Objectives
Assignment Categories



Assignment : 2.
LanExplorer & ETHEREAL software.
Problem Statement :
Study any protocol analyzer software (eg. LAN Explorer) to learn and use its important features, Study of network monitoring software like ETHREAL software. Assignment to examine TCP/IP and non-TCP/IP protocols (IPX/SPX) and capture them using protocol analyzer Software.
LANExplorer Study
What is LANExplorer
Where to get LANExplorer
Requirement (e.g.OS,LAN,etc.).
Installation.
Key Features.
Network Analysis(Packet Capture,Protocol Decode,Capture Triggers.).
Network Monitoring.
Traffic Matrix.
Additional Features.(e.g. Send packet,Display filter.).

Where to get
Web Sites :
1. sunrisetelecomlansoftware/lanexplorer.shtml
2. sunrisetelecomlansoftware/LanExplorer.pdf
3. freedownloadscenterBest/lanexplorer-3_5.html
4. networkworlddetails/41.html
5. softlookupdisplay.asp

Traffic Monitoring


Launching Traffic Matrix Table

Launching Graphical Trace Route

Launching Traffic Matrix Chart

Launching Host Table

Launching Host Chart

Starting and Stopping Packet Capture

Packet Capture window
ETHEREAL Study
What is Ethereal
Intended purposes.
Features.
Platforms Ethereal runs on.
Where to get Ethereal
A brief history of Ethereal.
Installation.
User Interface.
How to start Ethereal with command line parameters
How to colorize the packet list
How to control protocol dissection
How to use the various preference settings

Building and Installing Ethereal
Obtain a binary package for your operating system, or
Obtain the source and build Ethereal for your operating system.
The following are the general steps you would use:
1. Download the relevant package for your needs, e.g. source or binary distribution.
2. Build the source into a binary, if you have downloaded the source.This may involve building and/or installing other necessary packages.
3. Install the binaries into their final destinations.



Installing Ethereal under Windows
Download the Ethereal installer from:
http://etherealdownload.html#releases
and execute it.
Components :
Install the necessary components for ethereal.

ETHEREAL User Interface
How the Ethereal user interface works
How to capture packets in Ethereal
How to view packets in Ethereal
How to filter packets in Ethereal


The Main window

The "File" menu


The "Edit" menu


The "View" menu


The "Go" menu


The "Capture" menu


The "Analyze" menu


The "Statistics" menu


The "Packet List" pane


The "Capture Options" dialog box

While a Capture is running ...


Ethereal with a TCP packet selected for viewing

Assignment : 3.
Windows 2003 server.

Problem Statement :
Assignment to learn and understand Windows 2003 server and its associated domain operations, to configure RAS and DHCP, to add users and computers to a domain

Windows 2003 Server
Windows 2003 Basics.
Active Directory.
Domain Controller.
Associated Domain Operations.
What is RAS and DHCP
Configuring RAS and DHCP.
Adding users to a domain.
Adding computers to a domain.

Configuring DHCP :

Configuring DHCP :


Adding users to Active Directory


Adding users to Active Directory

Adding a computer to Active Directory
Assignment : 4
Linux/Novel Netware configurations and commands.

Problem Statement:
Assignment to learn and understand Linux and/or Novel Netware Network configurations and commands

Linux configurations and commands.
Introduction to Linux .
Features of Linux.
Various types of Linux Commands.
Vi Editor.
Account Creation, Modification & Deletion.
Telnet Service.
Modes of Server ,Services.
NIC Configuration.
Mail Agents.
Web Server Configuration.
FTP Service.
Proxy Server Configuration.
Network File Sharing.



Assignment : 5
Installation of IIS/PWS/Apache server

Problem Statement :

Installation and configuration of IIS/PWS/Apache server. Study and use various facilities/commands and features.
Prerequsites for implementation
Live Demonstration of installation.
Requirement for installing the servers.
Creating Virtual directories using PWS,IIS,Apache.
Assignment : 6
Echo Server

Problem Statement :
Write a program in C/C++ to implement an ECHO server, using Socket programming with both TCP and UDP protocols.
Prerequisites for implementation
Echo Server.
TCP Basics.
UDP Basics.
Various functions available in C/C++ for Socket programming

Assignment : 7.
Quote of the Day Server using VB Winsock Control .
Problem Statement :
Implement a Quote of the Day Server using VB and WinSock Control. Also develop a client application where the user will select TCP or UDP Option, Provide the name of the Server and the Port Number. When the user clicks a button Get the Quote, the client will receive the quote from the server.
Prerequisites for implementation :
Client Server Model.
Winsock Control in VB(i.e. properties, methods & events.)
Possible Uses.
Selecting the protocol.
Setting the Protocol.
TCP Connection Basics.
UDP Basics.
Logic to develop the given application.
Expected Output

Assignment : 8
Internet Update program using Internet Transfer Control.

