Chapter 1: Network Switching Fundamentals; In Depth; Physical Media And Switching Types - Cisco RJ-45-to-AUX Brochure

Chapter 1: Network Switching Fundamentals

In Depth

Although writing the first paragraph of a book is probably the least important part, it's invariably the most
difficult section to write. To get a good picture of the different parts of networking, readers need to know
where networking began and the history behind the networks of today. You may have seen a lot of what is in
the first section of this chapter in any basic networking course, such as Networking Essentials; or you may
have covered most of it in a CCNA class; but a refresher never hurt.
In this chapter, you will become acquainted with the history of networks and how networks evolved into those
you see in today's corporate environments. I will also discuss the inventors of the different types of
networking equipment found at each layer of the network.
As we progress through the chapter I will also cover the different network architectures, from legacy networks
to the fast high−speed media types found in today's networks. A clear understanding of the networking
technologies and challenges found at each layer of the network will aid you in assessing problems with the
switches you'll deal with later.
I have a favorite quote that helps me to remember why I continuously study, so that I can better support my
customers' equipment. It is a quote by Albert Einstein, and I remember it from one of my mentors: "The
significant [technical] problems we face cannot be solved by the same level of thinking that created them."
This chapter will contain some of the following information:
The history of networking
The different pieces of networking equipment
How to identify problems in a flat network topology
The how to's and the when to's of upgrading to a switched network
When to upgrade your flat topology network
Network upgrade planning and basic strategies
Two terms to keep in mind when reading this chapter are resource nodes and demand nodes. A resource node
is a node on an interface attached to a device that provides resources to the network. These nodes can be
everything from printers, servers, and mainframes, to wide area network (WAN) routers. A demand node is an
interface on the network that makes requests or queries to the resource nodes. The interfaces can be devices
such as workstations, terminals, or even client applications. Network conversations occur when resource
nodes and demand nodes send a series of requests and responses through the network.

Physical Media and Switching Types

The following are the most popular types of physical media in use today:
Ethernet—Based on the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard.
However, it doesn't rely on the Carrier Sense Multiple Access Collision Detection (CSMA/CD)
technology. It includes 10Mbps LANs, as well as Fast Ethernet and Gigabit Ethernet.
Token−Ring—Not as popular as Ethernet switching. Token−Ring switching can also be used to
improve LAN performance.
FDDI—Rarely used, chiefly due to the high expense of Fiber Distributed Data Interface (FDDI)
equipment and cabling.
The following are some of the protocol and physical interface switching types in use today:
6