Topologies and Network Technology

NTC/361

Monday, August 8, 2011
Thomas Krawczyk

Topologies and network technology

In every project, it is important to have a goal, and that goal should be the foundation on which a project team spring into action. The foundation should involve an infrastructural plan, and the usability of the components of the infrastructure. A project plan, as in any other plan, should outline the premise of the project and answer some basic questions like why a particular project is being proposed, what the project will accomplish, who will be the members of the project team and their responsibilities, and when the project will start and terminate. When it comes to a network design, the same principle of project planning applies, and a network topology is an important part of a successful network design. Network topology is the elemental organization of a network; it dictates the media that the network uses, the type of channel it accesses, the architecture of the network, and its operating speed (Tomsho, Tittel, & Johnson, 2004). A network topology deals with the physical layout of the network’s computers, cables, and many more components; a network topology also deals with how the components communicate with each other (Tomsho, et al., 2004). A network topology gives a diagrammatical picture of the network’s physical interconnections. A network topology can be discussed in its physical and logical forms; the physical form deals with the physical arrangement of cables, and the logical form deals with path on which the data travels between the network’s devices (Tomsho, et al., 2004). Network topology has standard types and variant types of the major types. Standard topologies

The bus, star, and ring topologies are the major topologies that all networks that are operational use (Tomsho, et al., 2004). Variations and extensions of these major topologies do exist; however, they are the basis on which other branches of topology derive. Because technology in general and network technology in particular are very diverse, the topologies have major differences in their forms and functions.
Bus topology

A bus topology is the most common methodology of computers interconnecting to each other on a network; it is a network design that involves a linear connection, in which the computer on the network connect to each other via a one cable segment (Tomsho, et al., 2004). Because of the way a network works, sending electronic signals (data) from one computer to the other, the communication in a bus topology becomes vital to the effective use of such topology. The bus network operates on a passive network topology, in that instead of receiving signals, processing them, and sending them back the host, it listens to the data being transmitted (Tomsho, et al., 2004). A bus topology network is not responsible for the movement of data from one device to the other. The disadvantage of this is that a bus topology is passive, and the advantage is that one defective computer does not bring down the entire network (Tomsho, et al., 2004). A break in the cable segment that connects the computers in a bus topology will however cause the entire network to fail (Tomsho, et al., 2004). A bus topology also has a disadvantage one computer transmitting data at a time; what this does is make all network users to equally share transmission time (Tomsho, et al., 2004). The downside of this is that the more devices on a bus network means a slower network, as every user shares a piece of the available transmission time. Star topology. The most stable and most dominant topology of today’s network is the star topology. In a star topology, all of the network devices are connected to a central hub and the central hub retransmits the data that it receives down to the dependent devices. Like the bus topology, all the computers on the star topology hear the transmission signal; however, while the bus topology remains passive, the computers in a star topology will check the destination address (Tomsho, et al., 2004).
After the computers check the destination address, the computers to which the data is addressed will further process the data (Tomsho, et al., 2004).

The centralization of resources is a beneficial factor to the start topology; however, a notable drawback is the effect that the failure of a hub has on the entire network. When a hub fails, all computers and other devices that are attached to the failed hub loose access to the network (Tomsho, et al., 2004). In a bus topology, one user can bring down the entire network simply by disconnecting his or her network cable; however, in a star topology, that is not the case (Tomsho, et al., 2004). Ring topology. A ring topology is a network technology in which computers connect to one another in a circular formation; one computer connects to the next computer in line (Tomsho, et al.,
2004). In this topology, data travels in one direction, and the computers in the ring circle will either act on the data or regenerate the data and push it along (Tomsho, et al., 2004). Dependability is a huge factor with a ring topology because every computer in this topology is responsible for retransmitting data, and because of this, the ring is an active topology. An advantage of a ring topology network is that it can be wired to work like a star, where a central hub passes a data through a virtual ring
(Tomsho, et al., 2004). Mesh topology. Although all of the aforementioned topologies have their individual benefits, some combinations or extensions of them may proof more efficient in the network environment, and one of the extensions is the mesh topology. The mesh topology is a mesh of network connectivity that connects each device in a network to every other device, and it creates multiple connections to a point of redundancy. The advantage of this is that a cable or a device failure is not devastating to the network (Tomsho, et al., 2004). Because of the complexity of this network, it costs more to implement a mesh topology; however, it is more fault-tolerant (Tomsho, et al., 2004).

Ethernet. This is a networking technology that was developed to connect computer systems to form a network (local area network) that is controlled by a protocol that passes information between two or more systems in an effort to avoid collision (WiseGeek, 2011). Ethernet connection has limitations when it comes to data travel distances, which is why it is an ideal technology for homes and small offices (Tomsho, et al., 2004). Ethernet is a baseband system that uses repeaters; repeaters receive network signals and refresh them as a restoration process before retransmitting them to other devices (Tomsho, et al., 2004). This is the concept of regeneration, a concept that extends longevity- span of a network in the case of Ethernet. Token ring. This is a network that uses twisted pair cable, a wiring structure that connect computers to outlets in the wall; this type of network architecture make the network more reliable and faster (Tomsho, et al., 2004) Token ring takes the form of a star topology and a function of a logical ring. An advantage of using a token ring network is that the network ensures equal usage time for all computers on the network; this discourages monopolization of access to a network by one user.
Another advantage of the token ring network is the ability to pinpoint faults in the network; this process is known as beaconing (Tomsho, et al., 2004). In the beaconing process, one computer, the first computer that is powered on a token ring network, is responsible for ensuring the proper routing of incoming data. Fiber Distributed Data Interface (FDDI). FDDI is a networking standard the allows for the transmission of data on fiber optics lines in a local area network (LAN), and unlike other network capabilities, FDDI can extend service range to as high as 124 miles (Search network, 2011). It also has an advantage of connecting thousands of users on the same network (Search network, 2011).
Like the token ring network, FDDI uses the token-passing channel access; however, FDDI networks do not take a star formation (Tomsho, et at., 2004).
FDDI takes on physical ring wiring arrangement, and the devices do not connect to a central hub, although concentrators can be used, they connect to each other (Tomsho, et at., 2004). FDDI also has an advantage of prioritization of data based on material content. Wireless. Wireless is a telecommunications technology that uses something, electromagnetic wave, rather than wires to transmit network signals over a communication path (Search mobile computing, 2011). Many people use wireless technology without regards to its architecture or the actual technology that goes into its functionality; the use of cellular phones and pagers. Wireless technology has many advantages, among which are accessibility, mobility, speed, and many more. A disadvantage can be security issues. Because this technology is wireless, it makes it easier for people who want to gain access a particular network do so by having a wireless scanner and other means like software (Tomsho, et al., 2004). A potential hacker can see all available networks on his or her computer, some of which can be easily access, so a person can simply gain network access by being in the vicinity of a network that he or she wants to access.

References:

Tomsho, G., Tittel, E. & Johnson, D. (2004). Guide to networking essentials (4th ed.). Boston, MA: Thomson Learning.
WiseGeek. (2011). What is the Ethernet? Retrieved from http://www.wisegeek.com/what-is-ethernet.htm

Search Network. (2011). FDDI (Fiber Distributed Data Interface). Retrieved from.

http://searchnetworking.techtarget.com/definition/FDDI

Search Mobile Computing. (2011). Wireless. Retrieved from

http://searchmobilecomputing.techtarget.com/definition/wireless