1.0 INTRODUCTION
Today, there are various types of networks, including local area network (LAN) and wide area network (WAN). The largest network in the world is the Internet. All of these networks has its own design according to the required network. Network design is also known as network topology. One definition of the network topology is “In communication networks, a topology is a usually schematic description of the arrangement of a network, including its nodes and connecting lines” (TechTarget, 2010).
There are two ways of defining network geometry, the physical topology and the logical topology. The physical topology of a network is the actual geometric layout of workstations. Whereas logical or signal topology refers to the nature of the paths the signals follow from node to node. In many instances, the logical topology is the same as the physical topology. But this is not always the case. For example, some networks are physically laid out in a star configuration, but they operate logically as bus or ring networks.
In this task, I will discuss the bus topology, ring topology, star topology and mesh topology. Each topology have their own advantages and disadvantages. Design of network topology depends on the use of network requirements and the total cost required. I will discuss the overview, implementation, practical application, advantages and disadvantages of each topology.
2.0 Bus Topology
According to ask.com, they define bus topology as “It is when multiple clients are connected together using a single communication line that they share”. A bus topology is also known as a bus network. Bus topology usually use an ethernet network. It operating in a computer or device connected to a computer or other devices using only one cable. The cable in the bus topology is called the backbone. When needed, other computers can be added between the backbone.
Bus topology construction design is very simple and reliable. This is because if a node fails to operate, other nodes are not affected and can still connect to the internet. Figure 1.0 below shows the picture of the bus network. Bus topologies are usually built using coaxial cable (10BASE-2 and 10BASE-5). But one thing to remember, “These cables are more expensive than simple twisted-pair cables. In the case of 10BASE-5, the cable is not very flexible and can be difficult to route through wall or ceiling structures”(Freeopenbook, 2011).
2.1 Implementation & Example of Bus Topology
Bus networks use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach into with an interface connector. Bus topology is a network topology which all of the nodes from the network are connected to a common transmission medium which has exactly two endpoints. Since the bus topology use only one cabel, it is much cheaper to implement when compared to other topologies.
Bus topology is particularly suitable for small business. Such as law firms. Several computers can be connected directly to the internet using the bus topology. Network can be altered or added in accordance with current requirements. Besides, internet access for every computer is not interrupted if another computer cut off from the Internet.
2.2 Advantages & Disadvantages of Bus Topology
Bus topology also has its own advantages and disadvantages as in the table 1.0 below.
Advantages
• Easy to implement and extend as necessary
• Very cheap and easy. Only one main cable connecting all to the stations together.
• Reduces the time and cost of installation.
• Easy troubleshooting.
• It is best suited for small networks
Disadvantages
• The cable length is limited
• This network topology can perform well only for a limited number of nodes.
• Entire network shuts down if there is a break in the main cable.
• Difficult to identify the problem if the entire network shuts down.
• As the number of workstations increase, the speed of the network slows down.
Table 1.0
Bus topology diagram is as figure 1.0.
Figure 1.0
3.0 Ring Topology
The second type o topology is the ring topology. “A ring topology is a network topology or circuit arrangement in which each network device is attached along the same signal path to two other devices, forming a path in the shape of a ring”(akshaya bhatia R K, 2008). 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 will take down the entire system.
Token Ring is an example of a ring topology. Token Ring networks support three types of cable: Unshielded Twisted Pair (UTP), IBM Cabling System Shielded Twisted Pair (STP), and Fiber Optic. This allows the designer of a Token Ring network to use the cable type which will work the best in their environment network.
3.1 Implementation & Example of Ring Topology
To implement a ring network we use the Token Ring technology. A Token is passed from one computer to another which enables each computer to have equal access to the network. To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. In any event, data goes around the ring, and each computer has both a downstream neighbour and an upstream neighbour. The ring is an active topology, because each computer regenerates the signal before passing it on.
Ring topology is commonly used in office buildings. This is because the relationship between the client computer does not require as much or as separate server. It is only connected through the hub. Ring topology also runs around a school campus or collection of buildings to form a high-speed backbone network.
