UNIT I
Introduction to Computer Networks: Need for Networking - Service Description –
Connectionless and Connection-Oriented Services – Circuit and Packet Switching – Access
Networks and Physical Media – Wireless Links and Characteristics – Queuing Delay and Packet
Loss – Internet Protocol stack – OSI Reference Model - Service Models – History of Computer
Networking and the Internet.
UNIT II
Application Layer: Principles of Network Applications – The Web and HTTP – FTP – Electronic
Mail – SMTP – Mail Message Formats and MIME – DNS – Socket Programming with TCP and
UDP. Multimedia Networking: Internet Telephony – RTP – RTCP – RTSP. Network Security:
Principles of Cryptography – Firewalls – Application …show more content…
They are an attractive media because require no physical "wire" to be installed, can penetrate walls, provide connectivity to a mobile user, and can potentially carry a signal for long distances. The characteristics a radio channel depend significantly on the propagation environment and the distance over which a signal is to be carried. Environmental considerations determine path loss and shadow fading (which decrease in signal strength as it travels over a distance and around/through obstructing objects), multipath fading (due to signal reflection off of interfering objects), and interference (due to other radio channels or electromagnetic signals).
Terrestrial radio channels can be broadly classified into two groups: those that operate as local area networks (typically spanning 10 's to a few hundred meters) and wide-area radio channels that are used for mobile data services (typically operating within a metropolitan region). A number of wireless LAN products are on the market, operating in the 1 to 10 's of Mbps range. Mobile data services (such as the CDPD standard we touched on in section 1.3), typically provide channels that operate at 10 's of