It's best for the test that you know...

Kcolon1

I'd like others that took the test to post what it's best to know in order to pass the test, like key things that should be "mastered"...

example:
"It's best to know how to subnet"
"It's best for the test that you know how to set up a RIP configured environment by heart"

This will help me focus on certain areas when I have 3 days left. Thanks!

r_durant

This is a tough questions...everyone doesn't get the same test and then NDA restrictions will prohibit people from saying what they actually got on their test...

One guy might say in general, know ACL, VLAN, VTP, Frame....Another guy might say know EIGRP, OSPF, RIP and Subnetting...when you add up all of what people say in general, you're back to square one...and that's trying to know everything!!

I know this post doesn't help you much, but that's the reality...

Most people might say not to worry much about ISDN, but as one guy mentioned...I'd hate to know I failed because I missed one ISDN question...

I'll say be familiar with everything....Just my 2 cents...

Netstudent

Read the cisco blueprint....Those are the topics that you must master to pass the test. If you just read through old posts you will find plenty of people who posted thier pass and they may write, "know this and know that and this is important and this isn't." Just read around and try to pick up clues.

Plazma

Frame-relay, ACL's, Switching, VLANs, intervlan routing using dot1q/ISL, ISDN.. etc

Komkommer

Don't forget VLSM and route summary!

GT-Rob

ACLs like whoa

dtlokee

Know your technoogies, not just how to configure somthing but what is behind it. You will find many of the questions are not going to ask you to find the corect answers, but eliminate all the wrong answers and the ones that are remaining are correct (even if they are unrelated to the question/information presented).

Kcolon1

Komkommer wrote:

Don't forget VLSM and route summary!

I believe I know my VLSMs, but I'm not sure about Route summaries... Could you please describe? Thanks

techster79

How could you best summarize the following into a single route?

10.1.5.64/28
10.1.6.80.33/30
10.1.7.99/24
10.1.4.210/25

You should get to a point where you can look at the addresses listed and in your head do these steps:

1) Automatically you know the address will begin with 10.1 because all addresses have those octets in common

2) Concentrate on the third octet and notice that you have a range of 4-7, which would translate to a 10.1.4.0 network.

3) Figure the optimium subnet mask, which one will give you a range of 4-7 in the third octet?

Answer: 10.1.4.0/22 is the best summarized route

The third octet on each example above looks like this:

1) 00000101
2) 00000110
3) 00000111
4) 00000100

Common bits are in bold, each individual subnet portion is underlined. Now I used .4 because it is easy to display but be prepared for a harder question possible on the test.

Kcolon1

Wow. I didn't really put all my subnetting and VLSM into mind like that. Honestly, I'd take about 2-3 minutes to solve that... but not instantly...

dtlokee

For any summarization question on the CCNA (note I said CCNA) you can simply use 2**n to figure out how many ones to subtract from the subnet mask. Subtracting one 1 will summarize 2 addresses (2**1) subtracting 2 bits will summarize 4 addresses (2**2) and so on. Now I know this isn't always the case in practical application because not every range of addresses to summarize will start on an even increment and may not fit nicely into a block of 2, 4, 8, 16... but for the CCNA it will be limited to summarizing contigious addreses.

Even if you are presented with a discontigious block you can summarize it using the same "magic number" approach used to subnet. Figure out the range of addresses (high and low) then find the smallest increment of 2**n that it will fit into.

10.1.5.64/28
10.1.6.80.33/30
10.1.7.99/24
10.1.4.210/25

in this case the third octet has 4 - 7 so a block of 4 (256 - 4 = 252) so 255.255.252.0. Converting to binary takes too long.

borumas

You need to be familiar with everything Cisco outlines for the test on their site, no matter what people tell you here, it isn't a garantee that you will see what they are saying when you test. I've failed the ICND twice and was told that if I didn't know subnetting very well that there was no shot at passing. I had almost no questions on subnetting, when I was under the impression that a fair part of the test would cover it. The CCNA isn't like other exams where they may only have 3 different versions of the test, they randomly pull questions from a huge database so you never get the same test, which makes it a hard and respectable cert to have.

techster79

dtlokee wrote:

in this case the third octet has 4 - 7 so a block of 4 (256 - 4 = 252) so 255.255.252.0. Converting to binary takes too long.

Great explanation. Another thing you can do to find subnet numbers based on subnet mask is to figure the difference between the subnet mask and 256. For example:

What are the subnet numbers given mask 255.255.224.0?

256-224=32

X.Y.0.Z
X.Y.32.Z
X.Y.64.Z
X.Y.96.Z
X.Y.128.Z
...
The trick to subnetting is finding shortcuts with the math and knowing some binary to decimal conversions in your head. If you get stuck you can always reference things you can write down quickly before taking the test or count on your fingers.

You need to be familiar with everything Cisco outlines for the test on their site, no matter what people tell you here, it isn't a garantee that you will see what they are saying when you test.

I agree 100%. Although I saw alot of a few types of questions and nothing of a certain WAN standard, you are asked ~53 questions out of hundreds of possible questions. Does anyone know if the test is still adaptive? I read somewhere it wasn't anymore. One of the hardest things about Cisco tests is you cannot mark an item and spend alot of time figuring out the answer, you need to budget your time. At the same time, don't sweat it too bad if you know what you're doing the test should last about an hour or less.

I can tell you be prepared for unorthadox methods of gathering information when given access to one piece of hardware and need to find out information that may come from across the network. Know VLAN, STP, VTP, TCP/IP, OSI, Frame Relay, ACL, NAT, OSPF, EIGRP. Be able to know what a show or debug statement means for the various routing protocols and vtp/stp commands.

fonque

before attempting any subnetting examples or questions, the first thing I do is make a visual key that consists of 2 rows of 8 number:


top row ......... 128, 192, 224, 240, 248, 252, 254, 255
bottom row .... 128,..64,.. 32,.. 16,... 8,.... 4,.... 2,...1

"example" ..........1.....0.....0......0......1.....0......0.....1

top row represents the subnet mask for however many bits counted off from left to right.
bottom row is used for converting decimal to binary and vice versa quickly, it represents the 8 binary digits in each octet.

so for the top row, if I see a subnet of either /20 or 255.255.240.0 I can easily count it off based on the top line that it would be 255.255.11110000.0

for the bottom row, if I have a decimal number like 12. I would go to "8" and "4" in the table and put a 1, so i would get 00001100


larger number I just use subtraction. I.E 137, largest binary digit = 128 put a 1 under 128, then subtract 128 from 137 = 9, largest binary digit = 8, put a 1 under 8, subtract 8 from 9 = 1, put 1 under 1, and done, answer is "example" up top.

Binary to decimal is even faster, just add up all digits that have 1s. If you use "example" 128+8+1 = 137

this system reduces subnetting to simple addition and subtraction so I dont have to think about it or worry about memorizing alot binary conversions.