D-Link DES-3326SR [200/240] Class a subnet masks

D-Link DES-3326SR Layer 3 Switch

Multiplying the number of subnets times the number of nodes gives 12,582,900 possible nodes.

Note that this is less than the 16,777,214 possible nodes that an unsubnetted class A network would have.

Subnetting reduces the number of possible nodes for a given network, but increases the segmentation of the network.

Classless Inter-Domain Routing – CIDR

Under CIDR, the subnet mask notation is reduced to a simplified shorthand. Instead of specifying all of the bits of the subnet

mask, it is simply listed as the number of contiguous “1”s (bits) in the network portion of the address. Look at the subnet

mask of the above example in binary - 11111111.11100000.00000000.00000000 – and you can see that there are 11 “1”s or

11 bits used to mask the network address from the node address. Written in CIDR notation this becomes: 10.32.0.0/11

Class A Subnet Masks

# of

Bits

Subnet Mask

CIDR

Notation

# of

Subnets

# of Hosts Total Hosts

2 255.192.0.0 /10 2 4194302 8388604

3 255.224.0.0 /11 6 2097150 12582900

4 255.240.0.0 /12 14 1048574 14680036

5 255.248.0.0 /13 30 524286 15728580

6 255.252.0.0 /14 62 262142 16252804

7 255.254.0.0 /15 126 131070 16514820

8 255.255.0.0 /16 254 65534 16645636

9 255.255.128.0 /17 510 32766

10 255.255.192.0 /18 1022 16382 16742404

11 255.255.224.0 /19 2046 8190 16756740

12 255.255.240.0 /20 4094 4094 16760836

13 255.255.248.0 /21 8190 2046 16756740

14 255.255.252.0 /22 16382 1022 16742404

15 255.255.254.0 /23 32766 510 16710660

16 255.255.255.0 /24 65534 254 16645636

17 255.255.255.128 /25 131070 126 16514820

18 255.255.255.192 /26 262142 62 16252804

19 255.255.255.224 /27 525286 30 15728580

20 255.255.255.240 /28 1048574 14 14680036

21 255.255.255.248 /29 2097150 6 12582900

22 255.255.255.252 /30 4194302 2 8388604

16710660

190