05 computer networks - wordpress.com · 2015. 10. 5. · classification of a computer network by...
TRANSCRIPT
Introduction to
Computer Networks
Budditha Hettige
Computer Network ???
• A computer network is an interconnection of a
group of computers and the world of computers
Why Computer Networks?
• Resource Sharing
– Sharing a peripheral device (disk, printer, etc.)
among several users
• Communication
– Email, web, Skype, VOIP
• Security
– Restrict the user access
Network Classification
• By scale
• By connection method
• By functional relationship (Network Architectures)
• By network topology
• By protocol
Source: http://www.slideshare.net/MukeshChinta/networks-classification
7/11/2015 Budditha Hettige ([email protected]) 5
Classification of a Computer network by Scale
• Personal Area Network (PAN)
• Local Area Network (LAN)
• Campus Area Network (CAN)
• Metropolitan Area Network (MAN)
• Wide Area Network (WAN).
• Global Area Network(GAN)
PAN- personal area network
• Is a computer network used for communication
among computer devices (including telephones and
personal digital assistants) close to one person
• Typically a few meters
• Wireless Connections
– Bluetooth
– IR Remote sensers
LAN- local area network
• A local area network (LAN) is a computer network
covering a small geographic area, like a home,
office, or group of buildings
• Up to 1 KM
• Wireless/ wired
– Ethernet
– Wireless
MAN- Metropolitan Area Network
• A Metropolitan Area Network is a network that
connects two or more Local Area Networks
• Connections
– Optical fiber
– Telephone
WAN-Word Area Network
• A WAN is a data communications network that
covers a relatively broad geographic area
Classification of a Computer network by Connection method
• Optical fiber
• Ethernet
• Wireless LAN
• Home PNA,
• Power line communication
Optical fiber
• A glass or plastic fiber designed to guide light along
its length
Ethernet
• family of frame-based computer networking
technologies for local area networks (LANs)
Wireless LAN
• linking of two or more computers without using wires
Classification of a Computer network by functional relationship
• Active Networking
• Client-server networking
• Peer-to-peer (workgroup) architectures
Active Networking
• Active networking is a communication pattern that
allows packets flowing through a
telecommunications network to dynamically modify
the operation of the network
Client-server networking
• Client
• Server
• Nodes
Peer-to-peer Network
Client-Server & Peer-to-peerClassification of a Computer network by Network Topology
• Bus network topology
• Star network topology
• Ring network topology
• Mesh network topology
• Star-bus network topology
• Tree or Hierarchical topology
Bus network topology Star Network
Ring Network Mash Topology
Tree Network Topology Hardware for Computer Networks
IP address
• Internet Protocol (IP) address
• IP addresses are usually expressed in four-octet,
dotted-decimal form—w.x.y.z
• octet ranges in value from 0 to 255
• Consist of
– network ID and a host ID
Address
• IP 192.168.1.2
• Subnet:
– 255.255.255.0
Name Sangeetha Silva
Address:
No 23, Panadura
IP Address classes
IP Address Class Used For
Class A 1 -126 Very large networks
Class B 128-191 Medium to large networks
Class C 192-223 Small networks
Class D 224-239 Multicasting
Class E 240-255 Reserved (experimental)
Private IPv4 network ranges
ANA-reserved private IPv4 network ranges
Start End No. of addresses
24-bit block (/8
prefix, 1 × A)10.0.0.0 10.255.255.255 16777216
20-bit block (/12
prefix, 16 × B)172.16.0.0 172.31.255.255 1048576
16-bit block (/16
prefix, 256 × C)192.168.0.0 192.168.255.255 65536
IP Address
• IP addresses whose first octet is 127 (127.0.0.0)
represent the loopback address and are used for
troubleshooting purposes only, not for naming hosts
Terms in the Computer Network
Node
• Client
• Sever
– Mail Server
– File Server
– Web Server
– Proxy Server
– DHCP Server
– DNS Server
Web Server Proxy Server
DHCP Server DNS Server
Lab Activity
• Show Network Settings in your computer
– ipconfig
Lab Activity
• Show other computers that are available in the network
– net view
Network Configuration
• Acknowledge to other computer using ping command
– ping <ip address>
Example
• According to your PC configuration identify the following facts.
– IP Address
– Subnet mask
– Gateway
– DNS server
– Identify Other computers in your network
– Identify IP for the following URLs
• www.google.com
• www.ou.ac.lk
7/11/2015 Budditha Hettige ([email protected]) 40