SIMPLE NETWORKING

1. Organizations that set standards for networking.

Standards are documented agreements:

i. ANSI (American National Standards Institute) which set wireless standards.

ii. EIA (Electronic Industries Alliance) helps write ANSI standards.

iii. TIA (Telecommunications Industry Association) Standards for information technology, wireless, satellite, fiber optics, and telephone equipment.

iv. TIA/EIA 568-B Series Guidelines for installing network cablein commercial buildings

v. IEEE (Institute of Electrical and Electronics Engineers) Promote development and education in electrical engineering and computer science fields.

vi. ISO (International Organization for Standardization) Establish international technological standards to facilitate global information exchange and barrier free trade.

vii. ITU (International Telecommunication Union) for Global telecommunications issues and Worldwide Internet services implementation.

viii. ISOC (Internet Society) which sets Internet system communication standards.

ix. IANA (Internet Assigned Numbers Authority) which IANA performs system administration.

x. ICANN (Internet Corporation for Assigned Names and Numbers)which remains responsible for IP addressing and domain name management.

2. Described the purpose of the OSI model and each of its layers:i. Application layer.ii. Presentation layer.

iii. Session layer.iv. Transport layer.v. Network layer.

vi. Data link layer.vii. Physical layer.

3. The most used model today is the TCP/IP model.

4. The two types of addressing schemes:i. Static IP addressing assigned manually.ii. Dynamic IP addressing assigned using DHCP (Dynamic Host

Configuration Protocol).5. Basic data transmission concepts:

i. full duplexing, ii. attenuation, iii. latency, and iv. Noise.

6. Transmission Media

When choosing the transmission media, what are the factors to beconsidered?

Transmission Rate Distances Cost and Ease of Installation Resistance to Environmental Conditions Quality needed over some estimated distance. Security may also be an issue.

There are two types of transmission media: Guided Unguided

Guided Media: Unshielded Twisted Pair (UTP) Shielded Twisted Pair Coaxial Cable Optical Fiber

Unshielded Twisted Pair (UTP) : UTP is the copper media, inheritedfrom telephony, which is being used for increasingly higher datarates, and is rapidly becoming the de facto standard for horizontalwiring, the connection between, and including, the outlet and thetermination in the communication closet. A Twisted Pair is a pair of copper wires, with diameters of 0.4-0.8mm, twisted together and wrapped with a plastic coating. The twistingincreases the electrical noise immunity, and reduces the bit errorrate (BER) of the data transmission. A UTP cable contains from 2 to4200 twisted pairs. UTP is a very flexible, low cost media, and can be used for eithervoice or data communications. Its greatest disadvantage is the limitedbandwidth, which restricts long distance transmission with low errorrates. Shielded Twisted Pair (STP) : STP is heavier and more difficult tomanufacture, but it can greatly improve the signaling rate in a giventransmission scheme Twisting provides cancellation of magneticallyinduced fields and currents on a pair of conductors. Magnetic fields arise around other heavy current-carrying conductorsand around large electric motors. Various grades of copper cables areavailable, with Grade 5 being the best and most expensive. Grade 5 copper, appropriate for use in 100-Mbps applications, has moretwists per inch than lower grades. More twists per inch means morelinear feet of copper wire used to make up a cable run, and morecopper means more money. Shielding provides a means to reflect or absorb electric fields thatare present around cables. Shielding comes in a variety of forms fromcopper braiding or copper meshes to aluminum or Mylar tape wrappedaround each conductor and again around the twisted pair. Features of twisted-pair cables:

Inexpensive Easy to install Easy to tap Can accommodate up to 1000 devices.

Limitations:

The network coverage area is between 300 feet and 1000 feet only.

Twisted PairUTP comes in several varieties:

Category 3: Was the earliest successful implementation of UTP. It’s primarily used for voice and lower-speed data applications. It’s rated for a maximum of 10 Mbps.

Category 4: Never achieved the popularity of Cat 3 or Cat 5. It’sprimarily used for voice and lower-speed data at a maximum of 16 Mbps.

Category 5: As Fast Ethernet became a standard, Cat 5 became the basis for most high-speed data implementations. Cat 5 runs at a maximum of 100 Mbps.

