The Transport and Application Layers Flashcards
One of the TCP control flags. Short for acknowledge. A value of one in this field means that the acknowledgement number field should be examined
ACK FLAG
The number of the next expected segment in a TCP sequence
ACKNOWLEDGEMENT NUMBER
The layer that allows network applications to communicate in a way they understand
APPLICATION LAYER
The entire contents of whatever data applications want to send to each other
APPLICATION LAYER PAYLOAD
A connection state that indicates that the connection has been fully terminated, and that no further communication is possible
CLOSE
A connection state that indicates that the connection has been closed at the TCP layer, but that the application that opened the socket hasn’t released its hold on the socket yet
CLOSE_WAIT
A data-transmission protocol that establishes a connection at the transport layer, and uses this to ensure that all data has been properly transmitted
CONNECTION-ORIENTED PROTOCOL
A data-transmission protocol that allows data to be exchanged without an established connection at the transport layer. The most common of these is known as UDP or User Datagram Protocol
CONNECTIONLESS PROTOCOL
The number of the next expected segment in a TCP packet/datagram
DATA OFFSET FIELD
Taking traffic that’s all aimed at the same node and delivering it to the proper receiving service
DEMULTIPLEXING
The port of the service the TCP packet is intended for
DESTINATION PORT
Status indicating that the TCP connection is in working order, and both sides are free to send each other data
ESTABLISHED
One of the TCP control flags. Short for finish. When this flag is set to one, it means the transmitting computer doesn’t have any more data to send and the connection can be closed
FIN
A TCP socket state indicating that a FIN has been sent, but the corresponding ACK from the other end hasn’t been received yet.
FIN_WAIT
A device that blocks or allows traffic based on established rules
FIREWALL
An older method used for transferring files from one computer to another, but you still see it in use today
FTP
A way for two devices to ensure that they’re speaking the same protocol and will be able to understand each other
HANDSHAKE
The actual implementation of something defined elsewhere
INSTANTIATION
It means that a TCP socket is ready and listening for incoming connections
LISTEN
It meant that nodes on the network have the ability to direct traffic toward many different receiving services
MULTIPLEXING
It is sometimes used for more complicated flow control protocols
OPTIONS FIELD
A 16-bit number that’s used to direct traffic to specific services running on a network computer
PORT
It is responsible for making sure that the unencapsulated application layer data is actually able to be understood by the application in question
PRESENTATION LAYER
A TCP control flag short for push. this flag meant that the transmitting device whats the receiving device to push currently-buffered data to the application on the receiving end as soon as possible
PSH FLAG
A TCP control flag short for reset. This flag means that one of the sides in a TCP connection hasn’t been able to properly recover from a series of missing or malformed segments
RST FLAG
A 32-bit number that’s used to keep track of where in a sequence of TCP segments this one is expected to be
SEQUENCE NUMBER
A program running on a computer waiting to be asked for data
SERVER or SERVICE
The network layer responsible for facilitating the communication between actual applications and the transport layer
SESSION LAYER
The instantiation of an endpoint in a potential TCP connection
The instantiation of an endpoint in a potential TCP connection
SOCKET
A high numbered port chosen from a special section of ports known as ephemeral ports
SOURCE PORT
A TCP flag that stands for synchronize. This flag is used when first establishing a TCP connection and make sure the receiving end knows to examine the sequence number field
SYN FLAG
A TCP socket state that means that a socket previously in a listener state, has received a synchronization request and sent a SYN_ACK back
SYN_RECEIVED
A TCP socket state that means that a synchronization request has been sent, but the connection hasn’t been established yet
SYN_SENT
A mechanism that makes sure that no data is lost or corrupted during a transfer
TCP CHECKSUM
A payload section of an IP datagram made up of a TCP header and a data section
TCP SEGMENT
The range of sequence numbers that might be sent before an acknowledgement is required
TCP WINDOW
A TCP control flag short for urgent. A value of one here indicates that the segment is considered urgent and that the urgent pointer field has more data about this
URG FLAG
A field used in conjunction with one of the TCP control flags to point out particular segments that might be more important than others
URGENT POINTER FIELD
