738 Appendix A: Answers to the "Do I Know This Already?" Quizzes and Q&A Sections
34
How many IP addresses could be assigned in each subnet of 220.8.7.0, assuming that a
mask of 255.255.255.240 is used? If the same (static) mask is used for all subnets, how
many subnets are there?
There will be 2
hostbits
, or 2
4
hosts per subnet, minus two special cases. The number of
subnets will be 2
subnetbits
, or 2
4
, in this case. The chart that follows summarizes the related
information in the same manner as the "Foundation Topics" section of Chapter 5
described the binary algorithm to solve this type of problem.
35
How many IP addresses could be assigned in each subnet of 140.1.0.0, assuming a mask
of 255.255.255.248 is used? If the same (static) mask is used for all subnets, how many
subnets are there?
There will be 2
hostbits
, or 2
3
hosts per subnet, minus two special cases. The number of
subnets will be 2
subnetbits
, or 2
13
, in this case. The chart that follows summarizes the
related information in the same manner as the "Foundation Topics" section of Chapter 5
described the binary algorithm to solve this type of problem.
36
Create a minimal configuration enabling IP on each interface on a 2501 router (two
serial, one Ethernet). The NIC assigned you network 8.0.0.0. Your boss says you need at
most 200 hosts per subnet. You decide against using VLSM. Your boss also says to plan
your subnets so that you can have as many subnets as possible rather than allow for larger
subnets later. You decide to start with the lowest numerical values for the subnet number
you will use. Assume that point-to-point serial links will be attached to this router and that
RIP is the routing protocol.
router rip
network 8.0.0.0
interface ethernet 0
ip address 8.0.1.1 255.255.255.0
interface serial 0
ip address 8.0.2.1 255.255.255.0
interface serial 1
ip address 8.0.3.1 255.255.255.0
Network and
Mask
Number of
Network Bits
Number of
Host Bits
Number of
Subnet Bits
Number of
Hosts per
Subnet
Number of
Subnets
220.8.7.0,
255.255.255.
240
24
4
4
14
16
Network and
Mask
Number of
Network Bits
Number of
Host Bits
Number of
Subnet Bits
Number of
Hosts per
Subnet
Number of
Subnets
140.1.0.0
16
3
13
6
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apA.fm Page 738 Monday, March 20, 2000 5:24 PM