Introduction to Networking

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1 Introduction to Networking 1

2 What is a Network? A network consists of 2 or more computers connected together, and they can communicate and share resources (e.g. information) 2

3 Why Networking? Sharing information Data communication Sharing hardware or software Print document Centralize administration and support Internet-based, so everyone can access the same administrative or support application from their PCs 3

4 Network Classification Depending on one s perspective, we can classify networks in different ways Transmission media: Wired (UTP, coaxial cables, fiber-optic cables) and Wireless Network size: LAN, WAN and MAN Management method: Peer-to-peer and Client/Server Topology (connectivity): Bus, Star, Ring 4

5 Network Classification Transmission Media Two main categories: Guided wires, cables Unguided wireless transmission, e.g. radio, microwave, infrared, sound, sonar We will concentrate on guided media here: Twisted-Pair cables: Unshielded Twisted-Pair (UTP) cables Shielded Twisted-Pair (STP) cables Coaxial cables Fiber-optic cables 5

6 Network Classification Transmission Media Twisted-Pair Cables Unshielded Twisted-Pair (UTP) Shielded Twisted-Pair (STP) 6

7 Network Classification Transmission Media Categories of UTP Cables EIA classifies UTP cables according to the quality: Cat 1 for voice (Old Telephone Cable) Cat 2 good for voice and low data rates (up to 4Mbps for low-speed token ring networks) Cat 3 at least 3 twists per foot, for up to 10 Mbps (common in phone networks in residential buildings) Cat 4 up to 16 Mbps (mainly for token rings) Cat 5 (or 5e) up to 100 Mbps (common for networks targeted for high-speed data communications) Cat 6 more twists than Cat 5, up to 1 Gbps 7

8 Coaxial Cables Network Classification Transmission Media Fiber-Optic Cables 8

9 Network Classification Network Size LAN and WAN Local Area Network (LAN) Examples: Network inside the Student Computer Room Network inside CF502 Network inside your home 9

10 Network Classification Network Size Wide Area Network (WAN) Examples: Network of our Campus Internet LAN 3 LAN 1 WAN LAN 2

11 Network Classification Network Management Peer-to-Peer Networks Computer-to- computer Clients and Servers Network Clients (Workstation) Computers that request network resources or services Network Servers 11

12 Network Classification Topology Topology Bus Topology Ring Topology Star Topology 12

14 Data is a piece of information. LAN is Local Area Network WAN is Wide Area Network Computers on a network can act as a client or a server.

15 A client is a computer that requests for resources. A server is a computer that controls and provides access to resources. A computer that operates independently from other computers is called a stand-alone computer.

16 Open Systems Interconnection model

20 Common Number Systems System Base Symbols Used by humans? Used in computers? Decimal 10 0, 1, 9 Yes No Binary 2 0, 1 No Yes Octal 8 0, 1, 7 No No Hexadecimal 16 0, 1, 9, A, B, F No No

21 Quantities/Counting Decimal Binary Octal Hexadecimal

22 Quantities/Counting Decimal Binary Octal Hexadecimal A B C D E F

23 Quantities/Counting Decimal Binary Octal Hexadecimal

24 Conversion Among Bases The possibilities: Decimal Octal Binary Hexadecimal

25 Quick Example = = 31 8 = Base

26 Decimal => 5 x 10 0 = 5 2 x 10 1 = 20 1 x 10 2 =

27 Binary to Decimal Bit => 1 x 2 0 = 1 1 x 2 1 = 2 0 x 2 2 = 0 1 x 2 3 = 8 0 x 2 4 = 0 1 x 2 5 =

28 Octal to Decimal => 4 x 8 0 = 4 2 x 8 1 = 16 7 x 8 2 =

29 Decimal to Binary =? =

30 Octal to Binary =? =

31 Hexadecimal to Binary 10AF 16 =? A F AF 16 =

32 IP Addresses

33 What is an IP Address? An IP address is a 32-bit address. The IP addresses are unique. The IP addresses define the network where the computer is registered and can access.

34 Dotted-decimal notation

35 Example 1 Change the following IP address from binary notation to dotted-decimal notation Solution

36 Example 2 Change the following IP address from dotted-decimal notation to binary notation: Solution

37 Example 3 Find the error in the following IP Address Solution There are no leading zeroes in Dotted-decimal notation (045)

38 Example 3 (continued) Find the error in the following IP Address Solution In decimal notation each number <= is out of the range

39 Example 4 Change the following binary IP address Hexadecimal notation Solution 0X810B0BEF or 810B0BEF16

40 CLASSFUL ADDRESSING In class addressing the address space is divided into 5 classes: A, B, C, D, and E.

41 IP Address Classes Class A N.H.H.H can not be used as Net ID 127 is reserved for loop back functions 126 Different Networks Hosts per Network N : is the Network ID (the street name) H : is the Host number (building number)

42 IP Address Classes Class B N.N.H.H The first IP Address is the NET ID The last IP Address is the Broadcast Address Different Networks Hosts per Network N : is the Network ID (the street name) H : is the Host number (building number)

43 IP Address Classes Class C N.N.N.H The first IP Address is the NET ID The last IP Address is the Broadcast Address Different Networks 254 Hosts per Network N : is the Network ID (the street name) H : is the Host number (building number)

44 IP Address Classes CLASS D Used for multicast broadcasts CLASS E Experimental addresses not available to the public

45 SUBNET MASKING Smaller broadcast domains More manageable networks Save IP Addresses Default Subnet Mask CLASS A CLASS B CLASS C

46 SUBNET MASKING 4000 Hosts NET ID CLASS B 2 12 =4096 D.S.M is the Subnet = 16

47 SUBNET MASKING Subnet Mask is Net ID Broadcast

48 Private Addresses There are certain address in each class that are not assigned. These are called private addresses. Private addresses are not routed on the internet. Network Address Translation (NAT) can be used to connect these Private Networks to the Internet

CN1047 INTRODUCTION TO COMPUTER NETWORKING CHAPTER 1 BASIC CONCEPTS OF NETWORK

CN1047 INTRODUCTION TO COMPUTER NETWORKING CHAPTER 1 BASIC CONCEPTS OF NETWORK DEFINTION & APPLICATIONS DEFINTION: A computer network is defined as the interconnection of two or more computers. It is done