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Final Practical File for Computer Networks!!!3rd year CSE!!!

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C n practical file

  1. 1. Aim 1– To study diff types of networks.LAN - Local Area NetworkA LAN connects network devices over a relatively short distance. A networked office building, school, or homeusually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one perroom), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is oftenbut not always implemented as a single IP subnet.In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a singleperson or organization. They also tend to use certain connectivity technologies, primarily Ethernet and TokenRing.WAN - Wide Area Network
  2. 2. As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning theEarth.A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to aWAN. In IP networking, the router maintains both a LAN address and a WAN address.A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by anyone organization but rather exist under collective or distributed ownership and management. WANs tend to usetechnology like ATM, Frame Relay and X.25 for connectivity over the longer distances.Metropolitan Area NetworkIt is a network spanning a physical area larger than a LAN but smaller than a WAN, such as a city. A MAN istypically owned an operated by a single entity such as a government body or large corporation.
  3. 3. Aim 2- To study diff types topologies used in networking.TopologyTopology means how the computers/ nodes are physically connected to each other.Bus topology• Uses a trunk or backbone to which all of the computers on the network connect.• Systems connect to this backbone using T connectors or taps.• Coaxial cablings ( 10Base-2, 10Base5) were popular options years ago.Bus Topology characteristics-Does not use any specialized network to troubleshoot equipment.-A break in the cable will prevent all systems from accessing the network.-Require less cable-Network disruption when computers are added or removed-Cheap and easy to implementRing Topology• Logical ring– Meaning that data travels in circular fashion from one computer to another on the network.– Typically FDDI, SONET or Token Ring technology are used to implement a ring– Ring networks are most commonly wired in a star configuration• Token Ring has multi-station access unit (MSAU),equivalent to hub or switch. MSAU performs the tokencirculation internally.
  4. 4. Ring Topology characteristics-A single break in the cable can disrupt the entire network.-Ring networks are moderately easy to install-Expansion to the network can cause network disruption-Cable faults are easily located, making troubleshooting easierStar Topology• All computers/devices connect to a central device called hub or switch.• Each device requires a single cable• point-to-point connection between the device and hub.• Most widely implemented• Hub is the single point of failureStar Topology characteristics-More difficult-Easy to troubleshoot and isolate to implement problems-A central connecting device allows for a single point of failure-Cable failure affects only a single user-Easily expanded without disruption Requires more cable to the networkMesh Topology
  5. 5. • Each computer connects to every other.• High level of redundancy.• Rarely used.– Wiring is very complicated– Cabling cost is high– Troubleshooting a failed cable is tricky– A variation hybrid mesh – create point to point connection between specific network devices, often seen inWAN implementation.Mesh Topology characteristics-Complicated-The network can be expanded implementation without disruption to current uses-Requires more cable than the other-LAN topologies Provides redundant paths between devices
  6. 6. Aim 3: To study various types of guided transmission media in detail.Transmission MediaCommunication of data propagation and processing of signals is called transmission. Signals travel fromtransmitter to receiver via a path. This path is called medium. Medium can be guided or unguided.Twisted-Pair Copper WireThe least-expensive and most commonly-used transmission medium is twisted-pair copperwire. For over one-hundred years it has been used by telephone networks. In fact, more than99% of the wired connections from the telephone handset to the local telephone switch usetwisted-pair copper wire. Most of us have seen twisted pair in our homes and workenvironments. Twisted pair consists of two insulated copper wires, each about 1 mm thick,arranged in a regular spiral pattern:. The wires are twisted together to reduce the electricalinterference from similar pairs close by. Typically, a number of pairs are bundled together in acable by wrapping the pairs in a protective shield. A wire pair constitutes a singlecommunication link.Unshielded twisted pair (UTP)It is commonly used for computer networks within a building, that is, for local area networks(LANs). Data rates for LANs using twisted pair today range from 10 Mbps to 100 Mbps. Thedata rates that can be achieved depend on the thickness of the wire and the distance betweentransmitter and receiver. Two types of UTP are common in LANs: category 3 and category 5.Category 3 corresponds to voice-grade twisted pair, commonly found in office buildings.Officebuildings are often prewired with two or more parallel pairs of category 3 twisted pair; one pairis used for telephone communication, and the additional pairs can be used for additional
