Dear Fahmy,

I was in the network field for a short time 10 years ago. Since then I have been out of touch. I would suggest you go straight into TCP/IP and forget about the OSI 7-layer stuff. Go to www.amazon.com and search for TCP/IP you should find the books that other pepole like. Even better is go to the local college bookstore to see what books are being used as textbook.

I just checked amazon, Douglas Comer's books (I have the old edition of "Internetworking with TCP/IP Vol. I: Principles, Protocols, and
Architecture") still rank highest. Maybe you can start from there.

Regards, Oliver (sorry for the late reply)