Module 3 Transport and Application Layer Flashcards
ACK Flag
One of the TCP control flags. ACK is short for acknowledge. A value of one in this
field means that the acknowledgment number field should be examined
Acknowledgement number
The number of the next expected segment in a TCP sequence
Application layer
The layer that allows network applications to communicate in a way they
understand
Application layer payload
The entire contents of whatever data applications want to send to
each other
CLOSE
A connection state that indicates that the connection has been fully terminated, and
that no further communication is possible
CLOSE_WAIT
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
Connection-oriented protocol
A data-transmission protocol that establishes a connection at
the transport layer, and uses this to ensure that all data has been properly transmitted
Connectionless 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
Data offset field
The number of the next expected segment in a TCP packet/datagram
Demultiplexing
Taking traffic that’s all aimed at the same node and delivering it to the proper
receiving service
Destination port
The port of the service the TCP packet is intended for
ESTABLISHED
Status indicating that the TCP connection is in working order, and both sides
are free to send each other data
FIN
One of the TCP control flags. FIN is 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_WAIT
A TCP socket state indicating that a FIN has been sent, but the corresponding ACK
from the other end hasn’t been received yet
Firewall
It is a device that blocks or allows traffic based on established rules
