Computer Network??? A computer network is an interconnection of a group of computers and the world of computers Introduction to Computer Networks Budditha Hettige 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 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) Source: http://www.slideshare.net/mukeshchinta/networks-classification 7/11/2015 Budditha Hettige (budditha@yahoo.com) 5
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 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 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 Peer-to-peer Network Client Server Nodes
Client-Server & Peer-to-peer 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 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 IP 192.168.1.2 Subnet: 255.255.255.0 Name Sangeetha Silva Address: No 23, Panadura IP Address classes Private IPv4 network ranges 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) 24-bit block (/8 prefix, 1 A) 20-bit block (/12 prefix, 16 B) 16-bit block (/16 prefix, 256 C) ANA-reserved private IPv4 network ranges Start End No. of addresses 10.0.0.0 10.255.255.255 16777216 172.16.0.0 172.31.255.255 1048576 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 (budditha@yahoo.com) 40