What is another name for Classless Interdomain Routing (CIDR)?
A.
Subnetting
B.
Supernetting
C.
IP forwarding
D.
Multicasting
Explanation:
CIDR is a form of supernetting. It is essentially subnetting in reverse. In supernetting, or CIDR, we
combine subnets to make a larger network. Remember in subnetting, we take a network and slice
it up into subnet pieces. In Supernetting, we take pieces and splice them together to make a larger
address space. Now supernetting does require that certain rules be followed, since you can’t just
take any pieces and splice them. The subnets being combined must be contiguous, the number of
subnets being combined a power of two, and the first subnet should start at that power of two.
What is done in the CIDR/Supernetting is to drop back on the 1 bits in the subnet mask.
(Remember, in subnetting, we added 1 bits to the subnet mask).
Incorrect Answers:
A: AS explained in the answer, subnetting is essentially the opposite to supernetting, and
supernetting is the process for CIDR.
C: IP Forwarding is the process where the routing function passes an IP packet to the next hop. IP
addressing has to be considered during this process, but this is not an alternative name for CIDR.
D: Multicasting is a form of broadcasting where a specified group will receive the packets. In
reality, broadcasting is a special form of multicasting where in broadcasting – everyone gets the
packet. In either case, these are not related to CIDR.