  7. 7. telephone lines or for LAN networking. 10 Mbps Ethernet, one of the most prevalent LANtypes, can use category 3 UTP. Category 5, with its more twists per centimeter and Tefloninsulation, can handle higher bit rates. 100 Mbps Ethernet running on category 5 UTP hasbecome very popular in recent years. In recent years, category 5 UTP has become common forpreinstallation in new office buildings. When fiber-optic technology emerged in the 1980s,many people disparaged twisted-pair because of its relatively low bit rates. Some people evenfelt that fiber optic technology would completely replace twisted pair. But twisted pair did notgive up so easily. Modern twisted-pair technology, such as category 5 UTP, can achieve datarates of 100 Mbps for distances up to a few hundred meters. Even higher rates are possible overshorter distances. In the end, twisted-pair has emerged as the dominant solution for high-speedLAN networking.Twisted-pair is also commonly used for residential Internet access. We saw that dial-up modemtechnology enables access at rates of up to 56 Kbps over twisted pair. We also saw that ISDN isavailable in many communities, providing access rates of about 128 Kbps over twisted pair. Wealso saw that ADSL (Asymmetric Digital Subscriber Loop) technology has enabled residentialusers to access the Web at rates in excess of 6 Mbps over twisted pair.Coaxial-CableLike twisted pair, coaxial cable consists of two copper conductors, but the two conductors areconcentric rather than parallel. With this construction and a special insulation and shielding,coaxial cable can have higher bit rates than twisted pair. Coaxial cable comes in two varieties:baseband coaxial cable and broadband coaxial cable. Baseband coaxial cable, also called 50-ohm cable, is about a centimeter thick, lightweight, and easy to bend. It is commonly used inLANs; in fact, the computer you use at work or at school is probably connected to a LAN witheither baseband coaxial cable or with UTP. Take a look at the the connection to your computersinterface card. If you see a telephone-like jack and some wire that resembles telephone wire,you are using UTP; if you see a T-connector and a cable running out of both sides of the T-connector, you are using baseband coaxial cable. The terminology "baseband" comes from thefact that the stream of bits is dumped directly into the cable, without shifting the signal to adifferent frequency band. 10 Mbps Ethernets can use either UTP or baseband coaxial cable. It is
  8. 8. a little more expensive to use UTP for 10 Mbps Ethernet, as UTP requires an additionalnetworking device, called a hub. Broadband coaxial cable, also called 75-ohm cable, is quite abit thicker, heavier, and stiffer than the baseband variety. It was once commonly used in LANsand can still be found in some older installations. For LANs, baseband cable is now preferable,since it is less expensive, easier to physically handle, and does not require attachment cables.Broadband cable, however, is quite common in cable television systems.With broadband coaxial cable, the transmitter shifts the digital signal to a specific frequencyband, and the resulting analog signal is sent from the transmitter to one or more receivers. Bothbaseband and broadband coaxial cable can be used as a guided shared medium.Specifically, a number of end systems can be connected directly to the cable, and all the endsystems receive whatever any one of the computers transmits.Fiber Optics
  9. 9. An optical fiber is a thin, flexible medium that conducts pulses of light, with each pulserepresenting a bit. A single optical fiber can support tremendous bit rates, up to tens or evenhundreds of gigabits per second. They are immune to electromagnetic interference, have verylow signal attenuation up to 100 kilometers, and are very hard to tap. These characteristics havemade fiber optics the preferred long-haul guided transmission media, particularly for overseaslinks. Many of the long-distance telephone networks in the United States and elsewhere nowuse fiber optics exclusively. Fiber optics is also prevalent in the backbone of the Internet.However, the high cost of optical devices -- such as transmitters, receivers, and switches – hashindered their deployment for short-haul transport, such as in a LAN or into the home in aresidential access network. AT&T Labs provides an excellent site on fiber optics, includingseveral nice animations.
