assignment test on network media

1. 2.Fiber Optical Cables
2.1 Basics of fiber optical transmission.
2.2 Characteristics of Fiber cables
2.3 Types of Fiber
2.4 type of connectors and equipment used with fiber cables.
2.5 Advantages and Disadvantages

2. 2.1 Basics of fiber optical
transmission

3. REFLECTION OF LIGHT
Reflection is when light bounces off an object. If the surface is smooth and
shiny, like glass, water or polished metal, the light will reflect at the same
angle as it hit the surface. This is called specular reflection.Light reflects
from a smooth surface at the same angle as it hits the surface

4. REFRACTION OF LIGHT
Refraction is the bending of a wave when it enters a medium where its speed is
different. The refraction of light when it passes from a fast medium to a slow medium
bends the light ray toward the normal to the boundary between the two media.

5. TOTAL INTERNAL REFLECTION
• Total internal reflection, in physics, complete reflection of a ray of light within a medium such as
water or glass from the surrounding surfaces back into the medium. The phenomenon occurs if
the angle of incidence is greater than a certain limiting angle, called the critical angle.

6. TOTAL INTERNAL REFLECTION IN FIBER
• A light ray that is being turned on and off to send data (1s and 0s) into an optical fiber
must stay inside the fiber until it reaches the far end.
• The ray must not refract into the material wrapped around the outside of the fiber.
• The refraction would cause the loss of part of the light energy of the ray.
• A design must be achieved for the fiber that will make the outside surface of the fiber act
like a mirror to the light ray moving through the fiber.
• If any light ray that tries to move out through the side of the fiber were reflected back into
the fiber at an angle that sends it towards the far end of the fiber, this would be a good
“pipe” or “wave guide” for the light waves.

7. TOTAL INTERNAL REFLECTION
• The core is the light transmission element at the center of the optical fiber. All the light signals travel through the
core.
• Cladding is also made of silica but with a lower index of refraction than the core. Light rays traveling through the
fiber core reflect off this core-to-cladding interface as they move through the fiber by total internal reflection.
• Surrounding the cladding is a buffer material that is usually plastic. The buffer material helps shield the core and
cladding from damage.
• The strength material surrounds the buffer, preventing the fiber cable from being stretched when installers pull it.
The material used is often Kevlar, the same material used to produce bulletproof vests.
• The outer jacket surrounds the cable to protect the fiber against abrasion, solvents, and other contaminants.

8. 2.2 Characteristics of Fiber cables

9. WHAT ARE OPTICAL FIBERS
Optical Fibers are thins long (km) strands of ultra pure glass (silica) or plastic that can to
transmit light from one end to another without much attenuation or loss.
Fiber Construction
Fiber cables consists of 3 parts
1-Core: it is where the light propagates and have the biggest refractive index.
2-Clad:part of the light wave propagate and have lower refractive index value
3-Caut:the output cover

10. LIGHT PROPAGATION
• Light propagates due to total internal
reflection
• Light > critical angle will be confined
to the core
• Light < critical angle will be lost in the
cladding

11. TYPES OF FIBERS

12. SINGLE MODE FIBER
Single Mode fiber optic cable has a small diametral core that
allows only one mode of light to propagate. Because of this,
the number of light reflections created as the light passes
through the core decreases, lowering attenuation and
creating the ability for the signal to travel further. This
application is typically used in long distance, higher
bandwidth runs by Telcos, CATV companies, and Colleges and
Universities.
Left: Single Mode fiber is usually 9/125 in construction.
This means that the core to cladding diameter ratio is 9
microns to 125 microns.

13. MULTIMODE FIBER
Multimode fiber optic cable has a large diametral core
that allows multiple modes of light to propagate. Because
of this, the number of light reflections created as the light
passes through the core increases, creating the ability for
more data to pass through at a given time. Because of the
high dispersion and attenuation rate with this type of
fiber, the quality of the signal is reduced over long
distances. This application is typically used for short
distance, data and audio/video applications in LANs. RF
broadband signals, such as what cable companies
commonly use, cannot be transmitted over multimode
fiber.
Above: Multimode fiber is usually 50/125 and 62.5/125 in
construction. This means that the core to cladding
diameter ratio is 50 microns to 125 microns and 62.5
microns to 125 microns.

