Networking 102 Topologies and Models

In this Learning Lab you will learn about various network topologies and cables along with the OSI and TCP/IP Suite network models.

Objective

Completion Time: 15 minutes

  • Learn about network topologies
  • Understand network cable categories and types
  • Delve into the networking OSI and TCP/IP models

Prerequisites

  • You have some knowledge about networks or have completed the lab Networking 101.
  • Our focus in this lesson will be on wired networks which for our purposes is what you need to learn. Wireless networks have other network components not covered here.
  • The discussion is based upon IPv4 protocol; otherwise known as Internet Protocol version 4.

Additional Information

Step 1. Physical and Logical Topologies

Every network has a physical and logical topology. The physical topology represents how the network is physically laid out. Below are some pictures of physical topologies.

Network Physical Topologies

  1. Let's briefly discuss each of the topologies.
    • Bus: There is one centralized cable or hardware device to which the host devices are connected via twisted pair wiring. Network data travel is bi-directional which means that data can collide.
    • Full Mesh: All devices are connected to each other for redundancy. This network is the most reliable; however it is also the most expensive and difficult to set up due to extensive wiring. As an alternative a partial mesh topology can be created.
    • Star: A central device connects network and host devices via twisted pair wiring.
    • Ring: All devices are connected via a single cable and data is routed through each device traveling in a single direction until it reaches its intended target. The advantage of this topology is that there are no network collisions; however, it is susceptible to failure if a single node fails.
    • Dual Ring: Two rings allow data to be sent in opposite direction creating redundancy so that if one ring fails the other continues to transmit data.

The logical topology represents how the physical topology operates. For example, the physical topology might be laid out in the form of a star topology, but its logical operation functions like a ring topology. This difference means that you cannot always tell how the network operates just based upon the physical topology.

Stuff to Think about

  1. What are some other network physical topologies?

  2. Compare the Bus and Ring Topologies. What are the advantages/disadvantages of each?

Next Step: Learn about network wiring and cables.