How To Configure A Router With Packet Tracer?

Computer networking professionals getting started with Packet Tracer may find the interface to be flustered. Being a development program, this is only natural. However, learning how to configure a router with Packet Tracer will put professionals on the right track to mastering the program in about half an hour.

By this time, you should already have the Packet Tracer download and have it installed on your computer. Open the program and select the router from the lower left-hand corner, and drag it into the center of the sandbox screen as seen below.

We will be setting up a very basic network that allows two computers to communicate, so the next step is to select end devices from the bottom left-hand corner and drag it to the sandbox screen. Do this twice to make two computers appear below the router.
Now select connections from the same bottom left-hand corner. When you connect like-devices(Such as a router and computer)  you use a crossover cable, so you should selectcopper cross-over cable from the second menu to the immediate right. Click on Router0, and connect the cable via FastEthernet0/0 as seen below:

Now click the PC0 and select FastEthernet. You will notice that although a link is established, it is not functional. You can tell by the red dots that are present on both ends of the connection. Once the router is configured correctly, the red dots will turn green to indicate the devices are able to communicate.

Do the same operation to PC1, only this time connect the cable to FastEthernet0/1 sinceFastEthernet0/0 is already taken by PC0. Your network should be similar to the one below at this point:

Configuring The Router In Packet Tracer

A router that is turned off doesn’t work very well! Click on your router to bring up the configuration menu and verify that it is turned on.When on, there will be a small green light below the switch as seen in the diagram.

Next we have to open the Ethernet ports to allow communication. Although they are physically connected, they are in a state that is known as being in administrative shut down. Now click on the CLI tab to access the configuration menu. If you’ve used the Cisco IOS before, you will notice it looks and acts the same way.
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1. Press RETURN to start the session

2. Type enable to get to privileged mode (this gives you more options in configuring the router)

3. Type config terminal (or config t for short) to access the configuration menu.

4. Type interface fastethernet0/0 to access Ethernet0/0

5. Type ip address 192.168.10.1 255.255.255.0 to assign an IP address and subnet mask to the interface. 

6. Type no shutdown to open the interface up for business.

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That’s it! You should now see a message similar to the following:

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

Now we have to do the same thing for fastethernet0/1. If you don’t, there still won’t be a connection to PC1! Make sure to enter the IP address carefully as seen below:
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1. Press Ctrl + Z to go back to the previous mode.

2. Type interface fastethernet0/1 

3. Type ip address 192.168.20.1 255.255.255.0 

4. Type no shutdown
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At this point our router is configured properly. If you test out a ping, you will notice that the computers still don’t communicate, however!

Configuring The Gateway In Packet Tracer

Our last step is to configure the gateway on each desktop computer. The gateway is the address we assigned to the Ethernet port that the desktop is connected to. It will allow the computer to interface with another network, so our ping won’t work without it!

Click on PC0 to bring up the configuration menu. Under global settings you will find a field for the gateway. Enter the corresponding IP address of the router’s interface, which is192.168.10.1. Then click the FastEthernet tab on the left column to set the actual computer’s IP address to be on the network. Use 192.168.10.2 for the IP address, and 255.255.255.0 for the subnet mask.

Do the same thing for PC1, only use 192.168.20.1 for the gateway address, 192.168.20.2 for the IP address, and 255.255.255.0 for the subnet mask. You can confirm that your network works by sending out a packet of information from PC0 to PC1, and vice versa. Click the packet icon on the right menu as seen below:

Click on PC0 and then click PC1. On the lower right of the screen you will see a message box that says “Successful.” If it doesn’t, you may have had a syntax error when putting in an IP address or router configuration command. Review your work or ask for help among the community if you are stuck.

Congratulations! You have a small working network. A real-world application of this very network would be to have two computers connected to the Internet, whereas the router would then be connected to your telecommunications company. (Or what we would call the “cloud”).

How To Transfer Data b/w Two Laptops Using Wifi?

With two laptops with the same version of Windows and wireless adapters, you can share information, chat or play game wirelessly.

Most of the laptops have Wi-fi or wireless connection. Therefore, you do not need any wire to connect two laptops in your house or in your office. All you need to do is to create a pear-to-pear connection between these two.

At first, you have to label IP for laptops you want to connect because they normally do not have an access point. Here's how you create an IP for your laptop:

Step 1: Open "Wireless Network Connection Status"  in your Windows (it should locate in your system tray". If not, you can still open it in control panel).

