Computer Networking Overview

Computer Networking Overview

Computer networking jobs

• 1.       Client support – To solve the problem of the client in ISP (6 month course)
• 2.       System Administration – To maintain the server

·         Windows (Course MCSE/MCSA)

·         LINUX Red hat (Course RHCE)

·         Free BSD

·         Sun Solaris

·         To Contact IT Bangladesh

• 3.       Working in network core Layer & Distribution Layer. 

·         CCNA

·         CCNP

·         CCSP

·         CCIE

·         To contact www.cisco.com or CISCO valley (Bangladesh)

History of Networking or Internet

• 1.       In 1958 SAGE- Sami Automated Ground Environment. This is used in Canada and USA for radar station for connects their computer.
• 2.       In 1960- IBM-CTSS(Computable Time Sharing System) - Modem
• 3.       In 1964 Dial up Service for American airlines.
• 4.       In 1960 ARPANET (Advance Research Agency Network)- For US Military.
• 5.        In 1971- E-Mail ARPANET for email.
• 6.       In 1989 – Internet- DARPANET

Classification of Network

Depend on Area Network

• 1.       LAN
• 2.       MAN
• 3.       WAN

Depend on Function Network

• 1.       Peer TO Peer Network- In a central device, no server, all are equal, No Control.
• 2.       Client Server Network- In a central device, server allow and the other server facilities.
• 3.       Hybrid Network – Both of peer to peer network and Hybrid Network.

OSI (Open System Interconnection) Model

• 1.       OSI is created by International Organization for Standardization (ISO) 1974
• 2.       OSI Model defines that how the network will work.
• 3.       It allows various type of Hardware and software.
• 4.       OSI Model is a logical model
• 5.       There are seven Layers in OSI model. Top 3 is upper layers and bottom 4 is lower layers.

 

How it works…

UDP - User Datagram Protocol

LLC –Logical link control

Layer 1 devices

• 1.       Hub
• 2.     Repeater 
• 3.       CSU/DSU
• 4.       Media converter

ayer 2 devices (work related to the Mac or the Hardware address.)

• 1.       NIC
• 2.       Bridge
• 3.       Switch
• 4.       Brouter

Layer 3 devices

• 1.       Router
• 2.       Brouter

Layer 4,5,6,7 devices

Gateway – It translates protocols and it used to connect two separate networks that different communication protocols.

Depend on speed there are three kind of Ethernet

• 1.       10 Mbps.
• 2.       100 Mbps (Fast Ethernet).
• 3.       1000 Mbps (Gigabit Ethernet).

Topology

Topology is the physical layout of network and how the network can be seen from the top that call the topology. Network has both physical and logical topology.

Physical topology

• 1.       Bus topology – In a single link like Bus, the cable is coaxial cable, both end must have terminator.
• 2.       Star topology – In a switch or Hub and this is look like Star.
• 3.       Ring topology – look like ring and all computers is linking each other.
• 4.       Mesh topology – Normally Use in wide area network and there have many paths which connect all computers if any one connection disconnects then the other one can connect by the other link.
• 5.       Hybrid topology – This is combination of star and bus topology.

Logical topology

• 1.       Logical Bus
• 2.       Logical Ring

TCP/IP Layer

                                     OSI Model Layer                               TCP/IP Layer.

Wireless network

1.       Wi-Max( Worldwide Interoperatibility Microwave Access)  – One tower which telecast the network. It give network to 60-70km.speed 70mbps,unlimited user

2.       Wifi – Three standards is use 1.802.11a 2. 802.11b 3.802.11g.Give network 100 mitre. Speed 15+55mbps.User limited.

3.       Bluetooth- In limited range 10 miter. Speed 20kbps.User limited.

IP address

There are 2 kind o IP address

• 1.       Private
• 2.       Public

Classification of media

• 1.       Cable media – 1. Twisted pair cable (UTP and STP 2. Coaxial cable 3. Fiber optic cable
• 2.       Wireless media

The diagram of UTP cable and the STP cable is same characteristic as cat-5 cable

The coaxial cable

Fiber optic cable

• 1.       Multimode fiber optic cable
• 2.       Single mode fiber optic cable

There are two type of connector in fiber optic cable

1. SC connector
2. ST connector

Wireless media

• 1.       Micro wave transmission.

                  a.        Terrestrial microwave – In a level connection, 1-50 km
                  b.       Satellite microwave – 50000 km

• 2.       Radio wave transmission – Speed 1-10 mbps
• 3.       Infrared transmission.

Ethernet cabling

• 1.       Straight throw cable- Host to sw and router to sw
• 2.       Cross throw cable- sw to sw, Hub to Hub, Host to Host, Hub to sw, Router direct to Host
• 3.       Rolled cable- Is not used to connect any Ethernet connections together. IT USE TO 

• CONNECT A HOST TO A ROUTER/SW CONSOLE SERIAL COMMUNICATION (COM PORT).

Modem

Modem – which convert the digital signal to the analogue signal and also make the digital signal to the analogue signal.

1.       Internal modem

2.       External modem

a.       Cable modem – Download speed 1.5 mbps

b.      DSL Modem – Download speed – 1.8 mbps

c.       ADSL Modem – Download Speed - 1.5 to 9 mbps

d.      EDGE (Enhanced data GSM environment) Modem (USB wireless) - also call dialup modem, bandwidth 384 kbps, this system is given by mobile company.

e.      GPRS (General packet radio service) Modem (USB wireless) – speed 48 kbps

f.        CDMA (Code division multiple access) Modem (USB wireless) – speed 153.6 kbps, citycell company give the modem.

g.       EVDO (Evolution, Data only or Evolution, data optimized) Modem (USB wireless) – This is a advance CDMA technology. Speed- 2.4 mbps.