Answers to the Chapter 5 Q&A Section 729
2
Name the parts of an IP address.
Network, subnet, and host are the three parts of an IP address. However, many people
commonly treat the network and subnet parts of an address as a single part, leaving only
two parts, the subnet and host parts. On the exam, the multiple-choice format should
provide extra clues as to which terminology is used.
3
Define the term subnet mask. What do the bits in the mask whose values are binary 0 tell
you about the corresponding IP address(es)?
A subnet mask defines the number of host bits in an address. The bits of value 0 define
which bits in the address are host bits. The mask is an important ingredient in the formula
to dissect an IP address; along with knowledge of the number of network bits implied for
Class A, B, and C networks, the mask provides a clear definition of the size of the network,
subnet, and host parts of an address.
4
Given the IP address 134.141.7.11 and the mask 255.255.255.0, what is the subnet
number?
The subnet is 134.141.7.0. The binary algorithm is shown in the table that follows.
5
Given the IP address 193.193.7.7 and the mask 255.255.255.0, what is the subnet
number?
The network number is 193.193.7.0. Because this is a Class C address and the mask used
is 255.255.255.0 (the default), there is no subnetting in use. The binary algorithm is shown
in the table that follows.
6
Given the IP address 10.5.118.3 and the mask 255.255.0.0, what is the subnet number?
The subnet is 10.5.0.0. The binary algorithm math is shown in the table that follows.
Address
134.141.7.11
1000 0110 1000 1101 0000 0111 0000 1011
Mask
255.255.255.0
1111 1111 1111 1111 1111 1111 0000 0000
Result
134.141.7.0
1000 0110 1000 1101 0000 0111 0000 0000
Address
193.193.7.7
1100 0001 1100 0001 0000 0111 0000 0111
Mask
255.255.255.0
1111 1111 1111 1111 1111 1111 0000 0000
Result
193.193.7.0
1100 0001 1100 0001 0000 0111 0000 0000
Address
10.5.118.3
0000 1010 0000 0101 0111 0110 0000 0011
Mask
255.255.0.0
1111 1111 1111 1111 0000 0000 0000 0000
Result
10.5.0.0
0000 1010 0000 0101 0000 0000 0000 0000
apA.fm Page 729 Monday, March 20, 2000 5:24 PM