Internet

Internet is a global network of interconnected computers over world wide web. It allows individuals to communicate with each other. History :- In 1969, Department of defense (DOD) of U.S started ARPAnet. Divided into MILNET, ARPAnet In 1970’s other network like BITNET and USENET also came in being. In 1980’s NSFNET was created.

MILNET – Military Network BITNET – Because it’s Time Network USENET – User Network NSFNET – National Science Foundation Network ARPANET – Advanced Research Project Administration Network

Internet Service Provider (ISP) An Internet service provider (ISP) is a company that provides access to the Internet. Companies like BSNL, Sify, Reliance, HCL Infinet etc. The job of this ISP is to provide the link between your browser and internet. The main components of providing access to the internet consists of: 1.International connectivity. 2.Domestic connectivity.

There are three ways an ISP can connect to the Internet : 1.VSNL ( Videsh Sanchar Nigam Limited ) / DOT (Department of telecommunication) 2.STPI ( Software Technology Park India ) 3.Private Operators.

Internet Connection Types

Connection Types Dial-up Access ISDN(Integrated Services Digital Network Leased Lines Cable Internet Value added Services

Dial-Up Access Also known as narrowband Least expensive way to get connected with Internet Speed is too low. Use the Point-to-Point Protocol. To use a Dial-up You need a modem. Doesn’t require any special H/W. Only used for & light Web Browsing.

To establish a dial-up connection to the Internet,following things are needed: – An account with an Internet Access Provider(VSNL). – A telephone connection – A computer with serial port(for external modems) – A modem(Internal /External) – A communication software(Browser)

Steps to Configure Demonstration

The Integrated Services Digital Network is a set of communications standards allowing a single wire or optical fiber to carry voice, digital network services and video. Originally developed in the mid 1980s.

ISDN(Integrated Services Digital Network) Integrated Service – Voice – Video – Image – Data – Media Digital – Signaling – Switching – Channels Network – World wide – Inter Operating Communication

ISDN(Cont..) Highly Reliable Very Fast High Cost ISDN is all digital

Components of ISDN ISDN Channels ISDN Access Types ISDN Devices ISDN Interfaces

ISDN Channels Three types of channels are there: – B Channels – D Channels – H Channels B Channels 64 kbps unit No restrictions D Channels Signaling Channel X.25 Protocol BRA-16 kbps PRA-64 kbps H Channels High speed H0-384 kbps H Mbps H12-entire European PRA

Access Types There are two types: – BRA(Basic Rates Access) – PRA(Primary Rates Access)

BRA(Basic Rates Access) Provide service to individual user or small business. Access provides two 64 kbps B channel and one 16 kbps D Channel – i.e. 2B + D = 144 kbps – 1 B=>voice conversation – 1 B=>Medium speed data session – 1 D=>Signaling exchange Uses an additional 48 kbps of bandwidth for maintenance and synchronization. – i.e. 2B + D + 48 = 192 kbps

PRA(Primary Rates Access) Based on pre-ISDN digital carrier Technology High capacity service to large customers Two kinds of PRA – 23B + D – 30B + D In North America & Japan 23B +D PRA operates at Mbps Rest of the world 30B + D PRA,operates at Mbps.

ISDN Devices It is not actually a hardware but it is a standard collection of functions that usually performed by the hardware units. Devices are: – Terminal Equipment (TE) – Terminal Adapter (TA) – Network Termination 1 (NT1) – Network Termination 2 (NT2) – Exchange Termination (ET)

ISDN Device(Cont….) TE is a piece of communicating equipment that compiles with the ISDN standards. TA is a special interface conversion device that allows communication of devices that don’t confirm to ISDN standards to communicate over ISDN. NT1 –performs the logical interface function of switching & local device control(local signaling). NT2- performs physical interface conversion between dissimilar customer & n/w sides of the interface. ET- same as NT but it separates the B channels and terminates signaling path of the customer’s D channel

ISDN Interface Standard Reference Point not a physical interface There are 4 distinct interface in the customer’s connections to network R, S, T and U. R-reference point between non-ISDN equipments & TA. S- reference point between terminals(TE/TA) & NT. T-reference point between NT1 and NT2. U- reference point between NT1(NT2) and ISDN carrier’s local transmission loop.

Leased Line It is a telephone line that has been leased for private use. Contrasted with a switched line. It does not have a telephone number,each side of the line being permanently connected to the others.

Cable Internet Cable TV companies also provide Internet services. High bandwidth internet service for homes or small offices. Accessed over the same line as the cable TV. Although, the cable and TV signal are transmitted on the same media,no interference with two different signals. Cable TV lines are coax cables. Cable internet is continuous connection. Cable modem is needed & there is no need for username & password to connect.

Advantages of Cable Internet High connection speed Convenient Does not affect your phone line. Connection speed is not affected by the distance from ISP operation center Easy setup with self installation kit

Disadvantages of Cable Internet Expensive than Dial up Higher Security risk than Dial up Bandwidth is shared over the same cable line. Upload speed is slower than download speed.

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