who likes cake? vlsm? •get maximum usage from your addresses •192.168.1.0/24 = 1 network – 254...
TRANSCRIPT
Why VLSM?
• Get maximum usage from your addresses
• 192.168.1.0/24 = 1 network – 254 hosts
• 192.168.1.0/26 = 4 subnets – 62 hosts
• 192.168.1.0/28 = 16 subnets – 14 hosts
BITS 128 64 32 16 8 4 2 1
Subnets
128
192
224
240
248
252
254
255
2-2
4
8
16
For working out which subnet a host is in
For working out how many subnets and hosts per subnet
BITS 128 64 32 16 8 4 2 1
Subnets
128
192
224
240
248
252
254
255 Subnets Hosts
2-2
4
8
16
32
64
4 subnets 64-2 so 62 hosts per subnet
Subnets Hosts
2-2
4
8
16
32
64
128
256
512
1024
2048
Example – 172.16.0.0 We need 60 subnets & 1000 hosts per subnet
BITS 128 64 32 16 8 4 2 1
Subnets
128
192
224
240
248
252
254
255
2-2
4
8
16
We have stolen 6 bits so mask is /22 (16+6) or 255.255.252.0
Change to 192.168.1.0/26
192.168.1.0/26 Subnet Hosts
192.168.1.0 1 62 hosts
192.168.1.64 2 62 hosts
192.168.1.128 3 62 hosts
192.168.1.192 4 62 hosts
Change to 192.168.1.0/26
192.168.1.0/26 Subnet
192.168.1.0 1 62 hosts
192.168.1.64 2 62 hosts
192.168.1.128 3 62 hosts
192.168.1.192 4 62 hosts
Change to 192.168.1.0/27
192.168.1.0/27 Subnet
192.168.1.0 1 30 hosts
192.168.1.32 2 30 hosts
192.168.1.64 Can’t Use