Connections & Networks

[darthshearer]

Hi all

Jonty should be able to help me with this one /me bows down to him.

I would like to know more on the differnt connections to the net & networks LAN..

I keep hearing about T1 & T3 & DSL I would like to know some stuff about these, speeds, costs, types etc and also ISDN. I know a little about these already.

If you can slap a link in that would be great.

Thanks

 

[Jonty]

Hi darthshearer

You hold me in way too higher regard, and sadly I'm not too hot on all of this, so you may well be best asking someone else Basically, focusing on Internet connections for now, you have a range of options.

• Dial-Up - Requires a simple modem and a normal telephone line. A telephone number is given by your provider which your modem dials in order to connect to the Internet. Using v.92 technology (think modified 56k), if your provider supports it, you can achieve around 52Kbps using this method.
  
  Dial-Up providers are everywhere. With some, you enter into a contract whereby you pay £x per month and you can then dial-up as much as you want (ntl offer this 24/7 dial-up access to their customers for £10 per month). Alternatively, some offer access without a subscription, but you pay for the cost of the call. Ordinarily calls are charged at local rates, so costs can soon mount up. Alternatively BT offer a system whereby you pay them so much per month, pay one of a certain list of providers so much per month, and in return get unlimited access to the Internet at evenings and weekends (I'm not with BT, though, so I'm not too sure about this).
• ISDN - This stands for Integrated Services Digital Network, just in case you were curious. This type of Internet connection is effectively a high-speed dial-up service, and (as far as I know) requires a special digital telephone line to be installed before it will work. This type of connection improves overall speed, but it can be costly, and if I recall correctly, the speed is only 128Kbps when using both lines. Usually ISDN is only considered nowadays when broadband connections are not available in a certain area.
  
  I'm fairly sure that only BT offer ISDN services, with rivals like ntl offering around about ISDN speeds (150Kbps) but using broadband cable technology instead. As I mentioned above, most homes and businesses require the installation of a special line by BT in order to get ISDN setup, which increases costs considerably.
• Cable Broadband - Broadband connections are always on, meaning you never have to dialup, and your normal phone line will be left free for voice calls and such even when you're using the Internet. For cable broadband to work, you require a special cable modem, cables and a computer(s) with a compatible network card. All this is usually provided by your cable company, although I believe you have to switch over to them in order to get this, which means leaving BT, or whoever, and transferring your phone and/or TV to, say, ntl (again, I'm not too sure, but I believe that's the deal). The way in which this technology works is that you effectively share a 'pipeline' with your street or neighbours. Whilst they can't see what you're doing, if everyone on your street was to use the Internet intensively at the same time, performance may theoretically decrease. In reality, you'd probably never notice any difference, but it's worth mentioning (also this means there has to be demand in your area before broadband cable services are activated).
  
  Taking ntl as an example, you can various speeds via their broadband service. 150Kbps, 600Kbps, 1Mbps are all available, you simply pay more for the greater bandwidth. The speed you choose is controlled remotely, so you could, say, upgrade from 150Kbps to 1Mbps without having to change any of your settings or hardware. Currently ntl are offering free installation (they have to come and put in a special line, provide you with all the hardware etc.) and one month's free access, which is quite a substantial saving.
• DSL Broadband - DSL comes in many different flavours, xDSL, vDSL, but the one chosen for use in Britain by BT is ADSL (which stands for Asynchronous Digital Subscriber Line). ADSL can be as fast as, if not faster than, cable connections, but the only caveat is that the closer you are to the main telephone switching station, the faster your connection speed will be. Sadly, it appears BT has been ignoring the recommended advice when introducing ADSL, which means signal degradation is higher than it need be. This in theory means you could be losing out slightly performance wise, but like the cable problem highlighted above, more often than not you'd never notice, so I wouldn't worry too much about this.
  
  Once again, to get ADSL you require a special modem, cabling etc. as well as BT engineer to come and sort everything out with regards the line. You usually pay an installtion charge, and (like cable broadband) a fixed subscription thereafter. Unlike cable broadband, I think I'm right to say, BT resell the ADSL technology meaning you can get it from different providers, rather than being limited to BT themselves. It all uses the same technology, but you may prefer one company over an other, or you may be able to get a cheaper deal elsewhere.

Crikey, I didn't mean to write that much, as I'm genuinely not too sure about the specifics. Essentially, you have dial-up (readily available, cheapest solution, but slow speeds); ISDN (slightly improved connection speeds, but often costly, and now defunct thanks to broadband); cable broadband (wide range of speeds to suit all budgets, but requires a change of telephone and/or TV provider); ADSL (as with cable broadband, a wide range of speeds available, but this time with the ability to choose your provider from the likes of Tiscali, Telewest/Blueyonder etc., but can prove expensive).

Both BT and ntl have lots and lots of information about their services, together with where they are available, how much they cost and any special offers they have. Just check their websites or give them a call for more details.

Well, I think that's me done. Like I said, the above is just off the top of my head, and I'm sure others will be able to better advice you on this topic. Just one thing, don't worry about T1 and T3 lines. These tend to be very high-speed leased lines, usually found in America, but more often than not they're associated with businesses and such, rather than home consumers.

Kind Regards

Jonty

P.S. Forget about networks, but I'm sure someone will fill you in. Basically they are a high speed way for computers to connect to one and other, in your home, business, college etc. They come in both wired and wireless formats, the latter being more expensive, but often saving you all the hassle of having lots of wires everywhere. It is becoming increasing common to have a broadband Internet connection, and then share it across all the PCs in a house using a network.

 

[pcg79]

Also in the DSL

Theres also RADSL - Rate Adaptive DSL so you can live more than the 5.5Km from your local exchange.

And some companies (Easynet, Bulldog) own their own physical phone networks so they can provide services higher than BT's 2MBps.

 

[Ulysses777]

And to finish off the original question:

T1 and T3 are leased lines, which have dedicated bandwidth and no contention ratios.

T1 speeds range from 64Kbps to 1.5Mbps, and can cost from around a hundred to a few thousand pounds per month, and installation can be around £1000.

T3 is actually made up of 28 T1's, totalling a maximum of 44Mbps. Can cost tens of thousands of pounds per month.

Some providers also supply OC-3, which can go up to 155Mbps. Can cost from around £100,000 to nearly a million per month.

The monthly cost of leased lines is not only determined by the amount of bandwidth, but by the length of the line as well.

 

[smurkin]

THIS site has a speed measure...the nice thing is that it compares various example speeds and puts things into context, and talks a little about Mbit and kbytes.

There is also a uk-based speed test at

adsl guide which shows similar and compares various dsl connections - at the top is 10 Mbps LAN.

I am lucky and have a fast connection so I get - Downstream 6832 Kbps (854.0 KB/sec) & Upstream 6050 Kbps (756.3 KB/sec) -although I am at work (you can see my speeds are sychronous, unlike most dsl...I believe this is a t1 LAN...good old Janet) [/brag mode OFF]

 

[darthshearer]

Gee guys thanks that should keep my busy