Problem Statement :
Write an Internet Update program using Internet Transfer Control provided in Visual Basic that will update the files on a local machine for which newer versions of these files are available on the server. Provide facility for the user to determine which files to be updated and which are not.
Prerequisites for implementation :
Internet Transfer Control in VB.
Possible Uses.
Basic Operation.
HTTP and FTP.
Setting Different properties of the control (Using Proxy Server,etc.)
Setting FTP Server.
Synchronous and asynchronous transmission.
Diff. Between OpenURL & Execute Methods.
Expected Output

Assignment :9
Email Application.

Problem Statement :

Develop a simple application using MAPI and TAPI.
Prerequisites for implementation :
MAPI Control in VB.
Possible Uses.
MAPI- complient email System (e.g. Microsoft Exchange , Outlook Express).
MAPISession control.
Setting different properties of MAPISession Control.
The MAPIMessages control.
Using various properties & methods to manage messages.
Prerequisites for implementation :
HTML Basics.
Writing HTML Document( format ).
Basics Tags & their syntax.
Examples using various tags.
Stress on the tags essential for developing given application.
Browser Support.
Displaying HTML Pages in the Browser
e.g. Internet Explorer, Netscape Navigator,etc.


Assignment :11
PHP Script.
Problem Statement :
Write a PHP Script that computes total cost of the ordered items from assignment 4, after adding sales tax. The script will show exactly what items have been ordered.
Prerequisites for implementation :
PHP Basics.
PHP installation/ compatibility.
A PHP File.
PHP Syntax.
PHP browser support.
Using different servers to run PHP.
Displaying PHP in browser.


Assignment : 12
XML DTD & XML Schema.
Problem Statement :
Create a DTD for a catalog of cars, where each car has the child elements and two or three child elements have their own child elements, each of these elements are required and has the possible values Yes or No. Create an XML document with instances of the car elements defined in the DTD and process this document using the DTD and produce a display of raw XML document. Create an XML schema and CSS style sheet for the above-mentioned XML document. Create an XSLT style sheet for one car element of the XML document and use it to create a display of that element.
Prerequisites for implementation :
XML Basics.
XML Syntax.
How XML Works.
XML Elements.
XML Attributes.
XML Validation.
Editors for XML(e.g. Stylus Studio).
XML Browser Support.
Viewing XML Files.
XML DTD.
XML Schema.
Displaying XML with CSS.
Displaying XML with XSLT.
XML Parser.


Assignment : 8.
Client side Scripting.
Problem Statement:
Develop a simple Web based application. Use client-side and server-side scripting.

Prerequisites for implementation :
VBScript & JavaScript Basics.
Possible Uses.
Syntax.
Using these scripts in various web applications.


Assignment : 13
PHP MYSQL/Oracle.
Problem Statement :

Write an application that should read a SQL query from the user based on some database in say MySQL, call a PHP script to process the query and display the results.
Prerequisites for implementation :
MySQLBasics.
MySQL Syntax.
Running MySQL.
Commands for creating,modifying, deleting Databases, tables, records, etc.
Database Connectivity using PHP.
Mini Project
Students should work in a group to develop an Interactive Database-driven Web based application using ASP, VB and Backend Database and use Software Engineering Principals to develop the project and should deliver necessary documents such as SRS, Design details, User Interface, neatly documented code etc.

[attachment=5843]
Basics Of Networking

Created by waheed

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What is a Computer Network?
A network is a collection of computers, printers, routers, switches, and other devices that are able to communicate with each other over some transmission media.

