What is a network? 1.A network can be anything from a simple collection of computers at one location connected through a connectivity media to the internet (a global network of networks) 2.Local Area Network (LAN) is a server-based network confined to a particular area/place 3.Most LANs consist of many clients and a few servers

LAN setup Networ k server Client Machine Print Server Printer Hub

OSI Network Model 1.International Organization for Standards (ISO) 2.In 1970’s came ISO’s OSI model – a conceptual model for network communications 3.OSI - Open System Interconnection Reference Model 4.7 layer architecture

ISO OSI model Application layer Presentation layer Session layer Transport layer Network layer Data link layer Physical layer Application layer Presentation layer Session layer Transport layer Network layer Data link layer Physical layer Sender Side Receiver Side

ISO OSI model Application layer Presentation layer Session layer Transport layer Network layer Data link layer Physical layer Application layer Presentation layer Session layer Transport layer Network layer Data link layer Physical layer Sender Side Receiver Side

TCP/IP Stack Mapped To OSI Model OSI ModelTCP/IP Stack Application Presentation Session Transport Network Data Link Physical TelnetHTTPSMTPFTP TCPUDP IPRIPARP Network Interface Card Drivers

TCP/IP Protocol Stack Members HTTPUsed for web page requests TelnetTerminal Emulation Protocol – connects a local computer with a remote computer FTPFile Transfer Protocol - provides an interface and services for file transfer over the network – upload from local to remote & vice versa SMTPSimple Mail Transport Protocol – provides services on the internet TCPTransmission Control Protocol – connection-oriented transport protocol UDPUser Datagram Protocol – connectionless transport protocol IPInternet Protocol – provides basis for IP addressing on the network ARPAddress Resolution Protocol – maps IP address to MAC hardware address RIPRouting Information Protocol – Routing protocol used by routers to determine the best path for packets on the network

Host Machine

Getting the binary bits:Example

=57 Decimal To Binary

Binary To Decimal 2 0 x *0+2 2 *0+2 3 *1+2 4 *1+2 5 *1+2 6 *0+2 7 * 0=57

Look again at binary addresses????  Classes of networks – A,B,C,D and E  Network number starting with is the biggest number equal to 127 in decimal - So, is the range of class A networks  Network number starting with is equal to 128 in decimal is equal to 191 in decimal - So, is the range of class B networks  Network number starting with is equal to 192 in decimal is equal to 223 in decimal - So, is the range of class C networks  Network number starting with 111 -So, is the range of class D & E networks -Special multicast and experimental groups  Only first byte tells network class

Classes Class A – large networks (net 1 byte/host3) Class B – medium networks (net 2 bytes/host 2) Class C – small networks (net 3 bytes/host 1) 0Networkhost 1 0Networkhost Networkhost