We're computer guys right?? Help me figure out this subnetting question, please!

[BillGates]

It's kind of odd but here goes:

How many networks with a subnet mask of 255.255.255.128 can you divide a network with a subnet mask of 255.255.192.0 into?

11111111.11111111.11111111.10000000 <--- 255.255.255.128
11111111.11111111.11000000.00000000 <--- 255.255.192.0

This totally stumps me.... Help?

 

[BillGates]

71 minutes later and not one reply. Some technical crowd we have here.

 

[Jzero]

Is it a trick question?
Are we looking for the total number of subnets, or just how many subnets can you get out of *.192.0 ?
Didn't even know you could subnet subnets, but I guess....

Anyway, the number of subnets you can get out of *.192.0 is easy enough to determine.
The total number of subnets would, I think, be (*.192.0 subnets) * (*.128 subnets).
I think....It sounds right in my head, at least.

 

[BillGates]

Yeah, I am suspecting it is going to be a trick question. She did not even tell us whether it would be a Class A network or Class B network (couldn't work with a class C network)....

I have tons of charts, have looked at it in binary, and can't come up with anything. This is nuts. I want to play games, not think about this crap!

 

[Jzero]

Isn't the class implied by the subnet mask? 255.x.x.x = Class A, 255.255.x.x = Class B, 255.255.255.x=Class C
And I suppose now that i think of it, I suppose you could make many class C subnets within other Class B subnets.

Just sticking with 255.255.0.0 and 255.255.255.0. as masks and using theoretical IPs....

In the IP range 100.101.1.1-100.101.2.255, at a high level, an external router or some such device might see one class B subnet, but if each host had a 255.255.255.0 subnet mask, then they would be further broken down into a bunch of different class C subnets.

But I'm really just making this up b/c it's been 3 years since I last considered IP in this much detail

 

[BillGates]

The class *could* be implied by the subnet mask, in the real world, but in a classroom, anything goes. It could also be a class A subnet with a class B subnet, vice versa, or quite a few different combinations. What a pain. She is probably laughing her arse off thinking of the guys working on this stuff totally confused...

Thanks for the ideas though!

It gives me faith that there is one person here who actually knows HOW things work, not that "they just do" and also realize that there's a lot more to the internet than porn and video games.

Right?

...........

Guys?

 

[Jzero]

Originally posted by: billgates380
The class *could* be implied by the subnet mask, in the real world, but in a classroom, anything goes. It could also be a class A subnet with a class B subnet, vice versa, or quite a few different combinations. What a pain. She is probably laughing her arse off thinking of the guys working on this stuff totally confused...

If she's anything like the CS teachers I had that wrote those kind of questions, she's probably just a ditz and didn't even realize that perhaps she should have specified, but will somehow blame the students for not psychically guessing anyway.

It gives me faith that there is one person here who actually knows HOW things work, not that "they just do" and also realize that there's a lot more to the internet than porn and video games.

Right?

...........

Guys?

...........
uhhh.....
sure....
whate*fap*ver you s*fap*ay.