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Chapter 4, Wired Networking, Hands-On Project, Exercise 4-1

# The following activities give you critical thinking challenges. Challenge labs give you an opportunity to use the skills you have learned to perform a task without step-by-step instructions. Case projects offer a practical networking setup for which you supply a written solution. Building an Extended Star Topology Network Time Required: 30 minutes Objective: Use hubs and switches to build an extended star topology network. Required Tools and Equipment: Determine which type of devices and how many you need to build the network. Description: In this lab, you build an extended star network in which the computers are connected in a physical star and a logical bus topology; the computers form the outer arms of the extended star. The center of the extended star should be a device that creates one collision domain per port. Build the network with as much equipment as you have available, distributing computers evenly around the outer edges of the extended star. Draw the final topology and label the devices. If you lack equipment, you can simply draw the topology without building the physical network. Then answer the following questions: To what type of device are the computers attached?_____________________________________________________________________________________________________

### Explanation

Network Topology:

Network topology is the association of network nodes to form a logical and physical structure. The community topology consists of the complete procedure which includes the records about all nodes which are positioned within the network and shape a community structure. The community topology also consists of data about how the information can be switch among the network nodes. It is a kind of celebrity topology in which one extra extra networking device is without delay connected to the important networking device. It seems like a mesh of switches which might be interconnected to community and one imperative networking tool manipulate the network. Whereas the Star Topology is higher suitable for small networks, the Extended Star Topology is commonly better for the bigger ones.

Extended Star Topology:

The Extended Star Topology is a chunk extra advanced. Instead of connecting all gadgets to a vital unit, we've got sub-principal gadgets added to the mix. This permits greater capability for company and subnetting- yet additionally creates extra factors of failure. In many cases it's far impractical to use a Star Topology due to the fact that networks can span an entire building. In this case, the Extended Star Topology is all however important to save you degraded signals.

Network Devices:

The OSI version has seven layers and represents a general for network communication. Hubs send out facts to all hosts on the segment, developing a shared collision domain. Switches have one collision domain in line with port and keep an address desk of the MAC addresses which might be related to each port.

Repeaters and hubs :

A repeater is an electronic device that receives a network signal, cleans it of unnecessary noise and regenerates it. The signal may be reformed or retransmitted at a Higher electricity level, to the other side of an obstruction possibly using a exceptional transmission medium, in order that the signal can cowl longer distances with out degradation. Commercial repeaters have extended RS-232 segments from 15 meters to over a kilometer. In most twisted pair Ethernet configurations, repeaters are required for cable that runs longer than 100 meters. With fiber optics, repeaters may be tens or even loads of kilometers apart. Repeaters work in the physical layer of the OSI model, that is, there is no quit-to-quit change within the bodily protocol throughout the repeater, or repeater pair, even though a exceptional bodily layer can be used among the ends of the repeater, or repeater pair. Repeaters require a small quantity of time to regenerate the signal. This can cause a propagation put off that affects network performance and can affect proper function. As a result, many community architectures restriction the quantity of repeaters that may be used in a row, e.G., the Ethernet 5-4-3 rule.

A repeater with multiple ports is known as hub, an Ethernet hub in Ethernet networks, a USB hub in USB networks.

• USB networks use hubs to form tiered-star topologies.
• Ethernet hubs and repeaters in LANs have been mostly obsoleted by modern switches.

Switches :

A community switch is a device that forwards and filters OSI layer 2 datagrams (frames) between ports based totally on the vacation spot MAC address in each frame. A transfer is wonderful from a hub in that it simplest forwards the frames to the physical ports involved in the communication in place of all ports connected. It can be notion of as a multi-port bridge. It learns to associate physical ports to MAC addresses via analyzing the supply addresses of acquired frames. If an unknown vacation spot is targeted, the transfer proclaims to all ports but the source. Switches usually have severa ports, facilitating a celebrity topology for devices, and cascading additional switches.

The 5-4-3 rule divides the network :

The Solution :

Building an Extended Star Topology Network :

Objective : Use hubs and switches to build an Extended Star Topology Network

Design Considerations:

• To build an extended star network with the computers forming the outer arms of the extended star;
• Connections are by physical star and logical bus topology, ie by using Ethernet topology;
• The computers should be evnly distributed around the outer edges;
• Use as much equipment as available or draw the same if adequate resources are not available;
• The center of the extended star should be a device that creates one collision domain per port.

Required Tools and Equipment :

1. Clearly the centre of the extended star will be a switch whicht creates one collision domain per port as discussd in the explanation above.

2. This central switch can be connected to 3 hubs following the 5-4-3 Rule of Ethernet Networks

3. Each of these 3 8-port hubs will connect to 8 computers each as outer ring of the extended star.

based on the above observations the complete list of tools and equipment required are as follows:

1. A 4 port Switch

2. 3 8-port Hubs

3. 24 computers, 8 for each hub

4, Sufficient quantity of Ethernet Network Cable with RJ45 connectors

The Diagram :

Q. What type of devices are the computers attached to?

The computers are attched to 8 port hubs which are again connected to the central Switch.

Q. What type of device is at the center of the extended star?

The center of the star is a 4 port Switch which can create one collision domain per port.

Q. How many collision domains are in the network ?

The network consists of 3 collision domains corresponding to each of the 3 hubs connected to the central switch.

Hubs and switches are the devices computers attached to

Server which contains maximum number of computers

There are 5 collision domains are in this network.

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