Subnetting rook. Please help! I am gonna have a heart attack!

[whiteheight]

my network has 12 segments. My internal network address is 192.168.x.0. The network is non RFC compliant. How do I determine all subnet addys and available host addys for the whole internal network. I have 74 PC's, 7 hubs, and 4 routers. This is a school project, and I am begining to have a heart attack, because I am very new to this stuff. ... ---......---......---......---......---......---......---......--- SOS.
Thanks a mint if any of you can figure this one out.
b

 

[BradSQLGuy]

Your subnet mask is going to be
255.255.240.0 since you need 12 networks that subnet will give you 16 which is the lowest possible to support your needs.

Your range of addresses for each network will be:

192.168.12.x 1-254
192.168.13.x 1-254
192.168.14.x 1-254
192.168.15.x 1-254
192.168.16.x 1-254
and so on until you reach
192.168.28.x

 

[BradSQLGuy]

If you have any questions or problems getting it set up ask.

 

[jimbopalmer]

Do you mean you have 12 values for x? if so all the subnet masks are 255.255.255.0, unless you are attempting to aggregate routes, which with 12 subnets is not that worthwhile.

if you are asking for advice how to number subnets and devices to keep them straight, I can offer this advice:

Make all the user router ports .1 so you PC techs always get the same subnet mask and gateway address. (I reserve all the single digit IP addresses for infrastructure devices)

Number the four routers, then make x the two routers each routed subnet connects. So 192.168.14.1 connects to 192.168.14.4 when router 1 connects to router 4

use x > 100 for user subnets, make the second digit the Router number they use as a gateway so 192.168.141.1 is the main subnet on router 4's gateway

this embeds a great deal of topology into the naming structure, makes it easy to aggregate routes it the future, and simplifies the PC tech's life.
I tried to remain child-like, all I acheived was childish.

 

[whiteheight]

Thank you so much guys. My heart is back to normal. This site is so dope and I will definately be here often.
Peace from Canada.
b

 

[BradSQLGuy]

Sorry I hope you get this. Your subnet mask needs to be 255.255.255.240. I apologize I thought you were using a class B for some reason.

 

[BradSQLGuy]

Okay let me start over. I am sorry it has been 3 years since I've had to set this up.

Here is your formula. Keep within the range on each specified network and the computers will be able to communicate.

1st network -> 192.168.1-15.1-254 <--- any range will be on one network.
2nd network -> 192.168.17-31.1-254 <---any range will be on your next network.
3rd network -> 192.168.33-46.1-254
4th network -> 192.168.49-62.1-254
5th network -> 192.168.65-78.1-254
6th network -> 192.168.81-95.1-254
7th -> 192.168.98-111.1-254
8th -> 192.168.114-127.1-254
9th -> 192.168.129-143.1-254
10th-> 192.168.146-159.1-254
11th-> 192.168.162-175.1-254
12th-> 192.168.177-191.1-254
13th-> 192.168.194-207.1-254 <---if needed
14th-> 192.168-209-223.1-254
15th-> 192.168.226-239.1-254
16th-> 192.168.241-254.1-254 <--and finally the 16th.

This is actually a B class address the school has. You need to have your subnet be 255.255.240.0 I was correct the first time on that. If you have any questions let me know.

 

[CCIEWANNABE]

IP Address : 192.168.0.0
Address Class: C
Network Address: 192.168.0.0
Subnet Address : 192.168.0.0
Subnet Mask : 255.255.255.128
Subnet bit mask : 110nnnnn.nnnnnnnn.nnnnnnnn.nhhhhhhh
Subnet Bits : 25
Host Bits : 7
Possible Number of Subnets: 2
Hosts per Subnet: 126

Selected Subnet : 192.168.0.128 255.255.255.128
Usable Addresses: 126
Host range : 192.168.0.129 to 192.168.0.254
Broadcast : 192.168.0.255



IP Address: 192.168.0.0
Address Class : C
Network Address : 192.168.0.0

Subnet Address: 192.168.0.0
Subnet Mask: 255.255.255.128
Subnet bit mask: 110nnnnn.nnnnnnnn.nnnnnnnn.nhhhhhhh
Subnet Bits : 25
Host Bits : 7
Possible Number of Subnets : 2
Hosts per Subnet : 126

Selected Subnet : 192.168.0.0 255.255.255.128
Usable Addresses : 126
Host range : 192.168.0.1 to 192.168.0.126
Broadcast : 192.168.0.127

Subnet Mask 255.255.255.192 cannot accommodates 72 hosts Must use Subnet Mask 255.255.255.128. You will require 7 bits for hosts; unless host are broken up equally into separate segments etc.

Subnet Address>>>>>>> Hosts From>>>>>>> Hosts To>>>>>>>>>>Broadcast Address
192.168.0.0>>>>>>>>>>>192.168.0.0>>>>>>>>>192.168.0.254>>>>>>192.168.0.255
192.168.0.128>>>>>>>>>192.168.0.129>>>>>>>192.168.0.254>>>>>>192.168.0.255


Route once; switch many

 

[ChrisAC]

If your inside network is using the 192.168.x.0 address range (non-legal) then why bother using daft subnets. If you're gonna split your network up then make each network a /24.

192.168.1.1-254 /24
192.168.2.1-254 /24

etc....

Easy! Don't complicate stuff that can be kept simple!

Chris.
************************
Chris Andrew, CCNA
chrisac@gmx.co.uk
************************

 

[Dmasch]

Say you have
Network1
192.168.1.1 IP
255.255.255.0 subnet
192.168.1.254 router
Network2
192.168.2.1 IP
255.255.255.0 subnet
192.168.2.254 router

Can I get these two networks to connect with the settings that I have? I am not sure bout the subnets. Any suggestions

 

[CCIEWANNABE]

IP Address : 192.168.1.1
Address Class : C
Network Address : 192.168.1.0

Subnet Address : 192.168.1.0
Subnet Mask : 255.255.255.0
Subnet bit mask : 110nnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh
Subnet Bits : 24
Host Bits : 8
Possible Number of Subnets : 1
Hosts per Subnet : 254

Selected Subnet : 192.168.1.0/255.255.255.0
Usable Addresses : 254
Host range : 192.168.1.1 to 192.168.1.254
Broadcast : 192.168.1.255
IP Address : 192.168.2.1
Address Class : C
Network Address : 192.168.2.0

Subnet Address : 192.168.2.0
Subnet Mask : 255.255.255.0
Subnet bit mask : 110nnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh
Subnet Bits : 24
Host Bits : 8
Possible Number of Subnets : 1
Hosts per Subnet : 254

Selected Subnet : 192.168.2.0/255.255.255.0
Usable Addresses : 254
Host range : 192.168.2.1 to 192.168.2.254
Broadcast : 192.168.2.255

Bad design wont allow allow for future growth. Subnetting is a Technique used to allow a single IP network address to span multiple physical networks. How will you further subnet a network in the future. Would work though

Route once; switch many

 

[ChrisAC]

If it's a private network range then you can add as many subnets as you need and or subnet the range any way you see fit. It's not as though you'd run short of RFC1918 addresses is it?? If you want to add more /24 networks then you can. If you want to subnet a /24 down you can!

Going back to the original question by whiteheight, if you've got 74 PC's, 7 hubs and 4 routers, great, but how do you want your network subnetting? Is it a single logical network, two networks, three ....? As you will have seen, you've got a lot of choice as to how you address it, but it all depends on what you are trying to achieve.

Chris.
************************
Chris Andrew, CCNA
chrisac@gmx.co.uk
************************