14. FACTORS THAT AFFECT THE LIGHT WAVE
THROUGH PROPAGATION
1. Refractive index n for core and clade.
2. Fiber attenuation
3. Dispersion

15. FIBER ATTENUATION
( reduces the power of the signal)
The two main loss mechanisms in fiber is absorption and scattering,
1-Light absorption:
As light passes through fiber it is absorbed and converted into heat, due to molecular
resonance, for example hydrogen and hydroxide resonance occurs at 1244 nm and 1383
nm.
2-Rayleigh scattering:
Scattering causes the dispersion of light energy in all directions, and one of the directions
is the backward direction in this case the scattering is called "backscattering".
Forward light scattering (Raman scattering) and backward light scattering (Brillouin
scattering) are two additional types of scattering those can occur under high power
conditions.

16. ATTENUATION Vs. WAVELENGTH
Attenuation depends on fiber type and wavelength of the transmitted signal

17. DISPERSION
(reduces the effective bandwidth available for transmission )
There are three types of dispersion:
1- Modal Dispersion (MD) for multimode fiber.
Modal Dispersion typically occurs in multimode fiber, due to its large core
diameter, for example 62.5 um, it carries many modes those travel through
different paths thus a short pulse that consists of many modes will spread because
each mode will reach the destination in a different time.

18. DISPERSION
• 2- Chromatic Dispersion (CD).
• Chromatic Dispersion is about the difference in speed between the various
wavelengths contained in a light pulse, each light pulse consists of many
wavelengths, each wavelength travels on its own speed down the fiber, thus
it reaches the destination in a different time than other wavelengths, which
results in the pulse broadening phenomena, please see the below figure:

19. DISPERSION
• 3- Polarization Mode Dispersion (PMD).(significant for speeds more than 10Gb/s for
single mode fiber.
• Different polarizations travels through different paths thus different lengths down
the fiber which leads to different arrival time at the destination, this difference in
speed comes from the fact that a fiber core is perfectly a circle all the fiber length,
also mechanical stresses twisting, bending, and temperature variations all cause
PMD to change, that`s why its not a fixed value like the CD.

20. FIBER OPTIC LINK POWER BUDGET

21. 2.3 VARIOUS TYPES OF
OPTICAL FIBER CABLES

22. OPGW
• Optical Pilot Ground Wires are use on transmission lines at the top of the towers. It is using to
protect the phase conductor from lightning strikes and to evacuate faulty currents.

23. ADSS CABLES
• All Dielectric Self Supported cables are use in transmission lines, railway networks and data
communication networks for evacuate faulty currents in communication networks.

24. R1/ RIBBON SLOT ARMORED CABLE (DOUBLE
SHEATH)
• Ribbon slotted type fiber cables permits high fiber density because fiber ribbons are housed in to
grove of the slot.
• They are suitable for higher fiber count water proof requirements.
• These cables are sheathed with corrugated steel tape armor.

25. R-7 ALL DIELECTRIC RIBBON SLOT WB CABLE
• Ribbon slotted type fiber cables permits high fiber density, because fiber ribbons are housed into
the groove of the slot.
• These cables are applied for metallic materials in central strength member.
• They are suitable for higher fiber count and waterproof requirements using swellable polymer
technology (Water blocking tape)

26. 2.4 type of connectors and equipment used with
fiber-optic cable.

27. FIBER OPTICS CABLING
• Every fiber-optic cable used for networking consists of two glass fibers encased in
separate sheaths.
• One fiber carries transmitted data from device A to device B.
• The second fiber carries data from device B to device A.
• This provides a full-duplex communication link.
• Typically, these two fiber cables will be in a single outer jacket until they reach
the point at which connectors are attached.

28. TRANSMITTING DEVICES
• The transmitter converts the electronic signals into their equivalent light pulses.
• There are two types of light sources used to encode and transmit the data through the
cable:
• A light emitting diode (LED) producing infrared light.
• Light amplification by stimulated emission radiation (LASER) a light source producing
a thin beam of intense infrared light usually with wavelengths of 1310nm or 1550
nm.
• Lasers are used with single-mode fiber over the longer distances involved in WANs
or campus backbones.

