Network cabling

Type of cable:

Unshielded twisted pair







Coaxial cable

Fiber Optic




Unshielded twisted pair characteristics:

-Unshielded .

-least expensive cable.

-Twisted pairs of .insulated conductors.

-Covered by insulating sheath. 

-Radio and electrical frequency interference (should not be too close to electric motors, fluorescent lights.

Each pair is twisted with a different number of twist per inch to help eliminate interference from adjacent pairs and other electrical devices. 

The tighter the twisting, the higher the supported transmission rate and the greater the cost  per foot.

 Cat5e cable:

-1000Mbps data capacity.

-For runs of up to 90 meters.

-Solid core cable ideal for structural installations (PVC or Plenum).

-Stranded cable ideal for patch cables.

RJ-45 connectors:

-Terminated with RJ-45 connectors (plastic connector).

-RJ - Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. 

-This standard designates which wire goes with each pin inside the connector.

-Best option for school networks.

RJ-45 connectors          

Shielded Twisted Pair (STP) Cable: 

-Shielded twisted pair may be the solution for the interference of UTP connectors.

- Help to extend the maximum distance of the cables

- Available in three different configurations:

Each pair of wires is individually shielded with foil.

There is a foil or braid shield inside the jacket covering all wires (as a group).

There is a shielded around each individual pair, as well as around the entire group of wires (referred to as double twisted pair).

Coaxial Cable:

-Single copper conductor at its center.

-A plastic layer provides insulation between the center conductor and a braided metal shield 

-The metal shield helps to block any outside interference from fluorescent lights, motors, and others computer.

-Difficult to install.

-Highly resistant to signal interference.

-Support greater cable lengths between network devices than twisted pair cable.

-Thick coaxial and thin coaxial.

Thin coaxial:

-Also called thinnet. 

-10Base2 refers to the specifications for thin coaxial cable carrying Ethernet signals.

-2 refers to the approximate maximum segment length being 200 meters.

-Maximum segment length is 185 meters.

-popular in school networks, especially linear bus networks.

Thick coaxial :

-Also called thicknet.

-The 5 refers to the maximum segment length being 500 meters.

-has an extra protective plastic cover that helps keep moisture away from the center conductor.

-Great choice when running longer lengths in a linear bus network.

-One disadvantage does not bend easily and is difficult to install.

Coaxial Cable Connecter:

- Common type of connector used is the Bayone-Neill-Concelman (BNC) connector.

Fiber Optic Cable:

-Center glass core surrounded by several layers of protective .

-Transmits light rather than electronic signals eliminating the problem of electrical interference. 

-Environments  a large amount of electrical interference. 

-Made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting.

-To transmit signals over much longer distances than coaxial and twisted pair. 

-Carry information at vastly greater speeds.

-Capacity broadens communication possibilities to include services such as video conferencing and interactive services.

-The cost ofvis comparable to copper cabling; however, it is more difficult to install and modify.

-10BaseF refers to the specifications for fiber optic cable carrying Ethernet signals.

-center core of  is made from glass or plastic fibers.

-A plastic coating then cushions the fiber center, and kevlar fibers help to strengthen the cables and prevent breakage.

 single mode :

-Can provide more distance, but it is more expensive.

Multimode :

-larger diameter; however, both cables provide high bandwidth at high speeds.

Specification	Cable Type
10BaseT	Unshielded Twisted Pair
10Base2	Thin Coaxial
10Base5	Thick Coaxial
100BaseT	Unshielded Twisted Pair
100BaseFX	Fiber Optic
100BaseBX	Single mode Fiber
100BaseSX	Multimode Fiber
1000BaseT	Unshielded Twisted Pair
1000BaseFX	Fiber Optic
1000BaseBX	Single mode Fiber
1000BaseSX	Multimode Fiber

 Making connection:

-Cat5e cable

-RJ45 connectors

-Cable stripper

-Scissors

-Crimping tool

Making connection steps:

1.Strip cable end

 - Strip 1 – 1½” of insulating sheath.