Types of Networks

There are two basic types of networks currently in existence: 
A Local Area Network (LAN)
A Wide Area Network (WAN)

PRESENTED BY: KEVIN SHEA


Networking began its infancy in the mid -1960’s.
by the US Department of Defence (DoD).
The original intention of networking was being
developed to withstand a nuclear war.
Telephone networks were to vulnerable and would
terminate all conversations should a nuclear war
occur.


You wake up at 3 a.m. to go to the bathroom and
stop and check your e-mail on the way back to bed.


WE ARE DEALING WITH MACHINES INSTEAD OF
PEOPLE IN TODAY’S WORLD. OUR PRIVACY IS
AFFECTED AND ALMOST ALL OF OUR PERSONAL
INFORMATION CAN BE FOUND IN
THE “VIRTUAL WORLD” .



ARPA (Advanced Research Projects Agency)
was created in response with the launching of the Sputnik in 1957.
ARPA decided that a DoD network should be packet-
switched networked consisting of a subnet and
host computers.
Experimental network research was awarded to
UCLA, UCSB, SRI and Univ. of Utha in 1969. These
areas were because they all had a large number
of ARPA contracts.


For more information about this article,please follow the link:
http://googleurl?sa=t&source=web&cd=1&ve...inShea.ppt&ei=Q121TP6tOY-4vgP7mqTACg&usg=AFQjCNE-pns7Uc7H_G_ioMe__aJ2ZFIHPA

[attachment=6716]
computer networking full report

Objectives

Understand the state-of-the-art in network protocols, architectures and applications
Understand how networking research is done
Teach the typical constraints and thought process for networked systems
How is class different from undergraduate networking (15-441)
Training network programmers vs. training network researchers

Thanks a lot guys for these ppts.

please send me seminar report of network analyzer ethereal

SUBMITTED BY:
NC ANUM AHMED PIRKANI
NC SADIA RIFFAT

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[attachment=12743]
NETWORK SIMULATOR 2 (NS2):
This assignment has been done with the help of network simulator 2. Using this simulator, we have analyzed in detail TCP and UDP flows.
NS2 was installed using the ubuntu software.
Using this software, we made both the trace files and the NAM file for the different specifications of transport layer protocols i.e. TCP and UDP and corresponding application layer protocols given for them.
When the simulation is run, the trace file gives a lot of information about the simulation results i.e., using it; we can plot the graph which gives the relationship between different parameters.
With the help of NAM file, we can practically see the flow of packets between different nodes. Along with it, we can also see the packet loss.
INTRODUCTION:
Using this simulator, we tried to make different protocols and analyzed the changes occurring in them by changing the transport layer protocol and the application layer protocol.
MORE ABOUT NS:
 NS (network simulator) is basically used to design network protocols which may be wired and wireless.
 NS provides substantial support for simulation of TCP, routing and multicast protocols.
 Different network protocols can be compared with one another.
 Nam can be used to see the packet movement, queue build-up and packet loss directly. It is used to visualize the animation of the flow.
 It has two type of files:
• NAM file:
We can see animations of the network protocol designed using this NAM file.
A snapshot of a NAM file is as under:
NAM interface
Color
Node manipulation
Link manipulation
Topology layout
Protocol state
• TRACE FILE:
This file contains the code established for the network protocol. With the help of this file, we can get all the information about the specifications of network which may include
 Nodes involved( sources and destinations)
 Position of several nodes
 Bandwidths
 No of bytes during flow
 Window size
 Time for flow
 Throughput
 Type of transport and application layer protocol
Basically, with the trace file, we can come to know all what is happening in our network protocol.
With the help of this trace file, we can plot a graph which can be used to see the relationship between different parameters like the type of transport protocol e.t.c.
STEPS:
Some of the steps which can be used while designing the protocol are:
 Create simulator
 Create an event scheduler
 Turn the tracing on
 Create network topology
 setup packet loss, page link dynamics e.t.c
 setup routing agents
 Create connections(transport) between nodes
 Create traffic
 Start simulation
XGRAPH:
It draws a graph on an X display given data read from data files or from some input.
DESCRIPTION OF QUESTION:
Following specifications define the assignment.
 The delays have been mentioned on the figure.
 FLOW1: N1-N5
 FLOW2: N2-N6
 For the TCP transport layer protocol, we have FTP application layer protocol while, for the UDP transport layer protocol, we have CBR application layer protocol.
 For the given questions, we have different TCP flavors i.e. TCP reno and TCP tahoe.
 Queue size is specified to be 10 for all questions.
 For all the questions, we have to calculate the average throughput i.e. the throughput during whole time interval.
ANALYSIS
QUESTION NO. 1:
Read about TCP Reno, TCP Tahoe and TCP SACK. Provide a comparison of the three TCP flavors, preferably in a table format. Finally provide a short analysis/result on which of the three is better. Your analysis must be precise not exceeding 15-20 lines.
ANSWER:
TCP:
It is a reliable connection oriented protocol. It ensures reliability of packet transference due to acknowledgements. Reliability is ensured by starting a timer whenever a packet is sent. If the acknowledgement is received within the time then its fine else wise, there is packet loss.