29. RECEIVING DEVICES
• The receiver functions something like the photoelectric cell in a solar powered
calculator.
• When light strikes the receiver, it produces electricity.
• The semiconductor devices that are usually used as receivers with fiber-optic links are
called p-intrinsic-n diodes (PIN photodiodes).
• When struck by a pulse of light at the proper wavelength, the PIN photodiode quickly
produces an electric current of the proper voltage for the network.
• It instantly stops producing the voltage when no light strikes the PIN photodiode.
• This generates the voltage changes that represent the data 1s and 0s on a copper
cable.

30. ST AND SC CONNECTORS
• The type of connector most commonly used with multimode fiber is the
Subscriber Connector (SC connector).
• On single-mode fiber, the Straight Tip (ST) connector is frequently used.

31. FIBER OPTICS PATCH PANNEL

32. 2.5 Limitations

33. ADVANTAGES
1. Extremely high bandwidth
2. Easy to accomodate increasing bandwidth
3. Resistance to electromagnetic interference
4. Early detection of cable damage and secure transmissions
DISADVANTAGES
1. Installation costs, while dropping, are still high
2. Special test equipment is often required
3. Susceptibility to physical damage
4. Wildlife damage to fiber optic cables

34. 3 Wireless Media
3.1 Characteristics of wireless media
3.2 Types of Wireless media
3.3 Limitations

35. 3.1 Characteristics of wireless media

37. FREQUENCY

38. FREQUENCY

39. RADIO FREQUENCY BANDS

40. FREQUENCIES AND REGULATIONS
(ITU-R holds auctions for new frequencies)

41. 3.2 Types of Wireless media

42. TERRESTRIAL MICROWAVE
• used for long-distance telephone service
• uses radio frequency spectrum, from 2 to 40 Ghz
• parabolic dish transmitter, mounted high
• used by common carriers as well as private networks
• requires unobstructed line of sight between source and receiver
• curvature of the earth requires stations (repeaters) ~30 miles apart

43. SATELLITE MICROWAVE
• Most communications satellites are placed into orbit 22,300 miles above the
earth's surface. The earth's gravity keeps the satellite in orbit at the same rate as
the earth (geosynchronous orbit). Such satellites are called geosynchronous
orbiting satellites (GEOS).
• Low earth orbiting satellites (LEOS) orbit the earth at a height of 325-1,000 miles
and they orbit around the poles (not in a fixed position relative to the earth).
• Medium earth orbiting satellites (MEOS) are similar to LEOS but are positioned at
6,000-10,000 miles above the earth.
• Because microwaves use line-of-sight, the satellite signal can only reach a part of
the earth. This area is called a footprint.

44. CELLULAR RADIO
• Cellular telephones actually are radio devices that use cellular radio (form of
broadcast radio with restrictions on how far the signal is transmitted) to
transmit voice and data. The broadcast area of a cellular radio system is
divided into cells. Here is how it works:
• Using a cellular phone, the caller dials a number. The signal is sent from the
cell phone's antenna to the cellular antenna located in cell 1.
• The signal is sent to the regional cellular phone switching office.
• The signal is switched to the local Telephone Company switching station.
• The signal is now in the regular phone system and the call is switched to the
number dialed.

45. INFRARED TRANSMISSION
• Infrareds (IR) transmission involves sending light signals at a frequency between
visible light and radio waves. Commonly used in TV remote controls, now is used
to provide LAN connections.
• It is a line-of-sight transmission and has a maximum coverage of 30 to 80 feet.
• Increasingly, computers and devices such as printers come with IrDA ports, which
enable the transfer of data without the use of cables.

46. 3.3 Advantages and
Disadvantages

47. ADVANTAGES
• As wireless frequency penetrates the walls, wireless networks are easy to install
anywhere based on choice. This flexibility is one of the great benefits of wireless
network where wired cable can not be installed.
• Wireless networks are easy to install and easy to maintain compare to messy wired
counterparts. This will help when network grows and will have hundreds to
thousands of customers.

48. DISADVANTAGES
• Wireless signals can be easily hacked and hence it will hamper privacy.
• The earlier wireless networks were slower. Now-a-days wireless LANs with
advanced standards such as IEEE 802.11ac and 802.11ad are available which
provides same performance as traditional ethernet based LANs.
• Wireless networks require careful radio frequency planning at the beginning of the
installation.
• Wireless communication is subject to interference. There are various receiver
techniques and modulation techniques which make wireless system robust against
any kind of interference.