EC301-COMPUTER NETWORK FUNDAMENTALS

UNDERSTAND THE TRANSMISSION MEDIA IN NETWORKS

1)MUHAMMAD HISYAMUDDIN BIN DERAMAN (12QEP12F1001)

2)SITI RAUDHAH BT RAMYA @ ABD RAHIM (12DEP11F1017)

3)NOOR AZIZAH BINTI ABDUL AZIZ (12DEP11F1013)

4) MUHAMAD AIMAN BIN SHAMSUDIN (12DEP11F1019)

5) MOHD KHAIRUL AIMAN BIN OTHMAN (12DEP11F1038)

TRANSMISSION MEDIA IN NETWORK

Definition : Links that connect nodesChoice impacts :

• Speed• Security• Size

Transmission Media

Guided / Wired

Twisted Pair

Coaxial Fiber Optic

Unguided / Wireless

Radio Frequency

Microwave

Satellite

Infra-red

Twisted Pair (Kabel Pasangan Berlingkar)

• Is a type of wiring in which two conductor of a single circuit are twisted together.

• Twisted pair cable falls into one of 2 type:

1. Unshielded Twisted Pair (UTP)

2. Shielded Twisted Pair (STP)

• Twisted pair cables are found in many Ethernet networks and telephone system application.

• They are often grouped into sets of 25 pair according to a standard

25 pair color code originally developed by AT&T Corporation.

• Category : Standard EIA/TIA 568 set in the twisted pair cable specifications for computer connectivity. EIA/TIA uses the term category (Cat) to distinguish the type of cable used.

Twisted Pair Cabling Categories

CategoryData Rate

(Mbps)Bandwidth

(MHz)Intended Use

1 1 0.4 Voice only

2 4 4 4 Mbps token ring

3 16 16 10BaseT Ethernet

4 20 20 16 Mbps token ring

5100 (2pair) 100 100BaseT Ethernet

1000 (4pair) 100 Gigabit Ethernet

5e 1000 100 Gigabit Ethernet

6 1000 250 Gigabit Ethernet

6a 10000 500 10 Gigabit Ethernet

7 10000 600 10 Gigabit Ethernet

• Connector : Register Jack RJ11 (Phone) and RJ45 (Ethernet)

• Installation : two standard code used in the installation of cable EIA/TIA 568 A and EIA/TIA 568 B with two types of cable installation:

1. Straight-Through (Pemasangan Lurus)

2. Cross Over (Pemasangan Terbalik)

Coaxial Cable (Kabel Sepaksi)

• Coaxial cable looks similar to the cable used to carry TV signal. A solid-core copper wire runs down the middle of the cable. Around that solid-core copper wire is a layer of insulation, and covering that insulation is braided wire and metal foil, which shields against electromagnetic interference. A final layer of insulation covers the braided wire.

• All types have been assigned an RG (Radio Guide) specification number.

• The bandwidth for coaxial cable is 10 Mbps.

• Types (2):

1. Thinnet coaxial : • is a flexible coaxial cable about ¼ inch thick. • It’s used for short-distance and connects directly to a

workstation’s network adapter card using a British Naval Connector (BNC).

• The maximum length of cable is 185 meters.

2. Thicknet coaxial : • is thicker cable than thinnet.• Thicknet cable is about ½ inch thick.• Can support data transfer over longer distances than

thinnet. • The a maximum cable length of 500 meters and usually is

used as a backbone to connect several smaller thinnet-based networks.

Fiber Optic (Kabel Gentian Kaca)

• Optical Fiber cables use optical fibers that carry digital data signals in the form of modulated pulses of light (exceed 10Gbps)

• An optical fiber consists of an extremely thin cylinder of glass, called the core, surrounded by a concentric layer of glass, known as the cladding.

• There are two fibers per cable—one to transmit and one to receive. The core also can be an optical-quality clear plastic, and the cladding can be made up of gel that reflects signals back into the fiber to reduce signal loss.

•There are two types of fiber optic cable: 1. Single Mode Fibre (SMF)2. Multi Mode Fibre (MMF)

•Connector type (patch cord) are characterized by :

1. Low insertion loss (signal)

2. Good repeatability

3. Good interchange

4. Excellent environmental adaptability

3.2.2 : THE BENEFIT AND LIMITATIONS OF THE NETWORKING MEDIA

1) FIBER OPTIC CABEL

THROUGHPUT NOISE IMMUNITY

SIZE COST

Fiber has proved reliable in transmitting data at rates that exceed 10 Gigabits (or 10,000 Megabits) per second.

Because fiber does not conduct electrical current to transmit signals,it is unaffected by EMI.

Depending on the type of fiber-optic cable used, segment lengths from 150 to 40,000 meters.

Fiber-optic cable is the most expensive transmission medium.

2) TWISTED PAIR CABLE (UTP AND STP)

THROUGHPUT NOISE IMMUNITY SIZE COST

STP and UTP can both transmit data at 10, 100, and 1000 Mbps (1Gbps), depending on the grade of cabling and the transmission method in use.

Because of its shielding, STP is more noise-resistant than UTP.

The maximum segment length for both STP and UTP is 100 m, or 328 feet.

STP is more expensive than UTP because it contains more materials and it has a lower demand.

3) Coaxial Cable• Coaxial cables are a type of cable that is used by

cable TV and that is common for data communications.

• Taking a round cross-section of the cable, one would find a single center solid wire symmetrically surrounded by a braided or foil conductor. Between the center wire and foil is a insulating dialectric. This dialectric has a large affect on the fundamental characteristics of the cable. In this lab, we show the how the permittivity and permeability of the dialectric contributes to the cable's inductance and capacitance. Also, these values affect how quickly electrical data is travels through the wire.

