2.2 Common Protocols

The following are some of the more popular protocols.

-----|
application MIME--
layer |
-----|-----|-----|---------------|-----|
HTTP---FTP--SMTP---TELNET---SNMP---PING--
transport-----|---------- --------
layer -TCP-| -UDP-|
----------------------------------------
| |
|---------------------|
network --|
layer IP-

TCP (transmission control protocol)

Connection-based: The applications establish a connection before sending data back and forth over that connection.
Guarantees arrival of all data to the destination
Delivers the data in the same order it was sent.
TCP-based APIs: URL, URLConnection, Socket, ServerSocket

UDP (user datagram protocol)

A connection-less protocol.
Sends independent packets of data, called datagrams
Order of delivery is unpredictable
Delivery is not guaranteed
Less services than TCP; improved performance
UDP-based APIs: DatagramPacket, DatagramSocket, MulticastSocket

IP (Internet Protocol) is in charge of routing the packets