Learn the basics of Internet Speed
Data rates Dial-up modems are limited to a bitrate of about 60 kbit/s and require the dedicated use of a telephone line — whereas broadband technologies supply more than this rate and generally without disrupting telephone use.
Although various minimum bandwidths and maximum latencies have been used in definitions of broadband, ranging from 64 kbit/s up to 4.0 Mbit/s, a 2006 Organization for Economic Co-operation and Development (OECD) report defined broadband as having download data transfer rates equal to or faster than 256 kbit/s, while the United States Federal Communications Commission (FCC) as of 2010, defines "Basic Broadband" as data transmission speeds of at least 4 megabits per second, downstream (from the Internet to the user’s computer) and 1 Mbit/s upstream (from the user’s computer to the Internet). The trend is to raise the threshold of the broadband definition as the marketplace rolls out faster services. The standards group CCITT defined "broadband service" in 1988 as requiring transmission channels capable of supporting bit rates greater than the primary rate which ranged from about 1.5 to 2 Mbit/s.
Common consumer broadband technologies such as ADSL are "asymmetric"—supporting much lower maximum upload data rate than download. Data rates are defined in terms of maximum download because in practice, the advertised maximum bandwidth is not always reliably available to the customer. Consumers are also targeted by advertisements for peak transmission rates, while actual end-to-end rates observed in practice can be lower due to other factors. Physical link quality can vary, and ISPs usually allow a greater number of subscribers than their backbone connection or neighbourhood access network can handle, under the assumption that most users will not be using their full connection capacity very frequently. This aggregation strategy (known as a contended service) works more often than not, so users can typically burst to their full bandwidth most of the time; however, peer-to-peer (P2P) file sharing systems, often requiring extended durations of high bandwidth usage, violate these assumptions, and can cause major problems for ISPs. In some cases the contention ratio, or a download cap, is agreed in the contract, and businesses and other customers, who need a lower contention ratio or even an uncontended service, are typically charged more.
When traffic is particularly heavy, the ISP can deliberately throttle back users traffic, or just some kinds of traffic. This is known as traffic shaping. Careful use of traffic shaping by the network provider can ensure quality of service for time critical services even on extremely busy networks, but overuse can lead to concerns about network neutrality if certain types of traffic are severely or completely blocked. As consumers continue to adopt broadband services, available speeds are generally increasing. For existing connections, this most of the time simply involves reconfiguring the existing equipment at each end of the connection.
Technologies At the turn of the century most residential access was by dial-up while access from businesses was usually by higher speed connections. In subsequent years dial-up declined.
Access technologies generally use a modem, which converts digital data to analog for transmission over a particular analog network (ex. the telephone or cable networks).
Dial-up This technology dials into a remote network through the public switched telephone network (PTSN). A modem converts a computer's digital signal into an analog signal that travels over a phone line's local loop until it reaches a telephone company's switching facilities or central office (CO). Operating on a single channel, a dial-up connection monopolises the phone line and one of the slowest methods of accessing the Internet. Dial-up is often the only form of Internet access available in rural areas as it requires no infrastructure, other than the already existing telephone network, to connect to the Internet. Typically, dial-up connections do not exceed a speed of 56 kbit/s, as they are primarily made via a 56k modem.
Broadband This term includes a broad range of technologies, all of which provide high data rate access to the Internet. Broadband provides a continuous connection; there is no dial-up/in process required and it does not “hog” phone lines.
The standard broadband technologies in most areas are ADSL and cable Internet. Newer technologies in use include VDSL and pushing optical fibre connections closer to the subscriber in both telephone and cable plants. Fibre-optic communication, while only recently being used in fibre to the premises and fibre to the curb schemes, has played a crucial role in enabling Broadband Internet access by making transmission of information over larger distances much more cost-effective than copper wire technology.
In a few areas not served by cable or ADSL, community organizations have begun to install Wi-Fi networks, and in some cities and towns local governments are installing municipal Wi-Fi networks. The newest technology being deployed for mobile and stationary broadband access is WiMAX and LTE, and other technologies in use include fixed wireless, e.g. Motorola Canopy
From around of 2006, broadband mobile Internet access is increasingly available at the consumer level using "3G" technologies such as HSDPA and EV-DO technologies.
