Routing TCP[s]IP (Vol. 11998)

If the first four bits of a class D address are 1110, the lowest first octet is 11100000 and the highest first octet is 11101111. In decimal these two numbers are 224 and 239, respectively. Therefore, the first octet of a class D address will range from 224 to 239.

(a) Enough subnet bits n are needed so that 2 ⁿ - 2 >= 16,000. There must be enough host bits h remaining so that 2 ^h - 2 >= 700. A subnet mask of 255.255.252.0 provides 16,382 subnets of the class A address, and 1022 host addresses on each subnet. This mask is the only one that works. If one more bit is used for subnetting (255.255.254.0), there will not be enough host addresses. If one less bit is used for subnetting (255.255.248.0), there will not be enough subnets.

(b) Enough subnet bits n are needed so that 2 ⁿ - 2 >= 500. Enough host bits h must remain so that 2 ^h - 2 >= 100. A subnet mask of 255.255.255.128 provides 510 subnets of the class B address and 126 host addresses on each subnet. Again, this mask is the only one that works.

With six bits of subnetting, a class C address will have 2 ⁶ “ 2 = 62 subnets and 2 ² “ 2 = 2 host addresses per subnet. With this subnetting scheme, a single class C address can be used for 62 point-to-point links. A point-to-point link requires only two host addresses ”one for each end of the link.

A class C address with a 28-bit mask will have 14 subnets and 14 host addresses on each subnet. The subnets are derived first.

The subnets are:

111111111111111111111111 1111 0000= 255.255.255.240 (mask) 110000001010100010010011 0001 0000=192.168.147.16 110000001010100010010011 0010 0000=192.168.147.32 110000001010100010010011 0011 0000=192.168.147.48 110000001010100010010011 0100 0000=192.168.147.64 110000001010100010010011 0101 0000=192.168.147.80 110000001010100010010011 0110 0000=192.168.147.96 110000001010100010010011 0111 0000=192.168.147.112 110000001010100010010011 1000 0000=192.168.147.128 110000001010100010010011 1001 0000=192.168.147.144 110000001010100010010011 1010 0000=192.168.147.160 110000001010100010010011 1011 0000=192.168.147.176 110000001010100010010011 1100 0000=192.168.147.192 110000001010100010010011 1101 0000=192.168.147.208 110000001010100010010011 1110 0000=192.168.147.224

Next, the host addresses for each subnet are derived. The broadcast addresses for each subnet are also shown.

The host addresses for each subnet are:

110000001010100010010011 0001 0000=192.168.147.16(subnet) 110000001010100010010011 0001 0001=192.168.147.17 110000001010100010010011 0001 0010=192.168.147.18 110000001010100010010011 0001 0011=192.168.147.19 110000001010100010010011 0001 0100=192.168.147.20 110000001010100010010011 0001 0101=192.168.147.21 110000001010100010010011 0001 0110=192.168.147.22 110000001010100010010011 0001 0111=192.168.147.23 110000001010100010010011 0001 1000=192.168.147.24 110000001010100010010011 0001 1001=192.168.147.25 110000001010100010010011 0001 1010=192.168.147.26 110000001010100010010011 0001 1011=192.168.147.27 110000001010100010010011 0001 1100=192.168.147.28 110000001010100010010011 0001 1101=192.168.147.29 110000001010100010010011 0001 1110=192.168.147.30 110000001010100010010011 0001 1111 = 192.168.147.31(broadcast) 110000001010100010010011 0010 0000=192.168.147.32(subnet) 110000001010100010010011 0010 0001=192.168.147.33 110000001010100010010011 0010 0010=192.168.147.34 110000001010100010010011 0010 0011=192.168.147.35 110000001010100010010011 0010 0100=192.168.147.36 110000001010100010010011 0010 0101=192.168.147.37 110000001010100010010011 0010 0110=192.168.147.38 110000001010100010010011 0010 0111=192.168.147.39 110000001010100010010011 0010 1000=192.168.147.40 110000001010100010010011 0010 1001=192.168.147.41 110000001010100010010011 0010 1010=192.168.147.42 110000001010100010010011 0010 1011=192.168.147.43 110000001010100010010011 0010 1100=192.168.147.44 110000001010100010010011 0010 1101=192.168.147.45 110000001010100010010011 0010 1110=192.168.147.46 110000001010100010010011 0010 1111 = 192.168.147.47 (broadcast) 110000001010100010010011 0011 0000=192.168.147.48(subnet) 110000001010100010010011 0011 0001=192.168.147.49 110000001010100010010011 0011 0010=192.168.147.50 110000001010100010010011 0011 0011=192.168.147.51 110000001010100010010011 0011 0100=192.168.147.52 110000001010100010010011 0011 0101=192.168.147.53 110000001010100010010011 0011 0110=192.168.147.54 110000001010100010010011 0011 0111=192.168.147.55 110000001010100010010011 0011 1000=192.168.147.56 110000001010100010010011 0011 1001=192.168.147.57 110000001010100010010011 0011 1010=192.168.147.58 110000001010100010010011 0011 1011=192.168.147.59 110000001010100010010011 0011 1100=192.168.147.60 110000001010100010010011 0011 1101=192.168.147.61 110000001010100010010011 0011 1110=192.168.147.62 110000001010100010010011 0011 1111 = 192.168.147.63 (broadcast) 110000001010100010010011 0100 0000=192.168.147.64(subnet) 110000001010100010010011 0100 0001=192.168.147.65 110000001010100010010011 0100 0010=192.168.147.66 110000001010100010010011 0100 0011=192.168.147.67 110000001010100010010011 0100 0100=192.168.147.68 110000001010100010010011 0100 0101=192.168.147.69 110000001010100010010011 0100 0110=192.168.147.70 110000001010100010010011 0100 0111=192.168.147.71 110000001010100010010011 0100 1000=192.168.147.72 110000001010100010010011 0100 1001=192.168.147.73 110000001010100010010011 0100 1010=192.168.147.74 110000001010100010010011 0100 1011=192.168.147.75 110000001010100010010011 0100 1100=192.168.147.76 110000001010100010010011 0100 1101=192.168.147.77 110000001010100010010011 0100 1110=192.168.147.78 110000001010100010010011 0100 1111 = 192.168.147.79 (broadcast) 110000001010100010010011 0101 0000=192.168.147.80(subnet) 110000001010100010010011 0101 0001=192.168.147.81 110000001010100010010011 0101 0010=192.168.147.82 110000001010100010010011 0101 0011=192.168.147.83 110000001010100010010011 0101 0100=192.168.147.84 110000001010100010010011 0101 0101=192.168.147.85 110000001010100010010011 0101 0110=192.168.147.86 110000001010100010010011 0101 0111=192.168.147.87 110000001010100010010011 0101 1000=192.168.147.88 110000001010100010010011 0101 1001=192.168.147.89 110000001010100010010011 0101 1010=192.168.147.90 110000001010100010010011 0101 1011=192.168.147.91 110000001010100010010011 0101 1100=192.168.147.92 110000001010100010010011 0101 1101=192.168.147.93 110000001010100010010011 0101 1110=192.168.147.94 110000001010100010010011 0101 1111 = 192.168.147.95 (broadcast) 110000001010100010010011 0110 0000=192.168.147.96(subnet) 110000001010100010010011 0110 0001=192.168.147.97 110000001010100010010011 0110 0010=192.168.147.98 110000001010100010010011 0110 0011=192.168.147.99 110000001010100010010011 0110 0100=192.168.147.100 110000001010100010010011 0110 0101=192.168.147.101 110000001010100010010011 0110 0110=192.168.147.102 110000001010100010010011 0110 0111=192.168.147.103 110000001010100010010011 0110 1000=192.168.147.104 110000001010100010010011 0110 1001=192.168.147.105 110000001010100010010011 0110 1010=192.168.147.106 110000001010100010010011 0110 1011=192.168.147.107 110000001010100010010011 0110 1100=192.168.147.108 110000001010100010010011 0110 1101=192.168.147.109 110000001010100010010011 0110 1110=192.168.147.110 110000001010100010010011 0110 1111 = 192.168.147.111 (broadcast) 110000001010100010010011 0111 0000=192.168.147.112(subnet) 110000001010100010010011 0111 0001=192.168.147.113 110000001010100010010011 0111 0010=192.168.147.114 110000001010100010010011 0111 0011=192.168.147.115 110000001010100010010011 0111 0100=192.168.147.116 110000001010100010010011 0111 0101=192.168.147.117 110000001010100010010011 0111 0110=192.168.147.118 110000001010100010010011 0111 0111=192.168.147.119 110000001010100010010011 0111 1000=192.168.147.120 110000001010100010010011 0111 1001=192.168.147.121 110000001010100010010011 0111 1010=192.168.147.122 110000001010100010010011 0111 1011=192.168.147.123 110000001010100010010011 0111 1100=192.168.147.124 110000001010100010010011 0111 1101=192.168.147.125 110000001010100010010011 0111 1110=192.168.147.126 110000001010100010010011 0111 1111 = 192.168.147.127 (broadcast) 110000001010100010010011 1000 