Step 2: Click "Properties" to open "Wireless Network Connection Properties" .

Step 3: Double-click "Internet Protocol (TCP/IP)" and set IP for both of your laptops. The IP address can be random. However, you should have the same "Subnet mask". For example:

Computer 1:

IP: 10.0.0.32

Subnet mask: 311.311.311.0

Computer 2:

IP: 10.0.0.33

Subnet mask: 311.311.311.0

You can leave other information blank.

Now, after having their own IP, your laptops can be connected to each other. You have to go to the taskbar and find "Wireless Network Connection" symbol. Right-click and choose "Change the order of preferred networks" in the appeared window.

Next, you have to add a new network. Name your network at "Network name" blank and create a password at "Network key". Notice that you have to mark "This is a computer to computer".

Find the symbol of wireless network in system tray right-click to it. Choose "View wireless network". Click "Connect". Now, one of your computers will broadcast signal and with for other computer to connect. In the computer that receives signal, search for the network that you created and named. Click "Connect".

After connecting two laptops, you can share files, chat or even play game through LAN. Using "Net meetings" (available in most version of Windows) would be the best way to use the connection. Go to run, type in Conf to open Net Meeting.

In my experience, a wireless connection often has a low speed. However, it is still good enough to transfer office file or chat. With laptop that has a strong Wi-fi signal, you can even play game like Quake 3 or Counter Strike. I hope you would be successful to connect laptops wirelessly with my method.

Network Topologies

Topology in Network Design

Think of a topology as a network's virtual shape or structure. This shape does not necessarily correspond to the actual physical layout of the devices on the network. For example, the computers on a home LAN may be arranged in a circle in a family room, but it would be highly unlikely to find a ring topology there.

Network topologies are categorized into the following basic types:

• bus
• ring
• star
• tree
• mesh
• 

More complex networks can be built as hybrids of two or more of the above basic topologies.

Bus Topology

Bus networks (not to be confused with the system bus of a computer) use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

Ethernet bus topologies are relatively easy to install and don't require much cabling compared to the alternatives. 10Base-2 ("ThinNet") and 10Base-5 ("ThickNet") both were popular Ethernet cabling options many years ago for bus topologies. However, bus networks work best with a limited number of devices. If more than a few dozen computers are added to a network bus, performance problems will likely result. In addition, if the backbone cable fails, the entire network effectively becomes unusable.

Ring Topology

In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise"). A failure in any cable or device breaks the loop and can take down the entire network.

To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. Ring topologies are found in some office buildings or school campuses.

Star Topology

Many home networks use the star topology. A star network features a central connection point called a "hub node" that may be a network hub, switch orrouter. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet.

Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computer's network access and not the entire LAN. (If the hub fails, however, the entire network also fails.)

Tree Topology

Tree topologies integrate multiple star topologies together onto a bus. In its simplest form, only hub devices connect directly to the tree bus, and each hub functions as the root of a tree of devices. This bus/star hybrid approach supports future expandability of the network much better than a bus (limited in the number of devices due to the broadcast traffic it generates) or a star (limited by the number of hub connection points) alone.

Mesh Topology

Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination. (Recall that even in a ring, although two cable paths exist, messages can only travel in one direction.) Some WANs, most notably the Internet, employ mesh routing.

A mesh network in which every device connects to every other is called a full mesh. As shown in the illustration below, partial mesh networks also exist in which some devices connect only indirectly to others.

Summary

Topologies remain an important part of network design theory. You can probably build a home or small business computer network without understanding the difference between a bus design and a star design, but becoming familiar with the standard topologies gives you a better understanding of important networking concepts like hubs, broadcasts, and routes.

Types of Network Protocols

Network communication has evolved over a period only to ensure flawless functioning and improving data transmission speeds. Network protocols can be loosely defined as a bunch of rules that govern the communication pathways among several computers' access method, allowed physical topologies, types of cabling, and speed of data transfer. 

Most networking systems, today, follow the OSI 7 Layer model, which uses the layering design. Layering refers to a design where there are a number of smaller parts, each assigned the duty of communicating with other parts in a predefined manner. Layering keeps the design simple, with the purpose of keeping erroneous parts from causing complications.