  10. 10. Aim 4: To study various types of connectors used in computer networks.Connectors used in Computer Networks –A connector is best known for providing the physical link between two components. The use of a connectormight be a connector linking a cable and a network interface card or NIC card, a connector linking a transceiverand a cable or even a connector linking two cable segments. There are various types of connectors used fordifferent transmission media such as – 1. RJ – 45 A registered jack (RJ) is a standardized physical network interface — both jack construction and wiring pattern — for connecting telecommunications or data equipment to a service provided by a local exchange carrier or long distance carrier. The physical connectors that registered jacks use are mainly of the modular connector and 50-pin miniature ribbon connector types. RJ45 is a registered jack standard for a modular connector using 8 conductors, which specifies the physical male and female connectors as well as the pin assignments of the wires in a telephone cable. The "RJ45" physical connector is standardized as the IEC 60603-7 8P8C modular connector with different "categories" of performance, with all eight conductors present but 8P8C is commonly known as RJ45. The physical dimensions of the connectors are specified in ANSI/TIA-1096-A and ISO-8877 standards. 2. BNC The BNC connector (Bayonet Neill–Concelman) is a common type of RF connector used for coaxial cable. It is used with radio, television, and other radio-frequency electronic equipment, test instruments, video signals, and was once a popular computer network connector. BNC connectors are made to match the characteristic impedance of cable at either 50 ohms or 75 ohms. It is usually applied for frequencies below 3 GHz and voltages below 500 Volts. The BNC connector is used for signal connections such as: 1. analog and serial digital interface video signals 2. amateur radio antennas 3. aviation electronics (avionics) 4. test equipment.
  11. 11. 3. SC Connector SC stands for Subscriber Connector- a general purpose push/pull style Connector developed by NTT. SC has an advantage in keyed duplexibility to support send/receive channels. SC Connectors are frequently used for newer Network applications. The SC is a snap-in connector that is widely used in singlemode systems for its performance. The SC connector is also available in a Duplex configuration. They offer low cost, simplicity, and durability. SC connectors provide for accurate alignment via their ceramic ferrules. The square, snap-in connector latches with a simple push- pull motion and is keyed. They feature a 2.5mm Ferrule and molded housing for protection. Typical matched SC connectors are rated for 1000 mating cycles and have an Insertion Loss of 0.25 dB.4. ST Connector ST stands for Straight Tip - a quick release bayonet style Connector developed by AT&T. STs were predominant in the late 80s and early 90s. ST Connectors are among the most commonly used Fiber optic connectors in networking applications. They are cylindrical with twist lock coupling, 2.5mm keyed ferrule. ST Connectors are used both short distance applications and long line systems. The ST connector has a bayonet mount and a long
  12. 12. cylindrical Ferrule to hold the fiber. Because they are spring-loaded, you have to make sure they are seated properly. They are easily inserted and removed due to their design. If you experience high Light loss, try reconnecting. ST connectors come in two versions: ST and ST-II. These are keyed and spring- loaded. They are push-in and twist types. They are rated for 500 mating cycles. The typical Insertion Loss for matched ST connectors is 0.25 dB.5. MT-RJ Connector MT-RJ stands for Mechanical Transfer Registered Jack. MT-RJ is a fiber-optic Cable Connector that is very popular for small form factor devices due to its small size. Housing two fibers and mating together with locating pins on the plug, the MT-RJ comes from the MT connector, which can contain up to 12 fibers. The MT-RJ is one of the newly emerging small form factor connectors that are becoming more common in the networking industry. The MT-RJ utilizes two fibers and integrates them into a single design that looks similar to a RJ45 connector. Alignment is completed through the use of two pins that mate with the connector. Transceiver jacks found on NICs and equipment typically have the pins built into them. The MT-RJ is commonly used for networking applications. Its size is slightly smaller than a standard