Need help from network gurus!!!

[mikysee]

This isn't a question about setting up a network, this is a difficult networking question.
Can anyone please help me? The questions are:

1. For the Class C network 192.168.220.0, what subnet mask supports up to 14 subnets?

a) 255.255.255.252
b) 255.255.255.248
c) 255.255.255.240
d) 255.255.255.224

2. For the Class C network mask for 195.168.220.0 described in Question 1, how many hosts are available per subnet?

a) 2
b) 6
c) 14
d) 30

Can you give a short explanation to how you got the answer too? Thanks for any help. 🙂

 

[spidey07]

<< 1. For the Class C network 192.168.220.0, what subnet mask supports up to 14 subnets?

a) 255.255.255.252
b) 255.255.255.248
c) 255.255.255.240
d) 255.255.255.224
>>


14 subnets - round up to 16. 256-16=240. 255.255.255.240 is the correct mask and offers 16 subnets. You can also count binary on your fingers. 1,2,4,8=15. you have four bits of mask to encompass 14 networks. 128, 192, 224, 240. 240 is the mask for four bits.



<< 2. For the Class C network mask for 195.168.220.0 described in Question 1, how many hosts are available per subnet?

a) 2
b) 6
c) 14
d) 30 >>



256/16=16 addresses. take away the network and broadcast address and you have 14 hosts.

Best way is to remember and memorize this in your head-
1,2,4,8,16,32,64,128

128,192,224,240,248,252,254

 

[n0cmonkey]

What test is this for? I was under the impression that Class subnetting was out and CIDR was in...

 

[mikysee]

These are homework questions from Networking Essentials class.

 

[n0cmonkey]

<< These are homework questions from Networking Essentials class. >>



I took one of those classes, but I dont remember a whole lot. That was during my "MCSE period" 😛

 

[spidey07]

Yeah...the microsoft classes teach "microsoft TCP/IP" and have no real relation to the "rest of the known universe TCP/IP"

🙂

 

[n0cmonkey]

<< Yeah...the microsoft classes teach "microsoft TCP/IP" and have no real relation to the "rest of the known universe TCP/IP"

🙂 >>



Thats one of the main reasons I never completed (nor cared about) the MCSE. 😉

 

[pcmark]

a) 255.255.255.252
b) 255.255.255.248
c) 255.255.255.240
d) 255.255.255.224

Those are all Variable Length Subnet masks (VLSM). So this is "classless" subnetting 🙂

 

[Tallgeese]

<< Yeah...the microsoft classes teach "microsoft TCP/IP" and have no real relation to the "rest of the known universe TCP/IP" >>

I've had to "re-train" EVERY SINGLE employee of mine who learned TCP/IP "The Micro$loth Way." No foolin'

Have NOT had that problem with folks who learned it on their own, or via Novell's older TCP/IP course (the new one has some spotty areas), or Cisco's curriculum.

 

[JustinLerner]

<< This isn't a question about setting up a network, this is a difficult networking question.
Can anyone please help me? The questions are:

1. For the Class C network 192.168.220.0, what subnet mask supports up to 14 subnets?

a) 255.255.255.252
b) 255.255.255.248
c) 255.255.255.240
d) 255.255.255.224 >>

Can I be picky? None of the answers fit exactly 14 subnets and three of the possible answers have at least 14 subnets or more (16, 32 and 64; c, b, a, respectively). Didn't you all notice the problem with this question and the possible answers?
The question is poorly written. When one says up to, usually this means up to, but not more than or <=, but apparently this is not understood by most everyone else here. Notice, this question is not the same as asking, "Which subnet masks support at least 14 subnets?" nor "Which subnet supports the most number of subnets closest to 14 subnets in total number?" but actually closer to yet still not analogous to, "Which subnet supports not more than 14 subnets?" Since this is a preceding question with problems, the subsequent question also has problems.

I would like to hear some replies from the 'gurus' on this!