Computer network ,the internet, Network types, how to accessing the internet, Components of internet
The Internet :
- Backbones and provider networks are also called Internet Service Providers (ISPs).
- The backbones are often referred to as international ISPs ;the provider networks are often referred to as national or regional ISPs.
Accessing the Internet :
The Internet today is an internetwork that allows any user to become part of it. The user,
however, needs to be physically connected to an ISP. The physical connection is normally done
through a point-to-point WAN They are
- Using Telephone Networks
- Using Cable Networks
- Using Wireless Networks
- Direct Connection to the Internet
Using Telephone Networks :
- Today most residences and small businesses have telephone service, which means they are Today most residences and small businesses have telephone service, which means they are connected to a telephone network
- Since most telephone networks have already connected themselves to the Internet, one option for residences and small businesses to connect to the Internet is to change the voice line between the residence or business and the telephone center to a point-to-point WAN.
- Dial-up service.
- DSL Service.
Using Cable Networks :
More and more residents over the last two decades have begun using cable TV services instead
of antennas to receive TV broadcasting. The cable companies have been upgrading their cable
networks and connecting to the Internet. A residence or a small business can be connected to the Internet by using this service. It provides a higher speed connection, but the speed varies
depending on the number of neighbors that use the same cable.
Using Wireless Networks :
Wireless connectivity has recently become increasingly popular. A household or a small
business can use a combination of wireless and wired connections to access the Internet. With
the growing wireless WAN access, a household or a small business can be connected to the
Internet through a wireless WAN.
Direct Connection to the Internet :
A large organization or a large corporation can itself become a local ISP and be connected to
the Internet. This can be done if the organization or the corporation leases a high-speed WAN
from a carrier provider and connects itself to a regional ISP. For example, a large university with
several campuses can create an internetwork and then connect the internetwork to the
Internet.
Network types :
Personal Area Networks:
- PANs (Personal Area Networks) let devices communicate over the range of a person.
- A common example is a wireless network that connects a computer with its peripherals. In the simplest form, Bluetooth networks use the master-slave paradigm
- The system unit (the PC) is normally the master, talking to the mouse, keyboard, etc., as slaves. The master tells the slaves what addresses to use, when they can broadcast, how long they can transmit, what frequencies they can use, and so on. Bluetooth can be used in other settings, too.
- It is often used to connect a headset to a mobile phone without cords and it can allow your digital music player to connect to your car merely being brought within range.
- A completely different kind of PAN is formed when an embedded medical device such as a pacemaker, PANs can also be built with other technologies that communicate over short ranges, such as RFID on smartcards insulin pump, or hearing aid talks to a user-operated remote control.
Metropolitan Area Networks:
- A MAN (Metropolitan Area Network ) covers a city. The best-known examples of MANs are the
cable television networks available i
n many cities. - Initially these were designed locally, and then companies started to expand to wire up the entire cities. The next step was television programming and even entire channels designed for cable only.
- When the Internet began attracting a mass audience, the cable TV network operators began to realize that with some changes to the system, they could provide two-way Internet service in unused parts of the spectrum.
- Both the television signals and Internet is being fed into the centralized cable headend for subsequent distribution to people’s homes.
- Recent developments in high speed wireless Internet access have resulted in another MAN, which has been standardized as IEEE 802.16 and is popularly known as WiMAX.
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