In this lesson, you will learn terms multiplexing and demultiplexing and how TCP can support multiple network applications using port numbers.
Transport Layer protocols (TCP and UDP) are responsible for supporting multiple network applications at the same instance and these applications can send and receive network data simultaneously. Transport Layer Protocols are capable of doing this by making use of application level addressing, known as port numbers. The data from different applications operating on a network device are multiplexed at the sending device using port numbers and demultiplexed at the receiving device, again using port numbers.
The two 16 bit fields in the TCP Header, Source port and Destination port identifies the port number which the application is listening at the sending device and receiving device. Since port number is a 16 bit number, the maximum possible value is 65535 ((2^16)-1).
The port numbers are divided into three ranges.
The Well Known Ports are those in the range 0 - 1023. The Well Known Ports are assigned by the IANA for major protocols.
The Registered Ports are those in the range 1024 - 49151.
The Private Ports are those in the range 49152 - 65535.
Port Number |
Description |
1 |
TCP Port Service Multiplexer (TCPMUX) |
5 |
Remote Job Entry (RJE) |
7 |
ECHO |
18 |
Message Send Protocol (MSP) |
20 |
FTP - Data |
21 |
FTP - Control |
22 |
SSH Remote Login Protocol |
23 |
Telnet |
25 |
Simple Mail Transfer Protocol (SMTP) |
29 |
MSG ICP |
37 |
Time |
42 |
Host Name Server (Nameserv) |
43 |
WhoIs |
49 |
Login Host Protocol (Login) |
53 |
Domain Name System (DNS) |
69 |
Trivial File Transfer Protocol (TFTP) |
70 |
Gopher Services |
79 |
Finger |
80 |
HTTP |
103 |
X.400 Standard |
108 |
SNA Gateway Access Server |
109 |
POP2 |
110 |
POP3 |
115 |
Simple File Transfer Protocol (SFTP) |
118 |
SQL Services |
119 |
Newsgroup (NNTP) |
137 |
NetBIOS Name Service |
139 |
NetBIOS Datagram Service |
143 |
Interim Mail Access Protocol (IMAP) |
150 |
NetBIOS Session Service |
156 |
SQL Server |
161 |
SNMP |
179 |
Border Gateway Protocol (BGP) |
190 |
Gateway Access Control Protocol (GACP) |
194 |
Internet Relay Chat (IRC) |
197 |
Directory Location Service (DLS) |
389 |
Lightweight Directory Access Protocol (LDAP) |
396 |
Novell Netware over IP |
443 |
HTTPS |
444 |
Simple Network Paging Protocol (SNPP) |
445 |
Microsoft-DS |
458 |
Apple QuickTime |
546 |
DHCP Client |
547 |
DHCP Server |
563 |
SNEWS |
569 |
MSN |
1080 |
Socks |
You have learned the terms TCP multiplexing and demultiplexing and application addressing using port numbers. Click "Next" to continue.
Related Topics...
• TCP/IP Transport Layer
• Transmission Control Protocol (TCP)
• Transmission Control Protocol (TCP) Segment Header
• TCP Three-way Handshake
• Transmission Control Block (TCB)
• TCP Sliding Window
• TCP Connection Termination
• User Datagram Protocol (UDP)
• Differences between TCP and UDP
