- Internet Assigned Numbers Authortiy (IANA)
-> formed to track and distribute IP addresses to those who need them
- American Registry for Internet Numbers (ARIN)
-> American region of the IANA
- broadcast: every computer on the LAN hears the message
- unicast: one computer on the LAN hears the message
- multicast: multiple computers on the LAN hear the message
CIDR Subnetting
- subnetting: taking a single class of IP addresses and chopping it up into multiple smaller groups
Subnetting
- enables more efficient use of IP addresses
- allows separation of a network for security
- can extend the subnet mask by adding more ones
- never subnet without converting to binary
- has two goals
-> efficiency and making multiple network IDs
Calculating Hosts
- 2^x - 2 = number of hosts
-> x = number of zeros in the subnet mask
Calculating Subnets
- start with a beginning subnet mask and extend the subnet extension as far as you need
- 2^y where y = number of bits you add to the subnet mask
Manual Dotted Decimal to Binary Conversion
- best way to convert is with a calculator
- start with 128 and divide the number in half all the way to 1
- the place the binary numbers under the values from dividing
- then add the decimal values that have a one underneath
- 128 64 32 16 8 4 2 1
1 0 0 1 0 1 1 0
128 + 16 + 4 + 2 = 150
Subnetting is a really important topic, and while I can see you take good notes, I can't tell from these notes whether you get the "gestalt" of what subnetting gives you. You essentially divide a single network segment into several smaller network segments by borrowing the high order host bits and turning them into low order network bits. Arlington County has a class B address (2**16 - 2 or 65,535 hosts if left undivided -- do you know why you loose 2, btw?). This is subnetted into a County LAN and an APS LAN, each of which are further subdivided.
ReplyDeleteI would encourage you to do a bit of outside reading (perhaps starting with Wikipedia - http://en.wikipedia.org/wiki/Subnetting - to give you more of the "big picture" of this extremely important topic, which your study guide, deep into the details as it is, may obscure.