TCP AND UDP CONNECTIONS

Transport Control Protocol

refers to a connection-oriented TCP/IP standard transport layer protocol that provides reliable data delivery, duplicate data suppression, congestion control, and flow control on which many application protocols depend.

User Datagram Protocol

refers to a connectionless TCP/IP standard transport layer protocol that provides unreliable, best-effort service.

datagrams

UDP is a protocol that sends independent packets of data, called

32-bit IP address

The computer is identified by its _____, which it uses IP to deliver data to the specific computer on the network.

16-bit number

Ports are identified by a _____, which TCP and UDP use to deliver the data to the specific application.

Port numbers range from 0 to 65,535.

well-known ports

The port numbers ranging from 0 - 1023 are restricted; they are reserved for use by well known services such as HTTP and FTP and other system services

Source Port

identifies the application that sends the segment. This field is 16 bits long

Destination Port

identifies the application that receives the segment. This field is 16 bits long.

Sequence Number

refers to every byte of data sent over a TCP connection. The value of this field is equal to the sequence number of the first byte in a sent segment. This field is 32 bits long.

Acknowledgment Number

indicates the sequence number of the next segment's first byte that the receiver is expecting to receive. The value of this field is 1 plus the sequence number of the last byte in the previous segment that is successfully received. This field is 32 bits long.

Header Length

indicates the length of the TCP header. The unit is 32 bits (4 bytes). If there is no option content, the value of this field is 5, indicating that the header contains 20 bytes.

Reserved

this field is always set to 0 as it is intended for future protocol changes. It is 6 bits long.

Control Bits

include FIN, ACK, and SYN flags which indicate the TCP data segments in different states.

Window

is used for TCP flow control. The value is the maximum number of bytes that are allowed by the receiver.

Checksum

is a mandatory field in which it is calculated and stored by the sender and verified by the receiver.

Three-way handshake

is a method, in which the sender and the receiver inform their respective operating systems that a connection will be initiated before the actual data communication begins.

Sequence and Acknowledgment Number

fields to implement reliable and ordered data transmission.

Window Sliding Mechanism

requires the sender to receive an acknowledgment from the receiver after transmitting a certain amount of data.

TCP Shutdown (FourWay Handshake)

is engaged when the data transmission is complete in order to disconnect the TCP connection and release system resources.