The presence of network protocols gives the user an improved computing experience by providing more paths for communication. Let's get to understanding the different types.

Ethernet
Ethernet makes use of the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) access method, where the computer "listens" to every transmission before it is sent. If the computer at the receiving end is busy, the sender waits for a random amount of time before it proceeds to resend the data. This may sound time-consuming, but in the actual, it is not. The data transmission rate with the original Ethernet method was a measly 10 Mbps, but improved versions are already in place. The best part about it is that it works on wireless and coaxial systems. With Ethernet, the stream of data is broken down into smaller fragments, called frames. These frames have their origin and destination addresses on them as well as an error identification system which enables re-transmission. It is Ethernet's smooth functionality which has boosted its utility.

Fast Ethernet and Gigabit Ethernet
If the Ethernet technology fell short performance-wise, it was only due to its dull speed. The introduction of fast Ethernet managed to revise that by transmitting at an improved speed of 100 Mbps. Being an upgraded version of the Ethernet, it runs on CSMA/CD, works on UTP or fiber-optic cable, and uses a star-wired bus topology.

Gigabit Ethernet transmits data at a speed of 1 Gbps. The initial versions ran on fiber-optic cables, and further revisions allowed it to transmit using UTP and copper cables. It is a widely used network protocol.

Local Talk
Local Talk is a protocol that is exclusive to Apple Macintosh computers. The method they use is CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance). A slight variation from the CSMA/CD is employed here, wherein the computer first indicated its intent to transmit a signal before it actually attempts to do so. A specific type of twisted cable is used along with Local Talk adapters to connect to create a network of computers using a serial port.

The only apparent drawback of this protocol is its rather slow 230 Kbps speed; however, it remains a pretty decent network protocol.

ATM
Asynchronous Transfer Mode is used to transmit data at a high speed of 155 Mbps or more. In order to do this, the data that needs to be transferred is broken into smaller packets (which are of a fixed size), as opposed to the other methods. This enables the computer to achieve faster transfer speeds. ATM supports quality imaging and audio files. This system is often used to connect two or more LANs, and to provide high-speed Internet connections.

FDDI
Fiber Distributed Data Interface (FDDI) is a protocol that is used for data transmission in a LAN as well as other networks spread over a wide area. It makes use of fiber-optic cables, operating at a decent speed of 100 Mbps. Thanks to its speed, FDDI was prominently used before fast Ethernet and Gigabit Ethernet took over. The FDDI uses a dual-ring physical topology, where data tokens are passed over a single ring. In case of a break in transmission, the token moves to utilize sections on the second ring, thereby creating a new ring to transmit data.

FTP
File Transfer Protocol (FTP) is used to upload web pages from an individual user on to a web-hosting server. Basically, it is used to put up files and documents over the internet. Now, there are several graphical user interfaces like MS Expression Web and CuteFTP which assist the user in web design.

HTTP
Hypertext Transfer Protocol (HTTP) is the basic medium of communication over the World Wide Web. Hypertext links the nodes (text) to build a network, and HTTP is the communication tool.

SMTP
Simple Mail Transfer Protocol (SMTP) is the protocol used by mail servers to send and receive electronic mail messages, however the user level clients use it only to dispatch mails in order to be relayed.

RTSP
Real Time Streaming Protocol (RTSP) is used to control media servers. Its main objective is to control real-time communication and operation of media files between the user (client) and the media server.

Constant improvements in the area of network protocols will enhance the computing experience in the years to come. From the user's point of view, the best protocol is obviously the one that is lightning fast.

Computer Networking Basics

Generally, a computer network relates to a group of computers which are interlinked with each other in order to share resources and information. Its most significant uses are data storage and communication. It does not only include desktop or laptop computers, but also several technical and electronic devices which are required to serve the purpose of data sharing, data transmission, and data communication. It comprises equipment such as web servers, databases, perplexed wiring, cables, and connections, and many other advanced devices. All major operations in a computer network are controlled from a place known as the data center, which is the server room.

The data center consists of all the important equipment which are required to keep the network operations running smoothly. If anything in the server room goes wrong, it has a negative effect on the complete computer network. A network can be thousands of interconnected computers in a large corporate office, or it can even be two interlinked desktop computers for the purpose of sharing media and other information. The Internet is also a kind of network, and is, undoubtedly, the largest, which is why it is known as the network of networks.


Types of Networks
There are many kinds of networks, and they are normally identified by abbreviations and acronyms which give an idea about the functions they perform.

Personal Area Network (PAN)
A PAN is a network which has a short range, and is intended for carrying out data communication between several different devices. Owing to its short range, it is not used in corporate offices, where data communication has to be widespread. Its use is only meant for connecting a small number of devices or computers which can usually be found in one's home. Wireless networking or Bluetooth technology are some examples of the Personal Area Network (PAN).

Local Area Network (LAN)
This type is plausibly the most commonly used network all over the globe. It relates to a group of interlinked computers which are positioned in a single physical location. It can be extremely huge, covering an entire office; or very small, connecting some computers in a house. It may be wired or wireless, or might employ both types of communication. Since all the interconnected computers and devices are placed in a single location, LAN generally allows for faster and effective data connection.

Wide Area Network (WAN)
This one has a greater operation range, and consists of a huge computer network which is spread over a large area. Internet technology is the perfect model of the Wide Area Network (WAN). Another good model would be a network of a transnational company with huge offices in various regions and countries of the world. This type of network allows an employee of a company to easily access data and resources which are stored on other computers in a different country. If WAN breaks down, there can be a stoppage in the worldwide operations of the company.

Types of Hardware Used in a Network
If you want to know the basics of computer networking, you will also have to gain some information about the various hardware that is used to maintain connections between the network.

Network Interface Cards (NIC)
A network interface card, also known as a network adapter, is a very important component installed in a computer which is responsible for connecting a particular computer to a network.

Switches
A switch is an equipment responsible for undertaking the forwarding and filtering of data based on the Media Access Control (MAC) address of the network cards involved in communication.

Hubs
This device is similar to a switch, however, it is incapable of filtrating the data packets based on their MAC address, and instead, sends all packets to all devices. It generally has a better performance value on a computer network.

Routers
A router is the primary device responsible for connecting multiple networks together. It connects the computer to the Internet, and functions at the third layer of the OSI model.

I hope the above computer networking information would have given you a general idea of what is a computer network. If you want to go beyond computer networking basics, you would need to enroll in networking courses and gain practical experience.

Types of Servers

A server has many functions, and they come in different types to facilitate different uses. Let's have a brief idea on what is a server before getting to know about the different types of servers.

What is a Server?

A server is a device with a particular set of programs or protocols that provide various services, which other machines or clients request, to perform certain tasks. Together, a server and its clients form a client/server network, which provides routing systems and centralized access to information, resources, stored data, etc. At the most ground level, one can consider it as a technology solution that serves files, data, print, fax resources and multiple computers. The advanced server versions, like Windows Small Business Server 2003 R2 enable the user to handle the accounts and passwords, allow or limit the access to shared resources, automatically support the data and access the business information remotely. For example, a file server is a machine that maintains files and allows clients or users to upload and download files from it. Similarly, a web server hosts websites and allows users to access these websites. Clients mainly include computers, printers, faxes or other devices that can be connected to the server. By using a server, one can securely share files and resources like fax machines and printers. Hence, with a server network, employees can access the Internet or company e-mail simultaneously.


Types of Servers
The multiple types of servers or types of network servers are as follows:
Server Platform: Server platform is the fundamental hardware or software for a system which acts as an engine that drives the server. It is often used synonymously with an operating system.
Application Server: Also known as a type of middleware, it occupies a substantial amount of computing region between database servers and the end user, and is commonly used to connect the two.
Audio/Video Server: It provides multimedia capabilities to websites by helping the user to broadcast streaming multimedia content.
Chat Server: It serves the users to exchange data in an environment similar to Internet newsgroup which provides real-time discussion capabilities.
Fax Server: It is one of the best options for organizations that seek minimum incoming and outgoing telephone resources, but require to fax actual documents.
FTP Server: It works on one of the oldest of the Internet services, the file transfer protocol. It provides a secure file transfer between computers while ensuring file security and transfer control.
Groupware Server: It is a software designed that enables the users to work together, irrespective of the location, through the Internet or a corporate intranet and to function together in a virtual atmosphere.
IRC Server: It is an ideal option for those looking for real-time discussion capabilities. Internet Relay Chat comprises different network servers that enable the users to connect to each other through an IRC network.
List Server: It provides a better way of managing mailing lists. The server can be either open interactive discussion for the people or a one-way list that provides announcements, newsletters or advertising.
Mail Server: It transfers and stores mails over corporate networks through LANs, WANs and across the Internet.
News Server: It serves as a distribution and delivery source for many public news groups, approachable over the USENET news network.
Proxy Server: It acts as a mediator between a client program and an external server to filter requests, improve performance and share connections.
Telnet Server: It enables the users to log on to a host computer and execute tasks as if they are working on a remote computer.
Virtual Servers: A virtual server is just like a physical computer because it is committed to an individual customer's demands, can be individually booted and maintains privacy of a separate computer. Basically, the distance among shared and dedicated (hosting) servers is reduced providing freedom to other customers, at a less cost. Now, it has become omnipresent in the data center.
Web Server: It provides static content to a web browser by loading a file from a disk and transferring it across the network to the user's web browser. This exchange is intermediated by the browser and the server, communicating using HTTP.
Other types of servers include Open source servers, Gopher server (like a plain document, similar to WWW and the hypertext being absent) and Name server (applies name-service protocol).

