http://www.net.aapt.com.au/learning/ball.htm

http://www.erg.abdn.ac.uk/users/gorry/course/phy-pages/phy.html( crc,Nrz-l,manchester encoding)

http://www.echelon.ca/handyman/nettech/phys.htm(frame work)

http://www.awstevenson.demon.co.uk/SYSNOTES/physic.htm(services provided)

www.mindspring.com/~cari/networks/physlayer.html (computer networks)

http://www.dsi.unive.it/~franz/reti/dll/Protocolli.html(datalink)

http://www.docs.uu.se/~carle/datakomm/Notes/Networking/20_DatalinkLayer.html

http://www.vislab.usyd.edu.au/photonics/networks/networks/ether/ether.html

Network layer

http://www.cisco.com/warp/public/535/2.html

http://www.ee.siue.edu/~rwalden/networking/ip.html (internet protocol)

http://ntrg.cs.tcd.ie/4ba2/network/overview.html(overview)

http://www.net.aapt.com.au/learning/network.htm(interactive computer networks site)

http://www.compsci.buu.ac.th/~jim/reference/ComputerNetworking/4_3.htm(hierarchical routing)

http://www.cs.uwa.edu.au/~chris/cnet/aricstewart/(distance vector routing implementation)

http://www.cis.upenn.edu/~messing/academic/tcomm.html(link state implementation)

http://www.cs.arizona.edu/llp/book/node84.html#SECTION00940000000000000000(congestion control)

http://www.cs.panam.edu/~meng/Course/CS6345/Notes/chpt-5/node21.html

http://www.ee.siue.edu/~rwalden/networking/tcphead.html(TCP header)

http://www.scit.wlv.ac.uk/~jphb/comms/(applications)

http://ntrg.cs.tcd.ie/4ba2/presentation/(presentation)