For the past 8 years I been using the Tanenbaum book for teaching my university networking class.
That book is really starting to show a bit of age (the author also recently retired). The Peter Dordal Creative Commons approach needs a bit more polishing. Just did a browse through and comparison, it goes quite deep (e.g. TCP Westwood). However, Tanebaum more applications and uses, including telnet to port 80, audio compression threshold of hearing and runlength encoding.
btw please put the slides online used to present this to students.. Every professor needs to make their own now.
I haven't read the linked book, so I can't comment on which is a better introduction.
I will say that having read the Tannenbaum book, it is a very thorough, bottom-up survey, and you will certainly know quite a lot about computer networking after reading it.