Prof. Michael P. Harris, CCNA CCAI
ITNW 1454 – Implementing & Supporting Servers
Chapter 4
Network Media, Connectors, and their Characteristics
Implementing & Supporting Servers - Chapter 4
Network Media, Connectors, and their Characteristics
Chapter Overview
In This chapter, we will discuss the characteristics of Ethernet networks, including the types
of cabling systems, the benefits and drawbacks of each, and the types of connectors that
each cable type uses. Here are some key points to remember:
Learning Objectives

Objective 1.3: Specify the characteristics (e.g., speed, cable type, cable lengths,
logical topology, physical topology, etc) of the following Ethernet specifications:
IEEE 802.3
10Base5
10Base2

10Base-T
10Base-FL
100Base-TX
100Base-T4
100Base-FX
Gigabit Ethernet (GbE)
Objective 1.4: Recognize common media connectors and describe their uses:
AUI
BNC
RJ-11
RJ-45
ST
SC
 Objective 1.5: Choose the appropriate media type and connectors to add a
client/host to an existing network.
 Objective 4.12: Given a network troubleshooting scenario involving a
wiring/infrastructure problem, identify the cause of the problem (e.g. bad media,
bad termination, excessive cable lengths, interference, network hardware, etc.).
Lecture Notes
Understanding Ethernet Standards
The IEEE 802 standard addresses hardware that interacts with the Physical and Data Link
layers of the OSI Mode. It establishes standards for components such as a network interface
card (NIC), wide area networking components, and the components used to make unshielded
twisted pair (UTP) and coaxial cable (Coax) networks; the two most cable types.
Twisted Pair Cable
Twisted pairs of conductors, similar to the type used to connect telephones, is used to
connect network devices together. Unshielded Twisted Pair (UTP) contains four conductor
pairs (eight wires total). Each cable includes four pairs of insulated copper wires that are
twisted together and housed in a plastic sheath or jacket. Higher bandwidth categories have
Jerry K. Ainsworth, Kristine A. Kriegel, SYSTEM ADMINISTRATION
EMCParadigm ©2004
Page 1 of 4
ISBN: 0-7638-1972-7
Prof. Michael P. Harris, CCNA CCAI
ITNW 1454 – Implementing & Supporting Servers
Chapter 4
Network Media, Connectors, and their Characteristics
more twists per foot, which provides for better throughput and less chance of crosstalk or
outside electromagnetic interference (EMI).
For 10Base-T networks, the twisted pair cabling must be rated a minimum of Cat3. Twisted
pair wire used in data networks can be either unshielded (UTP) , screened (ScTP), or
shielded (STP). The sheath, or exterior covering, of the cable pairs can be either plenum
grade (flame resistant) or non-plenum grade. Twisted pair cables use RJ-45 connectors.
10Base-T
10Base-T (10 –Mbps, Baseband, Twisted Pair) Ethernet uses Unshielded Twisted Pair (UTP)
cable and has a 10Mbps bandwidth. RJ-45 connectors are used to terminate one or more ends
of the cable. The cable may also be terminated at a 110 punch-down block in the back of a
patch panel or behind a networking wall jack. Each host will have its own network cable not
shared with any other workstation. A maximum of 1,024 hosts are allowed per network. The
maximum distance of a cable run is 100 meters (328feet).
100Base-T
100Base-T Ethernet also know as Fast Ethernet works just like regular Ethernet except that
it can obtain data transfer speeds up to 100Mbps. Fast Ethernet can be divided into three
categories: 100Base-TX (using two pairs within a Cat5 or higher cable), 100Base-T4
(backward compatible with older Cat3 cable —using all four pairs to achieve the higher
bandwidth), and 100Base-FX (using fiber optic cable).
10Base2 and Thinnet Coaxial Cable
Coaxial cable has two conductors: a copper center conductor that is shrouded by insulating
Teflon or plastic foam (the dielectric), and a foil wrap or a braided metal shield that covers
the insulating dielectric. The inner center conductor carries the electric signals, while the
outer braided metal shield -shields against noise. Thinnet Ethernet was used in a bus
configuration. 10Base2 networks use RG-58 cable (Thinnet). Coax types RG_58 A/U or
RG-58 C/U are commonly used. Each end of a network segment must be equipped with a
50-ohm terminating resistor. Coaxial cable segments may be no shorter than 0.5 meter
(1.64 feet). This means that the minimum spacing between network connections must be at
least 0.5 meter. Thinnet segments may be a maximum of 185 meters (607 feet).
10Base5 and Thicknet Coaxial Cable
Thick coaxial cable, also known as Thicknet (RG-8 and RG-11) were commonly used in
10Base5 Ethernet networks. Thicknet was well suited for network backbones or for
connecting hubs, as it has a solid center conductor. This coax has a thick (0.4-inch) diameter
and is a very inflexible coaxial cable. The outer jacket of the cable may be polyvinyl
chloride (PVC), which will be yellow, or Teflon (plenum), which will be orange or brown.
Plenum cable may be required to meet fire regulations. Like 10Base2, 10Base5 needed to be
terminated at each end with 50-ohm terminators and be grounded at one end for electrical
safety reasons. A 10Base5 segment may have a maximum of 100 devices attached. Pieces of
Thicknet coax may be no shorter than 2.5 meters. This means that the minimum spacing
between network connections must be at least 2.5 meters. Transceivers were used to attach
nodes to the cable, sometimes using a vampire tap connector.
Jerry K. Ainsworth, Kristine A. Kriegel, SYSTEM ADMINISTRATION
EMCParadigm ©2004
Page 2 of 4
ISBN: 0-7638-1972-7
Prof. Michael P. Harris, CCNA CCAI
ITNW 1454 – Implementing & Supporting Servers
Chapter 4
Network Media, Connectors, and their Characteristics
Fiber-Optic Cabling
Instead of using copper wire to transmit electrical signals, fiber-optic cabling uses lightconducting glass fibers at its core. Data is then transmitted either through pulses of light
sent by a Laser or by a light-emitting diode (LED). There are several different types of
fiber-optic cabling:

