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| INTERNET CONNECTION |
| Senin, 15 Oktober 2007 |
Broadband Internet Access
Broadband is usually used to reference a type of Internet connection. Simply put, a broadband connection is one that allows for extremely high speeds, and supports data, voice, and sometimes even video information. It is considered broad because multiple kinds of information can travel across the wire, or band. High speed (or data rate) means that in addition to surfing the web without annoying delays, you will also be able to enjoy multimedia-rich applications such as streaming audio and videoconferencing. Broadband connections are typically always-on , so you don't have to waste time dialing in to a service provider- as soon as the computer connected to the service is turned on, you can start surfing!
What are the typical speeds of a broadband connection?
Just like with an analog modem, there are two directions information travels on a broadband connection. "Downstream" refers to information going from the Internet to your computer, like when a new web page is loaded. "Upstream" refers to information from your computer to the Internet, like the mouse-click that tells a web page where you'd like to go next. Using a standard 56 Kbps (Kilobits per second) analog modem, you experience a downstream data rate of up to 56 Kbps and an upstream data rate of up to 31.2 Kbps. With most broadband devices, the downstream rate is tremendously greater and the upstream rate is significantly faster than a 56k analog modem.
A significantly larger downstream data rate (ranging anywhere from 128 Kbps to 1 Mbps) means a significantly improved Internet surfing experience- similar to most office networks. Web pages can appear almost instantly with each click and downloading files or sites that have heavy graphics occurs much more quickly. Once most people experience Internet surfing on a broadband connection, they never go back.
Having an upstream rate that is similar to a 56k modem is usually not a problem for most people. During typical web surfing, the only information that is sent from your computer consists of mouse-clicks, keystrokes, or email- small bits of data.
Consequently, the upstream data rate can be lower than the downstream rate; which requires higher bandwidth because of the huge amount of information sent to you from web pages.
If we compare it with dial up connection so that dial-up modems are generally only capable of a maximum bitrate of 56 kbit/s (kilobits per second) and require the full use of a telephone line—whereas broadband technologies supply at least double this speed and generally without disrupting telephone use.
Since approximately the year 2000, broadband Internet access (cable and DSL) has been replacing dial-up access in many parts of the world. The reason for this is mostly due to broadband connections featuring speeds which far exceed the capacity of dial-up, many of which provide speeds greater than 20 Mbit/s, as well as reducing prices under dial-up prices offered by companies such as Verizon. An increasing amount of Internet content such as Adobe Flash, online gaming and streaming media require large amounts of bandwidth
Cable Modem Internet Access
As the name implies, this connection comes through the same wire as your cable TV service. Once the wire enters the home, the cable modem splits off a new extension to that wire to carry Internet traffic for your computer(s). Like
with DSL, the cable modem connection terminates in an Ethernet card in your computer. If you don't have one, a technician will install it for you.
Unlike DSL, you do not have a direct, unshared connection with a cable modem. The other end of the line does not connect directly to the cable provider's wiring station. With cable modem service, a certain number of users in your area share the connection, similar to how an office network is set up. During peak usage times, your speed can degrade as there are more people trying to use the same connection at the same time. However, because of the much larger capacity of the cable wire, even with degradation your data rate will be much greater than a 56k analog modem. The downstream data rate for a cable modem is typically 4 to 8 Mbps, with an upstream rate of 200 Kbps to 2 Mbps. Remember, though, that these speeds will be shared with other users in your service area. There are also some configurations that feature the downstream communication over cable, but upstream communication via a dial-up modem connection. If you are interested in cable modem service, you should contact your cable company to see if they offer it
DSL Broadband Internet Access DSL shares space and gives you amazingly high speeds. DSL, or Digital Subscriber Line, comes into the home over phone lines, into the DSL modem. The end of the line connects into your computer using an Ethernet Network Interface Card (NIC). The other end terminates at the phone company central office. Consequently, setup of a DSL connection requires a technician to install the line, which can then be used for voice and data traffic simultaneously. This means that you will always have access to a direct, personal connection (as you'll read below, cable modems operate slightly differently). The DSL modem translates the signal off the copper wires into a format your computer can understand, and connects to your computer via the Ethernet NIC. If you don't already have one in your computer (most computers do not), your service provider will usually install it for you. DSL typically provides a data rate of 128 Kbps to 6 Mbps (Megabits per second) on the downstream feed, and 128 to 640 Kbps upstream. You will typically find DSL service offered at different downstream data rates. The higher the data rate, the higher your per-month fee. Your local service provider can tell you what options are available. However, not all areas offer DSL service, since you
have to be located within a certain distance ofthe central office (this distance varies by implementation, but most often is 15,000 feet or less). If you are interested in DSL service, you should contact your phone company and see if they offer it- or you can look for independent companies who may offer service in your area
Two types of DSL transmission technologies:
· Asymmetrical Digital Subscriber Line (ADSL) – used primarily by residential customers, such as Internet surfers, who receive a lot of data but do not send much. ADSL typically provides faster speed in the downstream direction than the upstream direction. ADSL allows faster downstream data transmission over the same line used to provide voice service, without disrupting regular telephone calls on that line.
· Symmetrical Digital Subscriber Line (SDSL) – used typically by businesses for services such as video conferencing, which need significant bandwidth both upstream and downstream.
Faster forms of DSL typically available include:
· High-data-rate Digital Subscriber Line (HDSL)
· Very High-data-rate Digital Subscriber Line (VDSL).
Dial-Up Internet Access
Dial-up access is a form of Internet access via telephone line. The client uses a modem connected to a computer and a telephone line to dial into an Internet service provider's (ISP) node to establish a modem-to-modem link, which is then routed to the Internet.
Dialup is simply the application of the Public Switched Telephone Network (PSTN) to carry data on behalf of the end user. It involves a customer premises equipment (CPE) device sending the telephone switch a phone number to direct a connection to. The AS3600, AS5200, AS5300, and AS5800 are all examples of routers that have the capability to run a PRI along with banks of digital modems. The AS2511, on the other hand, is an example of a router that communicates with external modems.
Modern dial-up modems typically have a maximum theoretical speed of 56 kbit/s (using the V.92 protocol), although in most cases only up to 53 kbit/s is possible. These speeds are currently considered the maximum possible; in many cases transfer speeds will be lower, averaging anywhere between 33-43 kbit/s. Factors such as phone line noise and conditions, as well as the quality of the modem itself, play a large part in determining connection speeds. Some connections may be as low as 26.4 kbit/s depending on the various factors listed. Dial-up connections usually have high latency that can be as high as 400 ms or even more, which can make online gaming or videoconferencing difficult, if not impossible.
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posted by luckyFinn @ 23.42  |
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| Template Testing |
| Minggu, 14 Oktober 2007 |
| This post was created to test the template |
| posted by luckyFinn @ 22.07 |
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