CompTIA Network+

Videos:

Professor Messer’s Network+ tutorials – index
excellent 4 hour prep video – Powercert
OSI 7 layer protocol stack – Professor Messer
Ports – Professor Messer
Subnetting made easy – Sunset Learning Institute
Subnetting in 15 seconds – poor English but good if watched a few times… Ahmed

Practice Questions:

Examcompass.com – excellent example questions