Book Image

CCNA Routing and Switching 200-125 Certification Guide

By : Lazaro (Laz) Diaz
Book Image

CCNA Routing and Switching 200-125 Certification Guide

By: Lazaro (Laz) Diaz

Overview of this book

Cisco Certified Network Associate (CCNA) Routing and Switching is one of the most important qualifications for keeping your networking skills up to date. CCNA Routing and Switching 200-125 Certification Guide covers topics included in the latest CCNA exam, along with review and practice questions. This guide introduces you to the structure of IPv4 and IPv6 addresses and examines in detail the creation of IP networks and sub-networks and how to assign addresses in the network. You will then move on to understanding how to configure, verify, and troubleshoot layer 2 and layer 3 protocols. In addition to this, you will discover the functionality, configuration, and troubleshooting of DHCPv4. Combined with router and router simulation practice, this certification guide will help you cover everything you need to know in order to pass the CCNA Routing and Switching 200-125 exam. By the end of this book, you will explore security best practices, as well as get familiar with the protocols that a network administrator can use to monitor the network.
Table of Contents (24 chapters)
4
Subnetting in IPv4
21
Mock Test Questions
22
Assessments

Understanding router boot sequence

Please go through the following steps to understand the router boot sequence:

  1. The POST is performed; it will test the hardware to verify that all the components of the device are working and present. The POST checks for the different interfaces that exist. As we know already, POST exists in ROM:
Main phases of the router boot sequence
  1. Bootstrap will then search for and load the Cisco IOS. Bootstrap is a program in ROM that is used to execute programs. It is responsible for finding where each IOS program is located and then loading the file. As said previously, the IOS by default is stored in flash in all Cisco routers, but only after the configuration register is read and NVRAM is checked for the boot sequence.
  2. After the IOS is decompressed into RAM, the IOS looks for a valid configuration file in NVRAM.
  3. If a startup configuration file is...