COMPUTER NETWORK JAS

presentation

COMPUTER NETWORK

TERMINOLOGYOF NETWORKS

• NODES(Work stations): The term node refers to computers that are attactched to a network and are seeking to share resources. Eg: PC, Smartphones, Laptops etc..
• Server: A computer that facilitates sharing of data, software and hardware resources on the network. Servers tend to have more memory, processing power and storage than a normal workstation.
• Network Interface Unit (NIU) (MAC address): A network interface unit is an interpreter that helps in establishing communication between the server and the client. It is also called network adapter, LAN adapter or network interface controller.
• Clients: A client computer is a host computer that requests for some services from server. It serves the request of client computers.

• IP Address: Every Machine on a TCP/IP Network has a unique identifying number called an IP Address. It is Provided by ISP
• Domain Name: It is a way to identify and locate the computers connected to the internet. It must be unique.

NETWORK DEVICES

MODEM

A MODEM (Modulator DEmodulator) is an electronic device that enables a computer to transmit data over telephone lines. It is a device used to conver digital signals into analog signals and vce versa. There are two types of modems namely internal modem and external modem.We know computers store and process data in terms of Os and 1s. However, to transmit data from a sender to a receiver, or while browsing the internet, digital data is converted to an analog signal and the medium (be it free-space or a physical media) carries the signal to the receiver. There are modems connected to both the source and destination nodes The modem at the sender's end acts as a Modulator that converts the digital data into analog signals while the modem at the receiver's end acts as a Demodulator that converts the analog signals into digital data for the destination node to understand

RJ45 CONNECTOR

RJ-45 is a standard type of connector for network cables. The RJ-45 (Registered Jack) connectors are the plug- in devices used in networking and telecommunications applications. They are used primarily for connecting LANs, particularly EthernetRJ-45 is a short term for Registered Jack-45. It is an eight-wire connector used to connect computers on LANS, especially Ethernets

ETHERNET CARD

It is a hardware device that helps in the connection of nodes within a network. Ethernet card is also known as a network card, network adapter or NIC [network interface card). It is a card that allows computers to communicate over a computer network. On Ethernet card, a physical address of each communicating computer is mentioned Physical address is known as MAC address

HUB

It is multi-port and unintelligent network device which simply transfers data from one port of the network to another. A hub is a hardware device used to connect several computers together with different ports. When the packet reaches one port, it is copied to all other ports of the hub without changing the destination address in the frame. Rather, simply copies the data to all of the nodes connected to the hub. Hubs can be either active or passive. Hubs can usually support 8, 12 or 24 RJ-45 ports

SWITCH

A switch (switching hub) is a network device which is used to interconnect computers or devices on a network It filters and forwards data packets only to one or more devices for which the packet is intended across a network. It is also a multi port device but with some intelligence and so the data packets received from one port of network are refreshed and delivered to the other port of the network. The main difference between hub and switch is that hub replicates what it receives on one port onto all the other ports, while switch keeps a record of the MAC addresses of the devices attached to it.

BRIDGE

A bridge is a device that works on the physical layer as well as on data link layer. A network bridge connects multiple network segments (LANS) at the data link layer (layer 2) of the OSI model. Bridges relay frames between two originally separate segments that follow same protocols. When a frame enters a bridge the bridge not only regenerates the signal but also checks the physical address of the destination and forwards the new copy only to that port. An important advantage of using a bridge is that it is a smarter hub as it can filter network traffic on the basis of the MAC address.

GATEWAY

[A gateway is a device that connects dissimilar networks. In internet, several networks are communicating with each other and each network has a different configuration. In order to make reliable communication, there must be a device that helps in communicating. Gateway provides the necessary translation of data received from network into a format or protocol recognized by devices within the internal network.Gateway is a device which establishes an intelligent connection between a local area networks and external networks with completely different structures

REPEATER

A repeater is a device that operates only on the physical layer of the 051 model. As a signal travels a fixed distance, before attenuation of the signal, a repeater is used which amplifies and restores signals for long-distance transmission. A repeater is an electronic device that receives a signal before it becomes too weak and regenerates the original signa Also, it is a two-port network device that strengthens the signal intensity and connects two identical networks. In most twisted pair Ethernet configurations, repeaters are required for cable runs longer than 100 metres A repeater does not change the functionality of the network; instead, it makes the signal strong before it degrades. Repeaters are als extensively used in broadcasting where they are termed as translators or boosters

ROUTER

[A router is a networking device that forwards data packets from the source machine to the destination machine over a network by using the shortest path. A router uses IP address to connect a local area network to the internet. Compared to hub and switch a router has advanced capabilities as it can analyze the data being carried over a network decide/alter how it is packaged, and send it to another network of a different type For example, suppose data has been divided into packets of a certain size and these packets are to be carried over a different type of network which cannot handle bigger packets. In such a case the data is to be repackaged as smaller packets and then sent over the network by a router

WIFI CARD

A Wi-Fi card is either an internal or external Local Area Network adapter with a built-in wireless radio and antenna. A Wi-Fi card is used in a desktop computer that enables a user to establish an internet connection. Wi-Fi cards are known as wireless fidelity cards as they allow the user to set up connection without any wires. Wi-Fi cards are widely used in notebook computers due to their highly portable nature. The most common Wi-Fi card used in desktop computers is PCI-Express Wi-Fi card made to fit the PCI-Express card slot on the motherboard

TYPES OF NETWORK

Computer network may be small or big depending upon the number of computers and other network devices linked together. Thus, networks vary in size, complexity and geographical spread. Computer network can be on a table, in a room, building, city, country, across continents or around the world. Computer networks can logically be divided into two types: 1. Client-Server network 2. Peer-to-Peer network

DATA COMMUNICATION

MODES OF DATA TRANSMISSION

(a) Analog or Broadband Transmission .

