Unit 2 Competency 2 - Explain basic network components.
Suggested Objective a: Discuss the terminology and components of a successful network
Terminology for this unit is provided on the glossary page, the first page of this module. Be sure to take note of the important points and concepts that are provided. A good understanding of the terms and their meanings will help you successfully master the concepts in this module.
Compuer Network Components Links to an external site. by All About Computer Computer Parts Links to an external site. provides basic information of the major pieces to build a computer network. Items required include a network interface card (NIC), hub, switch, modem, and router. Software is also required so the parts know how to communicate. Look at the information Links to an external site.provided and make notes as needed. All parts are described in detail.
Microsoft Links to an external site.provides on its website information for building a home network. Click the link to read more about What You Need to Set Up a Home Network Links to an external site.. Links inside the article Links to an external site.will provide more indepth information - including pictures.
Building Your Own Network for a Computer Lab
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7 Essential Elements of Communication.pptx Download 7 Essential Elements of Communication.pptx
Suggested Objective b: List advantages of using a network
The TCP/IP Guide Links to an external site. provides a list of advantages for networking. Click the link for The Advantages (Benefits) of Networking Links to an external site.. You will that among the advantages of networking are connectivity, data sharing, hardware sharing, Internet access, and data security and management. Look closely at the information, take notes, and click the links inside the article to learn more.
Chapter 1 Introduction to Computer Networks Networking Basic
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Suggested Objective c: Differentiate among different types of networks
Topology refers to the physical layout of the network devices and the cabling, and how all the components communicate with each other. Just as a topological map shows the layout of the land, computer network topology refers to how the computer network is arranged.
There are four basic types of computer network topologies: the mesh topology, and three multipoint topologies: bus, ring and star.
What is a Topology?
Network topology is the physical arrangement of the various elements (links, nodes, etc.) of a computer network.
Four main types of topologies:
- Mesh – is a network topology in which each node relays data for the network. All nodes cooperate in the distribution of data in the network.
- Bus – is a network topology in which each node is connected to a single cable. Each computer or server is connected to the single bus cable. A signal from the source travels in both directions to all machines connected on the bus cable until it finds the intended recipient.
- Ring – is a network topology that is set up in a circular fashion in which data travels around the ring in one direction until it reaches its destination.
- Star – is a network topology in which every node or workstation is connected to a central node called hub or switch.
Topology PowerPoint.pptx Download Topology PowerPoint.pptx
Mesh Topology:
In a mesh network topology, each of the network node, computer and other devices, are interconnected with one another. Every node not only sends its own signals but also relays data from other nodes. In fact a true mesh topology is the one where every node is connected to every other node in the network. This type of topology is very expensive as there are many redundant connections, thus it is not mostly used in computer networks. It is commonly used in wireless networks. Flooding or routing technique is used in mesh topology.
Advantages of Mesh topology
- Data can be transmitted from different devices simultaneously. This topology can withstand high traffic.
- Even if one of the components fails there is always an alternative present. So data transfer doesn’t get affected.
- Expansion and modification in topology can be done without disrupting other nodes.
Disadvantages of Mesh topology
- There are high chances of redundancy in many of the network connections.
- Overall cost of this network is way too high as compared to other network topologies.
- Set-up and maintenance of this topology is very difficult. Even administration of the network is tough.
Bus Topology
A bus topology has one starting point and one ending point. A single cable, sometimes called a segment, runs the length of the computer network. The cable has two ends. At each end of the cable is a device known as a terminator. The terminator is critical to a bus topology, in fact, a bus topology cannot function without one terminator on each end of the cable.
A packet is a small unit of data that is transferred across a network. When a packet is sent from one computer to the segment, it moves toward both ends of the cable. The packet is carried on an electrical signal that flows along the cable, which serves as a conductor. This moving of a packet is like a home with several telephones. Although the line comes into a home at just one place, the electrical impulse of a call flows freely in all directions to each of the phones connected to the phone line.
If the packet were to reach the end of the cable with no terminator, it would bounce back toward the other end of the cable. Upon reaching the other end, it would bounce again, causing the packet to tie up the network unneccesarily. But, with a terminator, the packet is "absorbed" when it reaches it.
As a packet is sent out onto the segment, it contains the address of the destination computer. When the packet encounters any device attached to the segment, that device examines the packet's destination address. If the packet is intended for it, the device will grab the packet. If not, the device simply ignores the packet. Thus, all computers will receive the packet, but only the recipient will accept the packet.
Network bus topologies use baseband signaling, which means only one device can transmit at a given time. All devices must wait until the segment is clear before attenpting to send a packet. As more devices are added to a bus topology network, more packets will be sent. This means the network slows down.
Advantages:
- It is simple and reliable.
- It requires a small amount of cable.
- Adding more devices to the network is easy to do.
Disadvantages:
- Troubleshooting problems is difficult to do
- It becomes slower as more devices are added to the network.
- A cable problem can shut down the entire network.
Ring Topology
A ring topology is the opposite of a bus topology. A ring is a circle with no ends. All the devices on the network are connected to the ring. The packets travel in a loop in one direction.
A ring topology works well for a computer network with many devices attached to it. Unlike a bus topology, when a device examines a packet, it doesn't ignore it, but it "boosts" it further along the cable.
A ring does not slow down as a bus topology does when more devices are added. It is easier to find cable breaks because there are fewer cable segments.
However, a ring can require more cable and other special equipment.
Advantages:
- It is easy to manage.
- It is good for networks with many devices.
- Cable problems are easy to locate.
Disadvantages:
- It can require more cable and special equipment.
- It is not as widely used as a bus topology.
- One malfuntioning computer can shut down the entire network.
Star Topology
The most common type of multipoint topology is a star topology. A multipoint star topology gets its name from the fact that it resembles a star when viewed from above. The star topology describes a network in which all the devices are connected to a central device, known as a hub.
The hub is responsible for receiving and forwarding the packets to the other devices on the network. The hub receives the packet and then sends it out to all the other devices that are connected to it. As with the bus and the ring, each device examines the packet's destination address. Only the recipient accepts the device, while all other devices ignore it.
Because everything is centralized in a star topology, it is the easiest to manage and troubleshoot.
Advantages:
- It is easiest topology to manage and troubleshoot.
- Adding additional devices is easy to do.
- One malfunctioning computer or cable doesn't stop the entire network.
Disadvantages:
- If the hub fails, the entire network stops.
- It requires more cable.
- Cable installation can be more difficult.
Multipoint Topologies
Instead of using point-to-point topology such as a mesh, LANs typically use a multipoint topology. The key to a multipoint topology can be summed up in a single word: sharing. The three most common multipoint topologies are: bus, ring, and star.
Instead of a separate connection and cable being connected to every other computer on a network, with a multipoint topology, each computer on the network has just one connection. This connection is attached to a single cable that is shared by all other devices on the network. All transmissions are sent and received across one cable.
Computer Networking Tutorial - 11 - Protocols
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Computer Networking Tutorial - 12 - Bus Topology
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Computer Networking Tutorial - 13 - Ring Topology
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Computer Networking Tutorial - 14 - Star Topology
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Computer Networking Tutorial - 15 - Mesh Toplogy
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