Cisco CCNA Routing and Switching 200-120 Fourth Edition Concepts in IP Addressing

Cisco CCNA
Routing and Switching
200-120
Fourth Edition
Concepts in IP Addressing:-
1. What are the eight binary values found in a single octet of an IP address?
A. 256 128 64 32 16 8 4 2
B. 254 62 30 14 6 4 0
C. 128 64 32 16 8 4 2 1
D. 0 2 4 6 8 10 12 14
2. What is the decimal value of binary 00001110 ?
A. 13
B. 14
C. 1,110
D. 16
E. 15
3. What is the binary value of decimal 256?
A. 11111111
B. 1111111111
C. 100000000
D. 10000000
Answers
1. Answer C is correct.
2. Answer B is correct
3. Answer C is correct.
Conversion Between Binary, Hex, and
Decimal:-
1. Write the following binary IP in dotted-decimal format:
11000000.10101000.00000001.11111110.
2. Write the following sub-net mask in binary format: 255.255.255.240.
3. What is 127.0.0.1 in binary?
Answers
1. 192.168.1.254
2. 11111111.11111111.11111111.11110000
3. 01111111.00000000.00000000.00000001
IP Address Components
1. What class of IP address is 191.168.1.0?
2. What is the range (in decimal) of Class B addresses?
3. What is the range of private Class A addresses?
4. Is the address 172.16.1.0/24 sub netted?
Answers
1. Class B.
2. 128.0.0 .0 to 191.255.255.255
3. 10.0.0.0 to 10.255.255.255
4. Yes. The default mask is /16; /24 is longer so the address is sub netted.
IP Address Components:-
1. If the mask assigned to a private Class C address is 24 bits, is the address
Sub netted?
2. Which of the following are private IP addresses that can be assigned to a host?
P A. 12.17.1.45
P B. 10.255.255.254
P C. 172.15.255.248

, P D. 192.168.1.5
P E. 239.0.0.1
3. Why can’t Duncan assign the address of 17.21.12.1111 to his Internet web
server?
Answers
1. No. /24 is the default mask, so the address is not sub netted.
2. Answers B and D are correct. The other addresses are not in the private unicast ranges.
3. Because it is not a valid IP address: .1111 in any octet is not a valid IP.
Subneting:-
1. How many hosts are on the network 172.16.41.0/27?
A. 65,534
B. 32
C. 254
D. 30
E. 27
F. 14
2. How many subnets are created by the address 192.168.1.0
255.255.255.248?
A. 1
B. 2
C. 4
D. 8
E. 16
F. 32
G. 64
3. What is the broadcast ID of the seventh subnet created using
172.16.0.0/28?
A. 172.16.111.0
B. 172.16.0.0
C. 172.16.0.7
D. 172.16.0.96
E. 172.16.0.110
F. 172.16.0.111
G. 172.16.0.112
4. What is the ideal mask to use on point-to-point serial links?
5. Is 172.16.255.0/18 a valid host IP?
6. Julie’s IP address is 192.168.1.21 255.255.255.240. Joost’s IP is 192.168.1.14/28.
Their computers are connected together using a crossover Ethernet cable. Why
can’t they ping each other?
P A. The subnet masks are different
P B. They can. This is another trick question.
P C. Because they are in different subnets.
P D. Because the router does not support subnetting.
P E. Because it should be a straight-through cable.
Answers
1. Answer D is correct. Five 0s at the end of the mask; (25) – 2 = 30
2. Answer F is correct. 5 bits were stolen to extend the mask: (25) = 32
3. Answer F is correct. The seventh subnet ranges from the network ID of
172.16.0.96 to the broadcast ID of 172.16.0.111.
4. /30, or 255.255.255.252. That provides two valid host IPs, one for each end of
the link.
5. Yes. The subnet’s valid host IPs range from 172.16.192.1 to 172.16.255.254 .
6. Answer C is correct. Answer A is incorrect; the masks are the same, just written
differently. Answer B is incorrect, sorry. Answers D and E are incorrect. First of all,
the question specifically mentions that they are cabled back to back with a crossover; Second, a
router that doesn’t support subnetting probably came as a prize