Assignment
For this assignment paraphrase the following-
1. We are considering class B network beginning with 172.0.0.0.0,Converting this value to binary as:10101100.00010100.00000000.00000000 Totally 32 bits,Out of this the First 16 bits are used as network ID and next 16 bits are used as HostID.Out of the 16 bits sued for Network ID the 2 bits namely Bits 15, 16 are set and can't be changed and hence only 14 bits are used as network ID.Thus from your above problem statement in case you need 50 subnets you need to change 6 bits in the Network ID to give 50 unique subnets.
2. Since you require 50 subnets you need to change 6 bits from the total 16 bits of the host portion. You have already used 6 bits to create 50 subnets (actually changing 6 bits gives 64 subnets). Similarly changing all 16 bits from the host portion and adding it to network ID will give you 2 power 14(since other 2 bits cannot be used), Hence 2 power 14 will give us 16,384 unique subnets out of which 50 are already created and are being used. Thus 16,384-50 =16,334 unique subnets can be created in future for expansion.
3. The new subnet mask starts with 172.20.0.0/24, Hence the first subnet mask will be 172.0.0.0,Second one will be 172.20.1.0 and so on till 24.
4. Classless Inter-Domain Routing, or CIDR, is an alternative to traditional subletting. With CIDR you can add a specification in the IP address itself. For the network above 172.20.0.0/24 is the CIDR notation
5. The broadcast address of the subnet for the host at 172.20.6.139 is 172.20.6.255 since 255 is the highest.
6. Following the explanation mentioned above 172.20.11.250 host belongs to subnet 172.20.11.0 and host 172.20.6.255 host belong to subnet 172.20.6.0 hence both these hosts belong to different subnets. Since the value for host 172.20.11.250(11) specifies that it belongs to subnet 172.20.11.0 and 172.20.6.255(6) specifies that it belong to subnet 172.20.6.0.