DCN286 INTRODUCTION TO DATA COMMUNICATION TECHNOLOGY Network Basics Introduction Instructor: Ataur Rahman

What we know already…or should An IP address is 32 bits long – 4 separate bytes An IP Address is represented in dotted- decimal notation Each byte represents a decimal number separated by a period Example: or ( ) Each byte has a total of 256 values – 0-255

IP address 1. Traditionally, the IP address was classified in classes: Class A: network 1 – 126 (Network 127 is reserved for loopback and internal testing) Class B: network 128 – 191 Class C: network 192 – 223 Class D: network (Reserved for multicast) Class E: network 240 – 255(Reserved for Experimental, used for research) 2. There are public IP address used in Internet and private IP address used in company/organization internal networks. Class A: Class B: – Class C: –

IP Address Continued-  There are three (3) usable IP address classes - A, B and C The first byte identifies the class – “Classification” ClassExampleNetworksHosts A - 1 to ,777,214 B- 128 to ,38465,534 C- 192 to ,097, D – Multicast E – DoD Reserved

Subnet Mask Subnet mask is to divide IP address into two sections: network ID and host ID. Say the IP address is with subnet mask Translate all decimal into binary: IP address would be Subnet mask would be Final result: Network id: which equals to Host id: meaning 64

What we know already…or maybe not Question: How many of these addresses are valid IP Number for a Host ? Correct Response? How do you know?---

Practice: Classification – What Class? A B C B A Nice Work!!!!

Practice: Class Boundary- Draw the line Network | Host Network | Host A  10.| B  | Network | Host C  | 210

What is the Network address of /20?

Class B table # of bit borrowedSubnet Mask# of Usable Subnets # of available Hosts , , ,094