7.1
Chapter 7
Transmission Media
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7.2
Figure 7.1 Transmission medium and physical layer
The physical layer is responsible for movements of
individual bits from one hop (node) to the next (see bot_L2.ppt).
Note
7.3
Figure 7.2 Classes of transmission media
7.4
7-1 GUIDED MEDIA
Guided media, which are those that provide a conduit
from one device to another, include twisted-pair cable,
coaxial cable, and fiber-optic cable.
Twisted-Pair Cable
Coaxial Cable
Fiber-Optic Cable
Topics discussed in this section:
7.5
Figure 7.3 Twisted-pair cable
7.6
Figure 7.4 UTP and STP cables
7.7
Table 7.1 Categories of unshielded twisted-pair cables
7.8
Figure 7.5 UTP connector
RJ-45 (Registered Jack)
7.9
RJ-45 types
Straight-through: PC HUB/Switch or Switch Router
Crossover: PC PC, Switch Switch or Router Router
7.10
Rollover cable or also Console cable: Use this cable to
configure a Switch or Router using the Console port.
Connect the other end of the cable to PC’s COM port
and open the terminal.
RJ-45 types
7.11
Figure 7.6 UTP performance
7.12
Figure 7.7 Coaxial cable
7.13
Table 7.2 Categories of coaxial cables
7.14
Figure 7.8 BNC connectors
BNC = Bayonet Neill Concelman
7.15
Figure 7.9 Coaxial cable performance
7.16
Ethernet cables
Type Cable
Length of the
segment Topology Connector
10Base2 Thin coaxial 185 m Bus BNC
10Base5 Thick coaxial 500 m Bus AUI
10Base-T UTP, CAT3,4,5, 2-pairs 100 m Star RJ-45
100Base-TX UTP, CAT5, 2-pairs 100 m Star RJ-45
100Base-FX 62.5/125 µm, multimode 400 m Star
Fiber
conncetor
1000Base-CX STP 25 m Star RJ-45
1000Base-T UTP, CAT5, 4-pairs 100 m Star RJ-45
1000Base-SX 62.5/50 µm, multimode 275 / 550 m Star
Fiber
conncetor
1000Base-LX 9 µm, singlemode 3 - 10 km Star
Fiber
conncetor
7.17
Figure 7.10 Bending of light ray
7.18
Figure 7.11 Optical fiber
7.19
Figure 7.12 Propagation modes
7.20
Figure 7.13 Modes
7.21
Table 7.3 Fiber types
7.22
Figure 7.14 Fiber construction
7.23
Figure 7.15 Fiber-optic cable connectors
SC (Straight Contact), ST (Straight Tip), MT-RJ (Mechanical Transfer -
Registered Jack)
7.24
Figure 7.16 Optical fiber performance
850nm, 1300nm and 1550nm
7.25
7-2 UNGUIDED MEDIA: WIRELESS
Unguided media transport electromagnetic waves
without using a physical conductor. This type of
communication is often referred to as wireless
communication.
Radio Waves
Microwaves
Infrared
Topics discussed in this section:
7.26
Figure 7.17 Electromagnetic spectrum for wireless communication
7.27
Figure 7.18 Propagation methods
7.28
Table 7.4 Bands
7.29
Figure 7.19 Wireless transmission waves
7.30
Figure 7.20 Omnidirectional antenna
7.31
Radio waves are used for multicast communications, such as
radio and television, and paging systems.
Note
Microwaves are used for unicast communication such as cellular
telephones, satellite networks,
and wireless LANs.
Infrared signals can be used for short-range communication in a
closed area using line-of-sight propagation.
7.32
Figure 7.21 Unidirectional antennas