3.2 Advantages & Disadvantages of Ring Topology
Advantages and disadvantages of ring topology described in the table 2.0 below ;
Advantages Disadvantages
• Performs better than a bus topology under heavy network load.
• Does not require a central node to manage the connectivity between the computers
• Very orderly network where every device has access to the token and the opportunity to transmit
• To manage the connectivity between the computers it doesnt need network server. • Bandwidth is shared on all links between devices
• Token Ring networks using STP cable can be very difficult to physically install due to the size, weight, and stiffness of the STP cable
• One malfunctioning workstation can create problems for the entire network
• One malfunctioning workstation can throw away the entire network.
Table 2.0
Ring topology diagram is as figure 2.0.
Figure 2.0
4.0 Star Topology
“Star Network Topology requires the use of a central top level node to which all other nodes are connected. This top level node may be a computer, or a simple switch, or just a common connection point”.(Raj Jain, 2008). In local area networks with a star topology, each network is connected to a central hub with a point-to-point connection. Data on a star network passes through the hub, switch, or concentrator before continuing to its destination.
4.1 Implementation & Example of Star Topology
Compared to the bus topology, a star network normally requires more cable. All traffic that traverses the network passes through the central hub. This hub will acts as a signal repeater. We can consider that the star topology is the easiest topology to design and implement. But, a failure in any star network cable will only take down one computer network access and not the entire local area network. But if the hub fails, the entire network also fails.
Many home networks use the star topology. A star network features a central connection point called a "hub" that may be a hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet. However, it can also be used with coaxial cable or fiber optic cable.
4.2 Advantages & Disadvantages of Star Topology.
Advantages and disadvantages of star topology described in the table 3.0 below ;
Advantages Disadvantages
• No server required
• Can create much larger network using Token Ring
• Easy to add new nodes without any disruption
• A failure of the cable will only affect one node
• More secure connection as data is sent directly between nodes • One malfunctioning workstation can create problems for the entire network.
• Any changes to any devices can affect the network.
• Network adapter cards are much more expensive than Ethernet cards and hubs.
• Slower than an Ethernet network under normal load.
Table 3.0
Star topology diagram is as figure 3.0.
Figure 3.0
5.0 Mesh Topology
Mesh topology is defined as “The organization of sharing access points working in harmony is known as the mesh topology”. (Don Moskaluk, 2010) The defined mesh topology of a given area defined by the access points is known as mesh cloud. Access to this mesh cloud is dependent on the network created by the access points.
There are two types of mesh topologies: full mesh and partial. In Full Mesh topology each node is connected to every other node in the network. In partial mesh topology every node is not connected to each node in the network.
5.1 Implementation & Example of Mesh Topology
Mesh topology is one of the network architectures in which devices are connected with many redundant interconnections between network nodes such as switches and routers. Each computer is connected to every other computer by separate cabling. This topology is not commonly used or implement for most computer networks because it is difficult and expensive to have redundant connection to every computer. In a mesh topology if any cable or node fails, there are many other ways for two nodes to communicate.
Mesh topology using thicknet coaxial cable or fiber optic cable. This topology is commonly used for wireless networks. As we know, many places such as private sector buildings, schools and other public areas are equipped with wireless technology.
5.2 Advantages & Disadvantages of Mesh Topology
Advantages and disadvantages of mesh topology described in the table 4.0 below ;
Advantages Disadvantages
• Efficient when one node fails, others continue to work without disruption
• Network can be easily expanded anytime
• In one particular instance you can send the data from one node to many nodes
• Message travels along dedicated link, it gives mesh topology is more secure
• Ease of troubleshooting • Quite expensive since a higher length of cable is required.
• Implementation can be a very arduous task.
• Setup and maintenance of this topology is very difficult.
• High chances of redundancy in many of the network connections.
Table 4.0
Mesh topology diagram is as figure 4.0.
Figure 4.0
TASK B
6.0 Choosing a network topology for a SME
I am tasked to build a network for small and medium industries which has branches throughout Malaysia. After many consideration, I choose the bus network topology to be implemented. The following is the consideration that I do:
• Length of cable needed. The linear bus network uses shorter lengths of cable. This indirectly saves the company money.
• Future growth. With a bus topology, expanding a network is easily done. suitable for short-term planning if you want to increase the number of computers in quantities less than 10 units per branch. However, in the long run it is not suitable if you want to upgrade the system to the massive-scale network.
• Easy troubleshooting. During troubleshooting, only the connection to the bus line must be made or disconnected.
• High rate of data tansmittion. Is suitable for many branches throughout the country that always require medium data transfer
• Failure of one of the station does not affect others. If a branch has an Internet connection problem, this condition does not interfere with other branches.
As a small and medium companies, the cost is a major factor taken into account. Thus, the bus topology is the right choice because of low construction costs. Besides, the bus topology is also easy to be upgraded in the future. Besides, it is easily maintained by IT administrators in their respective branches. The main aspects of the most important thing is there is no interference between the branch network. Internet activities of other branches is not affected if one of the branch have internet problem.
7.0 REFERENCES
http://fcit.usf.edu/network/chap5/chap5.htm
http://www.moskaluk.com/Mesh/wireless_mesh_topology.htm
http://it.toolbox.com/wiki/index.php/Ring_Topology
http://www.answers.com/topic/ring-network
http://www.datacottage.com/nch/troperation.htm
http://compnetworking.about.com/od/networkdesign/a/topologies.htm
http://www.cs.wustl.edu/~jain/cse567-08/ftp/topology/index.html
http://whatis.techtarget.com/definition/network-topologies.html
http://www.freeopenbook.com/upgrading-repairing-networks/ch13lev1sec4.html
http://www.firewall.cx/networking-topics/general-networking/103-network-topologies.html
http://www.computerhope.com/jargon/m/mesh.htm
http://www.edrawsoft.com/Mesh-Network.php
http://www.completepcpedia.com/mesh_topology.html
Today, there are various types of networks, including local area network (LAN) and wide area network (WAN). The largest network in the world is the Internet. All of these networks has its own design according to the required network. Network design is also known as network topology. One definition of the network topology is “In communication networks, a topology is a usually schematic description of the arrangement of a network, including its nodes and connecting lines” (TechTarget, 2010).
There are two ways of defining network geometry, the physical topology and the logical topology. The physical topology of a network is the actual geometric layout of workstations. Whereas logical or signal topology refers to the nature of the paths the signals follow from node to node. In many instances, the logical topology is the same as the physical topology. But this is not always the case. For example, some networks are physically laid out in a star configuration, but they operate logically as bus or ring networks.
In this task, I will discuss the bus topology, ring topology, star topology and mesh topology. Each topology have their own advantages and disadvantages. Design of network topology depends on the use of network requirements and the total cost required. I will discuss the overview, implementation, practical application, advantages and disadvantages of each topology.
2.0 Bus Topology
According to ask.com, they define bus topology as “It is when multiple clients are connected together using a single communication line that they share”. A bus topology is also known as a bus network. Bus topology usually use an ethernet network. It operating in a computer or device connected to a computer or other devices using only one cable. The cable in the bus topology is called the backbone. When needed, other computers can be added between the backbone.
Bus topology construction design is very simple and reliable. This is because if a node fails to operate, other nodes are not affected and can still connect to the internet. Figure 1.0 below shows the picture of the bus network. Bus topologies are usually built using coaxial cable (10BASE-2 and 10BASE-5). But one thing to remember, “These cables are more expensive than simple twisted-pair cables. In the case of 10BASE-5, the cable is not very flexible and can be difficult to route through wall or ceiling structures”(Freeopenbook, 2011).
2.1 Implementation & Example of Bus Topology
Bus networks use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach into with an interface connector. Bus topology is a network topology which all of the nodes from the network are connected to a common transmission medium which has exactly two endpoints. Since the bus topology use only one cabel, it is much cheaper to implement when compared to other topologies.
