HERY HAMDI AZWIR 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 Tool RJ-45 connector UTP cable tester Multimeter

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

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 9

Static IP dan Dynamic IP Dua metode pemberian alamat IP Static 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 ini 10

Some Network Utilities ipconfig ping traceroute / tracert (Microsoft) netstat Note : protocol used is icmp

TCP/IP Protocol Architecture developed by US Defense Advanced Research Project Agency (DARPA) for ARPANET packet switched network used by the global Internet protocol 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 systems allows layers above to ignore link specifics

Internet Layer (IP) routing functions across multiple networks for systems attached to different networks using IP protocol implemented in end systems and routers routers connect two networks and relays data between them

Transport Layer (TCP) common layer shared by all applications provides reliable delivery of data in same order as sent commonly uses TCP

Application Layer provide support for user applications need a separate module for each type of application

Operation of TCP and IP

Addressing Requirements two levels of addressing required each 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 medium issues 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 buildings point-to-point wireless link  Not a LAN per se connect bridges or routers

Nomadic Access link LAN hub & mobile data terminal  laptop or notepad computer  enable employee to transfer data from portable computer to server also 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 Networking temporary peer-to-peer network

Wireless LAN Requirements throughput - efficient use wireless medium no of nodes - hundreds of nodes across multiple cells connection to backbone LAN - using control modules service area to 300 m low power consumption - for long battery life on mobiles transmission robustness and security collocated network operation license-free operation handoff/roaming dynamic 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 USA narrowband microwave  microwave frequencies but not use spread spectrum  some require FCC licensing

Infrared LANs Transmission 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 ring omnidirectional  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