computer network 1lecture 11 pengantar jaringan komputer iwan syarif hero yudo martono

Computer Network 1 Lecture 1 1

Pengantar Jaringan Komputer

Iwan SyarifHero Yudo Martono


Apa itu Jaringan

Kumpulan dua atau lebih dari komputer yang saling berhubungan satu sama lain


Kegunaan Jaringan

Sharing resource (data, printer, dll) Efisiensi waktu Efisiensi tempat Effisiensi dana


Kerugian Jaringan

Membutuhkan biaya tambahan Memungkinkan adanya serangan ke

komputer kita Mengurangi human communication


Types of Computer Networks

Local Area Networks (LANs) within a building or campus usually based on broadcast channels often connected via gateways to wide area

networks Examples: (Fast)Ethernet, FDDI rings,

Myrinet, ATM LANs Bit rates: 10-1000 Mbps

Cable Computer

(b)(a)

Computer


Type of Computer Networks

Metropolitan Area Networks (MANs) covers area of a city usually based on LAN technology Examples: DQDB (Distributed Queue

Dual Bus), cable television networks


Type of Computer Networks

Wide Area (Long Haul) Networks may cover country, continent Most communication links are point-to-point usually irregular topology

usually organized as a “subnet” to which hosts have access.

switching elements are generically referred to as routers


Wireless Networks

Wireless: Cordless telephones, TV remote control, Analog cellular telephones

Wireless LANs Mobile vs. wireless

mobile, not wireless mobile, wireless not mobile, not wireless not mobile, wireless


Internetworking Many (mutually incompatible) network

technologies No one technology appropriate for

every situation Internetworking glues together

networks of dissimilar technologies with routers

Result is virtual network whose details are invisible


Internetworking (example)Different network technologies can be connected to create an internetwork


Peralatan Jaringan Sederhana

PC (komputer) LAN card Kabel UTP RJ 45 Tang Crimping Multimeter Hub Switch


LAN card


Pasang LAN card ke PC


What’s a protocol?a human protocol and a computer network protocol:

Q: Other human protocol?

Hi

Hi

Got thetime?

2:00

TCP connection req.

TCP connectionreply.Get http://gaia.cs.umass.edu/index.htm

<file>time


Transmission media Transmitted energy is carried through some

sort of medium Transmitter encodes data as energy and

transmits energy through medium Requires special hardware for data encoding Requires hardware connection to transmission

medium Media can be copper, glass, air, ...


Copper wires •Twisted pair uses two wires

•Coaxial cable includes shield for improved performance


Kabel UTP


Glass fibers • Thin glass fiber carries light with encoded data • Plastic jacket allows fiber to bend (some!) without

breaking • Fiber is very clear and designed to reflect light internally for efficient transmission • Light emitting diode (LED) or laser injects light into fiber • Light sensitive receiver at other end translates light back into data


Radio •Data transmitted using radio waves •Energy travels through the air rather than copper or glass •Conceptually similar to radio, TV, cellular phones •Can travel through walls and through an entire building •Can be long distance or short distance

•Long distance with satellite relay •Short distance - wireless computer network


Wireless Example •Wireless bridge and antenna

Base-station antenna for a wireless radio-frequency network; this antenna is attached to a unit that also connects to a wire-based network and forwards data between the wireless and wire-based networks


Wireless Example

•Remote station (laptop) interface


Microwave High frequency radio waves Unidirectional, for point-to-point

communication Antennas mounted on towers

relay transmitted data


Infrared Infrared light transmits data through the

air Similar to technology used in TV remote

control Can propagate throughout a room

(bouncing off surfaces), but will not penetrate walls

Becoming common in personal digital assistants


Laser Unidirectional, like microwave Higher speed than microwave Uses laser transmitter and photo-

sensitive receiver at each end Point-to-point, typically between

buildings Can be adversely affected by

weather


RS-232 wiring and connectors


Modems If external to computer, RS-232 can be used

between modem and computer


Modems If internal, direct bus connection used Can also be rack-mounted

Modems in a computer center for dial-up modem access to the organization network


What's next? --Data Transmission

Two issues-- MEDIUM FORM OF ENERGY

copper -- electrical current fiber optics (glass) -- light air -- electromagnetic radio waves combination of copper and fiber -- both energy

forms （ cable modem technology)

computer network 1lecture 11 pengantar jaringan komputer iwan syarif hero yudo martono

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