Electro/Telecom Industry Trends
May 2003
Ethernet and 1394: What each brings to the table
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Most people in the consumer electronics industry believe both Ethernet and IEEE 1394 protocols will be integral to the future of home networking, and they should be. Each delivers specific benefits.
"1394 was designed from the ground up to transport audio/visual (A/V) content,” explains Glen Stone, director of Hardware Architecture and Standards for Sony. Ethernet was created to transport data, a job it performs quite well. While Ethernet may be the network protocol working in U.S. household connections today, 1394 will add the entertainment element to home networking. Here’s a quick look at why each technology will be vital in linking consumer electronics (CE) devices together.
Highway versus railway
Ask Bill Rose, president of WJR Consulting and chairman of the Consumer Electronics Association (CEA) R7 Home Networking Committee to explain the main difference between Ethernet and 1394, and he’ll point you to the analogy of highway versus railway travel. “Like a highway, anyone can get onto an Ethernet network whenever they want to, and like a highway, you’ll go as fast as traffic will allow. As traffic builds, things slow down and it gets more difficult for people to get on.”
Ethernet traffic works this way because the protocol is asynchronous, meaning that data isn’t transmitted in regular intervals or a continuous stream. “The Internet is called a best effort network because Ethernet technology makes its best effort to move your data,” Rose explains.
Compare that to the synchronous protocol of 1394, which operates like a train in that it allows you to reserve space (bandwidth) and operates on a predictable schedule. That makes it perfect for A/V applications where you can’t have delayed data packets or you’re likely to have a blank TV screen. Such quality of service (QoS) guarantees make 1394 appear the better network of the two, but that’s not necessarily the case. It has its limits, and Ethernet has undeniable strengths.
Taking the best of the best
Among Ethernet’s virtues, you’ll find price. “Ethernet is very affordable,” notes Stone. “Plus, it’s available now. You can go to a store and buy all sorts of Ethernet devices.” Ethernet networks can have unlimited nodes (or device connection points) Stone explains, but that’s a mixed blessing. “If you link many devices together in a complex way, you can have topology problems. You can inadvertently hide subnets and make devices hard for the network to find.”
In contrast, 1394 was designed as a cluster interconnect where a group of devices physically connect on a common medium and need no translation between the media access layers in which the devices discover each other. Says Stone, “In a home you could have a 1394 set-top box on the TV, a 1394 M3P player, a 1394 DVD player and a computer, all connected into a cluster. Originally, a 1394 cluster was limited to a room because the cables are only about 10 feet long. Now there’s 1394.1, which is a bridge for clusters so you can get more nodes and there’s 1394B, which allows longer distances so you could build a whole home network with 1394,” But chances are, the home network will be a mix of networks.
Even if newer consumer electronic devices are equipped with 1394 ports, legacy products won’t be. And high speed Ethernet is the likely whole-house distribution network or backbone that connects devices from room to room so you can start downloading a movie in the den and finish watching it in the bedroom. For better or worse, both 1394 and Ethernet will have a partnering role in the future of home networking. And the team at CEA is now creating the standards to ensure these disparate technologies work well together.