Developer to demo 400Mbps powerline Ethernet
Double today's LAN-over-mains bandwidth
DS2, the Spanish chip maker behind one of the two rival ethernet-over-mains-wiring technologies, will next month demo a next-gen version of powerline that runs at up to 400Mbps - double today's top speed.
It may be ready to show the technology working, but it's some way from releasing chips that can be incorporated into products consumers can buy and install. DS2 said it was targeting the technology at people who want to stream around at least three HD signals and two standard-definition feeds around the home. It expects such an application to be in demand "from 2009 onwards", and that's when it expects to get 400Mbps technology into powerline Ethernet adaptors.
DS2 also promised the 400Mbps system would be compatible with its 200Mbps version, though it's unclear whether it means the two will co-exist on the same wiring - as today's 200Mbps links co-exitst but won't talk to older 85Mbps and 14Mbps adaptors - or will be able to communicate with them.
Like earlier powerline technologies and wireless networking systems such as Wi-Fi, the quoted speed is an all-out raw data transfer rate - and one that assumes perfect transmission conditions. Real-world speeds are likely to be rather lower than 400Mbps.
Using 200Mbps powerline links yields a real-world bandwidth of around 40-50Mbps, for example - sufficient for two HD streams. DS2's 400Mbps technology will need to deliver real-world bandwidth of approximately double that to handle three or more HD streams and various SD signals.
Rival powerline group, the HomePlug Powerline Alliance, has yet to detail its own plans to push its 200Mbps technology beyond that speed.
MB/s vs Mbps
The speeds given on this and other network gear are in Mbps. That is megaBITS per second. There are 8 bits in a byte, meaning that 400 Mbps is about 50 MB/s, and that's ideal theoretical throughput. A single SATA drive's real world throughput can usually saturate even this ideal throughput. Heck, my EIDE laptop drive can push close to 30 MB/s.
DS2 not Homeplug - ARRL comments on Homeplug
The ARRL is the US national amateur radio organisation:
ARRL Laboratory Supervisor Ed Hare, W1RFI, knows HomePlug well. “ARRL has had a long-standing cooperative relationship with HomePlug,” Hare said, “helping them to make the decision not to use the amateur bands in their product specification. This has been a successful model. Over the past 7 years, even though there are over 6 million HomePlug devices deployed, ARRL does not have a single report of harmful interference to AmateurRadio involving HomePlug products. If the entire BPL industry could follow their lead and formally do what HomePlug has determined needs to be done, interference from BPL could become a manageable problem.”
However, DS2 is NOT a HomePlug Alliance member or compliant to the HomePlug spec - and although they can notch out Ham radio bands, this is not their default as it harms their performance...
BTW, several of the HomePlug silicon vendors will have silicon released next year with PHY layer performance up to 1Gbps..
If you think about using a powerline/ethernet adapter, I'd recommend a HomePlug compliant one (there are around 40 different vendors which have been tested for compliance, look for the logo..) - they really are plug and play - and perfect for networking video around the home...
RE: sampler & Barry
400Mbps = 400,000,000 bits per second
300MB/s = 8*300,000,000 bits per second
= 2,400,000,000 bits per second
A SATAII hard disk could easily saturate a 400Mbps link (if both ran at theoretical maximums, neither will).
With 200Mbps adaptors getting 'real world' performance of around 30-40Mbps, a 100Mbit ethernet adaptor would be plenty. Going on those numbers, 400Mbps adaptors would probably be fine with a 100Mbps NIC as well - with a real world performance of around 60-80Mbps (probably).