70-270 Help, if thats what you can call it..

[Deception]

Hello Everyone.

I seem to be having a little trouble with grasping some stuff in the 70-270 course material im studying. In one question it mentions acquiring the Broadcast Address of an IP and then using it to find out a range of IP address in which im allowed to use for a connection. It tells me the broadcast address when I get the question wrong, but doesnt tell me how it figured it out, it does tell me what to do when I have it, so that isnt a problem. I just wondered if anyone here could provide any input in how to work out a broadcast address, like a calculation, something I can learn myself. Ive checked a few things on the net, but nothing too good has came to my attention.

Cheers.

*Edit* Ill provide a screenshot of the sort of question it gives and answer.

Question:
http://img297.imageshack.us/img297/9822/questionlh8.jpg

Exibit:
http://img407.imageshack.us/img407/5408/exibit1ud0.jpg

Answer:
http://img407.imageshack.us/img407/6913/answer1po5.jpg

 

[crashuk]

Hello Everyone.

I seem to be having a little trouble with grasping some stuff in the 70-270 course material im studying. In one question it mentions acquiring the Broadcast Address of an IP and then using it to find out a range of IP address in which im allowed to use for a connection. It tells me the broadcast address when I get the question wrong, but doesnt tell me how it figured it out, it does tell me what to do when I have it, so that isnt a problem. I just wondered if anyone here could provide any input in how to work out a broadcast address, like a calculation, something I can learn myself. Ive checked a few things on the net, but nothing too good has came to my attention.

Cheers.

*Edit* Ill provide a screenshot of the sort of question it gives and answer.

Question:
http://img297.imageshack.us/img297/9822/questionlh8.jpg

Exibit:
http://img407.imageshack.us/img407/5408/exibit1ud0.jpg

Answer:
http://img407.imageshack.us/img407/6913/answer1po5.jpg

224 mean 30 hosts
lets say xxx.xxx.xxx.0 = Subnet ID
xxx.xxx.xxx.xxx.31 Broadcast Address xxx.xxx.xxx.32 Subnet ID
xxx.xxx.xxx.63 Broadcast Address


xxx.xxx.xxx.240 14 hosts, it should be 16 but you always take away 2 to give you the number of hosts which is 14 ( 1 for the subnet id and other for the broad cast address)

xxx.xxx.xxx.1 = Subnet ID xxx.xxx.xxx.xxx.15 Broadcast Address xxx.xxx.xxx.16 Subnet ID xxx.xxx.xxx.31 Broadcast Address

broadcast address is the last digit in the subnet, all you need is to see the last digit of the subnet range.


http://www.subnet-calculator.com/