Subnetting Flashcards
What is a subnet mask?
Subnet mask—A 32-bit combination used to describe which portion of an address refers to the subnet and which part refers to the host.
(Cisco.com)
What are some benefits of subnetting?
- Smaller broadcast domains (broadcasts don’t disrupt as many devices).
- Easier to manage multiple smaller subnets than one large network.
- More efficient allocation of IPv4 addresses, which have become scarce.
- You can apply security policies more easily.
What is a subnet?
Subnet—A portion of a network sharing a particular subnet address.
(Cisco.com)
What is the equation for determining the number of subnets available for a given IP address/subnet mask combination?
2^x where x = the # of bits turned on in (or “borrowed” from) the host portion of the address
What is the equation for determining the number of host addresses available for a given IP address/subnet mask combination?
2^y - 2 where y = the number of off bits in the (default) host portion of the subnet mask.
How many subnetworks would be available on network 131.64.0.0 255.255.248.0?
32
131 = class B Class B IP's have a default mask of 16
255.255.248.0
=
1111111.11111111.11111000::
(/21)
5 bits are borrowed from the host portion.
2^5 = 32