Just a few Network related documents and links.
1. My own short notes:
Short and Simplified factsheet TCPIP v4 on Unix
Overview Frametypes
Overview Protocols
Quick introduction IPv6
Listing of some Cisco router commands (old file)
2. Free Network protocol "posters" from "media.packetlife.net":
Page containing a large number of really Great posters (!):
Posters from packetlife.net
3. Other free Network protocol "posters":
General network protocol Poster (www.protocols.com)
Last update: 8 June, 2012