Hello
I want to know about computer network concept and principle
Bus,star,. configuration ,network devices router,hub,modem,.
Please introduce me well papers or send them me.
Thanks a lot

Here are some places to start:

Network Topologies Bus Ring Star Mesh Tree (http://compnetworking.about.com/od/networkdesign/l/aa041601a.htm)
Networking Basics - Essential Concepts in Computer Networking (http://compnetworking.about.com/od/basicnetworkingconcepts/)
Networking 101 (http://lowendmac.com/tech/net101.html)

There are so many topics that it is really hard to know where to begin. Try googling for various terms such as "network 101", "network star bus topology", etc and you'll get more hits than you can shake a stick at.

If you have anything specific to ask we would also be happy to help answer your question.

Casey