phone jack and just as easy to connect and disconnect. Its half the size of the SC Connector it was designed to replace. The MT-RJ connector is a small form-factor Fiber optic connector which resembles the RJ-45 connector used in Ethernet networks. Compared to single-fiber terminations such as SC, the MT-RJ Connector offers lower Termination cost and greater density for both electronics and cable management hardware. The MT-RJ Connector is significantly lower in cost and smaller in size than the SC Duplex interface. The small MT-RJ Interface can be spaced the same as copper, effectively doubling the number of fiber ports. The net effect is a Drop in the overall price per fiber Port making fiber-to-the- desktop solutions more competitive with copper
  13. 13. Aim 5: To study diff. types of protocols in tcp/ip suitTCP/IP Protocol SuiteThe TCP/IP model is a descriptive framework for computer network protocols created in the 1970s by DARPA,an agency of the United States Department of Defense. The name derives from the two most importantprotocols of the networking protocol suite, the Transmission Control Protocol (TCP) and the Internet Protocol(IP). The model evolved from the operational principles of the ARPANET, which was an early wide areanetwork and a predecessor of the Internet. The TCP/IP model is formalized in the Internet protocol suite and issometimes called the Internet model or the DoD model.The TCP/IP model describes a set of general design guidelines and implementations of specific networkingprotocols to enable computers to communicate over a network. TCP/IP provides end-to-end connectivityspecifying how data should be formatted, addressed, transmitted, routed and received at the destination.Protocols exist for a variety of different types of communication services between computers.TCP/IP has four abstraction layers as defined in RFC 1122, The TCP/IP model and related protocols aremaintained by the Internet Engineering Task Force (IETF).User Datagram ProtocolThe User Datagram Protocol is very simple. The PDU used by UDP is called a datagram. Datagrams areconsidered unreliable,in that there is no guarantee datagrams will be received in the correct order, if at all. Ifreliability of the information transmitted is needed, UDP should not be used.While UDP is unreliable, the lackof error checking and correction make UDP fast and effic -ient for many less data intensive or timesensitiveapplications, such as the Domain Name Service (DNS), the Simple Network Management Protocol (SNMP),
  14. 14. the Dynamic Host Configuration Protocol (DHCP) and the Routing InformationProtocol (RIP). UDP is alsowell suited for streaming video.Transmission Control ProtocolIn the TCP/IP protocol suite, TCP is the intermediate layer between IP below it, and an application above it.Using TCP, applications on networked hosts can establish reliable connections to one another. The protocolguarantees in-order delivery of data from the sender to the receiver. Both tcp and udp works on port no.fromrange.0-32768.TCP connections have three phases:1. Connection establishment2. Data transfer3. Connection termination• File Transfer Protocol (FTP)— It works on port no.21. Provides a mechanism for moving data files betweensystems. The FTP client and server programs, as well as most Web browsers, contain an implementation of theFTP protocol.• HyperText Transfer Protocol (HTTP)— It works on port no. 80.Protocol used to move Web pages acrossan internet connection. The HTTP protocol is built into Web browsers and Web servers.• Interactive Mail Access Protocol (IMAP)— It works on port no. 143.Provides clients access to e-mailmessages and mailboxes over a network. It is incorporated into e-mail applications.• Post Office Protocol (POP)— It works on port no. 110.Allows clients to read and remove e-mail residing ona remote server. It is incorporated into e-mail applications.• Remote Login (Rlogin)— Provides network remote login capability.• Simple Mail Transfer Protocol (SMTP)— It works on port no. 25.Used to deliver email from one system toanother. It is incorporated into email applications.• Secure Shell (SSH)—Provides remote access to computers while providing encryption of the data.• Telnet— It works on port no. 23.Provides network terminal, or remote login capability.The Internet Protocol (IP)It is a data-oriented protocol used for communicating data across a network. It is a best effort protocol; it doesnot guarantee delivery. It also makes no guarantee as to the correctness of the data it transports. Transmissionusing IP may result in duplicated packets and/or packets out-of-order. All of these contingencies are addressedby an upper layer protocol(For example, TCP) for applications that require reliable delivery.Address Resolution ProtocolThe Address Resolution Protocol is a method for translating between Internet layer and network layer address.The ARP module in a computer or router maintains a translation table of logical to physical mappings it isaware of, called the ARP cache. If there is not a translation for the address in the table, it will make an ARPbroadcast.RARP (Reverse Address Resolution Protocol)
