Solutions for CIDR Exercises

1 List the individual network numbers defined by the CIDR block

200.56.168.0/21.

a. Express the CIDR block in binary format: 

200.56.168.0/21 11001000.00111000.10101 000.00000000

b. The /21 mask is 3 bits shorter than the natural mask for a tradi 

tional /24. This means that the CIDR block identifies a block of 8 (or

23) consecutive /24 network numbers. 

c. The range of /24 network numbers defined by the CIDR block

200.56.168.0/21 includes: 

Net #0: 11001000.00111000.10101000 .xxxxxxxx 200.56.168.0 

Net #1: 11001000.00111000.10101001 .xxxxxxxx 200.56.169.0 

Net #2: 11001000.00111000.10101010 .xxxxxxxx 200.56.170.0 

Net #3: 11001000.00111000.10101011 .xxxxxxxx 200.56.171.0 

Net #4: 11001000.00111000.10101100 .xxxxxxxx 200.56.172.0 

Net #5: 11001000.00111000.10101101 .xxxxxxxx 200.56.173.0 

Net #6: 11001000.00111000.10101110 .xxxxxxxx 200.56.174.0 

Net #7: 11001000.00111000.10101111 .xxxxxxxx 200.56.175.0

2 List the individual network numbers defined by the CIDR block

195.24/13.

a. Express the CIDR block in binary format: 

195.24.0.0/13 11000011.00011000.00000000.00000000 

b. The /13 mask is 11 bits shorter than the natural mask for a tradi 

tional /24. This means that the CIDR block identifies a block of 2,048

(or 211) consecutive /24 network numbers. 

c. The range of /24 network numbers defined by the CIDR block

195.24/13 include:

Net #0: 11000011.00011000.00000000 .xxxxxxxx 195.24.0.0

Net #1: 11000011.00011000.00000001 .xxxxxxxx 195.24.1.0

Net #2: 11000011.00011000.00000010 .xxxxxxxx 195.24.2.0

.

.

.

Net #2045: 11000011.00011111.11111101 .xxxxxxxx 195.31.253.0

Net #2046: 11000011.00011111.11111110 .xxxxxxxx 195.31.254.0

Net #2047: 11000011.00011111.11111111 .xxxxxxxx 195.31.255.0

U N D E R S TA N D I N G   I P   A D D R E S S I N G

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