Two weeks ago I wrote about wired-broadband and it's comparison to "Plain Old Dial-Up" as I called it. Funnily enough, I completely ignored the fact (as pointed out to me by Andrew Booth - thanks!) that there are many different kinds of broadband delivery methods out there (well.. four for consumers, I can count), and not just the usual favourites, xDSL (ADSL in New Zealand) and 'Cable'. I could claim that it was for a reason (perhaps the miniscule penetration of these services, or maybe the fact that for most prospective broadband users, the 'forgotten' technologies aren't quite as good as the main two), but it really was a case of me simply not remembering that there were two alternative technologies out there! For those of you 'in the know' (so to speak), i'm talking about iHug's ULTRA broadband service, which uses a mixture of Satellite download with Dial-up uploads, and the new starter trialling in auckland, Woosh wireless, which uses wireless technology (similar to wireless internet technology used on cellphones). I'd just like to start by outlining the technologies for all four main residential broadband delivery techniques used in New Zealand:
DSL (Digital Subscriber Line)
DSL technology (commonly called xDSL as a collective term for all its various implementations) is quickly becoming a favourite among broadband networks around the world because it is able to be used on existing copper wiring (in most cases). To understand DSL you must first understand how your normal phone line works. It's basically a pair of copper wires, called a 'twisted pair' which enter your house and are capable of carrying much more than just voice data. Your own voice covers the frequency range on your wires of 0 to approximately 3500Hz (Hz - Hertz - meaning 'cycles per second'). For those of you in tune with speaker performance ratings, many include a 'frequency range' - usually covering at minimum 50-15,000Hz, considerably more than your voice uses. The signals getting to these speakers are carried on copper wire, and thus your normal phone lines (being copper wire) are able to handle a much larger frequency range too.
DSL technology utilises a higher frequency than the existing voice range (which partially explains why you're able to access the phone while using a DSL connection - the signals are at a totally different frequency and don't interleave), which results in more potential bandwidth - a LOT more. Unfortunately with all electronic signals, they degrade over long distances. This isn't a problem with voice signals, because your telco uses amplification coils to amplify the voice signal over distance. These coils aren't compatible with DSL signals, which cases distance from your telephone exchange to play a big part in your DSL performance. Generally if you're further than 5km away from your exchange, your DSL connection will probably be very unreliable, and not very fast.
There are various types of DSL technology available, in New Zealand we use ADSL (Asymmetrical Digital Subscriber Line), which as the name suggests, has differing upstream and downstream (send and receive) speeds. Because most of your usage on the internet will be receiving data, ADSL is tailored towards high downstream speeds, and lower upstream speeds. DSL is fairly reliable, and could be quite effective in terms of value for money.
Cable
Cable technology is somewhat second choice to many telcos, because it requires fibre optic cable to be laid wherever the technology needs to exist - it cannot run on existing twisted pair copper wires. If you're familiar with fibre optics, the internal cable is made of a solid material (usually glass) in which total internal reflection occurs. Total internal reflection means that the beam of light is 'pointed' into the material at such an angle that it reflects off the internal sides, bouncing back into the material. This technique loses none of the light's energy (as opposed to normal reflection, which cases energy losses every reflection), and is able to carry massive amounts of data. Of course, fibre-optic cable is obviously quite fragile and not particularly suited for internet connections, so in each neighbourhood, the fibre optic cable is terminated and signals move on to coaxial cable (similar to the cable your television uses, but much higher quality) which is much more flexible and durable. This is the cable that plugs into the back of your modem.
The principle is quite similar to DSL, in that signals have a frequency, and in coax/fibre it's divided up into 6MHz 'channels' - of which downstream takes a large number, and upstream takes (generally) a small number. Coaxial cable combined with fibre optic cable provides a much more stable data transfer method, as the fibre optic cable loses almost zero signal over any distance, and it travels at light speed, meaning your pings are superior to DSL connections.
Satellite Downstream
Satellite technology in New Zealand seems ideal, considering the limitations of laying new cable for fibre-optic, and the physical limitations of DSL technology, as we have a lot of unused space, and our country is quite spread out. Satellite technology basically does away with wires, and sends a radio signal to a satellite (or satellite receiver). There is only one major problem with our satellite service for most users - we are still sitting at the 'one-way' communications level (i.e. downstream via. satellite only), as opposed to two-way connections. This means that a normal phone line is required for upload. Satellite can produce very high speeds (up to 1mbit/s), but needs a clear view to the satellite with no obstructions to do this, meaning that bad weather can DRASTICALLY affect the service (those with SKY Digital's satellite service might be familiar with this already), and in extreme cases can mean that connections cannot be established.
