1. Networking Fundamentals
Physical Layer &
Transmission Media
2.1

2. Physical Layer and Media
7.2

3. 7.3
So a recap
• The physical layer is responsible for
movement of individual bits from one hop
(node) to the next. It deals with the mechanical
and electrical specifications of the interface and
transmission medium, as well as the procedures
and functions they have to perform for
transmission to occur.
• PR DSL PT

4. 2.4

5. 7.5
• The physical layer (Layer 1) specifications, which are also
typically standards from other organizations that are referred to
by OSI, deal with the physical characteristics of the
transmission medium. Connectors, pins, use of pins, electrical
currents, encoding, and modulation (depending upon the
media) are all part of different physical layer specifications.
• Multiple specifications are sometimes used to complete all
details of the physical layer. For example, RJ-45 defines the
shape of the connector and the number of wires or pins in the
cable. Ethernet (802.3) define the use of wires or pins 1, 2, 3,
and 6. So, to use a Category 5 cable with an RJ-45 connector
for an Ethernet connection, Ethernet, RJ-45 and CAT 5 cable
physical layer specifications are used.
• Example Standards: EIA/TIA-232, V.24, EIA/TIA-449,
V.35, RJ45, Ethernet (802.3), Token Ring (802.5), Wireless
LAN (802.11), Wireless MAN or BWA (802.16) etc.

6. 7.6
Transmission medium and physical layer

7. 7.7
Classes of transmission media

8. 7.8
GUIDED MEDIAGUIDED MEDIA
Guided media, are those that provide a conduit fromGuided media, are those that provide a conduit from
one device to another, include twisted-pair cable,one device to another, include twisted-pair cable,
coaxial cable, and fiber-optic cable.coaxial cable, and fiber-optic cable.

9. 7.9
Twisted-pair cable
One can simplistically say, that by twisting, unwanted signals
are mostly canceled out, when relative measurement is made.

10. 7.10
UTP and STP cables

11. 7.11
Categories of twisted-pair cables (EIA 568)

12. Twisted Pair
(a) Category 3 UTP.
(b) Category 5 UTP.

13. 7.13
UTP connector
8P8C (8 Position 8 Contact, also backronymed as 8 position 8 conductor )

14. 7.14

15. 7.15
Unshielded twisted pair cable with different twist rates
ScTP, also known as FTP
Shielded twisted pair cable with different twist rates
S/STP, also known as S/FTP
Single-core cable, 25-pair, 50 conductors

16. 7.16
UTP performance

17. Coaxial Cable
A coaxial cable.

18. 7.18
Categories of coaxial cables
The origin of the RG designations is in old, long-obsolete military specs; RG stands
for Radio Guide (Radio Govt as per Forouzan)
1.63/10.5 mm
0.9/5.0 mm
0.81/6.1 mm
Core/Dia

19. 7.19
Coaxial cable performance

20. 7.20
BNC connectors
Bayonet Neill-Concelman

21. 7.21

22. 7.22
Bending of light ray

23. 7.23
Optical fiber

24. 7.24
Propagation modes

25. 7.25
Modes

26. 7.26
Fiber types

27. 7.27
Fiber construction

28. Fiber Cables
(a) Side view of a single fiber.
(b) End view of a sheath with three fibers.

29. 7.29
Fiber-optic cable connectors

30. 7.30

31. Transmission of Light through Fiber
Attenuation of light through fiber in the infrared
region.

32. Fiber Optic Network
A fiber optic ring with active repeaters.

33. 7.33
UNGUIDED MEDIA: WIRELESSUNGUIDED MEDIA: WIRELESS
Unguided media transport electromagnetic wavesUnguided media transport electromagnetic waves
without using a physical conductor. This type ofwithout using a physical conductor. This type of
communication is often referred to as wirelesscommunication is often referred to as wireless
communication.communication.

34. The Electromagnetic Spectrum
The electromagnetic spectrum and its uses for
communication.

35. 7.35
Propagation methods

36. 7.36
Bands

37. 7.37
SEGMENT BAND
BANDWIDTH
USED
USER SATELLITES
UHF
200 - 400
MHz
160 KHz Military
FLTSAT,
LEASAT
L
1.5 - 1.6
GHz
47 MHz Commercial
MARISAT,
INMARSAT
SHF
C 6/4 GHz 800 MHz Commercial
INTELSAT,
DOMSATS,
ANIK E
X 8/7 GHz 500 MHz Military
DSCS,
SKYNET,
NATO
Ku 14/12 GHz 500 MHz Commercial
INTELSAT,
DOMSATS,
ANIK E
Ka 30/20 GHz
2500 MHz Commercial JCS
1000 MHz Military DSCS IV
EHF
Q 44/20 GHz 3500 MHz Military/DOT MILSTAR
V 64/59 GHz 5000 MHz Military CROSSLINKS
SATELLITE FREQUENCIES

38. 7.38
Wireless transmission waves

39. 7.39
Omnidirectional antenna

40. 7.40
Radio waves are used for multicast
communications, such as radio and
television, and paging systems.
Note

41. 7.41
Unidirectional antennas

42. 7.42
Microwaves are used for unicast
communication such as cellular
telephones, satellite networks,
and wireless LANs.
Note

43. 7.43
Infrared signals can be used for short-
range communication in a closed area
using line-of-sight propagation.
Note