Bus topology is particularly suitable for small business. Such as law firms. Several computers can be connected directly to the internet using the bus topology. Network can be altered or added in accordance with current requirements. Besides, internet access for every computer is not interrupted if another computer cut off from the Internet.
2.2 Advantages & Disadvantages of Bus Topology
Bus topology also has its own advantages and disadvantages as in the table 1.0 below.
Advantages
• Easy to implement and extend as necessary
• Very cheap and easy. Only one main cable connecting all to the stations together.
• Reduces the time and cost of installation.
• Easy troubleshooting.
• It is best suited for small networks
Disadvantages
• The cable length is limited
• This network topology can perform well only for a limited number of nodes.
• Entire network shuts down if there is a break in the main cable.
• Difficult to identify the problem if the entire network shuts down.
• As the number of workstations increase, the speed of the network slows down.
Table 1.0
Bus topology diagram is as figure 1.0.
Figure 1.0
3.0 Ring Topology
The second type o topology is the ring topology. “A ring topology is a network topology or circuit arrangement in which each network device is attached along the same signal path to two other devices, forming a path in the shape of a ring”(akshaya bhatia R K, 2008). 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 will take down the entire system.
Token Ring is an example of a ring topology. Token Ring networks support three types of cable: Unshielded Twisted Pair (UTP), IBM Cabling System Shielded Twisted Pair (STP), and Fiber Optic. This allows the designer of a Token Ring network to use the cable type which will work the best in their environment network.
3.1 Implementation & Example of Ring Topology
To implement a ring network we use the Token Ring technology. A Token is passed from one computer to another which enables each computer to have equal access to the network. To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. In any event, data goes around the ring, and each computer has both a downstream neighbour and an upstream neighbour. The ring is an active topology, because each computer regenerates the signal before passing it on.
Ring topology is commonly used in office buildings. This is because the relationship between the client computer does not require as much or as separate server. It is only connected through the hub. Ring topology also runs around a school campus or collection of buildings to form a high-speed backbone network.
3.2 Advantages & Disadvantages of Ring Topology
Advantages and disadvantages of ring topology described in the table 2.0 below ;
Advantages Disadvantages
• Performs better than a bus topology under heavy network load.
• Does not require a central node to manage the connectivity between the computers
• Very orderly network where every device has access to the token and the opportunity to transmit
• To manage the connectivity between the computers it doesnt need network server. • Bandwidth is shared on all links between devices
• Token Ring networks using STP cable can be very difficult to physically install due to the size, weight, and stiffness of the STP cable
• One malfunctioning workstation can create problems for the entire network
• One malfunctioning workstation can throw away the entire network.
Table 2.0
Ring topology diagram is as figure 2.0.
Figure 2.0
4.0 Star Topology
“Star Network Topology requires the use of a central top level node to which all other nodes are connected. This top level node may be a computer, or a simple switch, or just a common connection point”.(Raj Jain, 2008). In local area networks with a star topology, each network is connected to a central hub with a point-to-point connection. Data on a star network passes through the hub, switch, or concentrator before continuing to its destination.
4.1 Implementation & Example of Star Topology
Compared to the bus topology, a star network normally requires more cable. All traffic that traverses the network passes through the central hub. This hub will acts as a signal repeater. We can consider that the star topology is the easiest topology to design and implement. But, a failure in any star network cable will only take down one computer network access and not the entire local area network. But if the hub fails, the entire network also fails.
Many home networks use the star topology. A star network features a central connection point called a "hub" that may be a hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet. However, it can also be used with coaxial cable or fiber optic cable.
4.2 Advantages & Disadvantages of Star Topology.
Advantages and disadvantages of star topology described in the table 3.0 below ;
Advantages Disadvantages
• No server required
• Can create much larger network using Token Ring
• Easy to add new nodes without any disruption
• A failure of the cable will only affect one node
• More secure connection as data is sent directly between nodes • One malfunctioning workstation can create problems for the entire network.