Satellite internet is quite expensive - the user has to front up for both the modem AND the dish, along with (in NZ), a reliable phone line for uploads. Because of the sheer distance between your dish and the receiver (along with other aspects such as weather), satellite connections have high latency. The MINIMUM latency you can get is that of your normal dial-up connection, so in other words, satellite technology is useless for games. Although satellite connections are 'wireless', they require a permanent dish, which means they are not portable.
Wireless
Woosh is currently trialling it's new wireless technology, which is a partnership with Woosh wireless and Vodafone (currently only in Auckland) which uses wireless technology very similar to that found on cellular phone's wireless internet services. Woosh uses high frequency radio signals which bounce around receiver locations (currently the same as vodafone's cell towers), and a modem similar to a cellular handset's data receiver. As with satellite, the weather plays a part in wireless internet connections, however the distances that need to be travelled are somewhat less, and wireless is two-way, meaning no phone line is needed, therefore the lowest of wireless pings can better satellite.
Wireless is a relatively new technology in New Zealand, and has already developed quite a fan club among heavy downloaders who are interested in the new Woosh 256kbps service with 'unlimited' downloads. Wireless does have its advantages however - portability being one of them, it appeals to the road warrior.
Hopefully that gives you a little bit of an insight into the four main technologies - two wired (DSL and cable) and two wireless (Satellite and obviously, wireless). All four have their advantages and disadvantages, satellite being the only one of the four which ties up the phone line, and also the only one of the four which uses two different methods to transfer data. In terms of equipment costs, DSL and cable are the cheapest; DSL with a $99 installation fee, and modems (including free filters) can be bought for as little as $120, and cable with a $17/month rental fee along with a $149 installation fee (which can be totally scrapped if you sign up for 24months). Wireless installation fee is around $400, and satellite is weighing in at around the $300 mark.
Obviously this calls for some sort of comparison in terms of value, and I'm going to use the same methods I used in my last article, however satellite is tricky here, as on some plans, iHug implement both a fixed number of hours, and an international data cap. It's also quite hard to determine these figures for Woosh wireless, because their data cap is "unlimited" BUT subject to a reasonable use clause (which hasn't been defined). Putting these things aside, I'll apply the same logic as I used last week to the alternative technologies below.
Wireless
Woosh wireless (New Zealand's only competitive wireless provider, albeit still in testing) currently runs their residential broadband at a slight derivation from the mainstream speed (256kbit/s), 250kbit/s. I'm not entirely sure why they choose 250kbit/s as opposed to the more binary efficient 256, perhaps to be different?
Every 28 days, there are 2,419,200 seconds (28*24*60*60 seconds) which combined with a download speed of 250kbit/second, equivalent to 31.25kbyte/s as measured by your computer, can produce 31.25*2,419,200 = 75,600,000 kbytes, or:
Which is very similar to 256kbit/s (obviously).
Satellite
iHug Ultra's quoted speeds are 128kbit for it's Ultra STARTER service, and "up to 1000kbit/s" for it's premium-rate services. These are limited in two methods however - the numbers of hours, along with the data cap. Unfortunate for users.
At 128kbit/s, the speed is exactly the same as JetStream Starter, and thus the same calculation as previously used for Ultra STARTER:
Nothing exiting here.. moving on. 1000kbit/s isn't quite 1mbit - so we'll use the 1000kbit/s figure as opposed to simply halving the figure from the 2mbit/s JetStream plans:
1000kbit/s = 125kbytes/s - in a month, thats 2,419,000*125 = 302,375,000 or..
As I said for Telecom's full speed service - this figure is amazing. To put a quarter-terabyte into perspective - that's around 60,000 4-minute MP3's. Amazing!
There we have it (once again) - the hard figures for the heaviest downloader in you, that above is that max you'll get out of any Woosh 250kbit/s, or iHug Ultra plan. Ihug are a strange bunch, however, and like all telcos, work on the pretense "up to 1000kbit/s" - they're also the most susceptible to that figure being halved because of their satellite connectivity.