• The radius of our cable's inner copper wire was 42mm and there was 2.208mm of polyethylene between the inner wire and outer mesh conductors.

IT cables consist of a metal or fiber optic (glass) core wrapped in a plastic sheath .

These systems are usually separated into voice and data sub-systems .

Voice systems typically use twisted pair copper cables for both vertical (riser) and horizontal cables .

Data systems commonly use fiber optics for risers and copper for connecting PC’s to data network hubs .

Cabling building

cabling systems also include separate co axial cables for video systems.

The most common system for routing cables in commercial buildings is placing riser cable in sealed conduits that are firestopped according to fire code requirements.

Horizontal cables are usually routed through ceiling, wall and raised floor area generally with metal conduits used only as protective guides behind sheetrock walls.

The work area is the space inside a building where employees, building occupants, or system users work and use their communication equipment.

This is also the area where the horizontal communication cables are terminated.

Work area usually includes the user communication equipment such as computers, phones, modems, and data terminals.

Work Areas

Work area locations can be placed in any useable square footage in a building or on a building floor. Careful consideration must be given when planning locations in a building.

Industry cabling standards also require that a minimum of two approved media types be installed to each location.

Each outlet of connection must terminate one approved type of horizontal media. Therefore, each location must be supported by a minimum of two modular outlets/connectors and two approved horizontal cables.

Work area outlets can be placed in different locations for each area. The exact location is usually a function of the horizontal pathway connecting the area to the Telecom Room (TR). Work area outlet locations can be installed in any of the following areas.

1. On the wall2. On the floor3. On a power pole4. On the modular furniture

3.2.4 : Characteristic of Wireless Transmission

Signal Propagation

• Reflection The wave encounters an obstacle and reflects—or bounces back—toward its source. A wireless signal will bounce off objects whose dimensions are large compared to the signal’s average wavelength.

• DiffractionWireless signal splits into secondary waves when it encounters an obstruction. The secondary waves continue to propagate in the direction in which they were split.

• Scattering Reflection in multiple different directions of a signal. Scattering occurs when a wireless signal encounters an object that has small dimensions compared to the signal’s wavelength.

Signal Degradation

• Original signal issued by the transmitter will experience fading or a change in signal strength as a result of some of the electromagnetic energy being scattered, reflected, or diffracted after being issued by the transmitter.

• the strength of the signal that reaches the receiver is lower than the transmitted signal’s strength.

• Interference can distort and weaken a wireless signal and they are more vulnerable to noise.

Narrowband, Broadband And Spread Spectrum Signal

• Narrowbandtransmitter concentrates the signal energy at a single frequency or in a very small range of frequencies.

• Broadband uses a relatively wide band of the wireless spectrum. As a result of their wider frequency bands, offer higher throughputs than narrowband technologies.

• spread spectrum The use of multiple frequencies to transmit a signal.

• spread spectrum signaling is called FHSS (frequency hopping spread spectrum) & DSSS (direct sequence spread spectrum).

FSHH (frequency hopping spread spectrum)

• Signal jumps between several different frequencies within a band in a synchronization pattern known only to the channel’s receiver and transmitter.

DSS(direct sequence spread spectrum)

• signal’s bits are distributed over an entire frequency band at once. Each bit is coded so that the receiver can reassemble the original signal upon receiving the bits.

Fixed And Mobile Wireless Communication

• The operation of wireless devices or systems used to connect two fixed locations (e.g., building to building or tower to building) with a radio or other wireless link, such as laser bridge. Usually, fixed wireless is part of a wireless LAN infrastructure. The purpose of a fixed wireless link is to enable data communications between the two sites or buildings. Fixed wireless data (FWD) links are often a cost-effective alternative to leasing fiber or installing cables between the buildings.

Mobile Wireless

• The receiver can be located anywhere within the transmitter’s range. Allows the receiver to roam from one place to another while continuing to pick up its signal.

Infrared• Infrared (IR) light is electromagnetic radiation with

longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 700 nm to 1 mm. This range of wavelengths corresponds to a frequency range of approximately 430 THz down to 300 GHz. Infrared light is emitted or absorbed by molecules when they change their rotational-vibrational movements.

• infrared transmission is most often used for communications between devices in the same room.

• infrared signaling requires more power, travels shorter distances, and transmission around obstacles less successfully than the wireless technique.

Wireless LANs

• A wireless local area network (WLAN) links two or more devices using some wireless distribution method (typically spread-spectrum or OFDMradio), and usually providing a connection through an access point to the wider Internet. This gives users the mobility to move around within a local coverage area and still be connected to the network. Most modern WLANs are based on IEEE 802.11 standards, marketed under the Wi-Fi brand name. WLANs were once called LAWNs (for local area wireless network) by the Department of Defense.

Smaller wireless networks, in which a small number of nodes closely positioned need to exchange data, can be arranged in an ad hoc.

In an ad hoc WLAN, wireless nodes,

or stations, transmit directly to each other via wireless NICs without an intervening connectivity device.

WLANs can use the infrastructure mode, which depends on an intervening connectivity device called an access point.

AP (access point) is a device that accepts wireless signals from multiple nodes and retransmits them to the rest of the network.

Access point must have sufficient power and be strategically placed so that stations can communicate with it.

Like other wireless devices, access points contain an antenna connected to their transceivers

An infrastructure WLAN

Wireless LAN interconnection

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