CCNA 3 Labs and Study Guide - BINARYBB.INFO – @jagalbraith

2. 192.168.35.142/29
IP address 11000000.10101000.00100011.10001110
Subnet mask 11111111.11111111.11111111.11111000
Subnet address 11000000.10101000.00100011.10000000
Dotted-decimal 192.168.35.128
3. 172.28.23.54/21
IP address 10101100.00011100.00010111.00110110
Subnet mask 11111111.11111111.11111000.00000000
Subnet address 10101100.00011100.00010000.00000000
Dotted-decimal 172.28.16.0
4. 172.31.32.69/25
IP address 10101100.00011111.00100000.01000101
Subnet mask 11111111.11111111.11111111.10000000
Subnet address 10101100.00011111.00100000.00000000
Dotted-decimal 172.31.32.0
5. 10.64.150.197/18
IP address 00001010.01000000.10010110.11000101
Subnet mask 11111111.11111111.11000000.00000000
Subnet address 00001010.01000000.10000000.00000000
Dotted-decimal 10.64.128.0
VLSM Subnetting a Subnet Exercises
Note: Now is a good time to complete Curriculum Lab 1-1: Calculating VLSM Subnets (1.1.4), which walks you
through a VLSM addressing scenario.
VLSM is simply “subnetting a subnet.” In the following exercises, use your subnetting skills to further
subnet a given subnet. If it helps you, draw a topology that represents the requirement you are given.
Example:
Chapter 1: Introduction to Classless Routing 9
Use the subnet 192.168.1.64/27 and further subnet this address to provide four additional subnets with at
least six hosts per subnet. List all four subnets in network address/prefix format.
Step 1. Determine how many host bits you have available in the given subnet. For subnet
192.168.1.64/27, you have a total of 5 host bits.
Step 2. Determine how many host bits you can borrow to make an additional four subnets with at least
six hosts per subnet. Borrowing an additional 2 bits will make four subnets (2 2 = 4). Because
there are 3 host bits left after borrowing, each subnet will have exactly six host addresses
(2 3 – 2 = 6).
Step 3. Determine the new prefix and list the new subnets. Because you borrowed 2 bits, the new
prefix is /29. You start with the first address 192.168.1.64 and list the four subnets.