Network and OSI - More detailed explanation of the OSI and network models.
http://compnetworking.about.com/od/networkdesign/l/aa041601a.htm
Book Distrubuted Systems and Networks, William Buchanan, McGrawHill, 2002
http://eserver.bell.ac.uk/mirrors/networks/pt2_1.htm
http://eserver.bell.ac.uk/mirrors/networks/pt2_2.htm#start
http://eserver.bell.ac.uk/mirrors/networks/pt2_3.htm#start
http://www.homenethelp.com/network/index.asp
http://www.swhowto.com/