?
Solved

Subnets and reserved addresses for a Class C network

Posted on 2003-11-05
4
Medium Priority
?
441 Views
Last Modified: 2010-04-11
Just a basic IPv4 question about subnets. Simply dealing with a Class C network, let's assume that we are on network segment 192.168.1.xxx. I understand that the IP address of 192.168.1.0 is reserved for representing the entire netowrk segment for devices such as routers. If we wanted to break our Class C LAN into 4 subnets using a subnet mask of 255.255.255.192, our subnets would then be broken down as follows:

Subnet 1: 192.168.1.0 - 192.168.1.63
Subnet 2: 192.168.1.64 - 192.168.1.127
Subnet 3: 192.168.1.128 - 192.168.1.191
Subnet 4: 192.168.1.192 - 192.168.1.255

I also understand that 192.168.1.255 is reserved for transmitting a signal to the entire segment. This is where my question lies: Is 192.168.1.255 used to transmit a signal to all computers on 192.168.1.xxx or does 192.168.1.63, 192.168.1.127, 192.168.1.191 become reserved for each subnet and are used to transmit to all computers on the corresponding subnet to which the belong? If that is true would we need a router attached to each subnet, or can each subnet access a single router on subnet 1, for example, on 192.168.1.1?

If I am way off with my defining of subnets as well please set me straight.

Thanks for your help!

0
Comment
Question by:ucalgaryj
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 43

Accepted Solution

by:
JFrederick29 earned 200 total points
ID: 9689735
Each subnet would have its own broadcast address: (Last Address in Subnet)

Broadcast Addresses:

Subnet 1: 192.168.1.63
Subnet 2: 192.168.1.127
Subnet 3: 192.168.1.191

Yes, you need a router to communicate between subnets.  You can use a single physical interface and create logical subinterfaces to achieve this without extra hardware.

So your subnets would be the following with a possible router/gateway address associated:

192.168.1.0
255.255.255.192
Gateway=192.168.1.1

192.168.1.64
255.255.255.192
Gateway=192.168.1.65

192.168.1.128
255.255.255.192
Gateway=192.168.1.129
0
 
LVL 43

Expert Comment

by:JFrederick29
ID: 9689782
You could also use the following subnet as long as your router supports it:

192.168.1.192
255.255.255.192
Gateway=192.168.1.193
0
 
LVL 2

Expert Comment

by:ihuckaby
ID: 9689835
In any subnet, the lowest address is your network address, and the highest address is your broadcast address.

After subnetting, a machine on subnet 1 would broadcast to 192.168.1.63, subnet 2 would broadcast to 192.168.1.127, etc.

After subnetting as you laid it out, 192.168.1.255 would only go out to subnet 4.

If you want to connect the subnets, you would need a router that is configured to be in each subnet (not a router for each subnet, but one that is connected to all of them.)

For example, if you have one router that has 192.168.1.1, 192.168.1.65, 192.168.1.129, and 192.168.1.193 all as interfaces, with the appropriate subnet connected to each interface:  THEN said router could transmit packets between the subnets.  That's what routers do, they connect different networks (and subnets are essentially different networks).

On a side note, just because you are asking about broadcasts. . .  Broadcasts are not routed under normal circumstances.  One of the primary purposes of subnetting is to limit the size of broadcast domains (a collection of all the devices that will hear a given broadcast).  Therefore, your broadcast address is not going to be able to connect to all four subnets, just the subnet on which it resides.

If you want all your machines to communicate through broadcast, then the easiest answer is not to subnet in the first place.

I'm not sure exactly what you're trying to accomplish, so I'm not sure if I've answered your underlying question.  Be happy to follow up if there's something I've left out.
0
 

Author Comment

by:ucalgaryj
ID: 9690290
Thanks for the reponse ihuckaby. JFrederick29 answered it first so I gave him credit, but thank you for the detail on broadcasts and how to configure the router. I actually teach a basic networking course at a univeristy and the question came up during lecture and I was unsure of the answer. Thanks again!
0

Featured Post

Create the perfect environment for any meeting

You might have a modern environment with all sorts of high-tech equipment, but what makes it worthwhile is how you seamlessly bring together the presentation with audio, video and lighting. The ATEN Control System provides integrated control and system automation.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

When you try to share a printer , you may receive one of the following error messages. Error message when you use the Add Printer Wizard to share a printer: Windows could not share your printer. Operation could not be completed (Error 0x000006…
This month, Experts Exchange’s free Course of the Month is focused on CompTIA IT Fundamentals.
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
Suggested Courses

771 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question