• The signal is a radio frequency signal or analog, ie, it can consist of continuous electrical waves that are of varying amplitudes:

• Telephone networks use this type of transmission

• Requires modem for transmitting data over baseband medium

(b) Digital or Baseband Transmission

• . No special device for conversion of signal to be transmitted over baseband medium

• .The signal is a group of discrete electrical units which is transmitted in rapid succession.

(c) Parallel Communication

• . When data is transmitted through multiple wires, with each wire carrying each bit it is called parallel communication.

MODES OF DATA TRANSMISSION

((d) Serial Communication

• .When bits are sent one after another in a series along a wire, it is called serial communication

• .The signal is a group of discrete electrical units which is transmitted in rapid succession.

e) Synchronous or Asynchronous Transmission

• . When sender and receiver synchronize their checks before transmission. eg. the sender first sends control characters to the receiver and then sends the actual data, it is called synchronous transmission. There is no space between data, hence it is efficient for sending large amounts of data.

DATA COMMUNICATION TERMINOLOGY

• Channel: A channel is a communication path through which the data is transmitted trom sender device to the receiver deviceIt tells stories hierarchically
• Baud: The number of changes in a signal per second is known as baud It is the measuring of the data transfer rate Technically, baud refers to the number of discrete signal elem transmitted per second 1 baud represents only 1 signal change per second and is equal to 1 bit per second.

DATA COMMUNICATION TERMINOLOGY

• Bits per second: It is the measuring unit of speed at which data transfer takes place
• Bandwidth: The amount of data that can be passed along a communication channels given period of time [1 second) is termed as bandwidth, re, it measures the information carrying capacity of a line or a network It is the difference between the highest and l frequencies allowed on a transmission media.
• B = fh - fl
• where th and fl are the highest and lowest frequencies. The measuring unit is hertz (Hi where 10 Hz= 1 Kilo Hertz (KHz), 10 KHz 1 Mega Hertz (MHz).

DATA COMMUNICATION TERMINOLOGY

• Communication/Transmission Media: It is a means of communication or access (lines of communication) set up between two organizations to exchange data/information Communication media is the way of transmitting the signal from one place to another Communication media is also known as transmission media. It plays an important role in sending and receiving of data to and from the sender and receiver

DATA COMMUNICATION TERMINOLOGY

• Data and Signals: Information that is stored within computer systems and transferred over a computer network can be divided into two categories-data and signals Data are entities that are stored in the form of 0's and 1's, which convey some special meaning to the computer When this data is transmitted from one place to another, it is converted into signal. Signals are the electric or electromagnetic encoding of data and are used to transmit data system.

DATA COMMUNICATION TERMINOLOGY

• Data Transfer Rate: It is the amount of data transferred in one direction over a link divided by the time taken to transfer it in bits per second (bps). The various measuring units are bits per second (bps) and bytes per second (Bps) or baud, kilobits per second (kbps), megabits per second (mbps), gigabits per second (gbps), terabits per second (tbps.)

1 Kbps 2 bps=1024 bps 1 Mbps 2 bps-1024 Kbps 1 Gbps 2 bps=1024 Mbps 1 Tbps 2" bps 1024 Gbps

THANK YOU

A Media Access Control (MAC) address is a unique identifier assigned by the manufacturer to NIC for use as a networK address in communications. MAC address is a 12-digit hexadecimal number MAC addres usually written in any one of the following formatsMM:MM:MM:SS:SS:SS MM-MM-MM-SS-SS SS The first half of MAC address contains the ID number of the adapter manufacturer and second half represents the serial number assigned to the adapter by the manufactur For example. 00 : A0 : C9 : 18 : C5 : 38 Manufacturing ID number Id

PROBLEM WITH HUB

The problem with hub is that it is not an intelligent device. It shares bandwidth with a the attached devices and broadcasts the data, ie., sends the data frames to all the connecte nodes as it does not remember devices/computers connected to it. Also, it cannot filter th data and causes unnecessary traffic jams.A hub can both send as well as receive information, but only one task at a time. However hub is an inexpensive way to connect multiple nodes/devices to network

Client server network

In Client-Server network, multiple clients or workstations are connected at least one central server. A server is a powerful computer with all applications and hardware installed in it and a client is a computer which seeks any resource from another computer When clients need access to these resources, they access them from the server. This network is used for larger networks.

PEER -TO- PEER NETWORK

In Peer to Peer network, all nodes in the network have equivalent capability and function as both client and server In this network, all workstations are connected together for sharing devices, information or data. This network is ideal for small networks where there is no need of dedicated servers