What is Broadband and Internet services?

What is Broadband?

A definition to Broadband is a must as different service providers defines in their own term & context. An internet connection that is capable to support interactive services including access of devices and has the capability of the minimum  speed of 256Kbps for download to an personal subscriber from the point of presence(POP.

What is Internet?

The Internet is a global computer network made up of smaller networks it has been called a "Network of Network".

The smaller networks includes:-

1.LAN.

2.WAN.

3. State & Regional network.

4. National & International network.

Types of Internet Connection:-

1. Terminal dailup/modem.

2. SLIP

3. PPP

4. ISDN

5. DAIS.

6. Cable modem

7.DSL

8.Leased Line

9.Satellite connection.

10. Wireless connection.

Broadband Access Technology:-

1. Wireline                    2.Wireless

    a. DSL                         a. 4G/3G

    b. Cablem modem     b. WiFi

    c. PLC                         c.  Wimax

    d. OFT                        d. FSO

                                         e.LMDS & MMDS

                                         f. Satellite

Components of Broadband Access network:-

1. Broadband Remote access server (BB RAS.

2. Gigabit and Fast Ethernet Aggregation Switch.

3.Digital Subscriber line access multiplexers (DSLAM.

4. SSSS/SSSC .

5. Server for AAA,LDAP

6.Provisioning and configuration managements

7.DSL CPEs.

Broadband Multiply Components:-

1. L3PE

2. BNG.

3. RPR Tier-1 Switch.

4. Provide connectivity from BNG to Connecte.

5. RPR Tier-II Switch.

6. OCLAN Tier-2 Switch.

7. DSLAM

8. DSL.

Wired Line Acess:-

DSL:-It provide sevices on existing twisted-pair  of telephone lines 2wire as the access media.
         Various xDSL technologies are given below:-
1. ADSL(Asymmetric Digital Subscriber line).
2. VDSL(Very high speed digital subscriber line).
3. RADSL(Rate Adaptive digital subscriber line).
4. HDSL(High data rate digital subscriber line).
5. SDSL(Symmetric digital subscriber line).

About ADSL Technology:-

ADSL has the differential characteristics that the data can flow faster in one direction then the other. ADSL uses two distinct frequency bands with standard  ADSL. The bandwidth from 25.875 Khz to 138 Khz has applied for upstream communication,while 138Khz to 1104 Khz has applied for downstream  communication.

ADSL Modulation:-

1. CAP(Carrierless Amplitude phase modulation.

2. DTM(Discrete multi tone.

DTM is basically a multi-carrier modulation technique and widely used one.

Data rate      Wire size       Distance

1.5-2.0Mbps    0.5 mm        5.5 km

1.5-2.0Mbps    0.4 mm        4.6 km

6.1Mbps           0.5 mm       3.7 km

6.1Mbps          0.4 mm        2.7 km

Bridges versus Routers:-

1.both store and forward devices .

    routers- network layer devices.

    bridges- link layer deviecs.

2. Routers maintains routing tables,implements routing algorithms.

3.Bridges maintain bridge tables,implement filtering,learing and spanning tree algorithms.

4.Bridges do well in small network.

5. Routers used in large network .

Bridges + and -

+ Bridge operation is simpler requiring less packet processing and forwarding.

+ Bridge tables are self learning.

- All traffic confined to spanning tree even when alternative bandwidth is available in the network devices.

- Bridge do not offer protection from broadcast stroms.

Routers + and -

+ arbitrary topologies can be supported.

+ provide protection against broadcast stroms.

- required IP address configuration.

- require higher packet processing.

Switches versus Routers:-

Switches                                     Routers

1. Fast                                          1.Slow

2. Inexpensive                             2. Expensive

3. No benefits of alternative       3. Benefits of 

     routing                                         alternative routing

4. No hierarchical addressing    4.Hierarchical addressing

5. Alternative routing                  5. Routing.

Summary Comparison:-

                            Hub Bridge Router Switches

Traffic_isolation  no   yes       yes      yes
Plug&play           yes   yes       no       yes
Optimal.routing  no    no        yes      no
 Cut.through       yes    no        no       yes

About DATA Communication

Communication Plays a very important part in our life because we are almost always involved in some form of communiction.

------Face to Face communication.

------Reading a book.

------Sending or Receiving a letter.

------Telephone conversation.

------watching a Film or Tv.

Components of Data Communication.

In order to Send Data/Message from one point to another following these three components are must:-

1.Source.

2.Medium.

3. Receiver.

Types of Transmission codes

1. Baudot Code.

2.ASCII Code.

3. BCDIC Code.

4. EBCDIC Code.

What is ASCII Code:-

It is an eight bit code that consists of seven information bits and one additional bit for parity checking.This is most widely used data code  in signal transmission .seven information bits gives us 128 combinations of code.

What is BCDIC code:-

Binary code decimal interchange code  is a six-bit code that is used as an internal code by name computer with 6 information bits .we can  have 2x6=64 possible code combination.

What is EBCDIC code :-

Extended binary coded decimal interchange code is a 8-bit code in which all the 8-bits are used for information.it gives 256 possible code combinations.EBCDIC is used as in internal machine code.

Types of DATA  Transmission:-

1. Parallel Transmission.

2. Serial Transmission.