Jacko87

Know sub-netting, super-netting, SDM (for some instructors, I don't really know too much about this since we did everything from command line), all the routed protocols (RIP 1 and 2, OSPF, EIGRP) and routing protocols (especially IP routing). If you did sub-netting as much as me, you should be able to do it in your head fairly quickly. Some teachers want you know to know the parts of router and what they do ex. Startup-config is stored in NVRAM, running config in RAM etc.

And know the switching modes (cut through, store and forward, fragment free), know access control lists and how to make them, know address resolution protocol...there is just so much stuff....oh and basics like the OSI module and converting from base ten to hexadecimal and to binary.

If you need anything explained, feel free to ask!

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packardhell1

That's a dangerous statement I've got binary down, I'm still working on hex. I'd love to be able to subnet mentally - I don't know if I'll have time to write subnetting down completely for each question, so that would help. Got any tips on that? I regret now not spending every waking moment memorizing networking facts - I wrongly thought that doing the homework/mod exams were enough. Boy was I wrong

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Gentlemen, we have a PEBCAC error. Problem Exists Between Computer And Chair.

Jacko87

On the actual CCNA certification test there will be little time to write out sub-netting. Its really quite easy once you get the hang of it, always look at the class of the IP first, also make sure to pay attention to if the problem uses sub-net IP zero. If you do have time to write it out though, its always best to write it in binary to help visualize it better.

I don't know how you were taught sub-netting, but this is how I do it.

For instance, given:
190.1.2.251/25, how many hosts per subnet?
First we see that because of the 190, that this IP is class B, meaning the default subnet is 255.255.0.0 or 11111111.11111111.00000000.00000000 in binary.

The /25 means 25 straight ones in the sub-net, so the sub-net for this network is: 11111111.11111111.11111111.10000000 or 255.255.255.128. 9 ones were added because the default sub net for class B is 16 ones. 25-16=9 ones added to the default.

Now to get the number of hosts per subnet, you count the zeros on the end of the sub-net address and put it to the power of 2. So 2^7 = 128. 128-2=126 hosts per subnet. The minus 2 is for not using IP sub-net zero since one address is for the broadcast domain and the other is for another sub-net address.

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GH0

Gotta love high school free classes

Yeah, an easy way to remember subnetting is just think of bitshifting. It is probably the easiest way to remember it.
Obviously
11111111.11111111.11111111.00000000 = 255 So, it equals /24

To figure out the IP you need to use, you use AND and take the last octet.

I hit the reply button before I you posted, then you said the same thing I did, prolly explained it more though.

Jacko87

You mean 11111111 = 255 and 111111111.11111111.11111111.00000000 = /24 right?

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GH0

Yeah, I originally was going to say

.11111111.0 was going to be /24 "my shortcut"

Then I decided not and just added 24 1's.
Will fix that.

packardhell1

I failed. I`ll try again on Monday, but I have my doubts

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Gentlemen, we have a PEBCAC error. Problem Exists Between Computer And Chair.

GH0

Does your professor round or curb your grade at all? If so, ask him.
I really think that CCNA1 is alot of material for any college student to learn, more so for a high school student (myself).

reezin14

Hey, don't get down we've all tried something or other and failed just keep trying. As The_Rocker suggested study the things that you didn't do so well on.Try revisiting your lab companion.

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CrackClocker

Can you guys translate this into english?

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