Leased lines (T Carriers) Leased lines are a digital method of signaling primarily used by business customers to connect to the internet using the existing Public Switched Telephone Network (PTSN). T Carrier technology dates to 1957, and throughput ranges from 1.54-400 Mbit/s with T1 and T3 lines being the most common implementations. In Europe, the a slightly different standard called E1/E3 and in Japan an equivalent standard is J1 and J3. A T1 line carries 24 voice or data channels, so business customers may dedicate some channels to voice traffic. Businesses may also lease a fractional T1 line, allowing them to share a leased line with neighboring businesses. T-carrier lines also require special connectivity equipment which may be purchased or leased from an ISP.
DSL (Digital Subscriber Line) provides a connection to the Internet through the telephone network. Unlike dial-up, DSL can operate using a single phone line without preventing normal use of the telephone line for phone calls. DSL uses the high frequencies, while the low (audible) frequencies of the line are left free for regular telephone communication. These frequency bands are subsequently separated by physical filtering devices added to the telephones.
DSL originally stood for "digital subscriber loop". In telecommunications marketing, the term digital subscriber line is widely understood to mean Asymmetric Digital Subscriber Line (ADSL), the most commonly installed technical variety of DSL. The data throughput of consumer DSL services typically ranges from 256 kbit/s to 20 Mbit/s in the direction to the customer (downstream), depending on DSL technology, line conditions, and service-level implementation. In ADSL, the data throughput in the upstream direction, (i.e. in the direction to the service provider) is lower, hence the designation of asymmetric service. With a symmetric digital subscriber line (SDSL), the downstream and upstream data rates are equal.
Bonded dial-up modems To provide increased bandwidth over dial-up multilinking technology or modem bonding was developed. It required two modems, two phone lines, two dial-up accounts, and an ISP with support for multilinking - and of course any line and data charges would also be doubled. This inverse multiplexing option was briefly popular with some high-end users before ISDN, DSL and other technologies became available and Diamond and other vendors created special modem with bonding ability.
ISDN, a telephone data service standard, was one of the oldest digital access methods for consumers and businesses to connect to the Internet.
A basic rate ISDN line, known as ISDN-BRI, is an ISDN line with 2 data "bearer" channels (DS0 - 64 kbit/s each). These can be bonded together for 256 kbit/s or more and this technology has been used for video conference applications and broadband data transmission. Primary rate ISDN, known as ISDN-PRI, is an ISDN line with 23 DS0 channels and total bandwidth of 1544 kbit/s (US standard). ISDN E1 (European standard) line is an ISDN lines with 30 DS0 channels and total bandwidth of 2048 kbit/s.
Its use peaked in the late 1990s prior to the availability of DSL and cable modem technologies.
Cable modem Broadband Cable or cable modem access provides internet access via Hybrid Fiber Coaxial wiring developed for television signals. Either fiber-optic or coaxial copper cable may connect a node to a customer's business at a connection known as a cable drop. In a cable modem termination system, all nodes for cable subscribers in a neighborhood connect to a cable company's central office, known as the "head end." The cable company then connects to the internet using a variety of means – usually fiber optic cable or digital satellite and microwave transmissions. Like DSL, broadband cable provides a dedicated continuous connection with an ISP.
Downstream, the direction toward the user, bit rates can be as much as 400 Mbit/s for business connections, and 100 Mbit/s for residential service in some countries. Upstream traffic, originating at the user, ranges from 384 kbit/s to more than 20 Mbit/s. Broadband cable access tends to service fewer business customers because existing television cable networks tend to service residential buildings and commercial buildings do not always include wiring for coaxial cable networks. In addition, because broadband cable subscribers share the same local line, communications may be intercepted by neighboring subscribers. Cable networks regularly provide encryption schemes for data traveling to and from customers, but these schemes may be thwarted.
Cable Modem Flap Cable modems can have a problem known in industry jargon as "flap" or "flapping". A modem flap is when the connection by the modem to the head-end has been dropped (gone offline) and then comes back online. The time offline or rate of flap is not typically recorded, only the incidents. While this is a common occurrence and usually unnoticed, if a modem's flap is extremely high, these disconnects can cause service to be disrupted. If there are usability problems due to flap the typical cause is a defective modem or very high amounts of traffic on the service provider's network (upstream utilization too high). Types of flap include: Reinsertions, Hits and Misses, and Power Adjustments.
Fiber to the home Fiber optic cables convert electrical signals carrying data into light, and send this light through tiny transparent glass or plastic fibers. This method is extremely quick and has little interference. It is more expensive than other methods to deploy. Its speed is dependent on how close the fibers are to one's computer, the amount of bandwidth available, and how the service is configured. Most high-capacity Internet and cable television backbones already use fiber optic technology, with data relayed to other technology (DSL, cable, POTS) for final delivery to customers.
