My Core Network Fundamentals
Over the years I have learned from many different people and resources, but only a few have truly
influenced me. These have become part of my Core Network Fundamentals, not only in my basic network understanding, but
also in helping me think outside the box.
When I interview Network Engineers, I always ask if they are familar with Cisco SAFE. I'm always shocked when they are not; as well as, how many engineers don't know about this guide.
Yes I know Cisco just wants to sell you more routers. But, if you read their SAFE Reference Guide you
see how it covers core principles that span any network vendor.
The importance of syslog, SNMP, NTP, Tacacs, IP Spoof protection, BPDU Guard, etc... Their SAFE
guide lists out many other great methods (sometimes cisco only) of doing things. That reguardless of the vendor will help shape your design to a well thought out and secure network.
I believe that trouble shooting is one of the best and most difficult skills for a network engineer to master. I
have always said "Try to reproduce the issue." If you can do so, then you can begin to understand and find the issue. I see so many engineers try to resolve issues without even understanding what is wrong. You need to understand the problem first; only then can you start to find the cause. If you are able to reproduce the problem, then you've begun to understand it, and you can test your network changes against the issue to confirm if you have found and fixed the issue.
Packetlife has done a fantastic job outlining my same beliefs and expounding on them.
Understanding of Latency:
Many people just do not understand how latency (even a little) affects data over a network. Especially file transfers over a WAN. This
paper opened my eyes a decade ago and I've never forgotten it.
So easy to say, yet sometimes, so hard to do. This paper fantastically covers one guys fight
against a DDOS attack on his T1 line. How he wrote his own zombie bot to listen in on the hackers IRC
channel and eventually wins.