LECTURE 7 CT1303 LAN. LAN PHYSICAL LAYER Networks: Nodes: Service Units: PCs. Processing and interface Units Transmission medium. Local Circuits: connects.

L E C T U R E 7

CT1303 LAN

LAN PHYSICAL LAYER

• Networks: • Nodes:• Service Units: PCs.• Processing and interface Units

• Transmission medium.• Local Circuits: connects PCs in a limited\small networks.• Backbone Channel: connects processing units• Trunks: Transmission media that handle communication

between offices.

LAN CHANNEL

• Channel: • The media that digital\analog signal travel through from

sender to destination.

• Channel developed a lot to allow high speed transmission rate, and to send data to a farther distance. • LAN channels: • Wired channels.• Wireless channels.

LAN CHANNEL

• Wired channels: • Twisted pairs• Coaxial cable• Fiber optics

• Wireless channels:• Microwave• Infrared• laser

WIRE CHANNEL

• Twisted pairs: • Phone networks• The function of the twists is to decrees the attenuation

or noise that affects the media.

• Advantages:• Cheap• Fixable• Simple to use.

• Disadvantages:• Does not support high speed transmission rate.• Limited Frequency bandwidth (01 MHz)

WIRE CHANNEL

• To use twisted pairs in LANs:• Specific thick conductor• Specific isolation• Number of twists• Shield

WIRE CHANNEL

• Shielded twisted pairs STP• Unshielded twisted pairs UTP

WIRE CHANNEL

• Twisted pair wire connectors:• RG-45• Used in Ethernet LANs.• Has 8 pins

• USB connector:• Used to connect devices attached to PC and network wireless devices.• Shielded against Noise and interference. • Support electric energy to the attached devices through the port.

WIRE CHANNEL

• D-shell connector:• Connect numbers of STP cables

• Multi Access Unit (MAU):• Connect STP cables with network devices in token ring type

of networks.

WIRE CHANNEL

• Coaxial Cable:• Better than Twisted pairs.• Wide frequency bandwidth support ( 500 million Hz)• Support very high speed data rate (1Mbps – 1Gbps)• Used in T.V channels• Some LANs.• Thin Coaxial: Diameter :0.25 inch,

• Used in local circuits• Used to send digital signal to 185 m • used in 10-base-2 Ethernet LAN : 10 Mbit\sec , baseband digital

tranmission ,200 m

WIRE CHANNEL

• Thick Coaxial: Diameter: 0.4 inch• Less fixable than thin coaxial.• Can send digital signal to 500 m without the need to use

amplifier. • Used in backbones and Trunks that connects processing units to

IEEE LAN , 10-base-5 Ethernet LAN: 10 Mbit\sec, baseband digital transmission, 500 m

• Broad Band: Diameter: 0.4 – 1 inch • Less fixable• Expensive.• Can send Analog signals till 1800 m without amplifier.• Used in Video signals, Backbones and Trunks that connects

processing units to IEEE LAN: 10-broad-36 Ethernet LAN, 10 Mbit\sec

• Analog Broadband transmission, 3600 m

WIRE CHANNEL

• EIA standards for Coaxial Cables

WIRE CHANNEL

• Coaxial connectors:• BNC connectors:• Connects Thin Coaxial cables

• BNC-T connectors:• Connects Thin Coaxial cables

• BNC termination• Connects Thin Coaxial cables

• AUI connectors:• Connects Thick Coaxial cables.

WIRE CHANNEL

• Fiber Optics:• Stepped-Index Multimode fiber.

• Graded index fiber.

• Single mode fiber

WIRE CHANNEL

• For fiber optics: • Very wide frequency bandwidth: 5 Giga Hz• Light signals.• Transmission rate: 1 Giga bit\sec – 10 Giga bit\sec• Total isolation.• it doesn’t affected by interference, noise because its

light signals.

• Fiber optics are widely used recently and are replacing several transmission mediums.

WIRE CHANNEL

• Fiber Optics Connectors:• SC connector:

• 2.5 mm inner ring• Push-pull to install

• ST connectors:• 2.5 inner ring • Rotate- lock

WIRELESS CHANNEL

• Wireless channel send data using wave Propagation from Antenna of sender and receiver. • Wireless channels can be divided based on wave

frequency, and its propagation type. • Propagation type:• Surface propagation.• Reflection from troposphere (50 km above ground)• Reflection from Ionosphere (90 km above ground)• Line of sight ( 100 km )

WIRELESS CHANNEL

WIRELESS CHANNEL

• Wireless channels based on wave frequency:• Radio: 30 kHz – 300 MHz• Microwave: 300 MHz – 300 GHz• Infrared: 300 GHz – 300 THz• Laser: 1014 Hz– 1015 Hz

• Applications use wireless channels vary from TV, Voice applications, document/ data sending application, Radio.

WIRELESS CHANNEL

WIRELESS CHANNEL

WIRELESS LAN NETWORK

• Microwave: used to send signals between 30m-100m inside buildings, and 100m-300m outside.• Microwave can travel through walls or any type of

barriers that disallow wired or fixed transmission media.• It can be affected by Electromagnetic

Interferences and noise.• Signals and waves propagate in all the directions

around Omnidirectional from (aerial: special device) attached to NIC or any network devices

WIRELESS LAN NETWORK

• Microwaves signals use very high frequencies: 900MHz , 204 GHz. 507GHz or 18-19 GHz.• Microwave have two types of bands:• Spread Spectrum wireless LAN منتشر نظاق ذات محلية شبكة• have very broad band frequency• Continuous travel of signals• Used in wide area • Transmission rate: 1Mbps – 100 Mbps

• Narrow Band ضيق نطاق ذات السلكية محلية شبكة

• Have fixed or limited frequency.• Sending signals with low Electric power • No more that 30m length tall • Transmission rate: 10 Mbps – 20 Mbps

WIRELESS LAN NETWORK

• Infrared: uses waves with wavelength 500 – 900 nano meter (10 -5 m to10 -9 m).• Infrared have very broad band and high speed

transmission rate between PCs and\or other devices in LAN such as printer. • Can send data through limited area inside the

building.• Can NOT go through walls or any barriers.• Infrared signals affected by Sun light.• Unidirectional, Diffused

WIRELESS LAN NETWORK

• Broad band, high speed transmission rate: 1mbps -10Mbps. • Easy to install and maintain.• It does NOT affected by noise and interference

with any electromagnetic waves.

WIRELESS LAN NETWORK

• Laser: can concentrate the power or energy to be sent in a thin pack of light around 1mm, and can be send to 500 m or longer depends on the energy used.• 1014 Hz – 1015 Hz frequency.• 1 Mbps – 100 Mbps• Can NOT go through walls or barriers or fog or

heavy rain.• Affected by Sun Light.• Laser signals may curve, bend if affected by high

tempreture.

WIRELESS LAN NETWORK

• Laser is Unidirectional.• Simple to install and maintain.• It does NOT affected by noise and

Electromagnetic Interference.