4
I am learning the basics of subnetting however am faced with a dilemma on approaching the issue. For example I have been tasked to set up a network with 20 hosts using a Class C network addressing scheme which I understand to be 192.168.0.0 with the default subnet mask of 255.255.255.0. Now I understand that it leaves me with 254 hosts 0 being the subnet and 255 being the broadcast.
So if I have 20 hosts to setup that leaves 234 host spaces wasted unless the network grows to include that many hosts. Based on the requirements of 20 hosts I have the following questions.
- How do I accommodate future growth e.g. how many hosts do I allow for?
- If I were to simply restrict the number of hosts to 20 I take it that would leave me with a /27 subnet i.e. 192.168.0.0/27. Is that right?
- If 2 point is correct I would have 8 subnets with the following network subnet address, broadcast addess and starting and ending host address. Is that right?
- If 3 is right do I still a router to allow each subnet to communicate with one another?
Subnet addresses
192.168.0.0
192.168.0.32
192.168.0.64
192.168.0.96
192.168.0.128
192.168.0.160
192.168.0.192
192.168.0.224
The broadcast address of each of these would be
192.168.0.31
192.168.0.63
192.168.0.95
192.168.0.127
192.168.0.159
192.168.0.191
192.168.0.223
The starting and ending host addresses for each of these would be
192.168.0.1 - 192.168.0.30
192.168.0.62 - 192.168.0.94
192.168.0.126 - 192.168.0.158
192.168.0.190 - 192.168.0.222
Unless I have understood it incorrectly my host addresses should be as follows as opposed to what I thought they were above
192.168.0.1 - 192.168.0.30
192.168.0.64 - 192.168.0.94
192.168.0.96 - 192.168.0.126
192.168.0.128 - 192.168.0.158
192.168.0.192 - 192.168.0.222
192.168.0.224 - 192.168.0.254
The fact you refer to it as a Class C network addressing schemes tells me this is homework.... – Supercereal – 2011-10-25T21:24:15.707
@Kyle - Actually no. This is a real network deployment I have been asked to implement as part of my internship – PeanutsMonkey – 2011-10-25T21:54:47.927
@Kyle - Out of interest, what is wrong calling it as a Class C network? Almost very book I have read refers to Classes – PeanutsMonkey – 2011-10-25T21:57:39.843
1It's not wrong, but this classification is somehow outdated and used in academic context, because you're able to divide in other subnetwork sizes than these classes. See you /27-network above! – Jens Erat – 2011-10-25T22:58:22.030
.1-.30 is correct, .33-.62 is missing, then .65-.94, .97-.126 and so on. You always forgot the "network address" I guess (apart from the first subnet). – Jens Erat – 2011-10-26T09:39:05.453
1@PeanutsMonkey Nothing in particular is wrong with the phrasing. It's just very rare (I have never seen it) for someone refer to a network as class c outside of a school since classless inter-domain routing was introduced in 93 over 15 years ago... – Supercereal – 2011-10-26T12:31:52.807