Category 5e: With the need for higher speeds, Gigabit Ethernet has become the new replacement for Fast Ethernet. To make it work, Cat 5e extends the life of Cat 5 cable. It can run at a maximum of 1,000 Mbps.

Category 6: Cat 5e can run at gigabit speeds, but with 10-GigabitEthernet on the horizon, Cat 5e has stretched the Cat 5 standard to its limits. Cat 6 can currently run at 1,000 Mbps (1 Gbps). The Category 6 specification was released for publication very recently, however as designed, Category 6 cabling will be able tosupport speeds up to at least 10 Gbps.

UTP connector - The standard connector for UTP cabling is an RJ-45connector. This is a plastic connector that looks like a largetelephone-style connector. A slot allows the RJ-45 to be inserted onlyone way. RJ stands for Registered Jack.Coaxial Cable: Coaxial cable is a two-conductor cable in which oneconductor forms an electromagnetic shield around the other. The twoconductors are separated by insulation. It is a constant impedancetransmission cable. This media is used in base band and broadbandtransmission. Coaxial cables do not produce external electric andmagnetic fields and are not affected by them. This makes them ideallysuited, although more expensive, for transmitting signals. Features:

It provides better immunity than twisted pair. This cable is able to transmit data at higher rates.

Limitations: High installation cost High maintenance cost.

Optical Fiber : Optical fiber consists of thin glass fibers that cancarry information at frequencies in the visible light spectrum andbeyond. The typical optical fiber consists of a very narrow strand ofglass called the core. Around the core is a concentric layer of glasscalled the cladding. A typical core diameter is 62.5 microns .Typically cladding has adiameter of 125 microns. Coating the cladding is a protective coatingconsisting of plastic, it is called the Jacket. An importantcharacteristic of fiber optics is refraction. Refraction is thecharacteristic of a material to either pass or reflect light. Whenlight passes through a medium, it “bends” as it passes from one mediumto the other. An example of this is when we look into a pond of waterIf the angle of incidence is small, the light rays are reflected anddo not pass into the water. If the angle of incident is great, light passes through the media butis bent or refracted. Optical fibers work on the principle that thecore refracts the light and the cladding reflects the light. The corerefracts the light and guides the light along its path. The claddingreflects any light back into the core and stops light from escapingthrough it - it bounds the medium! Features:

Huge bandwidth. Optical fiber systems are not affected by external noise. The error rate for the data transmitted across fiber optic cable

is very low. Limitations:

Cost is high. Fibers fragility makes it more difficult to handle.

Unguided Media: Transmission media then looking at analysis of usingthem unguided transmission media is data signals that flow through theair. They are not guided or bound to a channel to follow. Followingare unguided media used for data communication:

Radio Transmission Microwave Satellite Communication

RF Propagation: There are three types of RF (radio frequency)propagation :

Ground Wave Ionospheric Line of Sight (LOS)

Ground wave propagation follows the curvature of the Earth. Groundwaves have carrier frequencies up to 2 MHz. AM radio is an example ofground wave propagation. Ionospheric propagation bounces off of theEarth’s ionospheric layer in the upper atmosphere. It is sometimes called double hop propagation. It operates in thefrequency range of 30 - 85 MHz. Because it depends on the Earth’sionosphere, it changes with the weather and time of day. The signalbounces off of the ionosphere and back to earth. Ham radios operate inthis range. Line of sight propagation transmits exactly in the line of sight. Thereceive station must be in the view of the transmit station. It issometimes called space waves or tropospheric propagation. It islimited by the curvature of the Earth for ground-based stations (100km, from horizon to horizon). Reflected waves can cause problems.Examples of line of sight propagation are: FM radio, microwave andsatellite. Radio Frequencies: The frequency spectrum operates from 0 Hz (DC) togamma rays (1019 Hz). Radio frequencies are in the range of 300 kHz to10 GHz. We are seeing an emerging technology called wireless LANs.Some use radio frequencies to connect the workstations together, someuse infrared technology. Microwave: Microwave transmission is line of sight transmission. Thetransmit station must be in visible contact with the receive station.This sets a limit on the distance between stations depending on thelocal geography. Typically the line of sight due to the Earth’scurvature is only 50 km to the horizon! Repeater stations must beplaced so the data signal can hop, skip and jump across the country. Microwaves operate at high operating frequencies of 3 to 10 GHz. Thisallows them to carry large quantities of data due to their largebandwidth. Advantages: (a) They require no right of way acquisition between towers. (b) They can carry high quantities of information due to their highoperating frequencies. (c) Low cost land purchase: each tower occupies only a small area. (d) High frequency/short wavelength signals require small antennae. Disadvantages: (a) Attenuation by solid objects: birds, rain, snow and fog. (b) Reflected from flat surfaces like water and metal. (c) Diffracted (split) around solid objects.

