Thanks to Randy of our CCNA program for this suggestion. Randy wanted some guidance on how to solve the subnetting questions in ICND1 and ICND2 very quickly. The ability to do this is often the difference between a passing score and a failed attempt.

WARNING: You must master subnetting using our course or some other trusted materials before you start using these shortcut approaches. It is a common issue for Cisco candidates to move directly to subnetting shortcuts for the exams without fully understanding exactly how subnetting functions.

For this series of posts, we will use simulated exam questions from ICND1 and ICND2. Well, with all that out of the way - let's have some fun. You will find that once you "turn the corner" on subnetting, you will pray for many of these questions in the exam. It is an opportunity to solve questions quickly and be 100% convinced that your response is "spot on".

ICND1 (CCENT)

Question 1: What is the last usable address in the subnet of a host with the address 192.168.1.134 and the subnet mask of 255.255.255.240?

Step 1: Since the is the first subnetting question I have encountered in my exam, I am going to use this as my opportunity to build my Powers of Two reference chart on my scratch paper.

2^7=128  |  2^6=64  |  2^5=32  |  2^4=16  |  2^3=8  |  2^2-=4 | 2  ^1=2  |  2^0=1

Step 2: 192 in the first octet tells me I have a Class C address. I memorized these number ranges; some students like to list those on the scratch paper as well. The default subnet mask for the Class C space is 255.255.255.0. You also need to memorize these, and again, many students like to list these on scratch paper as well.

Step 3: How many bits of subnetting are used in the fourth octet here? My Power of Two chart tells me. 1 bit = 128; 2 bits = 192; 3 bits = 224; 4 bits = 240.

Step 4: I go four bits deep (from left to right) in the Power of Two chart. This tells me that the subnets increment on 16:

192.168.1.16...32...48...64...80...96...112...128...144

Step 5: We can see that this host lives on the 192.168.1.128 subnet. The broadcast address for this subnet is one less than the next subnet of 144, so that is 143. The last usable is 142. Our answer - 192.168.1.142. Wooohooo! Bring on more of these!

Did you have an even easier way to arrive at the answer? Let us know in the comments.

I. Module 1: The Operation of Data Networks

A. Cisco Network Devices

B. The OSI Model

C. The TCP/IP Model

D. Voice Over IP and Video Over IP

E. Network Diagrams

F. Network Paths

G. Common Network Problems

H. LAN versus WAN Features

II. Module 2: Implementing a Small Switched Network

A. Physical Media

B. Ethernet

C. Network Segmentation

D. Basic Switching Concepts

E. Initial Switch Configuration

F. Switch Verifications

G. Basic Switch Security

H. Common Switch Issues

III. Module 3: IP Addressing and IP Services for a Small Network

C. DHCP

D. Create and Apply an Addressing Scheme

E. NAT

F. DNS

IV. Module 4: Implementing a Small Routed Network

A. Basic Routing Concepts

B. Operation of Cisco Routers

C. Initial Switch Configuration

D. Physical Media

E. RIPv2

F. Router Management

G. Router Security

H. Router Verifications

V. Module 5: WLAN

A. Standards

B. Wireless Components

C. Wireless Configuration

D. Wireless Security

E. Common Wireless Issues

VI. Module 6: Network Security

A. Security Threats

B. The Security Policy

C. Attack Mitigation Techniques

D. Common Security Appliances and Applications

E. Best Practices

VII. Module 7: WANs

A. Connecting a WAN

B. Configure a Serial Connection

C. Verify a Serial Connection

### Exam Details

Exam Number: 640-822
Exam Name: ICND1
Number of Questions: 40
Total Time: 90 Minutes
Passing Score: 804
Exam Sections:
Describe the operation of data networks
Implement a small switched network
Implement an IP addressing scheme and IP services for a small network
Implement a small routed network
Identify security threats to a network and describe general methods to mitigation

640-822 is one of the best Cisco (written) exams I have EVER seen. It does an excellent job of testing real world skills that an entry-level technician would need to succeed supporting small routed and switched networks.

The emphasis of the exam is on basic configuration and troubleshooting of Cisco devices. While there are a smattering of definitional type theory questions, the major focus is "hands-on", scenario based questions.

You should be ready to solve Simulations, scenario and exhibit-based multiple-choice questions, drag and drop, and standard multiple-choice queries. Be very careful about how much time you dedicate to any one question, since you might really burn the clock on a single given exercise. Time management is a key to success in this exam.

This exam does a superb job at reflecting the published exam blueprint, and as such, you can expect our course materials for CCENT to explain fully all questions.

You will feel very proud when you complete the CCENT certification with a passing score on this exam, as you will very clearly be ready to support the basic Cisco network!