

NET 222: Introduction to Routers and Routing
Review for Second Test
 What is a subnet?
 What are the classful subnet masks for classes A, B, and C?
 What formula tells you how many subnets can be made in a subnetting
problem? What is the difference in the formula when you can and cannot
use the IP subnetzero command?
 What formula tells you how many hosts can be placed on each subnet
you create?
 When you create a series of subnets, how do you determine the subnet
address for each one? How do you determine the broadcast address for
each one? How do you determine the range of host addresses for each
subnet?
 Examine this problem, and answer each question using the methods from
the chapter or from my notes.
Required number of subnets: 100
Required number of hosts/subnet:400
Classful network address: 192.168.0.0
What is the required subnet mask?
What is the actual number of possible subnets with that mask?
What is the actual number of possible hosts per subnet?
What is the value of delta (block size)?
Fill in this chart for the first four subnets:
Subnet address 
Broadcast address 
Range of host addresses 












 Examine this problem, and answer each question using the methods from
the chapter or from my notes.
Given subnet mask: 255.255.255.224
Classful network address: 192.168.10.0
What is the CIDR notation for this mask?
What is the actual number of possible subnets with that mask?
What is the actual number of possible hosts per subnet?
What is the value of delta (block size)?
Fill in this chart for the first four subnets:
Subnet address 
Broadcast address 
Range of host addresses 












 What is VLSM? Why does it allow us to do that classful subnetting
does not?
 What is CIDR notation? What other networking concept can you substitute
CIDR notation for?
 We will make a modification to the Microsoft example of VLSM. Assume
a starting network ID of 10.0.0.0/8. You are required to create three
subnets with up to 60,000 hosts each, 12 subnets with up to 2,000 hosts
each, and eight subnets with up to 250 hosts each. Start with the subnet
with the most hosts, and work down.
What is the subnet mask in use when you start this problem?
Can the requirements be met?
What are the steps that can be carried out?
 When troubleshooting, what series of pings does the text recommend
trying?
What might be indicated by a failure at each step?
 When you create a subnet, what two addresses on that subnet must
not be assigned to hosts? Why?