  15. 15. It is a protocol by which a physical machine in a local area network can request to learn its IP address from agateway servers Address Resolution Protocol (ARP) table or cache. A network administrator creates a table in alocal area networks gateway router that maps the physical machine (or Media Access Control - MAC address)addresses to corresponding Internet Protocol addresses. When a new machine is set up, its RARP client programrequests from the RARP server on the router to be sent its IP address. Assuming that an entry has been set up inthe router table, the RARP server will return the IP address to the machine which can store it for future use. Areverse address resolution protocol (RARP) is used for diskless computers to determine their IP address usingthe network.Internet Control Message Protocol (ICMP)It works on port no. 113.The Internet Control Message Protocol (ICMP) is a helper protocol that supports IP with facility for:– Error reporting– Simple queries• ICMP messages are encapsulated as IP datagramsInternet Group Management Protocol (IGMP)It works on port no.119. It work on It is a communications protocol used by hosts and adjacent routers on IPnetworks to establish multicast group memberships .IGMP is an integral part of the IP multicast specification. Itis analogous to ICMP for unicast connections. IGMP can be used for online streaming video and gaming, andallows more efficient use of resources when supporting these types of applications. IGMP is usedon IPv4 networks. Multicast management on IPv6 networks is handled by Multicast Listener Discovery (MLD)which uses ICMPv6 messaging contrary to IGMPs bare IP encapsulation.The Point-to-Point Protocol (PPP)-It is commonly used to establish a direct physical connection between two nodes. It can connect hosts usingserial cable, phone lines, cellular phones, radio links, or fiber optic cables. Most dial-up internet serviceproviders use PPP for customer access to the InternetVarious Protocols with respective Port Numbers.Sno. Protocol Port number1. TCPMUX 12. FTP Data Transfer 203. FTP Control 214. Telnet 235. SMTP 256. IMP 517. DHCP Server 678. DHCP Client 689. HTTP 8010. POP2 10911. POP3 11012. IRC 11313. NNTP 11914. NTP 12315. IMAP 14316. SGMP (Simple Gateway Monitoring Protocol) 15317. SNMP 16118. IRC 19419. IMAP v3 220
  16. 16. 20. HTTPS 44321. RIP 52022. DNS 953
  17. 17. Aim 6 :Discuss the working of E-Mail .E-MailElectronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from anauthor to one or more recipients. Modern email operates across the Internet or other computer networks. Someearly email systems required that the author and the recipient both be online at the same time, in common withinstant messaging. Todays email systems are based on a store-and-forward model. Email servers accept,forward, deliver and store messages. Neither the users nor their computers are required to be onlinesimultaneously; they need connect only briefly, typically to an email server, for as long as it takes to send orreceive messages.An email message consists of three components, the message envelope, the message header, and the messagebody. The message header contains control information, including, minimally, an originators email address andone or more recipient addresses. Usually descriptive information is also added, such as a subject header fieldand a message submission date/time stamp.Originally a text-only (7-bit ASCII and others) communications medium, email was extended to carry multi-media content attachments, a process standardized in RFC 2045 through 2049. Collectively, these RFCs havecome to be called Multipurpose Internet Mail Extensions (MIME).Electronic mail predates the inception of the Internet, and was in fact a crucial tool in creating it, but the historyof modern, global Internet email services reaches back to the early ARPANET.E-Mail WorkingConsider Alice composes a message using her mail user agent (MUA). She enters the email address of hercorrespondent, and hits the "send" button.Her MUA formats the message in email format and uses the Submission Protocol (a profile of the Simple MailTransfer Protocol (SMTP), see RFC 6409) to send the message to the local mail submission agent (MSA), in
