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 Email & 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•H11-1.536 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 1.544 Mbps

• Rest of the world 30B + D PRA ,operates at 2.048 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.

Any Question

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