university networking assignment question

[ciprian97pop]

hey everyone

i have an assignment to make for my networking class but i'm stuck on something

i have to make a computer network for a business with 950 hosts

i've thought to make it an IT company that has the following structure: 600 hosts for the IT and programming department(500 hosts for desktops and a private wifi network for 100 laptops), 200 hosts for the marketing and hr department and another 150 hosts for public free wi-fi

the first step is to calculate the subnet mask, right? that's what i did

my subnet mask is 255.255.252.0 (because 2^9 is 512 which is not enough and 2^10 is 1024)

now here comes my question. I know that i can use 1024 ips which is more than enough for me but what interval of ip s can i use? 

at first I thought that i can use any kind of private ips(like 10.x.x.x or 177.(21-32).x.x or 192.168.x.x) but if I put in Cisco Packet Tracer(the program in which i have to exemplify the network) 10.0.0.1 as an ip for a pc, it changes my subnet mask to 255.0.0.0(that's what I remember changing it to). if i set the subnet mask first to 255.255.252.0 and then enter an ip it gives me an error and I cannot continue

Can you please tell me what am I doing wrong? and what is the ip interval that i can use

thank you

[LyyK]

Quote

at first I thought that i can use any kind of private ips(like 10.x.x.x or 177.(21-32).x.x or 192.168.x.x)

Your host address range should be 10.0.0.1 - 10.0.3.254

 

Mind being more specific regarding the error that is thrown?

PS: I don't have any experience with the software you're using but 10.0.0.1 with netmask 255.255.252.0 is written as 10.0.0.1/22, although I'm guessing that isn't your issue here. Keep in mind the difference between host and network addresses.

[ciprian97pop]

47 minutes ago, LyyK said:

Your host address range should be 10.0.0.1 - 10.0.3.254

 

Mind being more specific regarding the error that is thrown?

PS: I don't have any experience with the software you're using but 10.0.0.1 with netmask 255.255.252.0 is written as 10.0.0.1/22, although I'm guessing that isn't your issue here. Keep in mind the difference between host and network addresses.

got it

i've set the default gateway to 10.0.3.254. the subnet mask auto-filled to 255.255.0.0 but i was able to change it this time without a problem to 255.255.252.0 and i started giving ip addresses to pcs from 10.0.0.2 (because I gave 10.0.0.1 to the main router) and now it works.

thank you for your help

P.S.: should the default gateway be the last ip address of the inerval like I've set it to be? it's a question that i keet asking myself

[espurritado]

15 minutes ago, ciprian97pop said:

P.S.: should the default gateway be the last ip address of the inerval like I've set it to be? it's a question that i keet asking myself

No, the first and the last address in a subnet are reserved, that's why you only go from 10.0.0.1 to 10.0.3.254, 10.0.0.0 would be the subnet address and 10.0.3.255 would be the broadcast address.

Even then, the default gateway should be the address where you would go in case what you are looking for is not in your network. The default gateway has to be the address where you send the package to connect to a system in a different (but accessible network), the internet or any other network.

I'm guessing right now that it has to be you main router

[ciprian97pop]

25 minutes ago, espurritado said:

No, the first and the last address in a subnet are reserved, that's why you only go from 10.0.0.1 to 10.0.3.254 10.0.0.0 would be the subnet address and 10.0.3.255 would be the broadcast address.

Even then, the default gateaway should be the address where you would go in case what you are looking for is not in your network. The default gateaway has to be the address where you send the package to connect to a system in a different (but accessible network), the internet or any other network.

I'm guessing right now that it has to be you main router

my bad, by the last address i was thinking at x.x.x.254 and by first at x.x.x.1

in the router config i have a few tabs

the first tab is lan in which i have the routers ip address(192.168.0.1) 

the second tah is internet in which i have these boxes(see the screenshot below)

it's named wi fi free because i've got the same router set as the free wi-fi part of the network

if i set the default gateway like this, to the last address and the ip address as being the first one, on the pcs which shoud i put as the default gateway, the one with 254 at the end?

edit: in the screenshot the dg is .2.254 but i've changed it to .3.254

[leadeater]

Couple of points I'd like to make, but not sure if it's applicable to the assignment but the person making it would be hard pressed to not agree.

 

You should have different subnets for each part of your network, don't just use one large flat address range:

• Servers subnet
• Desktop/Workstation subnet
• Managed Wireless Subnet
• Guest Wireless subnet

You would also breakup the Desktop/Workstation in to more subnets if there were multiple buildings or even floors in a building where it would make sense, how you determent that isn't a fixed guideline though and that is up to the network architect to decide.

 

35 minutes ago, ciprian97pop said:

should the default gateway be the last ip address of the inerval like I've set it to be? it's a question that i keet asking myself

Some people do first and some do last it doesn't actually matter and could actually be anything in the range, personally I use the last IP in the range as it's the least likely to conflict with someones device that has a statically assigned address and they decide to plug it in to the network without consent. 

[leadeater]

Here's some other topics on IP addressing you might find helpful:

https://linustechtips.com/main/topic/668967-understanding-the-jist-between-cidr-and-vlsm

https://linustechtips.com/main/topic/599858-cidr-and-number/?do=findComment&comment=7808088

https://linustechtips.com/main/topic/611110-subnetting

https://linustechtips.com/main/topic/467455-subnet-masks-reborn/?do=findComment&comment=6365689

 

[ciprian97pop]

4 minutes ago, leadeater said:

Here's some other topics on IP addressing you might find helpful:

 

 

thank you for all the links and all the help from the previous post.

It would be logical to create different subnets for different parts of the network and for different building stories but thankfully the assignment doesn't have to be that complex. Yeah, it could be, but the extra points that I would be getting for doing that isn't worth the effort because te assignment has also an economical part which includes things like the cost of the whole operation, amortization of equipement and many others. this was just a part of it

thank you again for everyone's help

[leadeater]

13 minutes ago, ciprian97pop said:

thank you for all the links and all the help from the previous post.

It would be logical to create different subnets for different parts of the network and for different building stories but thankfully the assignment doesn't have to be that complex. Yeah, it could be, but the extra points that I would be getting for doing that isn't worth the effort because te assignment has also an economical part which includes things like the cost of the whole operation, amortization of equipement and many others. this was just a part of it

thank you again for everyone's help

Funnily enough it wouldn't actually increase the equipment cost since you would bring each network cabinet/stack back to a layer 3 switch which would do the routing etc, this would be the same physical layout as a flat IP range network. Separation between those subnets would be done using VLANs and is done on the edge layer 2 switches, a topic you'll be covering soon enough. 

 

But yes don't go creating yourself any extra work and make sure you answer what is being asked, there is actually a thing called being too smart and not answering the question .

 

Some of the topics I linked you to are a bit ahead of where you are up to, VLSM, but that material will be coming soon enough, plus some of it explains quite well how subnet masks actually work and breaks it down to binary which is necessary to truly understand and learn it. Once you do you never actually do that but it's very hard to grasp subnet masks if you've never done it.