• Any changes to any devices can affect the network.
• Network adapter cards are much more expensive than Ethernet cards and hubs.
• Slower than an Ethernet network under normal load.
Table 3.0
Star topology diagram is as figure 3.0.
Figure 3.0
5.0 Mesh Topology
Mesh topology is defined as “The organization of sharing access points working in harmony is known as the mesh topology”. (Don Moskaluk, 2010) The defined mesh topology of a given area defined by the access points is known as mesh cloud. Access to this mesh cloud is dependent on the network created by the access points.
There are two types of mesh topologies: full mesh and partial. In Full Mesh topology each node is connected to every other node in the network. In partial mesh topology every node is not connected to each node in the network.
5.1 Implementation & Example of Mesh Topology
Mesh topology is one of the network architectures in which devices are connected with many redundant interconnections between network nodes such as switches and routers. Each computer is connected to every other computer by separate cabling. This topology is not commonly used or implement for most computer networks because it is difficult and expensive to have redundant connection to every computer. In a mesh topology if any cable or node fails, there are many other ways for two nodes to communicate.
Mesh topology using thicknet coaxial cable or fiber optic cable. This topology is commonly used for wireless networks. As we know, many places such as private sector buildings, schools and other public areas are equipped with wireless technology.
5.2 Advantages & Disadvantages of Mesh Topology
Advantages and disadvantages of mesh topology described in the table 4.0 below ;
Advantages Disadvantages
• Efficient when one node fails, others continue to work without disruption
• Network can be easily expanded anytime
• In one particular instance you can send the data from one node to many nodes
• Message travels along dedicated link, it gives mesh topology is more secure
• Ease of troubleshooting • Quite expensive since a higher length of cable is required.
• Implementation can be a very arduous task.
• Setup and maintenance of this topology is very difficult.
• High chances of redundancy in many of the network connections.
Table 4.0
Mesh topology diagram is as figure 4.0.
Figure 4.0
TASK B
6.0 Choosing a network topology for a SME
I am tasked to build a network for small and medium industries which has branches throughout Malaysia. After many consideration, I choose the bus network topology to be implemented. The following is the consideration that I do:
• Length of cable needed. The linear bus network uses shorter lengths of cable. This indirectly saves the company money.
• Future growth. With a bus topology, expanding a network is easily done. suitable for short-term planning if you want to increase the number of computers in quantities less than 10 units per branch. However, in the long run it is not suitable if you want to upgrade the system to the massive-scale network.
• Easy troubleshooting. During troubleshooting, only the connection to the bus line must be made or disconnected.
• High rate of data tansmittion. Is suitable for many branches throughout the country that always require medium data transfer
• Failure of one of the station does not affect others. If a branch has an Internet connection problem, this condition does not interfere with other branches.
As a small and medium companies, the cost is a major factor taken into account. Thus, the bus topology is the right choice because of low construction costs. Besides, the bus topology is also easy to be upgraded in the future. Besides, it is easily maintained by IT administrators in their respective branches. The main aspects of the most important thing is there is no interference between the branch network. Internet activities of other branches is not affected if one of the branch have internet problem.
7.0 REFERENCES
http://fcit.usf.edu/network/chap5/chap5.htm
http://www.moskaluk.com/Mesh/wireless_mesh_topology.htm
http://it.toolbox.com/wiki/index.php/Ring_Topology
http://www.answers.com/topic/ring-network
http://www.datacottage.com/nch/troperation.htm
http://compnetworking.about.com/od/networkdesign/a/topologies.htm
http://www.cs.wustl.edu/~jain/cse567-08/ftp/topology/index.html
http://whatis.techtarget.com/definition/network-topologies.html
http://www.freeopenbook.com/upgrading-repairing-networks/ch13lev1sec4.html
http://www.firewall.cx/networking-topics/general-networking/103-network-topologies.html
http://www.computerhope.com/jargon/m/mesh.htm
http://www.edrawsoft.com/Mesh-Network.php
http://www.completepcpedia.com/mesh_topology.html
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