Network and Telecommunications Concepts

Running head: WEEK4 INDIVIDUAL ASSIGNMENT

Week4 Individual Assignment

University of Phoenix

Network and Telecommunications Concepts

NTC/360

Joseph Hobbs

Nov 16, 2007

Mesh Topology

One of the more common topologies is the Mesh topology. The mesh topology is most commonly referred to as a Wide Area Network (WAN). (MicroTech Corp, 1998, Mesh) A Mesh topology involves multiple sites connected by multiple paths. Each site has a router that determines the best path for the data at that time. The best path is determined by least cost, time of day, and performance. (MicroTech Corp, Mesh) In Figure 1, the mesh topology is illustrated with lines indicating paths that data can follow. Each system has multiple paths to choose from.

Figure 1 Mesh Topology (Kathers, n.d., Mesh)

BUS Topology

With the BUS topology, as illustrated in Figure 2, workstations are connected by a long cable (Ethernet) or backbone. The cable or backbone never forms a close loop. The workstations are connected to the cable/backbone via cable drops and taps. BUS is a passive technology, meaning that the computers simply listen and receive signals. In a BUS topology, the backbone must be terminated. If there is no termination, or a break in the line before the termination, the network will go down.

Figure 2 BUS Topology (Kathers, n.d., BUS)

Ring Topology

In a Ring topology, each workstation is connected to two other workstations, which forms a loop. Data travels around the loop passing through each workstation. Each transmission is assigned a token, which contains the origination and destination information. This token is picked up and read by each workstation. If the workstation is not the destination, it will regenerate the token and pass the data back on to the loop. This process is repeated around the loop until the data reaches the destination. (MicroTech Corp, 1998, Ring)

Figure 3 Ring Topology (Kathers, n.d., Ring)

Star Topology

The Star topology is configured around a central switching or routing device, an intelligent hub, which receives and sends data to the appropriate recipient (see Figure 4). (MicroTech Corp, 1998, Star) The hub is an efficient, high-speed device that extends the capabilities of a simple cable. In the Star topology, each workstation is connected to one port on the hub. The Star topology is dominant in today's networks.

Figure 4 Star Topology (Kathers, n.d., Star)

The four different topologies mentioned have many advantages. The main advantages of each are listed below:

Mesh (MicroTech Corp, 1998, Mesh)

a. Stability for single application users

b. Redundant connections

c. Reliable

BUS (MicroTech Corp, 1998, BUS)

a. Easy to configure and manage

b. Stable network for under 30 users/nodes

c. Low cost

Ring (MicroTech Corp, 1998, Ring)

a. Stable network for more than 10 users/nodes

b. Relatively easy and inexpensive to install

c. Network continues to work even if one connection fails

Star (MicroTech Corp, 1998, Star)

a. Offers centralized configuration and security

b. High stability and speed

c. Low configuration costs

Of course, with every topology there are disadvantages. The main disadvantages of each are listed below:

Mesh (MicroTech Corp, 1998, Mesh)

a. Costly to reconfigure, replace, and administer.

b. Best suited for situations where it will not move or be expanded beyond five sites or nodes.

c. If one site fails, an entire application can fail.

BUS (MicroTech Corp, 1998, Bus)

a. If a problem occurs on the backbone, the entire network will go down

b. Difficult to troubleshoot.

c. Limited number of users/nodes

Ring (MicroTech Corp, 1998, Ring)

a. Older technology

b. Difficult to troubleshoot a failed connection

c. Cannot reconfigure without shutting down the network

Star (MicroTech Corp, 1998, Star)

a. Single point of failure (hub)

b. Number of ports available limited to the number of ports on the hub

c. Will need to add another hub to expand

So, to make a long story short; the mesh topology offers a multipath configuration that is great for redundancy, but not so great for management while the BUS topology is easy to configure and manage, but limited to distance and the number of nodes that can be supported. The Ring topology is better suited for a large number of nodes, but is expensive to reconfigure and hard to troubleshoot. This leaves the most popular topology, Star. Star offers a high-speed network that is easier to configure and manage due to the central management and security hub.

Ethernet

Ethernet is an IEEE-standard (802.3) data link protocol developed in 1976 by DEC and Intel, that specifies how data is