Presented By
Brian Bogue

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[attachment=12971]
Computer Networking
Internet Service Provider [ISP]Satellite, Wireless, Cable and Dial-up
Direcway Satellite is our ISP with a connection speed of 850K down and 35K up.
Wireless NetworkAllows us to share our internet connection and files to multiple sites. Sending a signal just under ½ mile.
Hardware RequiredLocation, Location, Location
Height and a clear line of sight is most important for speed.
Switch with 4-8 ports [may need a router]
Outdoor CAT 5 cable, RJ45 connectors and crimper tool.
Access Point {use power-over-ethernet; from experience}
UPS [battery backup – keep out power problems]
Hardware Required IILocation, Location, Location
Antennae at each location
Hardwire to remote location computer.
Be Patient and Secure your Network!!
Keep on trying and asking questions.
Make sure you turn on the security for your wireless network.
A firewall must be on all computers running on the network.

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Networking
Networking refers to creating networks.
A network is a group of devices linked to each other.
Computers are widely used to communicate by connecting them together.
This process is called computer networking.
A collection of computers connected to one and another is called a computer network.
Advantages of Computer Networking:
It allows different computers to communicate with one another.
It makes sharing of data and resources much easier.
It saves time and money.
Terminology of Networks
Server
The main computer from which all the other computers share information is known as the Server. The server serves all the nodes that are connected in the network.
Node:
A computer terminal attached to a network that shares information is a called a Node. It I also known as a Workstation.
Network Interface Unit (NIU):
It is a device used for connecting the server and the workstations. It helps in the communication between the server and the nodes.
Types of Networks
Based on the number of computers attached and the area in which they are spread out, networks can be divided into three types :
Local Area Network (LAN),
Metropolitan Area Network (MAN),
Wide Area Network (WAN).
Local Area Network (LAN)
A small group of computers connected in a localized area is called a Local Area Network (LAN).
It connects computers and devices in a limited geographical area such as home, school, computer laboratory or office building.
The defining characteristics of LAN, include their usually higher data-transfer rates, smaller geographical area, and lack of a need for leased telecommunication lines.
Different computers in this type of network are connected together by physical media like wires, cables, etc. LANs are usually installed by small organizations like schools, offices, hospitals etc.
Metropolitan Area Network (MAN)
A metropolitan area network (MAN) is a computer network that usually spans a city or a large campus.
A MAN usually interconnects a number of local area networks using a high-capacity backbone technology, such as fiber-optical links.
The technology used in MAN is similar to that of LAN but it covers a larger area as compared to LAN. A simple example of a Metropolitan Area Network is a Cable TV Network.
Wide Area Network (WAN)
The networks spread across cities and countries are known as Wide Area Networks. A wide area network (WAN) is a computer network that covers a broad area.
The computers are separated by large distances in different cities, states, countries and continents and are connected to each other through cables and even wireless communication channels. The internet which is spread throughout a world is an example of a Wide Area Network (WAN).
Components of a Computer Network
The main components essential for the successful operationing of a computer network can be divided into two main types.
These are :
HARDWARE COMPONENTS
SOFTWARE COMPONETS
Hardware Components
Hardware components in a computer network include :
computer systems (server or clients),
shared resources, like printers, scanners, etc,
physical media that connects them.
The various computers on a network are either named as servers or clients. Different computers that access shared resources on the network are called Clients. Servers are the computers that receive requests from network users (clients) and make the shared resources available to them.
Software Components
The software components required to run a computer network are of two types. These are :
Protocols,
Network Software
The protocols specify the rules, procedures and conventions for communication and data transfer over the network. An example of a protocol is TCP/IP. TCP stands for Transmission Control Protocol and IP stands for Internet Protocol.
Network software is the software that performs various network related functions such as data routing and error detection etc.
Topology of Networks
