Answers to the Chapter 5 Q&A Section 735
29
Given the IP address 10.5.118.3 and the mask 255.255.255.0, what are all the subnet
numbers if the same (static) mask is used for all subnets in this network?
The Class A network number is 10.0.0.0. The mask implies that the entire second and
third octets, and only those octets, comprise the subnet field. Essentially, the subnet
numbers have the same numbers in the network portion and the same (all binary 0)
value in the host portion of the number. Each individual subnet number has a unique value
in the subnet portion of the number.
The binary algorithm is shown in the table that follows. Refer to the section "Given a
Network Number and a Static Subnet Mask, What Are the Valid Subnet Numbers?" in
Chapter 5 for a review of the algorithm.
Step 2 (only one line shown)
1000 0110 1000 1101
Step 3 (only one line shown)
1000 0110 1000 1101 0000 0000
Step 4
1000 0110 1000 1101 0000 0000 0000 0000
134.141.0.0
Step 5
1000 0110 1000 1101 0000 0001 0000 0000
134.141.1.0
Step 6
1000 0110 1000 1101 0000 0010 0000 0000
134.141.2.0
Step 6
1000 0110 1000 1101 0000 0011 0000 0000
134.141.3.0
Step 6
1000 0110 1000 1101 0000 0100 0000 0000
134.141.4.0
Step 6
1000 0110 1000 1101 0000 0101 0000 0000
134.141.5.0
Skipped a few for brevity
Step 6
1000 0110 1000 1101 1111 1111 0000 0000
134.141.255.0
Step 2 (only one line shown)
0000 1010
Step 3 (only one line shown)
0000 1010 0000 0000
Step 4
0000 1010 0000 0000 0000 0000 0000 0000
10.0.0.0
Step 5
0000 1010 0000 0000 0000 0001 0000 0000
10.0.1.0
Step 6
0000 1010 0000 0000 0000 0010 0000 0000
10.0.2.0
Step 6
0000 1010 0000 0000 0000 0011 0000 0000
10.0.3.0
Step 6
0000 1010 0000 0000 0000 0100 0000 0000
10.0.4.0
Step 6
0000 1010 0000 0000 0000 0101 0000 0000
10.0.5.0
Skipped a few for brevity
Step 6
0000 1010 1111 1111 1111 1111 0000 0000
10.255.255.0
apA.fm Page 735 Monday, March 20, 2000 5:24 PM