Week Four Short Answers - Networking Topologies

Week Four Short Answers

University of Phoenix

Week Four Short Answers

Star topology

The star topology can be physically designed as a star but is not limited to one layout as long as there is one central resource control computer.

All transmissions between computers travel through the central connection point. One disadvantage is, if the central connection or hub fails, all the computers connected to that hub fail. If a computer or cable fails, the other computers are still operable because the hub is still operable. This is an advantage over the bus topology where one cable failure can crash the network.

Bus topology

This is a linear, passive topology. According to Johnson, Tomsho, 2004, "all the computers connected to the main cable only listen for data." This is misleading because in the paragraph prior to the quote the computers are sending signals. The cable is terminated on each end with a signal terminator preventing signal bounce. If the main cable fails, all the nodes fail but if a node fails it does not affect network operation (Kim, 1996). If a cable is not terminated, the signal will bounce continuously preventing data from being sent (Johnson, Tomsho, 2004, chapter 2). The advantages are a simple configuration and inexpensive implementation for a small business.

Ring topology

All computers are connected to one cable that has no open ends to terminate. Each computer is connected through that cable to the computer on either side of itself forming a ring of connected computers. One use of this configuration is token ring network in which a token is passed around the ring in one direction until the destination node is reached. The token is then modified and passed along. The disadvantage is one node failure can cause network failure. However, a ring topology that is physically wired as a star can use a smart hub to bypass the disabled node (Johnson, Tomsho, 2004, chapter 2).

Mesh topology

The pathways of the Internet can be an example of a mesh network. This is a network in which there are at least two paths to every node. A good example would be a problem with the UOP systems that prevented communication to the instructor. A second path may be taken through the personal email systems of the faculty and student. This a fault tolerant network and advantageous as such but is expensive to implement. In a full mesh architecture, each node can connect to every node in the mesh. "Multipoint to multipoint networks creates a routed mesh topology that mirrors the structure of a wired Internet" ( Moskaluk, 2004).

Token Ring

This is one of the two main LAN transmission methods with Ethernet as the second. "The Token Ring protocol was developed by IBM in the mid-1980s" (University of South Florida, 2009). As noted above a token is passed around the ring in one direction until the destination node is reached or the electronic token returns to the sender. The token is then modified if there is data to attach and passed along to the next computer in the circle.

"The