NETWORKING BASICS TUTORIALS "TOPOLOGIES"

An Overview of Computer Network Topology Here you will learn network topology introduction, how computers get connected, bus, star, hub, hybrid, mesh, tree topologies and network physical design. In Computer Networking “topology” refers to the layout or design of the connected devices. Network Topologies can be physical or logical. In this section I will illustrate on the different types of the topologies.

Physical Topology means the physical design of a network including the devices, location and cable installation. Logical Topology refers to the fact that how data actually transfers in a network as opposed to its design. Topology can be considered as a virtual shape or structure of a network. This shape actually does not correspond to the actual physical design of the devices on the computer network. The computers on the home network can be arranged in a circle shape but it does not necessarily mean that it presents a ring topology. Computer network topologies can be categorized in the following categories. • bus • star • ring • mesh • Tree. Hybrid networks are the complex networks, which can be built of two or more above mentioned topologies. Bus Topology Bus topology uses a common backbone to connect all the network devices in a network in a linear shape. A single cable functions as the shared communication medium for all the devices attached with this cable with an interface connector. The device, which wants to communicate send the broadcast message to all the devices attached with the shared cable but only the intended recipient actually accepts and process that message. Ethernet bus topologies are easy to install and don’t require much cabling and only a main shared cable is used for network communication. 10Base-2 and 10BaseT are two popular types of the Ethernet cables used in the Bus topology. Also, Bus network works with very limited devices. Performance issues are likely to occur in the Bus topology if more than 12-15 computers are added in a Bus Network. Additionally, if the Backbone cable fails then all network becomes useless and no communication fails among all the computers. Unlike in the Star topology in which if one computer is detached from a network then there is not effect on the other computers in a network. Ring Topology In ring Network, every computer or devices has two adjacent neighbors for communication. In a ring network, all the communication messages travel in the same directory whether clockwise or anti clockwise. Any damage of the cable of any cable or device can result in the breakdown of the whole network. Ring topology now has become almost obsolete. FDDI, SONET or Token Ring Technology can be used to implement Ring Technology. Ring topologies can be found in office, school or small buildings. Star Topology In the computer networking world the most commonly used topology in LAN is the star topology. Star topologies can be implemented in home, offices or even in a building. All the computers in the star topologies are connected to central devices like hub, switch or router. The functionality of all these devices is different. I have covered the detail of each networking devices in the separate portion of my website. Computers in a network are usually connected with the hub, switch or router with the Unshielded Twisted Pair (UTP) or Shielded Twisted Pair Cables. As compared to the bus topology, a star network requires more devices & cables to complete anetwork. The failure of each node or cable in a star network, won’t take down the entire network as compared to the Bus topology. However if the central connecting devices such as hub, switch or router fails due to any reason,then ultimately all the network can come down or collapse. Tree Topology Tree topologies are comprised of the multiple star topologies on a bus. Tree topologies integrate multiple star topologies together onto a bus. Only the hub devices can connect directly with the tree bus and each Hub functions as a root of a tree of the network devices. This bus/star/hybrid combination supports future expandability of the computer networks, much better than a bus or star. Mesh Topology Mesh topology work on the concept of routes. In Mesh topology, message sent to the destination can take any possible shortest, easiest route to reach its destination. In the previous topologies star and bus, messages are usually broadcasted to every computer, especially in bus topology. Similarly in the Ring topology message can travel in only one direction i.e clockwise or anticlockwise. Internet employs the Mesh topology and the message finds its route for its destination. Router works in find the routes for the messages and in reaching them to their destinations.The topology in which every devices connects to every other device is called a full Mesh topology unlike in the partial mesh in which every device is indirectly connected to the other devices. Summary Topologies are the important part of the network design theory. A better network can be built if you have the knowledge of these topologies and if you know the difference between each topology. Similarly you should have the knowledge of each network device so that you can properly use them according to your network needs. A misconfigured network can result in a waste of time and energy as well as a lots of troubleshooting methods to resolve the issue. So thebasic understanding of the network topologies and network devices is a must to build a good network.

