Best Subnetting method?

thinguy

Who has the best subnetting technique ? Not just to get you through certification but you're able to maintain the "know-how" after your test.

xenodamus

I started with Odom's book. I got it, but I was slow. The subnetting made easy article really made it click and got me down to that 10-15 seconds per problem.

Stuppored

IMO Lammle's got the best one. Just got to get your multiples down, as well as exponents...

I'm writing multiples out in a book. Multiples of 4... every time it hits a even 0 number (like 20 instead of 30) the numbers go like 0, 4, 8. When there's odd (like 30's) it's like 32, 36... Hope to have 4's, 8's, 16's, 32's(easier) all pat down so I can do this portion of the subnetting in my head on the fly (this is for solving block sizes). Next up I have to memorize and find easy ways for solving powers of 2.

Forsaken_GA

I can't vote for any of them. I learned to subnet before I'd touched any of their books. One of my teachers in college, while lacking in certain other areas, taught how to subnet really, really well, and it only took a few days for it to click.

Ironically enough, when I was a kid and teaching myself programming, I ran into a problem where I needed to know if a particular bit was on or off. I asked for advice (this was waaay before the big internet explosion), and everyone kept telling me stuff like "AND the variable by 64 and that will give you your result". I just couldn't get bitwise math. My solution ended up being a sloppy method.... I shifted all the bits to the right, and then shifted back to the left, so that the only possible bit that could be on was the bit I was looking for. It worked, but I always felt it was an ugly, ugly hack.

Fast forward to about 15 years later when I'm sitting in some classroom learning subnetting, and I had that epiphany on how subnetting worked. That moment where it all just clicked, and I didn't need **** sheets or memorized methods anymore. The moment where I became supremely confident in my ability to derive answers to subnetting questions in my head.

The moment where I finally said to myself 'Oh, *thats* what Todd meant by AND it by 64!'

Monkerz

I feel that Jeremy Cioara's method is easier for me. I do sometimes forget about "The Great Exception"...

jamesleecoleman

I had the hardest time with lammle's book. When I got odom's books, it was more easier to understand. Also the videos helped alot.

Deathgomper

I understood it a bit in college but didn't have my "A-Ha" moment till I read Lammle's book.

networker050184

That question is like asking whats the best beer. If you ask 20 people you will probably get 20 different answers. Just go with whatever feels natural to you.

Kaminsky

Why isn't TechExams not on the list ?

The amount of people that have been helped "click" subnetting on these forums is huge. Many use various different books but still don't quite get it. They eventually come here and asks questions where they are getting stuck and the forum readers explain subnetting far more than any book I have read.

gosh1976

I really like Tony Gibbs' method. I think you should all ready have a pretty decent understanding of subnetting before trying the method but this sped things up for me quite a bit. Creating Your Own Mental Subnet Calculator

ToddB

I found that after I understood subnetting made easy, I understood then all and now I use a mix for them all. I'm having more trouble remembering all the switchport and ssh commands and lets not even take about wlan.

WebWideJosh

thinguy wrote: »

Who has the best subnetting technique ? Not just to get you through certification but you're able to maintain the "know-how" after your test.

I don't like to memorize. I learned an addition/subtraction method years ago when I was doing my CCNA and still use it to this day.

I take the network size or the subnet mask or the bit pattern and do simple additional/subtraction.

A .240 will be 12, 20, or 28 bits for my CIDR conversion. Memorizing the bit patterns will help just a tad if you're working with CIDR but its unnecessary.

I take 256 minus 240 and that gives me 16. I then know that every 0 and every 16 after will be the networks:

x.x.x.0
x.x.x.16
x.x.x.32

For a /20 you're looking at the same:

x.x.0.0
x.x.16.0
x.x.32.0

It's fast and easy to me and at most I need a calculator to double-check.

Cyanic

I learned it in college. So I can't really answer.

chmorin

WebWideJosh wrote: »

I don't like to memorize. I learned an addition/subtraction method years ago when I was doing my CCNA and still use it to this day.

I take the network size or the subnet mask or the bit pattern and do simple additional/subtraction.

A .240 will be 12, 20, or 28 bits for my CIDR conversion. Memorizing the bit patterns will help just a tad if you're working with CIDR but its unnecessary.

I take 256 minus 240 and that gives me 16. I then know that every 0 and every 16 after will be the networks:

x.x.x.0
x.x.x.16
x.x.x.32

For a /20 you're looking at the same:

x.x.0.0
x.x.16.0
x.x.32.0

It's fast and easy to me and at most I need a calculator to double-check.

Same Method here.

viper75

Subnetting Made Easy was my way all the way. Thank you!!!!!!!!!