Subnetting Speed Practice #3: Answers
This post makes no sense without reading this post first. The earlier post lists 5 subnetting problems, and tells you to time yourself. The answers are below the fold in this post. Don’t look til you try it for yourself! Post questions if you have them.
1) 9.200.200.200/15
2) 100.100.100.100/19
3) 151.151.151.151/23
4) 201.201.201.201/27
5) 223.223.221.221/30
| Problem | Network Bits | Subnet Bits | Host Bits | # Hosts |
|
1 |
8 |
7 |
17 |
131,070 |
|
2 |
8 |
11 |
13 |
8190 |
|
3 |
16 |
7 |
9 |
510 |
|
4 |
24 |
3 |
5 |
30 |
|
5 |
24 |
6 |
2 |
2 |
The following table lists the subnet ID and subnet broadcast address. It does not list the range of addresses; the range of usable addresses is simply the range of numbers between the subnet ID and subnet broadcast address.
| Problem | Subnet ID | Broadcast Address |
|
1 |
9.200.0.0 |
9.201.255.255 |
|
2 |
100.100.96.0 |
100.100.127.255 |
|
3 |
151.151.150.0 |
151.151.151.255 |
|
4 |
201.201.201.192 |
201.201.201.223 |
|
5 |
223.223.221.220 |
223.223.221.223 |
6 minutes for all 5. On average I find it takes me about a minutes if there’s an “interesting” octet. 45s otherwise. Thanks for posting these practice drills and questions – they are helpful in prepping for the CCENT.
You’re welcome, Gavin! Keep up the practice – even a 25% reduction in time required is a big help on exam day.
There is a mistake in the answer on Problem 2’s Network bit and Subnet bit – it’s class B network.
Sorry@ it’s class A )