-Avoid cutting into conductor insulation.

2.Untwisted wire ends.

-Sort wires by insulation colors.

3.Arrange wires.
-TIA/EIA 568A: GW-G OW-Bl BlW-O BrW-Br

-TIA/EIA 568B: OW-O GW-Bl BlW-G BrW-Br

4.Trim wires to size.
lTrim all wires evenly
lLeave about ½” of wires exposed

5.Attach connector.

-Maintain wire order, left-to-right, with RJ45 tab facing downward.

6.Check.
-Do all wires extend to end?

-Is sheath well inside connector?

7.Crimp test.

-Squeeze firmly to crimp connecter onto cable end (8P)
8. Test.

-Does the cable work?

Installing Cable - some guidelines

When running cable, it is best to follow a few simple rules:

-Always use more cable than you need. Leave plenty of slack.
-Test every part of a network as you install it. Even if it is brand new, it may have problems that will be difficult to isolate later.
-Stay at least 3 feet away from fluorescent light boxes and other sources of electrical interference.
-If it is necessary to run cable across the floor, cover the cable with cable protectors.
-Label both ends of each cable.
-Use cable ties (not tape) to keep cables in the same location together.

Network Topology

Network Topologies

LANs and WANs- Geographical coverage

LANs

-A single geographical location, such as office building, school, etc.

-Typically High speed and cheaper.

WANs

-Spans more than one geographical location often connecting separate LANs.

-Slower.

-Costly hardware, routers, dedicated leased lines and complicated implementation procedures.

Topology- Physical and logical network layout

-Physical- actual layout of the computer cable and other network devices.

-Logical- the way in which the network appears to the devices that use it.

Common topologies: Bus, ring, star, mesh and wireless.

Bus topology

-Uses a trunk or backbone to which all of the computers on the network connect.

-System connect to this backbone using T connectors or taps.

-coaxial cablings (10Base-2, 10Base-5) were popular years ago.

Bus Topology

Advantages	Disadvantages
Cheap and easy to implements	Network disruption when computers are added or remove
Required less cable	A break in the cable will prevent all systems from accessing thee network
Does not use any specialized network equipment	Difficult to troubleshoot

Ring Topology

-Logical ring

- Meaning that data travels in circular fashion from one computer to another on the network.

-Typically FDDI, SONET or Token Ring technology are used to implement a ring network.

-Ring networks are most commonly wired in a star configuration.

Token ring has multi-station access  unit (MSAU), equivalent to hub or switch. MSAU performs the token circulation internally.

Advantages	Disadvantages
Cable faults are easily located, making troubleshooting easier	Expansion to the network can cause network distruption
Ring networks are moderately easy to install	A single break in the cable can distrup entire network

Star Topology

-All computers/ devices connect to a central device called hub or switch.

-Each device requires a single cable.

-Point-to-point connection between the device and hub.

-Most widely implement.

-Hub is the single point of failure.

Advantages	Disadvantages
Easily expanded without disruption to the network	Requires more cable
Cable failure affect only a single user	A central connecting device allows for a single point of failure
Easily to troubleshoot and isolate problem	More difficult to implement

Mesh Topology

-Each computer connects to every other.

-High level of redundancy.

-Rarely used.

         -Wiring is very complicated.

         -Cabling cost is high.

         -Troubleshooting a failed cable is tricky.

         -A variation hybrid mesh- create point to point connection between                                 in WAN implementation.

Advantages	Disadvantages
Provides redundant paths between Devices.	Requires more cable than the other LAN topologies
The network can be expanded without disruption to current uses.	Complicated implementation

Wireless networking

-Do not require physical cabling.

-Particularly useful for remote access for laptops users.

-Eliminate cable faults and cable breaks.

-Signal interference and security issues.

