Network Design

Week 4 Individual Assignment

NTC360

Table of Contents

Introduction 3

Mesh 3

Bus 4

Ring 4

Star 5

Ethernet 6

Token Ring 6

Fiber Distributed Data Interface (FDDI) 7

Wireless 7

Reference List 8

Introduction

This paper is an overview of some aspects of network architecture. Network architecture is defined as the communication products and services that ensure the various components can work together. I will discuss the different physical LAN topologies and how they work. Lastly, I will discuss several of the LAN Standards such as Ethernet and Token Ring.

Mesh

A Mesh topology is defined at a network where each device is connected to every other device on the network. A mesh topology provides for the best performance and reliability. This is good because if there is a failure in transmission, there are other ways within the mesh for the devices to communicate. There are two types of mesh topologies: full mesh and partial mesh. In a full mesh topology, every device is connected to each device on the network. The full mesh can be very expensive and is reserved for backbone networks. In a partial mesh, some devices are organized in a full mesh scheme. The partial mesh is less expensive than the full mesh. One of the biggest advantages of the mesh topology is fault tolerance. It is also not vulnerable to bottlenecks. On the other hand, the disadvantages of the mesh topology outweigh the advantages. The mesh topology is expense because each device has a physical connection to every other device on the network. It is also difficult to install and manage.

Bus

A bus topology is a multipoint electrical circuit. Bus topology employs a decentralized method of media access control known as carrier sense multiple accesses (CSMA). This enables the attached device to make independent decisions relative to media access and initiation of transmission. This type of transmission results in data collisions. In a bus topology, each device is connected to a single segment trunk. The trunk is the bus and this is where the data flows from one end of the truck to the other. At each end of the trunk is a terminator. The purpose of the terminator is to absorb the signal so that it does not reflect back across the bus. In the bus topology, the signal is broadcasted to all devices. Each device checks the address of the signal and if the address matches, the device processes the signal. If the signal does not match, the device does nothing. The bus topology is easy to setup and extend. It is best suited for temporary networks that must be setup on a short notice. It is very inexpensive to implement. If one of the devices fails, it does not affect the other devices on the network. Those are the advantages of the bus topology. The bus topology can be difficult to troubleshoot. If there is a failure in the trunk, the whole network will be disabled. As time goes on, it may cost more to maintain.

Ring

Ring topology is laid out in a physical ring or closed loop configuration. Information travels around the ring in only one direction. Each device on the network serves as a repeater. A ring topology employs a token passing method of media access control to ensure all nodes can access the network within a predetermined time interval. A master control station controls access to the transmission medium. The master control station has a backup in the event of failure. In order for a device to transmit, it must have the token. Once the device has the token, it attaches data and an address to it. The device transmits the token around the ring. The token travels around the ring until it reaches its destination. The device takes the token and sends out an acknowledgement of receipt and then the device releases the token back to the ring for another device to use. The greatest advantage of the ring is the performance is impacted very little with the growth of the network. All devices on the network have equal access to the transmission medium. On the other hand, the greatest disadvantage is the ring topology is the most expensive topology and it is very complex. If one device on the network fails, it can impact the entire network.

Star

A star topology consists of a central point of interconnection. All other devices on the network are connected directly to this central point via unshielded twisted-pair or shielded twisted-pair. This central point may be in the form of a hub, switch, or router. The best advantage of the star topology is the ease of adding new devices. A star topology is easy to troubleshoot. It can also accommodate different wiring. The