0000=192.168.147.128(subnet) 110000001010100010010011 1000 0001=192.168.147.129 110000001010100010010011 1000 0010=192.168.147.130 110000001010100010010011 1000 0011=192.168.147.131 110000001010100010010011 1000 0100=192.168.147.132 110000001010100010010011 1000 0101=192.168.147.133 110000001010100010010011 1000 0110=192.168.147.134 110000001010100010010011 1000 0111=192.168.147.135 110000001010100010010011 1000 1000=192.168.147.136 110000001010100010010011 1000 1001=192.168.147.137 110000001010100010010011 1000 1010=192.168.147.138 110000001010100010010011 1000 1011=192.168.147.139 110000001010100010010011 1000 1100=192.168.147.140 110000001010100010010011 1000 1101=192.168.147.141 110000001010100010010011 1000 1110=192.168.147.142 110000001010100010010011 1000 1111 = 192.168.147.143 (broadcast) 110000001010100010010011 1001 0000=192.168.147.144(subnet) 110000001010100010010011 1001 0001=192.168.147.145 110000001010100010010011 1001 0010=192.168.147.146 110000001010100010010011 1001 0011=192.168.147.147 110000001010100010010011 1001 0100=192.168.147.148 110000001010100010010011 1001 0101=192.168.147.149 110000001010100010010011 1001 0110=192.168.147.150 110000001010100010010011 1001 0111=192.168.147.151 110000001010100010010011 1001 1000=192.168.147.152 110000001010100010010011 1001 1001=192.168.147.153 110000001010100010010011 1001 1010=192.168.147.154 110000001010100010010011 1001 1011=192.168.147.155 110000001010100010010011 1001 1100=192.168.147.156 110000001010100010010011 1001 1101=192.168.147.157 110000001010100010010011 1001 1110=192.168.147.158 110000001010100010010011 1001 1111 = 192.168.147.159 (broadcast) 110000001010100010010011 1010 0000=192.168.147.160(subnet) 110000001010100010010011 1010 0001=192.168.147.161 110000001010100010010011 1010 0010=192.168.147.162 110000001010100010010011 1010 0011=192.168.147.163 110000001010100010010011 1010 0100=192.168.147.164 110000001010100010010011 1010 0101=192.168.147.165 110000001010100010010011 1010 0110=192.168.147.166 110000001010100010010011 1010 0111=192.168.147.167 110000001010100010010011 1010 1000=192.168.147.168 110000001010100010010011 1010 1001=192.168.147.169 110000001010100010010011 1010 1010=192.168.147.170 110000001010100010010011 1010 1011=192.168.147.171 110000001010100010010011 1010 1100=192.168.147.172 110000001010100010010011 1010 1101=192.168.147.173 110000001010100010010011 1010 1110=192.168.147.174 110000001010100010010011 1010 1111 = 192.168.147.175 (broadcast) 110000001010100010010011 1011 0000=192.168.147.176(subnet) 110000001010100010010011 1011 0001=192.168.147.177 110000001010100010010011 1011 0010=192.168.147.178 110000001010100010010011 1011 0011=192.168.147.179 110000001010100010010011 1011 0100=192.168.147.180 110000001010100010010011 1011 0101=192.168.147.181 110000001010100010010011 1011 0110=192.168.147.182 110000001010100010010011 1011 0111=192.168.147.183 110000001010100010010011 1011 1000=192.168.147.184 110000001010100010010011 1011 1001=192.168.147.185 110000001010100010010011 1011 1010=192.168.147.186 110000001010100010010011 1011 1011=192.168.147.187 110000001010100010010011 1011 1100=192.168.147.188 110000001010100010010011 1011 1101=192.168.147.189 110000001010100010010011 1011 1110=192.168.147.190 110000001010100010010011 1011 1111 = 192.168.147.191 (broadcast) 11000000101010001001001111000000=192.168.147.192(subnet) 110000001010100010010011 1100 0001=192.168.147.193 110000001010100010010011 1100 0010=192.168.147.194 110000001010100010010011 1100 0011=192.168.147.195 110000001010100010010011 1100 0100=192.168.147.196 110000001010100010010011 1100 0101=192.168.147.197 110000001010100010010011 1100 0110=192.168.147.198 110000001010100010010011 1100 0111=192.168.147.199 110000001010100010010011 1100 1000=192.168.147.200 110000001010100010010011 1100 1001=192.168.147.201 110000001010100010010011 1100 1010=192.168.147.202 110000001010100010010011 1100 1011=192.168.147.203 110000001010100010010011 1100 1100=192.168.147.204 110000001010100010010011 1100 1101=192.168.147.205 110000001010100010010011 1100 1110=192.168.147.206 110000001010100010010011 1100 1111 = 192.168.147.207 (broadcast) 11000000101010001001001111010000=192.168.147.208(subnet) 110000001010100010010011 1101 0001=192.168.147.209 110000001010100010010011 1101 0010=192.168.147.210 110000001010100010010011 1101 0011=192.168.147.211 110000001010100010010011 1101 0100=192.168.147.212 110000001010100010010011 1101 0101=192.168.147.213 110000001010100010010011 1101 0110=192.168.147.214 110000001010100010010011 1101 0111=192.168.147.215 110000001010100010010011 1101 1000=192.168.147.216 110000001010100010010011 1101 1001=192.168.147.217 110000001010100010010011 1101 1010=192.168.147.218 110000001010100010010011 1101 1011=192.168.147.219 110000001010100010010011 1101 1100=192.168.147.220 110000001010100010010011 1101 1101=192.168.147.221 110000001010100010010011 1101 1110=192.168.147.222 110000001010100010010011 1101 1111 = 192.168.147.223 (broadcast) 11000000101010001001001111100000=192.168.147.224(subnet) 110000001010100010010011 1110 0001=192.168.147.225 110000001010100010010011 1110 0010=192.168.147.226 110000001010100010010011 1110 0011=192.168.147.227 110000001010100010010011 1110 0100=192.168.147.228 110000001010100010010011 1110 0101=192.168.147.229 110000001010100010010011 1110 0110=192.168.147.230 110000001010100010010011 1110 0111=192.168.147.231 110000001010100010010011 1110 1000=192.168.147.232 110000001010100010010011 1110 1001=192.168.147.233 110000001010100010010011 1110 1010=192.168.147.234 110000001010100010010011 1110 1011=192.168.147.235 110000001010100010010011 1110 1100=192.168.147.236 110000001010100010010011 1110 1101=192.168.147.237 110000001010100010010011 1110 1110=192.168.147.238 110000001010100010010011 1110 1111 = 192.168.147.239 (broadcast)