NETWORKING BASICS TUTORIALS "INTRODUCTION TO NETWORKING"

Introduction To Windows Networking What is Windows Networking? The term networking covers a broad range of the topics and technologies. A computer network is segmented into different parts to share the data and resourced between the different computers of a network. Microsoft has released the operating systems that have the networking capabilities so Microsoft Windows 98, Microsoft Windows 2000, Windows 2003, Windows XP Professional and Windows Vista all are the network operating systems.

All these operating systems have built inn capabilities of files and printer sharing, security, network administrative control, protocols support such as TCP/IP, NetBIOS, IPX/SPX and network hardware support. Naming Computers All computers in a Windows based network requires a unique name for their identification i.e. the name of the computer A cannot be assigned to the computer B and so on. Assign a meaningful computer name to all the computers and the name should be easy to remember. All the names should be configured properly and ensure that the name is not longer than the 15 characters and they contain no spaces in them. Also try to avoid the special names while naming the computers such as / \ *,:,. To assign a computer name in Windows XP and Windows 2000 do the following things. 1. Right click on the My Computer. 2. Click Properties 3. Click on Computer name. 4. Assign a unique and meaningful computer name. Naming Workgroup and Domains A Windows based computer network can be a workgroup (Peer to Peer) or domain (client/server). You can make your computer a part of the workgroup or a domain. If you have centralized server then your computer will be part of the domain and if you have no server then all computers will be having peer to peer networking. In both cases, while joining your computer to a domain or a workgroup always assign unique, sequenced, memorable and meaningful names to the computers. Do not use duplicate names and the special characters such as / \ *,:,,. In order to join a computer to a domain or workgroup in Windows 2000 and Windows XP Professional do the following. 1. Right Click on My Computer 2. Click Properties 3. Click on Computer Name 4. In Workgroup or domain, enter the name of the workgroup or domain. If everything is correct such as unique computer name, unique IP address, correct workgroup or domain name then you computer will be the part of the workgroup or domain in the few seconds and you will be see a welcome to domain or workgroup message and will be prompted to restart the computer name. Files Sharing Being on network computer files and printer sharing is a must. To enable the files and folder sharing in Windows XP Professional 2000 and Windows 2000 do the following. 1. Right Click on the folder name you want to share. 2. Click on the properties. 3. Click Sharing. 4. Click on Share this computer on the network. 5. Assign a shared computer name. You can set the sharing rights for the users and also control the shared folder access by allowing and denying permissions to specific users or groups. If you want to share the individual files, you can put the files in the same shared folder. All the files and folders in the parent shared folder will be automatically shared. Network Cable Errors in Windows If your computer network cable is not working properly, you will see a repeated message or pop up “network cable is unplugged” on your desktop and the blinking status lights of the network will also stop blinking. There can be many causes of this problem and you can fix this error with these simple tips. If you have another Ethernet adapter installed but not using it, then disable it by right clicking on the monitor icons on the right side of the desktop and select the disable option. Check both ends of the cables and ensure that the RJ 45 connectors are properly inserted in the LAN card and in the Hub/Switch. Update the drive of the LAN card from the vendor’s website and if the problem still exist then replace the cable with new one. If the problem is still not resolved then replace the LAN card with a new one and try to use a new hub or switch and put cable’s one end into it. By these simple steps, you will be able to trace out and troubleshoot the problem. Introduction to Windows Firewall Windows firewall is a protective layer or boundary that monitors the in and out traffic from your network and internet. The firewall is a protective and defensive boundary against the intruders and unauthorized persons. You can enable the firewall in XP Professional with these simple steps. 1. Click Start > Settings > Control Panel 2. Windows Firewall > Double click. Network Troubleshooting Tips If you find a communication failure error in the TCP/IP network then try to find and troubleshoot the errors with the following methods. 1. Make sure you can ping the other computer by name. 2. Make sure you can pint the other computer by IP address. 3. Make sure you have assigned unique IP address and computer name to all the computers in the network. 4. Make sure you have assigned the correct gateway, subnet mask, DNS and DHCP addresses. 5. For troubleshooting purpose try to uninstall any firewall software and see if the problem is resolved. Windows Network Security Security a computer network should be the top priority of the network administrators, system managers and security specialists. You can secure your computer network by doing these things such as installing the updated operating system, up-to-date antivirus program, event log monitoring, encryption, group policy management, patch management, security scanners, auditing, firewall security, web application security, web content filtering and controlling the access to only the authorized users.

NETWORKING BASICS TUTORIALS "WHAT IS ETHERNET"

What is Ethernet ?

In this section you will learn about the lan terminology, basic ethernet networking overview, a general introduction to LAN, introduction to IEEE, lan topologies, wan standards. You can also find these categories in this site such as network tutorials, computer networking guide, what is networking, tech study guides, topologies, what is data recovery, wireless communication, computer interview questions and network certification. The IEEE standards have been developed by the International Standards Organization (ISO). The Institute of Electrical and Electronic Engineers (IEEE) in 1985 produced a series of standards for the Local Area Networks, which are called IEEE 802 standards.
These standards have been accepted widely throughout the IT world. One of the IEEE 802 standards, the IEEE 802.3 is known as “Ethernet”. Ethernet is the most widely used LAN technology. Ethernet was developed by Xerox corporations in 1972 and it was the first LAN.

According to the ISO standards allows manufactures to produce the devices and equipments, which are guaranteed to operate anywhere.


The Ethernet in its simplest form uses a passive bus that operates at 10 Mbps. The bus is formed from the co-axial cable, which connects all the PCs in the LAN.

A single LAN may have 1024 attached computers, although in the real practice most LANS have fewer computers than this number. One or more segments of the co-axial cable are attached to end to end to create the Ethernet Cable Segment. Each segment is terminated by 50 ohm resistors.


In today’s IT world the reliable and timely access to the information has become vital. Today coworkers thousands of miles apart from each other can share data, voice, video etc with the fractions of seconds. Similarly a larger number of the coworkers can review the research data simultaneously. The Internet allows businesses to share information and resources with their customers.

Ethernet is a communication protocol that is embedded in software and hardware devices that intended. Ethernet has become the standard computer networking protocol with the help of the Xerox, Intel and Digital

A basic LAN consists of the following components.

• Two or more computers.
• Network Interface card or LAN Card in each PC.
• Ethernet cable (Cat5, UTP/SPT) cable to connect the two computers.
• A hub, switch or router to route or direct the network traffic.
• Software for the communication/computer networking.

A network interface card (NIC) is attached and installed in each PC and is assigned a unique address. An Ethernet cable is used to connect two computers; Ethernet cable has RJ45connectors at both ends. There can be two scenarios 1. Two computers can directly connect with each other or 2. Each computer is directly connected with the hub/switch and hence communication occurs in the network. The hub or switch acts as relay.

Computer Network can be wireless. Despite of using Ethernet cable for the communication, Wireless Network Interface cards use radio waves to communicate with the wireless switch or hub. A small antenna is used in the wireless NICs, switches and hubs. Although the wireless networks are more easy to use as compared to the cabled networks, but more configurations and extra care is required to setup and run a wireless network.

The alternate technologies to Ethernet are “Token Ring”, which is used in the Ring Topologiesnetworks. Token Ring is designed by the IBM and ATM. In ATM networking, devices are connected with each other over a very large distance (thus forms the WAN), and behaves like LANs.

Ethernet is a well established and widely used network standard for small to medium sized Ethernet networks as well as for other networks. Ethernet has been used over the 3 decades and forms a very excellent networking/communication environment.
Ethernet Terms
Ethernet follows a simple set of rules. To understand these rules its important to understand the

following terminology.

• Node – The devices that are attached to the segments are nodes.
• Frame – The nodes (computers or network devices) communicates in the form of short messages that are known as frames. The frames are chunks of information with variable size.
• Segment – A single shared medium is known as a Ethernet segment.

• Medium – The Ethernet devices are attached to a common medium. The frames of the data travel along with that medium. This medium can be coaxial cable. Today most commonly used communication mediums are UTP/STP cable, fiber optic cables.

Frames are analogous in human language. We have some rules for constructed the sentences. The

Ethernet protocol specifies a set of rules for constructing the frames. The frames length varies. Each frame must contain source and destination address for the identification of the recipient and the send of the message. The nodes can be uniquely and easily identified. Each Ethernet devices must have a single unique address.

Compute networking standards has brought a revolution in the network computing and it made the communication very easy and standarized. Now every computer and networking devices has to to follow the same standard to communicate with each other.