Jeremy Cioara's Subnetting section ' The Great Exception ', HELP?

Beany

Afternoon,

love the way Jeremy explains how to subnet and i can do it well. But do not understand the bit when he explains 'The great Expection ' part in the notes that he provides. Can someone please help me with and explain with examples?

Also, took the TECHEXAMS CCNA subnetting practice test and came across two questions that had network diagrams that required me to solve the problem or find the problem. Are these two questions to come up in ICND2 and not ICND1?

I'm studying for the ICND1 and know all the other questions but struggled a bit on these two questions..

all responses will be appreciated.

thanks

Roguetadhg

VLSM is not covered with ICND1. You won't need to worry about that (Although it's quite simple when you get down to it)

What video is the great exception located?

Beany

https://learningnetwork.cisco.com/servlet/JiveServlet/previewBody/6014-102-1-19236/Subnetting%20Examples.pdf

look at the last page.

BTW the two questions i was referring to which you're saying are not covered in ICND1, i actually understand them and got them right, eventually

mapletune

I don't really use his method, but i can get the gist of the "Great Exception"

Basically, in binary addition, you have: 128 64 32 16 8 4 2 1

So if you started with 1 bit, that's 1 host/subnet right? not really, since binary starts at 0. So, 0 to 1 equates to a range of 2.

2 bits. 1+2= 3? 0 to 3 equals 4 range.

(with ip subnet zero)

if you need 2 hosts, you use 2 bits, not 3 bits. (2^2 = 4, first is subnet, last is broadcast, 2 usable host)

if you need 16 subnets, you use 4 bits, not 5. (1+2+4+8 = 15, 0~15 = 16)

etc, so on...

---

i find that all quite confusing to be honest.

just use exponents. 2^x

2^1 = 2
2^2 = 4
2^3 = 8

etc...

MickQ

mapletune wrote: »

just use exponents. 2^x

2^1 = 2
2^2 = 4
2^3 = 8

etc...

If your head is fried looking at that, just remember that those exponent values are your number of bits.

3 bits for subnets? 2^3 = 8 ........ that's 8 subnets from 3 bits.

mapletune

MickQ wrote: »

If your head is fried looking at that,

=p hehe sorry. I'm not very good at explaining things step-by-step in detail. but hopefully that provides a glimpse to the possible answers!

Beany

thanks for this

MickQ

It was very good, but I remember when I was learning it all
If you explain things well in one way, most people will understand it. If you explain it over and over, everyone should get it