This solution shows a shorter technique than the last solution in which every host address of every subnet was written out.

A class C address with a 29-bit mask means that there will be 30 subnets and six host addresses on each subnet.

The subnets are:

111111111111111111111111 11111 000= 255.255.255.248 (mask) 110000001010100010010011 00001 000=192.168.147.8 110000001010100010010011 00010 000=192.168.147.16 110000001010100010010011 00011 000=192.168.147.24 110000001010100010010011 00100 000=192.168.147.32 110000001010100010010011 00101 000=192.168.147.40 110000001010100010010011 00110 000=192.168.147.48 110000001010100010010011 00111 000=192.168.147.56 110000001010100010010011 01000 000=192.168.147.64 110000001010100010010011 01001 000=192.168.147.72 110000001010100010010011 01010 000=192.168.147.80 110000001010100010010011 01011 000=192.168.147.88 110000001010100010010011 01100 000=192.168.147.96 110000001010100010010011 01101 000=192.168.147.104 110000001010100010010011 01100 000=192.168.147.112 110000001010100010010011 01111 000=192.168.147.120 110000001010100010010011 10000 000=192.168.147.128 110000001010100010010011 10001 000=192.168.147.136 110000001010100010010011 10010 000=192.168.147.144 110000001010100010010011 10011 000=192.168.147.152 110000001010100010010011 10100 000=192.168.147.160 110000001010100010010011 10101 000=192.168.147.168 110000001010100010010011 10110 000=192.168.147.176 110000001010100010010011 10111 000=192.168.147.184 110000001010100010010011 11000 000=192.168.147.192 110000001010100010010011 11001 000=192.168.147.200 110000001010100010010011 11010 000=192.168.147.208 110000001010100010010011 11011 000=192.168.147.216 110000001010100010010011 11100 000=192.168.147.224 110000001010100010010011 11101 000=192.168.147.232 110000001010100010010011 11110 000=192.168.147.240

Next, the broadcast addresses of each subnet are derived by setting the host bits of each subnet to all ones.