  18. 18. this case smtp.a.org, run by Alices internet service provider (ISP). The MSA looks at the destination addressprovided in the SMTP protocol (not from the message header), in this case bob@b.org. An Internet emailaddress is a string of the form localpart@exampledomain. The part before the @ sign is the local part of theaddress, often the username of the recipient, and the part after the @ sign is a domain name or a fully qualifieddomain name. The MSA resolves a domain name to determine the fully qualified domain name of the mailexchange server in the Domain Name System (DNS).The DNS server for the b.org domain, ns.b.org, responds with any MX records listing the mail exchange serversfor that domain, in this case mx.b.org, a message transfer agent (MTA) server run by Bobs ISP. smtp.a.orgsends the message to mx.b.org using SMTP.This server may need to forward the message to other MTAs before the message reaches the final messagedelivery agent (MDA).The MDA delivers it to the mailbox of the user bob. Bob presses the "get mail" button in his MUA, which picksup the message using either the Post Office Protocol (POP3) or the Internet Message Access Protocol (IMAP4).That sequence of events applies to the majority of email users. However, there are many alternative possibilitiesand complications to the email system:Alice or Bob may use a client connected to a corporate email system, such as IBM Lotus Notes or MicrosoftExchange. These systems often have their own internal email format and their clients typically communicatewith the email server using a vendor-specific, proprietary protocol. The server sends or receives email via theInternet through the products Internet mail gateway which also does any necessary reformatting. If Alice andBob work for the same company, the entire transaction may happen completely within a single corporate emailsystem.Alice may not have a MUA on her computer but instead may connect to a webmail service.Alices computer may run its own MTA, so avoiding the transfer at step 1.Bob may pick up his email in many ways, for example logging into mx.b.org and reading it directly, or by usinga webmail service.Domains usually have several mail exchange servers so that they can continue to accept mail when the mainmail exchange server is not available.Email messages are not secure if email encryption is not used correctly.Many MTAs used to accept messages for any recipient on the Internet and do their best to deliver them. SuchMTAs are called open mail relays. This was very important in the early days of the Internet when networkconnections were unreliable. If an MTA couldnt reach the destination, it could at least deliver it to a relaycloser to the destination. The relay stood a better chance of delivering the message at a later time. However, thismechanism proved to be exploitable by people sending unsolicited bulk email and as a consequence very fewmodern MTAs are open mail relays, and many MTAs dont accept messages from open mail relays becausesuch messages are very likely to be spam.Your e-mail client allows you to add attachments to e-mail messages you send, and also lets you saveattachments from messages that you receive. Attachments might include word processing documents,spreadsheets, sound files, snapshots and pieces of software. Usually, an attachment is not text (if it were, you
  19. 19. would simply include it in the body of the message). Since e-mail messages can contain only text information,and attachments are not text, there is a problem that needs to be solved. The recipient would then save theuuencoded portion of the message to a file and run uudecode on it to translate it back to binary. The word"reports" in the first line tells uudecode what to name the output file. Modern e-mail clients are doing exactlythe same thing, but they run uuencode and uudecode for you automatically. If you look at a raw e-mail file thatcontains attachments, youll find that the attachment is represented in the same uuencoded text format shownabove! Considering its tremendous impact on society, having forever changed the way we communicate, todayse-mail system is one of the simplest things ever devised! There are parts of the system, like the routing rules insendmail, that get complicated, but the basic system is incredibly straightforward. The next time you send an e-mail, youll know exactly how its getting to its destination! The Real E-mail System For the vast majority ofpeople right now, the real e-mail system consists of two different servers running on a server machine. One iscalled the SMTP Server, where SMTP stands for Simple Mail Transfer Protocol. The SMTP server handlesoutgoing mail.The other is a POP3 Server, where POP stands for Post Office Protocol. The POP3 server handles incomingmail. A typical e-mail server looks like this: The SMTP server listens on well-known port number 25, whilePOP3 listens on port 110mail Clients. You have probably already received several e-mail messages today. Tolook at them, you use some sort of e-mail client. Many people use well-known stand-alone clients likeMicrosoft Outlook, Outlook Express, Eudora or Pegasus. People who subscribe to free e-mail services likeHotmail or Yahoo use an e-mail client that appears in a Web page. If you are an AOL customer, you use AOLse-mail reader. No matter which type of client you are using, it generally does four things: ·· It shows you a listof all of the messages in your mailbox by displaying the message headers. The header shows you who sent themail, the subject of the mail and may also show the time and date of the message and the message size. It letsyou select a message header and read the body of the e-mail message. It lets you create new messages and sendthem. You type in the e-mail address of the recipient and the subject for the message, and then type the body ofthe message. Most e-mail clients also let you add attachments to messages you send and save the attachmentsfrom messages you receive. Sophisticated e-mail clients may have all sorts of bells and whistles, but at the core,this is all that an e-mail client does.
  20. 20. Aim 7 : To study brief introduction of packet tracer.Packet TracerPacket Tracer is a Cisco router simulator that can be utilized in training and education, but also in research forsimple computer network simulations. The tool is created by Cisco Systems and provided for free distribution tofaculty, students, and alumni who are or have participated in the Cisco Networking Academy. The purpose ofPacket Tracer is to offer students and teachers a tool to learn the principles of networking as well as developCisco technology specific skillsPacket Tracer featuresThe current version of Packet Tracer supports an array of simulated Application Layer protocols, as well asbasic routing with RIP, OSPF, and EIGRP, to the extent required by the current CCNA curriculum. WhilePacket Tracer aims to provide a realistic simulation of functional networks, the application itself utilizes only asmall number of features found within the actual hardware running a current Cisco IOS version. Thus, PacketTracer is unsuitable for modeling production networks. With the introduction of version 5.3, several newfeatures were added, including BGP. BGP is not part of the CCNA curriculum, but part of the CCNPcurriculum.Use in educationPacket Tracer is commonly used by Cisco Networking Academy students working towards Cisco CertifiedNetwork Associate (CCNA) certification. Due to functional limitations, it is intended by Cisco to be used onlyas a learning aid, not a replacement for Cisco routers and switches
  21. 21. Aim 8 : To create a point to point topology using cisco packet tracer.Steps to follow:1.Select two computets and drag them on the editor.2.Use a copper cable and connect them3.Assign diff ip to both of them4.Select a msg and send it to pc1 from pc0.
  22. 22. Aim 9 : To create a star topology using cisco packet tracer.Steps to follow:1.Select four computets and a hub, drag them on the editor.2.Use a copper cable and connect them3.Assign diff ip to all of them except hub.4.Select a msg and send it to pc1 from pc0.
  23. 23. Aim 10 : To create a mesh topology using cisco packet tracer.Steps to follow:1.Select four computets and four swithes, drag them on the editor.2.Use a copper cable and connect them3.Assign diff ip to all of them except swithes.4.Select a msg and send it to pc1 from pc0.
  24. 24. Aim 11 : To create a bus topology using cisco packet tracer.Steps to follow:1.Select a server, five computers and five swithes, drag them on the editor.2.Use a copper cable and connect them3.Assign diff ip to all of them except swithes.4.Select a msg and send it to sever from pc4.5.Result successful as shown in fig .
