Networking classes alone would not give you any value in this case. In fact, they'd give you negative value because the real world never works like the text book, and offering advice that you yourself have not applied in practice is bad form.
I never finished Cisco networking classes either. I never really started them in the first place. I did however help develop the training and certification program for the Ascend/Lucent Certified Technical Expert course. That was after I already had about 8 years of daily hands-on LAN and WAN design and administration (late 90's timeframe). I was able to do that because I had been in the bowels of everything from a local travel agent office network to some of the worlds largest datacenters and NAPs (at the time).
Don't wish for network classes, instead spend some time with actual equipment, a copy of Wireshark, and some time on network admin forums/groups. Go work for a local ISP for even 6 months. You'll learn more about LAN/WAN networking in that time than in most formal network courses.
// finished 4 semesters of CCNA instruction only to be too poor to afford the testing. :)
Unless things have changed since I last looked, it's all labware. Sure, that's better than pure textbook, but still a far cry from reality.
so, you ready for the vacation?. :)
Part of the reason for my response is a bit of a personal nit, I guess. I come across a lot of talented and capable people who seem to feel that they need someone else to verify their skills. Schools and training programs and certs are all well and good for some people, but those things take time and money. Time and money that might be better invested on self-learning, or taking a mid-level job at a salary less than you are worth but such that your net income is still ahead of where you would be if you were going to school, and using that job as a learning/advancement opportunity. I'll take a guy with a GED and 4 years on an ISP tech support position before a guy with a Bachelors, 3 Cisco certs and no work experience in many cases. (YMMV).
The higher-ed/certification thing is so ingrained in so many people that I believe people do not often stop to consider the alternatives frequently enough. OR, they are led to believe that these degrees and certs are universally respected and the gate keepers to better career opportunities. This is of course not true.
My main point is that it's never too late to learn something new, and depending on how you personally develop new skills, the best approach may be non-traditional.
(Not that I got any in the end, someone who didn't care employed me first. But they make sense for a reasonably large group of people)
Funny story: so, my junior tech, who at some point had taken some Cisco course or another, had been tasked with finishing up some gigabit connections between two buildings.
In the main building, the network cabinet has two unmanaged Netgear Prosafe switches; one 10/100, and one gigabit.
Without thinking about it, he plugged some of the cables for the other building into one switch, and some into the other.
Both sets of cables ran to the other building, and then into another Netgear unmanaged switch. (There were multiple cables primarily for redundancy.)
So naturally the next day the network just starts going wild. He's tied a gigabit-size loop into the network, and the unmanaged switches are helpfully forwarding traffic back and forth to eachother, even though they're really not supposed to do that.
He's totally stumped. I get called in, sit down for a few minutes with tcpdump, and watch the traffic for a few devices on the network. Didn't take very long before I had a rough idea of what had happened, opened up the network cabinet, and found the misplaced connections.
So much for Cisco courses!