TCP/IP Tutor!
Go to LAC for appointment!
Available Thursday 4:30 - 6:30 & Friday
11-12, 2-5pm
Remy (rpluscard@aol.com
)
Test is 10/5 (not next week!)
Homework is to do the practice (Class 3 Practice) with a default subnet mask and for class A use a custom subnet of 255.248.0.0, Class B: 255.255.248.0 and Class C 255.255.255.248 Also tell me how many networks I will create for each class and how many hosts/network.
Subnetting is breaking the network into smaller networks. You would do this for a number of reasons such as security or to lower traffic over a router.
Subnet Mask:
You divide up the remaining bits of
a subnet mask to use for a network ID (the zeros.)
Default subnet mask.
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A custom subnet mask for a class B network might be 255.255.252.0
I used the third octet (252) to divide up
my network. I used
| 11111111 = 255 |
| 11111110 = 254 |
| 11111100 = 252 |
| 11111000 = 248 |
| 11110000 = 240 |
| 11100000 = 224 |
| 11000000 = 192 |
| 10000000 = 128 |
I used 6 bits (1s) to divide up my network into smaller parts. To figure how many subnets we need use the formula 2 (power of n) -2 n is the number of 1s in the subnet mask n=6 gives you 62 subnets.
To figure how many hosts you will have with that subnet mask you 2 (power
of h) -2
h is the number of 00 in the subnet mask. We have 2 zeros
left in this octet plus 8 left in the last octet for a total of
10.
2 (power of 10) - 2 = 1022 hosts.
| 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1 |
| Class A | 122 | 28 | 32 | 244 |
| Class B | 129 | 219 | 222 | 250 |
| Class C | 192 | 21 | 33 | 214 |