Benefits of an ADSL Broadband Internet Connection
An Asymmetrical Digital Subscriber Line (ADSL) is one of the many options that are available for achieving a high speed connection to the Internet. Although there are always pros and cons with everything, let’s consider the main benefits that come with employing an ADSL line in your business or residence.
An ADSL is known as an “always on” connection because it provides you with a continuous connection to the Internet. You simply access the connection by clicking on your browser unlike the antiquated method of dial-up access where it is necessary to sign on to your account.
ADSL broadband allows you to use your telephone and fax line while surfing the Internet at the same time. You do not have to worry about disconnecting your Internet connection whenever you want to talk on the telephone.
With an ADSL broadband connection downloading information from the Internet is much faster than the standard dial-up access connection and your multimedia applications will work much more efficiently with this type of connection.
Instead of paying for the time that you spend online, you can now enjoy a low fixed monthly fee that offers unlimited Internet access. This is a giant step forward from the days where you had to restrict yourself to surfing the Internet during off hours to save on the costs. With the many connection options that are emerging on the market, Internet Service Providers are reducing the monthly charge to compete with other providers.
ASDL broadband has made working from home a reality with its low cost and ability to split a single line into voice and Internet. Additionally, use of a Web cam when working from home is a snap due to the high speed of a broadband connection. This feature has provided many workers with relief from the stress of the daily commute to work.
If you are interested in online games, the technology for these applications has become quite sophisticated and virtually incompatible with a dial-up access connection. Additionally, multimedia applications such as iTunes and DVD movies are very dependent upon the speed of a broadband connection. Dial-up access is not even an option in this instance due to its slow speed.
ADSL broadband has changed the face of business by providing a way for workers to receive and respond to details of company business in a cost effective manner. Additionally, employees can easily obtain the information they need via the Internet very quickly and complete work responsibilities much faster.
Broadband Internet has also made it possible for companies to reduce the costs of employing an ISDN (Integrated Digital Services Network) line for accuracy, speed, and reliability. ADSL costs much less and works just as efficiently as an ISDN line.
Although there are a host of options for connecting to the Internet, you will find that ADSL is the most widely used because it is efficient, cost effective, and increases your productivity because you are not wasting time waiting for information to download. What’s more is that you are always connected and you never have to worry about busy signals that usually occur with a dial-up access connection.
Internet provided by Quantum Internet Solutions Ltd.
What is ADSL?
Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ADSL differs from the less common symmetric digital subscriber line (SDSL). In ADSL, Bandwidth and bit rate are said to be asymmetric, meaning greater toward the customer premises (downstream) than the reverse (upstream). Providers usually market ADSL as a service for consumers for Internet access for primarily downloading content from the Internet, but not serving content accessed by others.
ADSL works by using the frequency spectrum above the band used by voice telephone calls. With a DSL filter, often called splitter, the frequency bands are isolated, permitting a single telephone line to be used for both ADSL service and telephone calls at the same time. ADSL is generally only installed for short distances from the telephone exchange , typically less than 4 kilometres, but has been known to exceed 8 kilometres if the originally laid wire gauge allows for further[clarification needed] distribution.
At the telephone exchange, the line generally terminates at a digital subscriber line access multiplexer (DSLAM) where another frequency splitter separates the voice band signal for the conventional phone network. Data carried by the ADSL are typically routed over the telephone company's data network and eventually reach a conventional Internet Protocol network.
There are both technical and marketing reasons why ADSL is in many places the most common type offered to home users. On the technical side, there is likely to be more crosstalk from other circuits at the DSLAM end (where the wires from many local loops are close to each other) than at the customer premises. Thus the upload signal is weakest at the noisiest part of the local loop, while the download signal is strongest at the noisiest part of the local loop. It therefore makes technical sense to have the DSLAM transmit at a higher bit rate than does the modem on the customer end. Since the typical home user in fact does prefer a higher download speed, the telephone companies chose to make a virtue out of necessity, hence ADSL.
For example, in normal web browsing, a user will visit a number of web sites and will need to download the data that comprises the web pages from the site, images, text, sound files etc. but they will only upload a small amount of data, as the only uploaded data is that used for the purpose of verifying the receipt of the downloaded data or any data inputted by the user into forms etc. This provides a justification for internet service providers to offer a more expensive service aimed at commercial users who host websites, and who therefore need a service which allows for as much data to be uploaded as downloaded. File sharing applications are an obvious exception to this situation. Secondly internet service providers, seeking to avoid overloading of their backbone connections, have traditionally tried to limit uses such as file sharing which generate a lot of uploads.
Interleaving and fastpath
ISPs have the option to use interleaving of packets to counter the effects of burst noise on the telephone line. An interleaved line has a depth, usually 8 to 64, which describes how many Reed–Solomon codewords are accumulated before they are sent. As they can all be sent together, their forward error correction codes can be made more resilient. Interleaving adds latency as all the packets have to first be gathered (or replaced by empty packets) and they, of course, all take time to transmit. 8 frame interleaving adds 5 ms round-trip-time, while 64 deep interleaving adds 25 ms. Other possible depths are 16 and 32.
"Fastpath" connections have an interleaving depth of 1, that is one packet is sent at a time. This has a low latency, usually around 10 ms (interleaving adds to it, this is not greater than interleaved) but it is extremely prone to errors, as any burst of noise can take out the entire packet and so require it all to be retransmitted. Such a burst on a large interleaved packet only blanks part of the packet, it can be recovered from error correction information in the rest of the packet. A "fastpath" connection will result in extremely high latency on a poor line, as each packet will take many retries.