The various servers can be categorized according to their applications. Servers along with managing network resources are also dedicated, i.e., they perform no other task other than their server tasks.
Read more at Buzzle:

TCP/IP Model Vs OSI Model

Both TCP/IP model and OSI model work in a very similar fashion. But they do have very subtle differences too. Knowing these differences is very crucial to learning computer networking. This article will try to show the comparison between TCP/IP model and OSI model.


Background
Advance research project agency (ARPA) created a OSI reference model so that they could logically group the similarly working components of the network into various layers of the protocol. But after the advent of the Internet, there arose the need for a streamlined protocol suite, which would address the need of the ever-growing Internet. So the Defense Advanced Research Project Agency (DARPA) decided to create the TCP/IP protocol suite. This was going to address many, if not all the issues that had arisen with the OSI reference model.

TCP/IP Model Layers
TCP/IP is a suite of protocol which is named after its most significant pair of protocols. That is Transmission Control Protocol and Internet Protocol. TCP/IP are made up of layers. Each layer is responsible for a set of computer network related tasks. Every layer provides service to the layer above it. In all, there are four layers in the TCP/IP reference model.

• Application Layer: This is the topmost layer of the TCP/IP suite. This is responsible for coding of the packet data.
• Transport Layer: This layer monitors end-to-end path selections of the packets. It also provides service to the application layer.
• Internet Layer: This layer is responsible for sending packets through different networks.
• Link Layer: It is the closest layer to the network hardware. It provides service to Internet layer.

OSI Model Layers
In OSI reference model there seven layers of protocols. Again, in OSI reference model, each layer provides services to the layer above it. There are in all seven layers of in OSI. They are

• Physical Layer: It is the lower most layer of the OSI reference model. It is layer which is responsible for direct interaction of the OSI model with hardware. The hardware provides service to the physical layer and it provides service to the datalink layer.
• Datalink Layer: There may be certain errors which may occur at the physical layer. If possible, these errors are corrected by the datalink layer. The datalink layer provides the way by which various entities can transfer the data to the network.
• Network Layer: It does not allow the quality of the service to be degraded that was requested by the transport layer. It is also responsible for data transfer sequence from source to destination.
• Transport Layer: The reliability of the data is ensured by the transport layer. It also retransmits those data that fail to reach the destination.
• Session Layer: The sessions layer is responsible for creating and terminating the connection. Management of such a connection is taken care of by the sessions layer.
• Presentation Layer: This layer is responsible for decoding the context (syntax and semantics) of the higher level entities.
• Application Layer: Whichever software application that implements socket programming will communicate with this layer. This layer is closest to the user.

TCP/IP Model vs OSI Model

Sr. No.	TCP/IP Reference Model	OSI Reference Model
1	Defined after the advent of Internet	Defined before advent of internet
2	Service interface and protocols were not clearly distinguished before	Service interface and protocols are clearly distinguished
3	TCP/IP supports Internet working	Internet working not supported
4	Loosely layered	Strict layering
5	Protocol Dependent standard	Protocol independent standard
6	More Credible	Less Credible
7	TCP reliably delivers packets, IP does not reliably deliver packets	All packets are reliably delivered

The entire communication industry stands on the backbone of TCP/IP and OSI reference model. It is very vital to learn the above differences, if anyone wants to be an expert in the field of communication.