Lessons - Newbies

I was thinking the other day, what lessons need to be learned by everyone who wants to have a career in networking.
This topic comes up in a lot of different places, I've seen several articles over at packetpushers.net related to getting started and changing gears. I think about this a lot as I have students who have networking in their major, who work for the IT department, have some weird questions. We have a Cisco Academy, which the lab is on the other side of the wall from my cubicle.

So lets start with the list, in no particular order:

• Operation of Spanning Tree Protocol - I get yeah it prevents loops by.... What does it do when it is off and you put the loop in the network? What happens to a router which is setting up a vpn tunnel and looking for traffic from the lan to build that tunnel and you put a loop in the network? (Short answer: NO Tunnel) My last post was about STP: http://mrfogg97.blogspot.com/2012/04/spanning-tree-stp-love-it-hate-it.html
• 802.1Q operation between switch vendors, not everybody configures like Cisco.
• You will forget to save the config at some point, especially if you have multiple vendors gear - see point above.
• Shutting down the wrong interface - ie the one that connects you to the equipment, learned that one very early, had to walk across campus to fix my error.
• RTFM - Read Read Read, then ask questions.
• Multicast operations - because it is in use in a lot of places that you may not realize. Avaya One-X Quick Edition phones use it to save voice mails  between all the units on the network.
• Your gonna fail, learn from it
• Know the difference between a hub and a switch - use the terms correctly
• Any business, bigger than a 50 people probably has more than one subnet / vlan. That means that you can not just plug any cable into any switch port, as a rule.
• Structured Cabling is there for a reason, keep it neat. (I'm still working on this at times, past sins)
• If you encounter one of these:  It takes two cables to complete the patch. Switch to mid-span , mid-span to patch panel. See RTFM - the ports are labeled.

Avaya Mid-Span

So lets put this one in the bag... We are all still learning, keep an open mind. These are some of the things I see or have done. 

Disclaimer: This may be disjointed post, but I needed to get it out. Comments are welcome.