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:
“The Spanning Tree Protocol (STP) is an older network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.”
Meanwhile, the advent of early PC’s and the recognition of the value in networking devices together gave rise to Local Area Networks. These LAN’s were developed from a business customer perspective, which placed more emphasis on costs and ease of use over reliability. There were a number of different competing LAN technologies, two of the most common being Token Ring (IBM) and Ethernet (everyone else). The triumph of Ethernet in the marketplace, to the extent where it is included in every PC, game console and some refrigerators, provides a consistent and relatively inexpensive way to build internal networks with relative ease.
All computers are connected to a hub, switch or router. Require more cabling, but failure of one node does not break down the network.
Token ring is a local area network protocol which resides at the data link layer (DLL) of the OSI model. It uses a special three-byte frame called a token that travels unidirectionally around a star-wired logical ring. Token ring frames travel completely around the loop. The name 'Token Ring' is misleading since the physical topology is a loop.
The Open Systems Interconnection model breaks down host-to-host transmissions into seven different layers where each one performs a specific function. At the same time each layer has the ability to also communicate with adjacent layers in either direction. In essence each layer interacts directly with the layer below it and at the same time also provides support to the layer above it.
A switch can be used to make various connections. Ethernet, Token Ring, and various other types of packet switched network segments together to form a heterogeneous network operating at OSI Layer 2.
In a computer network, switches are devices that are used to connect devices together. Multiple cables can be connected to a switch to enable networked devices to communicate with each other. The role of a switch is to manage the flow of data throughout a network and this process is effective in its role due to the fact that the messages are sent only to the intended target. The media access control (MAC) is the identification that each device connected to the switch carries. By each device having individual IDs this increases the overall effectiveness and security of a network.
The Open Systems Interconnection (OSI) reference model is essential to the world of computer networking. The model was created in 1977 by the International Standards Committee, in response to a difficulty that was facing computer networkers at the time (Shelly, Cashman, and Serwatka 142). In order to understand the difficulty, one must first realize that computer networks consist of computer hardware, the software that is to be used in conjunction with this hardware, and the medium (such as wiring or cabling) that will interconnect the computing devices that are in the network. The computer networker’s job is to determine which hardware, software, and medium types will create the network that will best suit his client’s needs. Then, the networker must combine these elements into a functional system of interconnected computers (Fortino and Villeneuve 112). It was in attempting this latter task that the computer networker of the late 1970s often found himself in a pickle. The problem was that each vendor of computing equipment had developed his own unique set of products; products that were incompatible with the products of other vendors. This incompatibility made it very difficult for a computer networker to combine the various network components into an operational computer network (Stamper 27).
Our design includes hubs, switches and routers in the infrastructure. In this section we will provide a quick overview of these appliances. Network hubs, switch, and router all perform the job of connecting computers.
Troubleshooting media problems on a bus networks can be very tedious, since a break in the backbone will bring down the entire LAN. For this reason, bus topology is not considered one of the more robust network topologies, compared with star or mesh. A loose or missing terminating resistor can also bring down a LAN.
Next, the writer goes over the second type of network architecture - the TCP/IP reference model, the granddaddy of the wide area computer network. This architecture allows the connection of multiple networks seamlessly. The architecture is flexible and capable of running even if some of the subnet hardware is destroyed or non-functional as long as the source and destination machines are functioning. In a similar fashion to the OSI model, the TCP/IP model has layers as well. In this case, we have four layers: the link
Timothy Pintello (2013). Introduction to Networking with Network1. USA: John Wiley & Sons, Inc. 175-199.
A bus topology was one of the first topologies used in that it consists of a single bus (aka: backbone). Typically this is a coaxial cable where nodes can connect via a T' connector which allows the bus to continue to the end of the cable. Due to the nature of this design when the data reaches the end of the cable if it's not properly terminated (which kills the signal) then we can receive what's called bounce back. This ricocheting of the data could severely hinder the communication pathing of the bus. As I recall there is a general rule of thumb for a bus topology which is the rule of 5-4-3-2-1. This means that you can have 5 data segments of which there can be 4 connectors (continuing connections) which link the 5 data segments. 3 of the segments must be populated. There must be 2 terminators on the bus (1 at each end of the cable) and 1 network connection out.
Bus topology refers to a local area network (LAN) arrangement where each node or device is connected to a main cable or link called a bus. A bus network is simple yet very reliable. Since nodes themselves are not relied upon for communication, the failure of a single node is not problematic for the rest of the network. For a major issue to occur, there must be a problem with the bus itself.
The next network topology is the Bus topology. Bus topologies consist normally of one backbone or one transport media that all of the nodes are connected to. The linear bus configuration has only two end points and any information being transmitted through the network is received by all of the nodes simultaneously. Although networks based on a bus topology are relatively inexpensive to set up, they do not scale well. When you try to add mor...