The subnet broadcast addresses are:

110000001010100010010011 00001 111=192.168.147.15 110000001010100010010011 00010 111=192.168.147.23 110000001010100010010011 00011 111=192.168.147.31 110000001010100010010011 00100 111=192.168.147.39 110000001010100010010011 00101 111=192.168.147.47 110000001010100010010011 00110 111=192.168.147.55 110000001010100010010011 00111 111=192.168.147.63 110000001010100010010011 01000 111=192.168.147.71 110000001010100010010011 01001 111=192.168.147.79 110000001010100010010011 01010 111=192.168.147.87 110000001010100010010011 01011 111=192.168.147.95 110000001010100010010011 01100 111=192.168.147.103 110000001010100010010011 01101 111=192.168.147.111 110000001010100010010011 01100 111=192.168.147.119 110000001010100010010011 01111 111=192.168.147.127 110000001010100010010011 10000 111=192.168.147.135 110000001010100010010011 10001 111=192.168.147.143 110000001010100010010011 10010 111=192.168.147.151 110000001010100010010011 10011 111=192.168.147.159 110000001010100010010011 10100 111=192.168.147.167 110000001010100010010011 10101 111=192.168.147.175 110000001010100010010011 10110 111=192.168.147.183 110000001010100010010011 10111 111=192.168.147.191 110000001010100010010011 11000 111=192.168.147.199 110000001010100010010011 11001 111=192.168.147.207 110000001010100010010011 11010 111=192.168.147.215 110000001010100010010011 11011 111=192.168.147.223 110000001010100010010011 11100 111=192.168.147.231 110000001010100010010011 11101 111=192.168.147.239 110000001010100010010011 11110 111=192.168.147.247

Finally, the host addresses for each subnet are derived. They will be all addresses between the subnet addresses and the subnet broadcast addresses.

A class B address with a 20-bit mask will have 14 subnets and 4,094 host addresses on each subnet.

The subnets are:

1111111111111111 1111 000000000000 = 255.255.240.0 (mask) 1010110000010000 0001 000000000000=172.16.16.0 1010110000010000 0010 000000000000=172.16.32.0 1010110000010000 0011 000000000000=172.16.48.0 1010110000010000 0100 000000000000=172.16.64.0 1010110000010000 0101 000000000000=172.16.80.0 1010110000010000 0110 000000000000=172.16.96.0 1010110000010000 0111 000000000000=172.16.112.0 1010110000010000 1000 000000000000=172.16.128.0 1010110000010000 1001 000000000000=172.16.144.0 1010110000010000 1010 000000000000=172.16.160.0 1010110000010000 1011 000000000000=172.16.176.0 1010110000010000 1100 000000000000=172.16.192.0 1010110000010000 1101 000000000000=172.16.208.0 1010110000010000 1110 000000000000=172.16.224.0

The subnet broadcast addresses are:

1010110000010000 0001 111111111111=172.16.31.255 1010110000010000 0010 111111111111=172.16.47.255 1010110000010000 0011 111111111111=172.16.63.255 1010110000010000 0100 111111111111=172.16.79.255 1010110000010000 0101 111111111111=172.16.95.255 1010110000010000 0110 111111111111=172.16.111.255 1010110000010000 0111 111111111111=172.16.127.255 1010110000010000 1000 111111111111=172.16.143.255 1010110000010000 1001 111111111111=172.16.159.255 1010110000010000 1010 111111111111=172.16.175.255 1010110000010000 1011 111111111111=172.16.191.255 1010110000010000 1100 111111111111=172.16.207.255 1010110000010000 1101 111111111111=172.16.223.255 1010110000010000 1110 111111111111=172.16.239.255

Using the derived subnet and broadcast addresses, the host addresses are: