How to root Samsung Galaxy Note 2? I have no experience with rooting. Model number is GT-N7100. Android-version 4.1.1.
This will work on the following Galaxy Note 2:
1.International Galaxy Note 2 GT-N7100
2.T-Mobile Galaxy Note 2 SGH-T889
3.AT&T Galaxy Note 2 SGH-I317
Put your Galaxy Note 2 into Download mode by turning off your phone first then holding down Volume Down, Center Home, and Power buttons together.
Once you see the warning screen, hit Volume Up button to enter ODIN Download Mode then connect a micro-USB cable from your Note 2 to your computer.
If you have to install Samsung USB drivers
Next, download GalaxyNote2Root.zip
Unzip the files. Next, open up the ODIN program by double-clicking on the .exe file.
You should see a yellow-highlighted COM box with a random number. If you don’t see it, double-check your Windows drivers (the Samsung USB drivers you installed in Step 3) and unplug, plug your Note 2 back into your computer.
DO NOT TOUCH ANYTHING ELSE and click on “PDA” button then find the file cwm6-root-note2.tar(in unzipped folder).
Hit Start and let ODIN flash the custom CWM Recovery. When it’s done, your Galaxy Note 2 will reboot and you should have a fully rooted Galaxy Note 2.
Your phone will boot into newly installed CWM Recovery automatically once and install Superuser app and su binaries then reboot.
You should find a new Superuser app called “SuperSU”.
You can easily verify you have root by downloading Titanium Backup app (free on Play Store) and running it. (a Pop up will appear)
In here they described with details and video that "How to root Note 2" . You have to just go for the carrier name, under which you are now.
NOTE:I'm not responsible if you mess up your phone. Make sure you know what you are doing before following any instructions. Go here .Just read it.
I've used the following guide on XDA Developers: http://forum.xda-developers.com/showthread.php?t=1923956
And did the same for the S3 (for which they also have a toolkit and a thread)