HERY HAMDI AZWIR
Computer Network
Computer Network
Purposes Increase efficiency (Resource sharing) Information sharing or distribution of information
Categories LAN (Local Area Network) WAN (Wide Area Network)
Computer Communications type Peer-to-peer Client-Server (Ex: Web, Database, File, Mail)
LAN Topologies
Some Network Devices
Guided Media Network Interface Card (NIC) or LAN Card
Ethernet card Hub Switch (Smarter than Hub) Router
Unguided Media Wireless Adapter Wireless Access Point (Radio) Antenna Wireless Router
Twisted Pair Wiring Standard
Straight Cable
Twisted Pair Wiring Standard
Cross Cable (PC-to-PC)
Wiring Tool Set
Crimping ToolRJ-45 connectorUTP cable testerMultimeter
Network Setup
TCP/IP (Internet Concept) IP address Subnet Mask Default Gateway DNS (Domain name server) Alternate DNS DHCP (Automatic)
Microsoft Network Computer name Workgroup name Domain name
9
Set up Identitas Komputer
IP address : Alamat IP yang menunjukkan
identitas dari komputer agar dapat dikenal oleh jaringan
Default Gateway : Alamat IP dari Router yang
terkoneksi dimana permintaan akses internet akan diteruskan
DNS Server (Domain Name System) Alamat IP dari server yang
berfungsi melayani permintaan penterjemahan nama domain menjadi alamat IP
Static IP dan Dynamic IP
Dua metode pemberian alamat IPStatic IP
Diset secara manual. Semua jenis komputer bisa Untuk perangkat mobile umumnya tidak bisa
Dynamic IP Diset “obtain IP address automatically” Pemberian IP address dll dilakukan oleh yang disebut
DHCP server yang umumnya juga ada dalam router Perangkat mobile (HP, Smartphone, X-pad, dll)
umumnya menggunakan metode ini10
Some Network Utilities
ipconfigpingtraceroute / tracert (Microsoft)netstatNote : protocol used is icmp
TCP/IP Protocol Architecture
developed by US Defense Advanced Research Project Agency (DARPA)
for ARPANET packet switched networkused by the global Internetprotocol suite comprises a large collection of
standardized protocols
Simplified Network Architecture
TCP/IP Layers
no official model but a working one Application layer Host-to-host, or transport layer Internet layer Network access layer Physical layer
Physical Layer
concerned with physical interface between computer and network
concerned with issues like: characteristics of transmission medium signal levels data rates other related matters
Network Access Layer
exchange of data between an end system and attached network
concerned with issues like : destination address provision invoking specific services like priority access to & routing data across a network link
between two attached systemsallows layers above to ignore link specifics
Internet Layer (IP)
routing functions across multiple networksfor systems attached to different networksusing IP protocolimplemented in end systems and routersrouters connect two networks and relays data
between them
Transport Layer (TCP)
common layer shared by all applicationsprovides reliable delivery of datain same order as sentcommonly uses TCP
Application Layer
provide support for user applicationsneed a separate module for each type of
application
Operation of TCP and IP
Addressing Requirements
two levels of addressing requiredeach host on a subnet needs a unique global
network address its IP address
each application on a (multi-tasking) host needs a unique address within the host known as a port
Overview of Wireless LANs
use wireless transmission mediumissues of high prices, low data rates,
occupational safety concerns, & licensing requirements now addressed
key application areas: LAN extension cross-building interconnect nomadic access ad hoc networking
Single Cell LAN Extension
Multi Cell LAN Extension
Cross-Building Interconnect
connect LANs in nearby buildingspoint-to-point wireless link
Not a LAN per seconnect bridges or routers
Nomadic Access
link LAN hub & mobile data terminal laptop or notepad computer enable employee to transfer data from portable
computer to serveralso useful in extended environment such as
campus or cluster of buildings users move around with portable computers may wish access to servers on wired LAN
Infrastructure Wireless LAN
Ad Hoc Networkingtemporary peer-to-peer network
Wireless LAN Requirements
throughput - efficient use wireless mediumno of nodes - hundreds of nodes across multiple
cellsconnection to backbone LAN - using control
modulesservice area - 100 to 300 mlow power consumption - for long battery life on
mobilestransmission robustness and securitycollocated network operationlicense-free operationhandoff/roamingdynamic configuration - addition, deletion, and
relocation of end systems without disruption to users
Technology
infrared (IR) LANs individual cell of IR LAN limited to single room IR light does not penetrate opaque walls
spread spectrum LANs mostly operate in ISM (industrial, scientific, and
medical) bands no Federal Communications Commission (FCC)
licensing is required in USAnarrowband microwave
microwave frequencies but not use spread spectrum
some require FCC licensing
Infrared LANsTransmission Techniques
directed-beam IR point-to-point links range depends on power and focusing for indoor use can set up token ring LAN IR transceivers positioned so data circulates in
ringomnidirectional
single base station with line of sight to other stations
acts as a multiport repeater other stations use directional beam to it
diffused configuration stations focused / aimed at diffusely reflecting
ceiling