- What is a socket?
A socket is an abstraction that represents one endpoint of a communication link between systems.
- What is a connectionless protocol? What is a connection-oriented protocol?
A connection-oriented protocol sends data packets in the context of a larger stream of data. A connectionless protocol sends each packet of data independently of any before or after it.
- Is UDP a connectionless or connection-oriented protocol?
UDP is considered a connectionless protocol. Each message is sent independently of any before or after it.
- Is TCP a connectionless or connection-oriented protocol?
TCP is considered a connection-oriented protocol. Data is sent and received in order as a stream.
- What types of applications generally benefit from using the UDP protocol?
UDP applications benefit from better real-time performance while sacrificing reliability. They are also able to take advantage of IP multicasting.
- What types of applications generally benefit from using the TCP protocol?
Applications that need a reliable stream of data transfer benefit from the TCP protocol.
- Does TCP guarantee that data will be transmitted successfully?
TCP makes some guarantees about reliability, but nothing can truly guarantee that data is transmitted successfully. For example, if someone unplugs your modem, no protocol can overcome that.
- What are some of the main differences between Berkeley sockets and Winsock sockets?
The header files are different. Sockets themselves are represented as signed versus unsigned ints. When socket() or accept() calls fail, the return values are different. Berkeley sockets are also standard file descriptions. This isn't always true with Winsock. Error codes are different and retrieved in a different way. There are additional differences, but these are the main ones that affect our programs.
- What does the bind() function do?
The bind() function associates a socket with a particular local network address and port number. Its usage is almost always required for the server, and it's usually not required for the client.
- What does the accept() function do?
The accept() function will block until a new TCP client has connected. It then returns the socket for this new connection.
- In a TCP connection, does the client or the server send application data first?
Either the client or the server can send data first. They can even send data simultaneously. In practice, many client-server protocols (such as HTTP) work by having the client send a request first and then having the server send a response.