Single-mode fiber: Contains a single, tiny strand of fiber-optic glass, usually 7.1 or
8.5 microns in diameter. Single-mode fiber is typically used in very long distance
telephone applications, cable television, or as a network backbone.

Multimode fiber: In multimode fiber, the core is usually 62.5 microns in diameter
—much larger than that used by single-mode fiber, and just like single-mode fiber
—has an outer diameter of 125 microns. Multimode can handle many light ray paths
at once, making it ideal for voice and data applications. 62.5/125 multimode fiber
cable is the most common fiber optic cable used in computer networks.

Simplex fiber: Simplex is a cable containing a single strand of fiber.
 Duplex fiber: Duplex is a cable with two strands fiber bound together in separate
jackets for simultaneous two-way communication.
Installers of fiber optic cable must be careful not to exceed the prescribed bend radius
during installation; if the cable is bent too sharply, it starts to reflect the light path back on
itself and if bend a little farther will break. Fiber is difficult to terminate; several types of
fiber-optic connectors can be used. You must ensure match the correct connectors,
especially when working in an area where fiber has already been installed. Fiber-optic
networks are very secure, since data is transmitted using pulses of light rather than
electrical signals which can be intercepted. Fiber optic cable is immune to EMI, since it does
not conduct electrical signals. Maximum length for fiber optic runs are vary, but usually are a
minimum of 2.4 miles (4 kilometers). Fiber does not attenuate very quickly. The most
common fiber optic termination types are either ST or SC connectors.
100Base-FX
100Base-FX uses fiber-optic cabling to achieve extended segment distances while
maintaining the Fast Ethernet standard 100Mbps data transfer bandwidth.
Advantages:
 Fiber provides fast, reliable, and secure connection.
 Fiber is immune to EMI.
 Fiber can transmit out to a minimum distance of 4 kilometers (approx. 2.4 miles).
Disadvantages:
 Fiber is very expensive, especially when compared to 100Base-TX using copper wiring.
 Fiber is more difficult than copper to install and terminate.
 Converting to fiber cabling may involve the purchase of new networking hardware with
fiber optic connections, or purchase media converters.
Jerry K. Ainsworth, Kristine A. Kriegel, SYSTEM ADMINISTRATION
EMCParadigm ©2004
Page 3 of 4
ISBN: 0-7638-1972-7
Prof. Michael P. Harris, CCNA CCAI
ITNW 1454 – Implementing & Supporting Servers
Chapter 4
Network Media, Connectors, and their Characteristics
Gigabit Ethernet
Gigabit Ethernet (GbE) is a network transmission technology that is based on Ethernet
standards. GbE provides a data transfer of 1 billion bits per second (one gigabit).
Frequently Gigabit Ethernet is used as the backbone in large enterprise networks. Fiberoptic cable is the primary medium used on Gigabit Ethernet networks, although copper
cable may be used for very short distances.
Jerry K. Ainsworth, Kristine A. Kriegel, SYSTEM ADMINISTRATION
EMCParadigm ©2004
Page 4 of 4
ISBN: 0-7638-1972-7