Nymphia Ethernet

Water lillies.jpg

“Arc-en-ciel”, “Vesuve” and “Fireball” are just some of the colourful names given to the plant belonging to genus Nymphaea (from the Greek word nymphe or water spirit), the Water Lily. Characterised by deeply-cleft leaves mottled with maroon, or streaked with pink and with flowers displaying colours that span the spectrum, from whites and yellows, through pinks, reds, blues, lavenders and deep purples, is it any wonder that these plants should be inspirational to impressionist painters such as Monet?

The most common image of Water Lilies is of a dappled pattern of various sized leaves on the calm waters of a pond, sunlight twinkling on the water. With diameters ranging from a couple of inches to a couple of feet, the leaves play a vital role in reducing the amount of algae in the pond, and also provide places for fish to hide.

The “Water Lilies in the Pond” image is being used to describe a new wave of networks driven by WIFI (Wireless Fidelity). WIFI hotspots will interweave thousands, if not millions, of “micro-operators” to form a global patchwork quilt of broadband connectivity, replacing wired and wireless telecoms companies. Network access for the people, by the people, aka viral telecoms. Messages, like digital frogs, can hop from lily to lily.

Each electromagnetic lily in this pond would range from about 300ft to 1000ft in diameter, and given enough of them, so the theory goes, the new network will organically evolve, with the hotspot owners altruistically sharing access with their neighbours. There’s even a helpful logo “warchalked” onto the wall of WIFI hotspots so that the wireless laptop equipped drive by surfer can identify suitable places to drop in, log on and chill out. For the record an Open Node is represented by two back to back C’s, a Closed Node by a hollow circle and a WEPNode by a circle containing a W.

Lilies are not just free-floating leaves, they also have roots. The root of the WIFI lily in the common variant is “Broadband” ADSL, thus providing internet access (so I guess viral telecoms can’t quite totally displace old fashioned wires!). I have to declare at this point that I am not a fan of ADSL, though I applaud the attempt to e-Enable Britain. Asymmetric services made sense 15 years ago, but the Napsterisation of the web, and the arrival of video-based user generated content, has meant that home and office users alike need symmetrical broadband. It’s ironic that the WIFI revolutionaries are basing the success of their model on an outmoded fixed line technology.

And this is where the UK-based Channel 5 Gadget Show’s campaign to create a “lily-in-the-pond” style WIFI network around Britain is flawed. The enthusiastic Jason Bradbury, the smug Jon Bentley and rather lovely Suzy Perry seem to think that dropping WIFI nodes over the country will somehow solve all our internet access woes. Far from it - in fact this could actually make things a lot worse. Let’s think through the proposition to see what really happens.

ADSL is asymmetric. This means that whilst an ADSL service may be advertised as providing 500Kbps bandwidth, this is only one way, downstream from the web. The upstream speed is slower than the downstream speed, typically 128Kbps - which is a nuisance if you’re trying to upload some MP3 or even DVD files. At the DSLAM end, the service becomes contended, by as much as 50:1.

This means that the bandwidth the service provider is using on the network side of the DLSAM is shared between the number of users on the customer side. If the service provider is using a 1Mbps link and there are 100 x 500Kbps customers, the contention is very high. The best case, the dead of night when most folk are asleep, means an insomniac may get the full 500Kbps/128Kbps service. The worst case is when all 100 users are uploading and downloading which results in each user getting 1/50th of the 500Kbps/128Kbps service - less than dialup!

Let’s now add to this a WIFI hub to create a hotspot. The theoretical maximum speed is 11Mbps or 54Mbps, depending on which sub-genus of lily is used. This is then shared amongst x number of surfers, let’s say 5. In the 11Mbps space, theoretically each user will have just over 2Mbps each, and about 11Mbps each for 54Mbps WIFI. And all of this is going to cram down a 128Kbps uplink? Or a 1Mbps uplink, which is all ADSL can offer?

I don’t think so!

Those better informed will say at this point that the real speeds of WIFI are more like 5Mbps to 6Mbps, not 11Mbps and about 30Mbps instead of 54Mbps, which is of course true. These same informed folk may also point out that statistically it’s very unlikely that all users will simultaneously be uploading and downloading large files, so in practice the lowest bandwidth delivered by ADSL will be much higher than 1/50th of the 500Kbps/128Kbps, which is also true.

However the same principle applies, especially as the expectation is now set that WIFI delivers 11 Mbps or 54Mbps. It’s even referred to as delivering these speeds on the official WIFI website. The end result will be customer dissatisfaction and the WIFI lilies will suffer from the digital equivalent of crown rot. The better solution is to base the WIFI lilies on a sturdier, more hardy root. If the access network is wireless Ethernet, then surely the best backhaul network has got to be an optical Ethernet one? With a 10Mbps Ethernet backhaul link, at very low cost on an optical Ethernet network, the most common WIFI lily of 11Mbps will have plenty of bandwidth in the root to cope with the expected number of users.

In a more commercial setting, such as a Starbucks, a 100Mbps optical Ethernet circuit could be used and if the network delivers Liquid Bandwidth™, the Starbucks café manager can increase and decrease bandwidth as they need it to match the daily peaks and troughs of traffic. So they only pay for the bandwidth as they use it.

Which means that they get more for their money. Now that does paint a pretty picture.