(d) Reflected by atmosphere, thus causing beam to be projected awayfrom receiver.

Satellite: Satellites are transponders (units that receive on onefrequency and retransmit on another) that are set in geostationaryorbits directly over the equator. These geostationary orbits are36,000 km from the Earth’s surface. At this point, the gravitationalpull of the Earth and the centrifugal force of Earth’s rotation arebalanced and cancel each other out. Centrifugal force is therotational f0000000orce placed on the satellite that wants to fling itout into space. The uplink is the transmitter of data to the satellite. The downlink is the receiver of data. Uplinks and downlinks are also called Earth stations because they are located on the Earth. The footprint is the “shadow” that the satellite can transmit to, the shadow being the areathat can receive the satellite’s transmitted signal.

Types of Cables and Connecting a Networking DevicesStraight-Through Cable - Four-pair, eight-wire, straight-through cable, which means that the color of wire on Pin 1 on one end of the cable is the same as that of Pin 1 on the other end? Pin 2 is the sameas Pin 2, and so on. The cable is wired to either EIA/TIA T568B or T568A standards for 10BASE-T Ethernet, which determines what color wire is on each pin.Crossover Cable - A crossover cable means that the second and third pairs on one end of the cable will be reversed on the other end. The pin-outs are T568A on one end and T568B on the other end. All 8 conductors (wires) should be terminated with RJ-45 modular connectors.Crossover cable conforms to the structured cabling standards. If the crossover cable is used between switches, it's considered to be part of the "vertical" cabling. Vertical cabling is also called backbone cabling. A crossover cable can be used as a backbone cable to connect two or more switches in a LAN, or to connect two isolated hosts to create a mini-LAN. This will allow the connection of two hosts or a server and a host without the need for a hub between them. This can bevery helpful for testing and training. To connect more than two hosts,a switch is needed.Rollover Cable - A 4-pair "rollover" cable. This type of cable is typically 3.05 m long but can be as long as 7.62 m. A rollover cable can be used to connect a host or dumb terminal to the console port on

the back of a router or switch. Both ends of the cable have RJ-45 connectors on them. One end plugs directly into the RJ-45 console management port on the back of the router or switch. Plug the other end into an RJ-45-to-DB9 terminal adapter. This adapter converts the RJ-45 to a 9-pin female D connector for attachment to the PC or dumb terminal serial (COM) port. A DB25 terminal adapter is also available to connect with a PC or dumb terminal. This adapter uses a 25 pin connector.Structured cablingSite survey

1. Before beginning the site survey collect all the tools necessary for site survey such as tape measure, pen and a booklet.

2. After obtaining the necessary tools then move to the site to carry out the site survey.

3. Measure the room or floor plan of the areas that the network is to cover.

4. Look at the plans and identify major building obstacles such as walls, halls, elevators and floors that will block cabling.

5. Identify a secure point close to the power source to house the cabinet to use to keep active equipment i.e. switches, patch panel and cable organizer.

6. Note where users will be located and where they won't to determine coverage areas.

7. Determine where to locate APs based on power and cabling that we could run to connect the AP to the rest of the network.

8. Estimate the total number of APs needed for the overall coverage.

9. Relocate APs and retest, depending on the results of the survey.

10. Identify the topology to use for our network.11. Document the findings and note down what is required.

The importance of carrying out survey:

1. It helps to identify the factors that can affect cabling.2. Helps to know if there are underground or ceiling cables.3. Helps to identify the materials needed for the structured

cabling.4. Helps to know the man power needed to complete the project

successfully.5. Helps to identify the obstacle in the building.6. Helps to discuss and agree on the breakages.7. Helps to come up with a sketch and plan of the building for

example where to keep active equipment, passage, power sources and safety equipments.

