Superfast networking with IP over 1394

Introduction

IEEE 1394, also known as FireWire or by Sony's trademark name i.LINK, is best known as a high-speed serial data transmission protocol for connecting devices such as digital video cameras or storage devices to a PC or Mac. However, recent versions of Windows have added another dimension to its bag of tricks: two or more PCs equipped with IEEE 1394 ports and suitable cabling can be networked together, yielding data transmission speeds far faster than those possible with 10baseT Ethernet or even 100baseT "Fast Ethernet" connections. Best of all, it's surprisingly easy. In this article, we'll look at how to do it and why you might want to.

Configuration

Windows XP (Home and Pro) and Windows Me include IP over 1394 network support as a standard feature. Our test configuration included both of these operating systems. One was running Windows XP Pro; the other ran Windows Me. Plug and play operation of the FireWire connection was seamless in both cases. Windows XP automatically assigned a private IP address. Windows Me didn't seem to work correctly until we assigned a static IP address. (Your results may vary.) This address may be identical to an IP address already assigned to a different network adapter in the same machine.

Performance

We tested a pair of PCs connected via 10baseT, then equipped each machine with an Orange Micro FireWire card and, with the help of a 6-pin-to-6-pin IEEE 1394 cable (we paid $15), we compared the machines' network performance using a high-speed FireWire connection. There is nothing unique about the Orange Micro card, per se, any OHCI-complaint FireWire card supported by Windows should work.

IP over 1394 vs. Ethernet Emulation

An alternative to this IP over 1394 support built into Windows is offered by Unibrain's Firenet. This product (available for free evaluation from a download page on the company's website) supports both windows and Mac-based clients. It, too, is dramatically faster than 100baseT, as shown in a performance and feature summary at unibrain.com. In fact, Unibrain says it is even faster than IP over 1394. This is because, the company explains, it uses a simpler method to discover network nodes and translate Ethernet Addresses to 1394 Node IDs, thus it can locate faster the network nodes after each bus reset and also cause less bus traffic. It also uses a simpler method to transmit / receive Ethernet packets and does not require a packet fragmentation and reassembly procedure, so it reduces CPU usage and increases the throughput. It is solely dedicated to PC networking, while the  IP over 1394  is  designed as a solution for connecting various 1394 devices.

Cross-Platform Networking

Apple, in Dec. 2002, released (then, on Dec. 9th, withdrew) a developer preview version of an IP over 1394 kernel extension for Mac OS X. Like its Windows counterparts, it is supposed to support standard TCP/IP protocols. (I say "supposed to" because, at this writing, the two stacks don't appear to interoperate properly -- possibly due to the "developer release" status of the Apple product.) Apple's software does, however, support the emerging "ZeroConf" standard, known in the Apple world as Rendezvous. Slashdot has details.

There is also an effort to bring FireWire networking to the Linux world. Unfortunately, the Linux 1394 project hasn't progressed much yet.

Limitations

The main limitation of IP over standard 1394 network configurations is the relatively short distances permitted between network nodes. FireWire has a cable length limit of about 4.5 meters, beyond which FireWire repeaters must be used. While Ethernet is also limited, its range is substantially greater, at 100 meters for 10baseT, making it more convenient for large networks. (MacObserver.com has details.)

To fully address the distance issue, you would need a FireWire to Fiber transceiver. These devices are starting to appear on the market. Although prices are currently high (~US$500), they allow a FireWire signal to travel very far - up to 40km!

Conclusion

FireWire networking provides a cost-effective alternative to Gigabit Ethernet configurations, for closely-knit local area networks. Although the price of Gigabit Ethernet cards has declined dramatically since Y2K (research firm IDC estimated the average industry price for a Gigabit Ethernet NIC in 2000 to be about US$460; today it's about $50), Gigabit switches are still quite expensive -- at this writing, about US$800-$900.

For the cost of a couple of C$75 FireWire adapters and a $15 dollar cable, we achieved more than ten times the performance of our old 10baseT network. Providing about 44 percent more performance than a 100baseT network, our TCP/IP-over-IEEE 1394 solution clearly offered us the best bang for the buck when beefing up our office network, while simultaneously adding attractive expansion capabilities for simple connection of FireWire-based hard drives, high-speed CD burners, digital cameras, scanners and other devices. There are faster networking standards (e.g., Gigabit Ethernet, although its real-world speed is not that much higher), but none provide the flexibility and seamless plug-and-play ease of FireWire.

Networking Glossary (and archives)

FireWire – Sometimes called IEEE 1394 or "i.LINK," FireWire is a relatively fast digital input/output system, providing transfer rates of up to 400 megabits per second. FireWire is built into some new computer models from Apple and SGI and is available, via an add-on card, for most others. FireWire is a recommended I/O system on machines conforming to the PC99 spec and FireWire is becoming a standard feature on sound cards (e.g., Creative Labs' Audigy) and a growing number of inexpensive add-on cards. Faster 800Mbps and 1600 Mbps variants of FireWire are in the works, with the 800Mb 1394b variant likely to emerge (backwards-compatible with the existing standard) in 2003.

IEEE - an international engineering standards organization.

Mb - Megabit, sometimes written as Mbit. One Megabit is one-eighth of one Megabyte. Thus, 400 Mbps = 50 MB/sec.