Advantages	Disadvantages
Allows for wireless remote access	Potential security issues associted with wireless transmissions
Network can be expanded without disruption to current users	Limited speed in comparison to other network topologies.

IEEE and Networking standards

-Institute of Electrical and Electronic

Engineers (IEEE) developed a series of

networking standards.

– Networking technologies developed by

manufacturers are Compatible.

– Cabling, networking devices and protocols are

  all interchangeable under the banner of a

             specific IEEE.

802.3 IEEE standard

-Defines characteristics for Ethernet networks.

-New additions,

   – 802.3u for Fast Ethernet

   – 802.3z for Gigabit Ethernet, referred to as 802.3x.

   – … …

   – 802.3ac 10gbits/s, expe. 2009

   – … …

-Speed: Original 10Mbps, Fast Ethernet 100Mbps, Gigabit Ethernet

1000Mbps

-Topology: bus or star.

-Media: Coaxial and twisted pair cabling, also fiber optic cable.

-Access method: CSMA/CD

802.5 IEEE standard

-Specifies the characteristics for Token Ring

Networks.

-Introduced by IBM in the mid 80s, network

topology of choice until the rise of the popularity

of Ethernet.

-Speed: 4 to 16Mbps

-Topology: logical ring and most often a physical

star. Logical ring is often created in the

Multistation Access Unit (MSAU)

-Media: twisted pair cabling.

-Access method: token passing.

Networking

Apa itu Sistem Rangkaian (networking) ?

•  Penghubung antara sesuatu komputer dengan alat-alat komunikasi yang lain bagi membolehkan komunikasi berlaku. 
•  sebagai alat media untuk menghantar/mengawal data/signal. 
•  sebagai alat komunikasi untuk menerima/menghantar data daripada sesuatu sumber ke destinasi yang lain.

Antara jenis-jenis sistem rangkaian

• LAN - Local Area Network
• WAN - Wide Area network
• MAN - Metropolitan Area Network

Komponen-komponen rangkaian

Terminal:

 Semua perisian yang mengawal rangkaian telah dikhaskan sebagai satu file server oleh setiap komputer dan apa-apa perisian boleh dikongsi dengan semua komputer yang disambungkan kepada rangkaian.

workstation dikenali sebagai komputer-komputer yang bersambung dengan file server.

Media Penghantaran:

untuk segala jenis penghantaran data dan mengawal signal.

• (Bounded) : twisted pair, wire, co-axial cable, fibre optic cable.
• (Unbounded): Tv broadcasting, microwave radio, infrared signal, AM dan FM radio dan komunikasi satelit .

Alat-alat rangkaian elektronik:

·         Mengawal penghantaran data daripada sumber kepada destinasi.

e.g. bridges, routers, private branch exchange (PBX), hubs, multiplexor, switched dan seterusnya.

(a)Routers

·         Menterjemahkan maklumat antara rangkaian yang berasingan.

·         Menguruskan atau menyediakan  satu jadual laluan yang telah dikenal pasti.

·         Kerja-kerja penghantaran isyarat adalah begitu berkesan.

(b)Bridges (Jambatan)

·         Melakukan  satu rangkaian yang besar kemudiannya dibahagikan menjadi dua buah rangkaian yang kecil.

·         Menggunakan protokol yang mana setiap bridges menyediakan antaramuka (interface) yang serasi dan berkesan.

c) Hubs 

·         merupakan nadi bagi sesebuah rangkaian (main circuit).

·         Ada pengawalan trafik aliran maklumat dalam rangkaian supaya tidak berlaku percanggahan maklumat.

Software:

Sesuatu perisian pada node yang melibatkan protokol dan teknik yang bekerja bagi menentukan peraturan dan prosedur bagi menamatkan data, terjemahan data, menghantar data, mengawal kesalahan dan mempersembahkan data. Software dihasilkan bertujuan untuk memastikan data yang ingin dihantar sampai ke destinasi.