Temario Icnd 1 y 2

Authorized Self-Study Guide

Interconnecting Cisco Network Devices, Part 1 (ICND1)
Second Edition Steve McQuerry, CCIE No. 6108

Cisco Press
800 East 96th Street Indianapolis, Indiana 46240 USA

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Contents
Foreword xxii xxiii 3 Introduction Chapter 1

Building a Simple Network

Chapter Objectives 3 Exploring the Functions of Networking 3 What Is a Network? 4 Common PhysicalComponents of a Network 5 Interpreting a Network Diagram 6 Resource-Sharing Functions and Benefits 7 Network User Applications 9 The Impact of User Applications on the Network 10 Characteristics of a Network 11 Physical Versus Logical Topologies 12 Physical Topologies 12 Logical Topologies 13 Bus Topology 14 Star and Extended-Star Topologies 15 Star Topology 15 Extended-Star Topology 15 RingTopologies 17 Single-Ring Topology 17 Dual-Ring Topology 18 Mesh and Partial-Mesh Topologies 18 Full-Mesh Topology 18 Partial-Mesh Topology 19 Connection to the Internet 20 Summary of Exploring the Functions of Networking 21 Securing the Network 21 Need for Network Security 22 Balancing Network Security Requirements 25 Adversaries, Hacker Motivations, and Classes of Attack 26 Classes of Attack 27Mitigating Common Threats 28 Physical Installations 28 Reconnaissance Attacks 29 Access Attacks 30 Password Attacks 30 Summary of Securing the Network 31 References 31 Understanding the Host-to-Host Communications Model 31 OSI Reference Model 32 Layer 7: The Application Layer 34

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Layer 6: The Presentation Layer 34 Layer 5: The Session Layer 35 Layer 4: The Transport Layer 35 Layer 3: The NetworkLayer 35 Layer 2: The Data Link Layer 35 Layer 1: The Physical Layer 36 Data Communications Process 36 Encapsulation 37 De-Encapsulation 38 Peer-to-Peer Communication 39 The TCP/IP Protocol Stack 40 OSI Model Versus TCP/IP Stack 41 Summary of Understanding the Host-to-Host Communications Model 42 Understanding TCP/IP’s Internet Layer 43 IP Network Addressing 44 IP Address Classes 46 Network andBroadcast Addresses 49 Public and Private IP Addresses 53 Address Exhaustion 54 Dynamic Host Configuration Protocol 58 Domain Name System 58 Using Common Host Tools to Determine the IP Address of a Host 59 Summary of TCP/IP’s Internet Layer 62 Understanding TCP/IP’s Transport and Application Layers 63 The Transport Layer 63 TCP/IP Applications 67 Transport Layer Functionality 67 TCP/UDP Header Format69 How TCP and UDP Use Port Numbers 72 Establishing a TCP Connection: The Three-Way Handshake 74 Session Multiplexing 77 Segmentation 78 Flow Control for TCP/UDP 78 Acknowledgment 79 Windowing 80 Fixed Windowing 80 Example: Throwing a Ball 80 TCP Sliding Windowing 82 Maximize Throughput 83 Global Synchronization 83 Summary of Understanding TCP/IP’s Transport and Application Layers 83 Exploringthe Packet Delivery Process 84 Layer 1 Devices and Their Functions 84 Layer 2 Devices and Their Functions 85

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Layer 2 Addressing 86 Layer 3 Devices and Their Functions 86 Layer 3 Addressing 86 Mapping Layer 2 Addressing to Layer 3 Addressing 87 ARP Table 88 Host-to-Host Packet Delivery 89 Function of the Default Gateway 98 Using Common Host Tools to Determine the Path Between Two HostsAcross a Network 99 Summary of Exploring the Packet Delivery Process 103 Understanding Ethernet 104 The Definition of a LAN 104 Components of a LAN 105 Functions of a LAN 106 How Big Is a LAN? 107 Ethernet 108 Ethernet LAN Standards 108 LLC Sublayer 109 MAC Sublayer 109 The Role of CSMA/CD in Ethernet 109 Ethernet Frames 111 Ethernet Frame Addressing 112 Ethernet Addresses 113 MAC Addresses andBinary-Hexadecimal Numbers 113 Summary of Understanding Ethernet 114 Connecting to an Ethernet LAN 115 Ethernet Network Interface Cards 115 Ethernet Media and Connection Requirements 116 Connection Media 116 Unshielded Twisted-Pair Cable 118 UTP Implementation 119 Summary of Connecting to an Ethernet LAN 124 Chapter Summary 124 Review Questions 125

Chapter 2

Ethernet LANs

139

Chapter...