1. According to ARIN, the University of Maryland owns the IP block from 128.8.0.

ID: 3601776 • Letter: 1

Question

1. According to ARIN, the University of Maryland owns the IP block from 128.8.0.0 - 128.8.255.255.

a) How many different IP addresses does this block contain?
b) How is this subnet described using CIDR?
c) What would the netmask of this subnet be?

2. A possible IP address in the University of Maryland is 129.2.101.23.
a) Convert this IP address in dotted-decimal notation to a 32-bit number in base-10.
b) List seven different CIDR-ized subnets to which this IP address could belong.
c) For each of the seven different CIDR-ized subnets, you listed, provide their netmasks in dotted-decimal notation.

Please Help. Thank you so much!

Explanation / Answer

Question 1

a) The number of different IP addresses that the block contains is 256*256= 65536.But out of this 65536 IP addresses , two are reserved (1 for Network ID , 1 for Broadcast ID).Hence, effective number of IP addresses is 65536-2=65534.

b) The subnet can be described using the following CIDR notation : 128.8.0.0/16

c) The netmask of this subnet is 255.255.0.0

Question 2

4227072 + 2048 + 3232 + 23 = 4232375

b)&c)

CIDR-ized subnet

Masks

129.2.0.0/16

255.255.0.0

129.0.0.0/8

255.0.0.0

129.2.101.0/24

255.255.255.0

129.2.0.0/15

255.254.0.0

129.2.0.0/14

255.252.0.0

129.2.0.0/13

255.248.0.0

129.2.0.0/12

255.240.0.0