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

Administrative distances

As mentioned before, the Administrative Distance (AD) is the belief or trustworthiness of the route being advertised. The lower the AD, the more you can trust that route to be the best path to take; in the 0-255 range, 0 is the best and 255 cannot trusted at all. Routers will always choose the network with the lowest AD, but if a router receives the same route from two different locations and has the same AD, then it will use the metric, cost, or hop count to decide which would be the better route. It will always be the smallest number that would win.

Each routing protocol has an algorithm to calculate the best route to a network, and we will get into that later in the book. The following table gives the default AD to static and dynamic routes:

Route source

Administrative distance

Connected Interface

0

Static route

0 or 1

RIP

120...