OS 9 and X.

But because FireWire is daisy chained, it presents some challenges when linking a network of computers together. This means that you should not unplug cables that connect from one workstation to the next, especially during a day where data transfers are intensive.

Ideal FireWire work places
Some environments that can quickly realise the financial and productivity benefits are graphic studios and color separation houses, video post-production studios, computer animation studios, corporate e-learning departments, as well as bioinformatics laboratories.

If you do not require a FireWire NAS, you can also designate one of the computers as a FireWire NAS. For example, if you have a user who uses the computer for light-duty computing such as word processing, and the machine has sufficient data storage capacity (or can be easily upgraded with another internal hard disk of 50 GB and above), you can turn on file sharing through FireNet for the rest of the workgroup to move files into and out of this machine. Because file sharing is an inherently insecure mechanism, you want to ensure that this arrangement works behind a strict firewall implementation, so DHCP and NAT are turned on.

This will create a parallel data sharing network over the existing Ethernet backbone, without compromising speed and productivity of the network.

Moving from tape to disk
Capturing video on DV tapes is easy, but the real use of the video content is in mass distribution, especially over a network.

Rather than shooting corporate e-learning or other communication footage on DV tape, and then using a NLE (non-linear editor) to digitize the footage from tape to a digital format (such as QuickTime or raw DV data), there are now FireWire devices capable of allowing real-time capture of video to disk, without requiring the intermediary stage of digitization.

There are some common FireWire DV disks, including DV Bank FireWire DV Recorder from DataVideo (www.datavideo-tek.com), and FireStore from Focus Enhancements (www.firestore.com). Both disk recorders allow you to use a 4-pin to 6-pin FireWire cable to connect your miniDV camcorder to the disk recorder, and record directly to disk without recording to tape first.

The DV recorders can be seen by computers as merely another FireWire removable disk, typically without the need for driver software. In this fashion, the DV footage is usually in raw DV format, which most modern DV-compatible NLE software can edit right away. For Mac users, the DV footage can be imported into the iMovie software without conversion, or use QuickTime to import the DV footage and convert into MPEG4 footage.

Bringing video to networked desktops
QuickTime (www.apple.com/ quicktime) and DV are not the most ideal formats for networked delivery and streaming, since both formats are humongous in size. The current favorite is MPEG4, which is a streaming and bandwidth friendly video format suitable for networked delivery as well as mobile devices such as cell phones and PDAs. MPEG4, because it is a relatively new video format, has several variations to make it incompatible with different platforms. However, most platforms will accept MPEG4 Simple Profile, the baseline for MPEG4, which can scale from a baseline playback speed of 15fps (frames per second) to 30fps.

PacketVideo, one of the oldest MPEG players in this market, has PVAuthor (www.packetvideo.com), which is an encoder capable of generating Simple Profile MPEG4. PVAuthor also provides for automatic bandwidth negotiation, necessary for scaling MPEG4 video up or down, depending on the bandwidth of the playback hardware. For cell phone and PDA playback, PVAuthor is the best encoder around.

Ligos (www.ligos.com) is another veteran in the MPEG space, and has GoMotion, which produces the most compatible MPEG4 Simple Profile footage suitable for almost any playback mechanism.

For video streaming, it is important to have a dedicated streaming server. If you are using a Mac running OS X Server 10.2, you will have QuickTime Streaming Server provided. It is technically possible to run a workstation both as a client and a server, especially if the computing is light, since OS X has true multitasking. But with the rapidly decreasing costs of hardware, it makes more sense to dedicate a full-time machine to streaming content to other networked desktops.

Ethernet has become ubiquitous with most corporate networks, but its purpose as a general purpose networking protocol makes it less ideal as a bandwidth-hungry multimedia streaming protocol, especially where resources in organizations can be shared by hundreds of employees. With localized streaming using IEEE 1394 or FireWire, corporate workgroups can enjoy quality content streaming, and still have their Ethernet fully functional for other connectivity requirements.

Seamus Phan is research director at KnowledgeLabs News Center (www.knowledgelabs.net), an independent technology news bureau and writes for Network Computing-The Asian Edition.

E-mail at editor@networkmagazineindia.com

 
     
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