Function that allows receiving hosts to choose
the correct application for which the data is
destined, based on the port number.
IP address,Transport
protocol, Port number
(10.1.1.2, TCP, port
80)
Hosts typically
allocate dynamic
port numbers
starting at 1024
because the ports
below 1024 are
reserved for
well-known
applications.
20
TCP, FTP data
21
TCP,FTP control
22
TCP, SSH
23
TCP, Telnet
53
UDP, TCP, DNS
TCP for Zone Transfer
UDP for DNS Queries
25
TCP, SMTP
67,68
UDP, DHCP
UDP port 67 for sending data to the server,
and UDP port 68 for data to the client
69
UDP, TFTP
80
TCP, HTTP (WWW)
110
TCP, POP3
161
UDP, SNMP
443
TCP, SSL
Error recovery (reliability)
Process of numbering and
acknowledging data with Sequence
and Acknowledgment header fields.
Flow control using windowing
Process that uses window sizes to protect
buffer space and routing devices from being
overloaded with traffic.
Connection
establishment and
termination
Process used to initialize port
numbers and Sequence and
Acknowledgment fields.
Ordered data
transfer and data
segmentation
Continuous stream of bytes from an
upper-layer process that is “segmented”
for transmission and delivered to
upper-layer processes at the receiving
device, with the bytes in the same order.
Transmission Control Protocol
Provides error recovery
Relies on IP for
end-to-end delivery of
the data, including
routing issues
using 2 bits inside the
flag fields of the TCP
header. Called the SYN
and ACK flags
SYN means
“synchronize the
sequence numbers”
a three-way handshake
must complete before data
transfer can begin.