Computer Networks: Sockets and Network APIs

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What is the primary difference between connectionless sockets and TCP/IP?

Connectionless sockets use UDP, which provides an unreliable, best-effort networking service, whereas TCP/IP provides a reliable, connection-oriented service.

What is the analogy used to explain client-server addresses, ports, and sockets?

An apartment building, mailboxes, and post office, where the apartment building is the address, mailbox is the port, and socket is the key to access the mailbox.

What is the high-level process for a client to establish a connection?

Create a socket, set up the server address, connect to the server, read/write data, and shutdown the connection.

What is the primary function of the UDP protocol?

To provide transport layer addressing in the form of UDP ports, with an optional checksum capability. Signup and view all the answers

What is the purpose of the checksum field in the UDP header?

To allow the sender and receiver to check for data corruption. Signup and view all the answers

What is the key difference between UDP and TCP/IP in terms of transmission?

UDP does not require setting up special transmission channels or data paths beforehand, unlike TCP/IP. Signup and view all the answers

What is the main purpose of sockets in computer networking?

To provide an abstraction for interprocess communication and define an endpoint for communication Signup and view all the answers

What is the primary function of a socket in a client-server architecture?

To establish a connection between the client and server and facilitate data transfer Signup and view all the answers

What is the key difference between stream sockets and datagram sockets?

Stream sockets provide reliable, connected networking service, whereas datagram sockets provide connectionless service Signup and view all the answers

In a stream socket, how does the server process establish a connection with clients?

The server binds an address that clients can use to find the server and then waits for client requests Signup and view all the answers

What type of socket is used in applications such as telnet and http?

Stream socket (connection-oriented socket) Signup and view all the answers

What is the primary characteristic of datagram sockets?

They do not establish a connection before transferring data Signup and view all the answers

What is the purpose of computing a checksum before sending off a segment?

To create a fingerprint for the message/file that can be used to detect errors in the data. Signup and view all the answers

How does UDP handle acknowledgement and error detection?

It does not; acknowledgement and error detection must be done by the application layer. Signup and view all the answers

What is the significance of pseudo headers in UDP?

They help find transfer bit errors and protect against other network errors, such as IP datagrams reaching the wrong host. Signup and view all the answers

When is it better to use a TCP Socket for communication?

When acknowledgement is necessary. Signup and view all the answers

What type of service does UDP provide?

A byte stream service. Signup and view all the answers

What is the significance of the `count` variable in the `send()` and `recv()` functions?

The <code>count</code> variable returns the number of bytes transmitted or received, or -1 if an error occurs. Signup and view all the answers

What is the purpose of the `flags` parameter in the `send()` and `recv()` functions?

The <code>flags</code> parameter specifies special options, usually set to 0 for acknowledgement. Signup and view all the answers

What are the challenges of dealing with blocking calls in network programming, and how can they be addressed?

Blocking calls can be challenging because they can cause the program to wait indefinitely. This can be addressed by creating multi-process or multi-threaded code, turning off the blocking feature, or using the <code>select()</code> function. Signup and view all the answers

What is the role of the `select()` function in network programming?

The <code>select()</code> function allows the program to monitor multiple sockets for input and perform non-blocking I/O operations. Signup and view all the answers

What are the differences between a simple connection and a complex connection routine?

A simple connection involves a single connection and sequential sends and receives, while a complex connection routine involves multiple connections, simultaneous sends and receives, and non-networking processing. Signup and view all the answers

What is the purpose of the `bind()` function in TCP client socket creation?

The <code>bind()</code> function associates a local address and port with a socket. Signup and view all the answers

Connectionless Sockets

Sockets that use UDP for communication, providing unreliable, best-effort service.

TCP/IP

A reliable, connection-oriented networking protocol.