fun with subnets
DESCRIPTION
Learn how to Subnet for IPV4 Computer NetworksTRANSCRIPT
-
FUN WITH SUBNETS ANDMORE FUN WITH SUBNET MASKS
-
Why Use Subnets?Reduce size of broadcast domains.Allow Network Administrators more Flexibility.Its just good clean fun!
-
Remember the IP Address?The NETWORK part of the IP is assigned by ARINThe HOST part of the IP is assigned by the network administrator.
-
To Create a Subnet:Network administrator chooses. Borrow (re-purpose) bits from the HOST.
-
Bits come from the HOSTs First OctetClass A will borrow from the 2nd Octet.Class B will borrow from the 3rd Octet.Class C will borrow from the 4th Octet.
-
Before subnetting (Class B):After subnetting (Class B):
-
Class C Example
-
Questions/StepsHow many subnets needed?What is the subnet mask?What is the IP in binary?Addresses in new subnet?
-
How many subnets needed for: IP 203.15.82.0 ? (Class A, B, or C?)
-
# of Subnets and Bits BorrowedCannot borrow < 2 bitsMust leave at least 2 bits
-
Borrowing bits: Available subnetsWhere n = # of bits borrowed2n 2 = total subnets available for use23 2 = 6 available subnets
-
Borrowing bits:Available hosts/subnetWhere n = # of bits borrowed from 4th octet28-n 2 = total hosts/subnet available for use25 2 = 30 available hosts/subnet--------------------------------------------------Borrow from 3rd octet? (16-n)Borrow from 2nd octet? (24-n)
-
Determine subnet maskThree bits borrowed for Class CBorrowed | Remaining 111 | 00000 = 8 bits in octetHigher end values of bits = 128 + 64 + 32 = 224Mask = 255.255.255.224
-
The subnets:000|(not available - network)001|(1st available)010|(2nd available)011|(3rd available)100|(4th available)
110|(last available)111|(not available broadcast)
-
Hosts on 1st available subnet 203.15.82.__ 001|00000 (not available network) .32001|00001 (1st available - gateway) .33001|00010 (2nd available 1st host) .34
001|11110 (last available host) .62001|11111 (not available broadcast) .63
-
Hosts on 2nd available subnet203.15.82.__010|00000 (not available network) .64010|00001 (1st available - gateway) .65010|00010 (2nd available 1st host) .66
010|11110 (last available host) .94010|11111 (not available broadcast) .95
-
Hosts on last available subnet203.15.82.__110|00000 (not available network) .192110|00001 (1st available - gateway) .193110|00010 (2nd available 1st host) .194
110|11110 (last available host) .222110|11111 (not available broadcast) .223
-
ANDing with subnet maskRouters do this to ROUTE to correct subnet address.YOU DO IT to verify your host addresses.IT WILL ALWAYS RETURN THE SUBNET ADDRESSWHEN DONE WITH ANY SUBNET HOST.
-
ANDingConvert IP address and subnet mask to binary:IP = 203.15.82.3311001011.00001111.01010010.00100001 Subnet Mask= 255.255.255.22411111111.11111111.11111111.11100000
-
ANDing demonstrated:H = 11001011.00001111.01010010.00100001 M = 11111111.11111111.11111111.11100000S = 11001011.00001111.01010010.00100000H = Host M = Subnet MaskS = Subnet address
-
Verify subnet address convert to dotted decimalS = 11001011.00001111.01010010.00100000S = 203.15.82.32
That should equal the subnet address!
-
Yes we are done!
-
I said We are done! Go Away!