  25. 25. Aim 12: To create a ring topology using cisco packet tracer.Steps to follow:1.Select six computers and six swithes, drag them on the editor.2.Use a copper cable and connect them3.Assign diff ip to all of them except swithes.4.Select a msg and send it to pc2 from pc5.5.Result successful as shown in fig .
  26. 26. Aim 13 : To create a tree topology using cisco packet tracer.Steps to follow:1.Select seven computers and five hubs, drag them on the editor.2.Use a copper cable and connect them3.Assign diff ip to all of them except hubs.4.Select a msg and send it to pc2 from pc0.5.Result successful as shown in fig .
  27. 27. Aim 14: Difference between yahoo mail and Gmail (Google mail): YAHOO MAIL GOOGLE MAIL1Yahoo started its web mail services under the 1 Google entered the Webmail segment onname Yahoo mail on October 8, 1997, with April 1, 2004 under the name Gmail.Linux at the server end.2 Yahoo moves onto another page for 2Gmail lets you add attachments moreattachments. conveniently from the same screen where you are composing an email, 3 it is not so in gmail3 In Yahoo, you may require to add boxes formore than five attachments4 Yahoo sticks onto its independent Instant 4 Gmail offers the chat module integrated toMessenger for chatting. the email module.5 inYahoo Mail; you can opt to save a contactto your list or not. 5 Gmail automatically stores all email addresses to which you sent and receive emails to your contact list.6 , Yahoo Mail treats every conversationunique. 6 The webmail is arranged in a conversation model in Gmail as in an Instant Messenger. Every time you reply to someone, it will be added as a conversation to the primary email. 7 it is less vulnerable to spams7 Yahoo Mail is more vulnerable to Spamemails 8 With Gmail, the user gets email forwarding8 in Yahoo mail, a user has to upgrade to a paid and POP access for freeversion in order to gain these services. 9 Gmail is less cluttered9 YAHOO is more cluttered 10 While Gmail remains as the first webmail to10 Yahoo later created the Ajax version in employ Ajax Programming technique for its2004. search oriented interface 11 it allows you to send instant messages to your contacts that are online quickly and11 Yahoo has IM as well, it is not nearly as easily.accessible as the one found within Gmail. 12 Gmail’s IM is not separate from its e-mail service.12 Yahoo’s IM is separate from its e-mailservice. 13 it allows you to label folders, keeps all your
  28. 28. folders in approximately the same area, making13 it allows better folder creation and organization with a large amount of foldersorganization. Yahoo mail allows you to label difficult.and organize your folders how you like makingthe mail system . 14 Gmail allows for a bigger attachment14 Yahoo mail only allows attachments up to size.Upto 20 mb in its free version.10mb on its free version, 15 one of the more important aspects of Gmail15 it is considered less professional. is the fact that it is considered the more “professional” of the e-mail services. 16 Gmail, an issue for mobile users.16 Yahoo is better for mobile users. 17 Gmail gets weird on IMAP and is a devourer of bandwidth.17 For IMAP lovers, Yahoo’s implementationis much better. 18 when you make a gmailaccount, you can’t just make Gmail. You have other services like youtube, blogger, picasa, and other services18 An Yahoo id is just for Yahoo. No other linked to it.services are linked to it. 19 Gmail is more user friendly. 20 Gmail “remembers” previously used email19 Yahoo is less user friendly. addresses so that the address must only be keyed in for the initial email.20 Yahoo mail users need to type emailaddresses each time a user needed to send an 21 Google utilized a coding language calledemail. Ajax which allows Gmail users to delete mail, archive mail, and otherwise move it to any other folder without wasting a few seconds each21 when emails are either deleted or moved to a time waiting for the screen to refresh.new folder in Yahoo mail the screen must begiven time to refresh.

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