Choice of material

1. The material chosen should allow future expansion.2. The material used should allow for smooth transition.3. The material chosen should be durable.4. The material chosen should be efficient.

Required tools

1. Crimping tool for crimping cables such as patch codes and user cables.

2. Punch down for making termination at the patch panel.3. Push down for terminating at the jack or phase plate.4. Screw drivers (flat and star) for opening and closing the

trunk and fitting the phase plate on the trunk.5. Pliers for cutting the cables.6. Strippers for removing the sheath from the cables.7. Copper qualification tester for testing the cables after

crimping and after termination.

Pulling of cables

Procedure

1. Opened the trunk using the screw drivers.2. Label the cables before pulling to avoid confusion.3. Measure the cable long enough using the tape measure to

allow for termination and re-termination.4. Lay the cable in the trunk and then close.

Precautions when pulling cables:

1. Ensure there are no sharp bends.2. Avoid damaging the cables, use lubricants to pull cables to

reduce damage.3. Label cables at both ends for easy troubleshooting.

Termination of cables

How to terminate at the patch panel:

There are two standards for terminating at the patch panel i.e. Standard A and Standard B and each patch panel will come with thestandards on them. The specialist decides on either to use Standard A or Standard B. For my case I decide on Standard B i.e.the ISO Standard.

1. Assemble the cabinet then seal the top part.

2. Move the cables to pass through the lower part if the cablesare coming from the lower part of the wall or on the upper part if the cables are coming from the upper part of the wall.

3. Strip the sheath from the UTP cable to a considerable lengthusing a stripper.

4. Separate the wires.5. Using the Standard B arrange the wires as required by the

standard and place them in their respective positions on thepatch panel.

6. Using the punch down press the cables firmly on the patch panel then organize the cable into neatly using the cable organizer and then fitted the patch panel into the cabinet using the screws.

Terminating at the phase plate:

There are two standards for terminating at the phase plate i.e. Standard A and Standard B and each phase plate will come with thestandards on them. The specialist decides on either to use Standard A or Standard B. For my case I decided on Standard B i.e. the ISO Standard.

1. Strip the sheath from the UTP cable to a considerable lengthusing a stripper.

2. Separate the wires.3. Using the Standard B we arrange the wires as required by the

standard and placed them in their respective positions on the jacks.

4. Using the punch down push the wires firmly on the jack.5. Fix the phase plate on the wall using the screw.

There are two ways of crimping straight through i.e.T568A which follows the color code: white stripped with green, green, white stripped with orange, blue, white stripped with blue, orange, white stripped with brown and brown (g, G, o, B, b, O, br, BR) and T568B i.e. ISO Standard which follows the color code: white stripped with orange, orange, white stripped with green, blue, white stripped with blue, green, white stripped with brown, brown

(o,O,g,B,b,G,br, BR). We decided to use the ISO Standard i.e. T568B.

Procedure for crimping:

1. Cut your cable and strip about 1” of the outer jacket off the tip.

2. Clip away the spleen. Untwist and splay out the wires.3. Sort your wires in the proper pin out configuration and

insert each wire through the insert. Set the insert as far down and as closed to the outer jacket as possible.

4. Trim away the excess wires from then end.5. Insert the wire tips with the insert as far into the

connector as possible. The lip of the insert should be pointed down. Squeeze the outer jacket into the connector as well until it reaches the jacket clamp on the connector

6. Insert the plug into your crimper and crimp down.7. Pushed in place and the outer jacket of the cable secured to

the connector by the jacket clamp.

Common mistakes made when crimping:

1. Opens occurs when the wires in the cable fails to make a continuous path from end to end.

2. Shorts occur when the wires touch each other and short circuit occurs.

3. Split pairs occur when wires are changed or mixed the color codes.

4. Wire mapping errors.

Certification tests

i. Frequent range.ii. Attenuation for the cables.

iii. Amount of signals.iv. Near end cross talk i.e. signal interference.v. Cross talk ratio i.e. cable signal or noise on the same

cable.vi. Equal level far ends cross talk i.e. calculates the

measurement of cross talk.

vii. Return loss signals that bounce back.viii. Propagation delay.

ix. Delay skew.x. Power sum next.