Chapter 5 Topologies and Ethernet Standards

The chapter begins with explaining Logical and Simply Physical Topologies. Physical topology refers to the physical layout of the media, nodes, and devices on the network. The following are physical topologies:

• Bus topology – consists of a single cable that connects all the nodes on the network.
• Ring topology – each node is connected to the two nearest nodes so that the entire network forms a circle.
• Star topology – every node is connected through a central device.

Hybrid Topologies consist of more complex combinations of topologies. Two kinds of hybrid topologies are:

• Star-Wired Ring - This uses the physical layout of a star in conjunction with the ring logical topology.
• Star-Wired Bus – This topology combines the star and bus formations.

Logical Topologies – refers to the way in which data are transmitted between nodes, rather than the physical layout of the paths that data take.

Backbone Networks – is the part of the network to which segments and significant shared devices connect.

• Serial Backbone – is the simplest kind of backbone. It consists of two or more devices connected to each other by a single medium in a daisy chain fashion.
• Distributed Backbone – consists of several intermediate connectivity devices connected to one or more central connectivity devices.
• Collapsed Backbone – uses a router or switch as the single central connection point for multiple subnetworks.
• Parallel Backbone – is the most robust type of network backbone. The key point is that a parallel backbone is redundant.

The text goes into great detail about the Ethernet and how it is a flexible technology and that all Ethernet networks have a common thread which is their access method. This is known as CSMA/CD. The following diagram covers the process.

                                                                 CSMA/CD Process

It covers the Ethernet standards for copper cable and fiber optic cable. The following chart is a summary of common Ethernet standards.

I found the visual depictions to be very helpful in understanding the various concepts in this chapter. The chapter was presented in a logical and organized manner which helped in grasping the material.