In a Local Area Network (LAN) environment, the nodes can be interconnected in different ways. The pattern of interconnection of nodes using cables in a network is called Network Topology.
There are three basic topologies :
Bus Topology,
Star Topology,
Ring Topology.
Bus Topology
In a Bus network, also known as Linear network, all the computers and peripheral devices are connected to one single cable called the Bus.
In this type of network, computers can be easily added or removed from the network. The failure of a single node does not affect the performance of the rest of the network.
Star Topology
In a Star Network the server is placed at the center to which all the other nodes are connected. In this type of topology, it is easy to add or remove nodes.
A star network consists of one central switch, hub or computer, which acts as a conduit to transmit messages.
The star topology reduces the chance of network failure by connecting all of the systems to a central node.
Data on a star network passes through the hub, switch, or concentrator before continuing to its destination. The hub, switch, or concentrator manages and controls all functions of the network.
Ring Topology
In a Ring Topology the nodes are connected in a circular chain in which each node is connected to the next. The last node is connected to the first node.
It is difficult to add or remove nodes in this type of a structure. If any one node fails, the whole of the network goes down.
A ring network is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node - a ring.
Data travels from node to node, with each node along the way handling every packet.
Because a ring topology provides only one pathway between any two nodes, ring networks may be disrupted by the failure of a single link.
A node failure or cable break might isolate every node attached to the ring.
Communication Channels
All networks need to be linked to each other. Media or channels refer to the wires, cables or any other means by which data travels from the source to the destination.
The most commonly used media are :
Twisted Pair Cable,
Coaxial Cable,
Fiber Optic Cable,
Wireless Links.
Twisted Pair Cable
Twisted Pair Cable normally consists of strands of copper wire, insulated with plastic sheet and then twisted around each other.
This is the most commonly used media.
It is easy to install, has low weight and is flexible.
It is not capable of carrying data over long distances.
In video applications that send information across multiple parallel signal wires, twisted pair cabling can introduce signaling delays known as skew which results in subtle color defects and ghosting due to the image components not aligning correctly when recombined in the display device.
Coaxial Cable
Coaxial Cable consists of a solid wire core surrounded by a wire mesh with an insulator in between.
It is commonly used in the Cable TV networks.
A coaxial Cable can carry more data than twisted pair wire and is less susceptible to interference. It is more expensive as compared to twisted pair wire.
Coaxial cable is used as a transmission line for radio frequency signals, in applications such as feed lines connecting radio transmitters and receivers with their antennas, computer network (Internet) connections, and distributing cable television signals.
One advantage of coax over other types of radio transmission line is that in an ideal coaxial cable the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors.
Optical Fiber Cable
An Optical Fiber Cable is a thin strand of glass that transmits pulsating beams of light.
Fiber Optic Cables have a complete immunity to noise.
They are also very fragile, so they needed to be handled very carefully.
An Optical Fiber is a flexible, transparent fiber made of very pure glass not much bigger than a human hair that acts as a waveguide to transmit light between the two ends of the fiber.
The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics.
Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths than other forms of communication.
Fiber Optics are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. Optical fiber typically consists of a transparent core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by total internal reflection.
Wireless Links
Wireless communications rely on radio signals for transmitting data. Wireless communication is becoming increasingly popular. The advantage of wireless communication is the flexibility that it offers in terms of the network layout. There are four common applications of wireless communication in the field of computer networking. These are :
Office LAN can use radio signals to transmit data between nodes.
Cellular telephone equipment can be used along with a modem to connect computer systems so that business people can stay in touch with their offices.
Local Area Networks can be connected using microwave transmission within the metropolitan area.
Satellites and microwaves are used to connect WANs covering large distances.

