VLSM, addresses...

arvalea

Hello!

Could you please say me if 70-291 contains questions about VLSM (variable-length subnet mask)?.. I feel that it is one of my mostly weak areas ...
If I violate rules - I'm sorry! May be then someone can say me, what I must read for better understanding of this topic?.. And how it was "hard/not hard" for you?..

Claymoore

You need to understand subnetting - both classful and classless (CIDR,VLSM - whatever you want to call it). I have only had 2 direct subnetting questions - where they ask you to choose a subnet mask based on number of hosts or similar - on all the MS exams I have taken. MS wants to test your applied subnetting knowledge and not just your ability to count in binary.

For example, you need to be able to identify the symptoms of an incorrect subnet mask, such as not being able to communicate with hosts on the same or remote network. This is an example of where you would need to know the network ranges in a particular mask. The questions may use either CIDR /whatever notation or the traditional 255.whatever subnet mask, but I don't recall if they would use both formats in the same question.

Subnetting seems complicated at first, but once you start to get it you realize that it is easy - it took me two months of studying before I figured out that it only takes 10 minutes to learn.

Try LearnToSubnet.com or TCP/IP First-Step from Cisco Press. Personally, I liked all the First-Step books that I read.

arvalea

Thank you for great answer, Claymoore!
http://www.learntosubnet.com is really useful site.

Claymoore

You're welcome!

I was poking around on Cisco's site for some Spanning-Tree information this weekend and I stumbled across CCNA TV (free registration required) on the CCNA Prep Center and they have a couple of shows on subnetting from 2007 and 2005. There is also a Subnetting Game - in case Xbox Live is down and you get bored.