An Internet Service Provider is the name given to an organisation that provides connections to the internet. Besides basic connectivity, ISPs provide other services - see below. This writeup focuses on the residential market, and does not cover the more unusual types of connection, such as ISDN, Frame Relay or SDSL.

With the ever reducing cost of bandwidth and increasing data rates due to competition1, the subject of choosing an ISP has become an important decision for many more of us who want to use the Internet. There's no one size fits all solution, as there are many differing requirements, from casual non-technical individuals through to technical gurus, and from small businesses to large corporations. As with any technical decision that involves financial outlay, it's paramount to ask the right questions.

Here's my take on this, from a 2006 perspective.

  1. What kind of a connection am I looking for?

    There are three options: dial-up, ADSL broadband and Ultrawide wireless broadband (UWB).

    Dial-up is the best option for the extremely casual and/or infrequent non-technical user. It used to be the case that broadband was considerably more expensive than a voice phone line, but this is no longer the case1. Many telcos are in business as ISPs as well, so it's worth checking the full range of tariffs and options; there might be financial advantages in having the same company as your ISP and your telco (but the risk of lock-in). Having broadband does involve some technical hassle, to set up and maintain, but is usually a must for regular internet users, unless they are completely roaming.

    Ultrawide Wireless broadband is a relatively new option, and standards are still emerging for this type of connection. If you are truly mobile, such as living in a caravan or on a boat, UWB is the only practical option. ADSL is generally a more reliable service, as UWB is prone to dropouts, much like a cellphone.

    Do not confuse UWB with having a wireless LAN; the latter gets its internet connection through a land line via an ADSL router, which talks IEEE 802.11b or 802.11g wireless ethernet protocol to individual workstations. In this case, you can use your laptop walking around the house, but the range is limited, usually within one building.

  2. Do I need to change my phone line?

    Generally, the answer to this question is no. But, some ISPs provide their own circuits. This question is worth checking before signing up - changing your telecomms provider is potentially very disruptive, unless you are unhappy with your existing supplier and thinking of changing anyway. Many cable TV companies are offering broadband as part of their package.

  3. The ISP are giving me a modem. Do I need to buy anything else?

    If you are going ADSL, get a router. Seriously, it will be worth it for your peace of mind, even if you only ever have one computer connecting to the Internet. The ISP may have given you a cheap plastic ADSL modem that plugs into your USB port, but

    • You have to run Windows for the modem to work
    • You have to install special software too. This will usually change some registry settings, such as making IE have the text "provided by foobar inc" to the title bar. Lord knows what else this software might be doing.
    • A Windows PC connected directly to the Internet is extremely vulnerable to security weaknesses, even with up to date antivirus and firewall software. These weaknesses can be exploited by the unscrupulous; your machine gets added to zombie farms used for sending spam, DoS attacks and viruses. A router is all round much safer, blocking all incoming connections and allowing all outgoing connections as the default settings.

  4. What is the length of the contract?

    In the UK, signing up for one year is normal with broadband. Many ISPs offer a free month's trial period. Dial-up doesn't usually lock you in for a year, and many ISPs offer pay as you go dialup services.

    Normally, after the first year, you can terminate with a month's notice.

  5. What bandwidth should I go for with ADSL?

    This is one playing field where competition is much in evidence. The quality of your land line and the equipment at the exchange sets an upper limit on the bandwidth. There may be different tariffs for different bandwidths - in my opinion, this is less important than other criteria, but is a consideration if you intend to do much downloading.

  6. Do I need to worry about download capping?

    This really depends on your anticipated usage. A year ago, most services were capped, but market pressure has persuaded many ISPs to remove their caps. If there is a cap, 30Gb per month is typical. You are only likely to exceed this if you are:

  7. What is the contention ratio?

    Contention is a consideration if you are a heavy downloader. Although it may look as if you have a dedicated 2Mb line to your ISP, this is not the case. In fact, you are sharing cables and telecomms infrastructure with other broadband users of the same telco (they may be with a different ISP, but using the same telecomms provider).

    A contention ratio of 20 to 1, means that 20 users are sharing the line. They might not actually be using the bandwidth at the same time (you hope). Many users trying to download at the same time will potentially reduce the bandwidth, hence download speed.

    It is usually not possible for a single user to saturate the line, as capacity is deliberately underallocated. You may be paying for a 2Mb line, and this is the maximum bandwidth YOU will get; the line may be of a considerably higher capacity.

    Contention ratios of 50 to 1 are typical for residential lines. Businesses start at 20 to 1 and vary downwards.

  8. What other services are provided by an ISP?


1In your country this may not be true - your mileage may vary. I'm willing to add details about other countries to the writeup, so please /msg me.

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