Fiber to the home (FTTH), is essentially similar to cable Internet access, but promised much faster bit-rates - up to 150 Mbit/s down. Australia has already begun rolling out its National Broadband Network across the country using fiber-optic cables to 93 percent of Australian homes, schools and businesses. Similar efforts are underway in Italy and many other countries.
Satellite broadband Satellites in geostationary orbits are able to relay broadband data from the satellite company to each customer. Satellite Internet is usually among the most expensive ways of gaining broadband Internet access, but in rural areas it may be the only choice other than cellular broadband.
Broadband satellite Internet has a inherent high latency due to the signal having to travel to an altitude of 35,786 km (22,236 mi) above sea level (from the equator) out into space to a satellite in geostationary orbit and back to Earth again. The signal delay can be as much as 500 milliseconds to 900 milliseconds, making it unsuitable for applications requiring real-time user input such as remote RDP control, certain multiplayer Internet games, and potentially some VPNs due to latency issues. Satellite Internet providers also often have "Fair Access Policies" that throttle throughput to dial-up data rates after a certain download threshold is reached.
The proposed O3b Satellite Constellation is planned to orbit much lower - in medium earth orbit at an altitude of 8,063 km (5,010 mi) for a much reduced latency of 125 ms. The proposed new network is also designed for much higher throughput with links well in excess of 1 Gbit/s. Orbiting even lower at 1,000 km (620 mi) will be the planned COMMStellation™ scheduled for launch in 2015, expected to have a latency of just 7 ms.
1. True global broadband Internet access availability
2. Mobile connection to the Internet (with some providers)
1. High latency compared to other broadband services, especially 2-way satellite service
2. The narrow-beam highly directional antenna must be accurately pointed to the satellite orbiting overhead
3. The Fair Access Policy limits heavy usage, if applied by the service provider
4. VPN use is discouraged, problematic, and/or restricted with satellite broadband, although available at a price
Cellular broadband Cellular phone (mobile phone) towers are very widespread, and as cellular networks move to third generation (3G) networks they can support fast data; using technologies such as EVDO, HSDPA and UMTS.
These can give broadband access to the Internet, with a cell phone, with Cardbus, ExpressCard, or USB cellular modems, or with cellular broadband routers, which allow more than one computer to be connected to the Internet using one cellular connection.
According to the international Organisation for Economic Co-operation and Development (OECD), "Wireless broadband subscriptions in OECD countries had exceeded half a billion by the end of 2010, an increase of more than 10 percent on June 2010, according to new OECD statistics." In contrast, fixed broadband subscriptions reached 300 million in 2010.
Wireless ISP This typically employs the current low-cost 802.11 Wi-Fi radio systems to link up remote locations over great distances, but can use other higher-power radio communications systems as well.
Traditional 802.11b was licensed for omnidirectional service spanning only 100–150 meters (300–500 ft). By focusing the signal down to a narrow beam with a Yagi antenna it can instead operate reliably over a distance of many kilometres (miles), although the technology's line-of-sight requirements hamper connectivity in areas with hilly and heavily foliated terrain. In addition, compared to hard-wired connectivity, there are security risks (unless robust security protocols are enabled); throughputs are significantly slower (2 – 50 times slower); and the network can be less stable, due to interference from other wireless devices and networks, weather and line-of-sight problems.
Rural Wireless-ISP installations are typically not commercial in nature and are instead a patchwork of systems built up by hobbyists mounting antennas on radio masts and towers, agricultural storage silos, very tall trees, or whatever other tall objects are available. There are currently a number of companies that provide this service.
Power-line Internet Broadband over power lines (BPL), also known as power line communication, uses mains power lines to send and receive radio signals. Because of the extensive power line infrastructure already in place, this technology would allow people in rural and low population areas to access the Internet with little cost in terms of equipment, cables or wires.
It has developed faster in Europe than in the US due to a historical difference in power system design philosophies; the US uses a step-down transformer, through which the signal cannot pass, per house whereas in Europe, it is more common for a somewhat larger transformer to service 10 or 100 houses.
Concerns over interference in the 10 to 30 MHz range, used by licensed amateur radio operators, as well as international shortwave broadcasters and a variety of communications systems (military, aeronautical, etc.) have also been an issue, leading to the IEEE P1901 standard specifying that all powerline protocols must detect existing usage and avoid interfering with it.