In Brief

• Socket programming is the de fato standard by which computers running different operating systems communicate with one another.

• The two most important protocols for socket programming are TCP/IP and UDP. TCP/IP guarantees packet integrity but is slower than UDP. UDP packets are useful for such applications as streaming audio, where a bad packet doesn't harm the application much.

• Most of the chapter focuses on TCP/IP because it is the protocol used in the vast majority of applications.

• There are two popularly supported versions of the IP protocol on which TCP/IP and UDP rest: IPv4 and IPv6. Presently, the .NET Compact Framework supports only IPv4.

• The Socket class is the central socket connectivity object on the .NET Compact Framework. You must set up a connection with a Socket either as a host or a client before you can transmit data through a Socket .

• Once a Socket is connected, programs can read and write bytes using the Socket . With custom code you can serialize your .NET Compact Framework objects into byte arrays and transmit them through a Socket .

• You can use the UdpClient object to communicate using the UDP protocol. The UdpClient is also capable of multicasting, the act of sending packets to more than one destination.

• The HttpWebRequest encapsulates all of the logic needed to connect to a remote HTTP server, make a request, and receive a reply. It makes contacting HTTP servers with the .NET Compact Framework very easy.

• The HttpWebRequest is also capable of interacting with secure HTTPS servers without any special effort from the developer.

• The IrDAClient class encapsulates the logic needed to send and receive data through the device IrDA port.

• The IrDAClient can connect to a remote device's IrDA port either as a host or as a client. Establishing a connection requires special steps depending on whether the device acts as the host or client.

• Once an IrDAClient is connected, developers can access the underlying Stream object and use it to read and write data.