[attachment=14847]
INTRODUCTION TOCOMPUTER NETWORKS
Computer Networks
Computer network connects two or more computers.
The computers can be geographically located anywhere.
LAN, MAN & WAN
Network in small geographical Area (Room, Building or a Campus) is called LAN (Local Area Network)
Network in a City is call MAN (Metropolitan Area Network)
Network spread geographically (Country or across Globe) is called WAN (Wide Area Network)
Applications of Networks
Resource Sharing
Hardware (computing resources, disks, printers)
Software (application software)
Information Sharing
Easy accessibility from anywhere (files, databases)
Search Capability (WWW)
Communication
Email
Message broadcast
Remote computing
Distributed processing (GRID Computing)
Network Topology
The network topology defines the way in which computers, printers, and other devices are connected. A network topology describes the layout of the wire and devices as well as the paths used by data transmissions.
Bus Topology
Commonly referred to as a linear bus, all the devices on a bus topology are connected by one single cable.
Star & Tree Topology
The star topology is the most commonly used architecture in Ethernet LANs.
Larger networks use the extended star topology also called tree topology. When used with network devices that filter frames or packets, like bridges, switches, and routers, this topology significantly reduces the traffic on the wires by sending packets only to the wires of the destination host.
Ring Topology
A frame travels around the ring, stopping at each node. If a node wants to transmit data, it adds the data as well as the destination address to the frame.
The frame then continues around the ring until it finds the destination node, which takes the data out of the frame.
Single ring – All the devices on the network share a single cable
Dual ring – The dual ring topology allows data to be sent in both directions.
Mesh Topology
The mesh topology connects all devices (nodes) to each other for redundancy and fault tolerance.
It is used in WANs to interconnect LANs and for mission critical networks like those used by banks and financial institutions.
Implementing the mesh topology is expensive and difficult.
Network Components
Physical Media
Interconnecting Devices
Computers
Networking Software
Applications
Networking Media
Networking media can be defined simply as the means by which signals (data) are sent from one computer to another (either by cable or wireless means).
Networking Devices
HUB, Switches, Routers, Wireless Access Points, Modems etc.
Computers: Clients and Servers
In a client/server network arrangement, network services are located in a dedicated computer whose only function is to respond to the requests of clients.
The server contains the file, print, application, security, and other services in a central computer that is continuously available to respond to client requests.
Networking Protocol: TCP/IP
Applications
E-mail
Searchable Data (Web Sites)
E-Commerce
News Groups
Internet Telephony (VoIP)
Video Conferencing
Chat Groups
Instant Messengers
Internet Radio

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INTRODUCTION-
What is networking?
 A network is a collection of computers and devices connected to each other. The network allows computers to communicate with each other and share resources and information.
 In other words networking can be defined as inter-connection of two or more computers for sharing the resources(hardware and software)and provide security on them.
 Networks are built with a combination of computer hardware and computer software.
Types of computer networks :-
 LAN (LOCAL AREA NETWORK)
 WAN (WIDE AREA NETWORK)
 MAN (METROPOLITAN AREA NETWORK)
 PAN (PERSONAL AREA NETWORK)
 VPN (VIRTUAL PRIVATE NETWORK)
 CAN (CAMPUS AREA NETWORK)
 GAN(GLOBAL AREA NETWORK)
 SAN (STORAGE AREA NETWORK)
BASIC HARDWARE COMPONENTS
 All networks are made up of basic hardware building blocks to interconnect network nodes, such as Network Interface Cards (NICs), Bridges, Hubs, Switches, and Routers.
 In addition, some method of connecting these building blocks is required, usually in the form of galvanic cable .
 Less common are microwave links or optical cable (“optical fibre"). An Ethernet card may also be required.
Some of the basic components required for interconnecting the network nodes:
 NETWORK INTERFACE CARD
 REPEATERS
 NETWORK HUB
 NETWORK BRIDGE
 NETWORK SWITCH
 ROUTER
NETWORK INTERFACE CARD
 A network card, network adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network.
 It provides physical access to a networking medium and often provides a low-level addressing system through the use of MAC addresses.
REPEATER
 A repeater is an electronic device that receives a signal and retransmits it at a higher power level, or to the other side of an obstruction, so that the signal can cover longer distances without degradation.
 In most twisted pair Ethernet configurations, repeaters are required for cable runs longer than 100 meters.
NETWORK HUB
 A hub contains multiple ports.
 When a packet arrives at one port, it is copied unmodified to all ports of the hub for transmission.
 The destination address in the frame is not changed to a broadcast address.
ROUTER
 Routers are networking devices that forward data packets between networks using headers and forwarding tables to determine the best path to forward the packets.
 Routers work at the network layer .