Hi Everyone!
I PASSED MY CCENT this past Friday! I was so excited...

I'm curious though, about the differences between major IOS versions. I've been lucky enough to download from Cisco newer IOS's for my switches and routers to upgrade my own test lab. This has taught me ALOT about upgrading the IOS and what (and what NOT) to do.

I usually go for the latest version determined by numbers (ie. 11.x to 12.1, 12.2 to 12.4, etc). For example, I'm looking at upgrading a CAT3550 switch and when I go to download I'm presented with...
12.1EA
12.2SE
12.2SEA
12.2SEB
12.2SEC
12.2SED
12.2SEE
In regards to 'major release', what do all various letters mean?
I'm able to figure out the 'release' and 'feature set/licenses' differences but I get confused when looking at the letters on the major release.
Any suggestions and comments are greatly appreciated.
Your friend in Virginia,
Paul L.