TCP Protocol: Connection, Segments, and Reliability in Networking

What type of service is TCP?

TCP is a connection-oriented service.

What is the purpose of the three-way handshake in TCP?

It allows hosts to exchange preliminary information before sending data.

What does it mean that TCP is a full-duplex service?

Both hosts can act as sender and receiver simultaneously.

What is the nature of TCP connections?

TCP connections are point-to-point, meaning a segment cannot be sent to multiple receivers at once.

What is a send buffer in a TCP connection?

It is where each application process maintains data while waiting to be sent to the other application process.

How is the maximum segment size (MSS) determined in TCP?

MSS is usually chosen based on the link layer maximum transmission unit (MTU), typically 1460 bytes for Ethernet.

What are the key components of a TCP segment structure?

Source and destination port numbers, sequence and acknowledgment numbers, options field, header length, receive window, urgent data pointer, and flag field.

What do sequence numbers in TCP refer to?

Sequence numbers refer to bytes, not segments, indicating the order of data transmission.

What is the purpose of acknowledgment numbers in TCP?

They indicate the sequence number of the next byte expected to be received from the other host.

What happens when TCP receives out-of-order segments?

TCP can either discard them or buffer them until the missing segments arrive; most implementations choose to buffer.

How are starting sequence numbers generated in TCP?

Each host's starting sequence number is randomly generated at the beginning of a TCP connection to prevent reuse issues.

What is the role of timeouts in TCP?

Timeouts need to be at least as long as the expected round-trip time (RTT) between the two hosts.

What is cumulative acknowledgment in TCP?

It means TCP only acknowledges bytes up to the first missing byte.

What is the significance of the urgent data pointer in TCP?

It indicates the presence of urgent data that should be sent immediately, although it is rarely used in practice.

What is the TCP segment header length defined by?

The header length is defined in 32-bit words, accounting for the variable length due to the options field.

What is the typical size of a TCP header?

The TCP header is typically 20 bytes without options.

What does the flag field in a TCP segment indicate?

It indicates control flags such as acknowledgment (ACK), reset (RST), synchronize (SYN), and finish (FIN) for connection management.

How does TCP handle the transmission of application data?

TCP views application data as an unstructured, ordered stream of bytes.

What is the maximum transmission unit (MTU) for Ethernet?

The MTU for Ethernet is typically 1500 bytes.

What is the purpose of the options field in a TCP segment?

The options field is optional and can vary in length, allowing for additional features in the TCP segment.

How does TCP ensure reliable data transfer?

By using sequence and acknowledgment numbers to track the delivery of data segments.