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Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet and most commercial networks run. It is sometimes called the TCP/IP protocol suite, after the two most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were also the first two defined.
Today, most commercial operating systems include and install the TCP/IP stack by default. For most users, there is no need to look for implementations. TCP/IP is included in all commercial Unix systems, Mac OS X, and all free-software Unix-like systems such as Linux distributions and BSD systems, as well as Microsoft Windows.
Unique implementations include Lightweight TCP/IP, an open source stack designed for embedded systems and KA9Q NOS, a stack and associated protocols for amateur packet radio systems and personal computers connected via serial lines.
The layers near the top are logically closer to the user while those near the bottom are logically closer to the physical transmission of the data.
Each layer has an upper layer protocol and a lower layer protocol (except the top/bottom protocols, of course) that either use said layer's service or provide a service, respectively.
thumb|350px|IP suite stack showing the physical network connection of two hosts via two [routers and the corresponding layers used at each hop] thumb|511px|Sample encapsulation of data within a UDP datagram within an IP packet]
Viewing layers as providing or consuming a service is a method of abstraction to isolate upper layer protocols from the nitty gritty detail of transmitting bits over, say, Ethernet and collision detection while the lower layers avoid having to know the details of each and every application and its protocol.
This abstraction also allows upper layers to provide services that the lower layers cannot, or choose not, to provide.
For example, IP is designed to not be reliable and is a best effort delivery protocol. This means that all transport layers must choose whether or not to provide reliability and to what degree. UDP provides data integrity (via a checksum) but does not guarantee delivery; TCP provides both data integrity and delivery guarantee (by retransmitting until the receiver receives the packet).
Internet Assigned Numbers Authority (IANA) is broadly responsible for the allocation of globally-unique names and numbers that are used in Internet protocols that are published as RFC documents. It maintains a close liaison with the IETF and RFC Editor in fulfilling this function.
The tables below indicate a status with the following colors and tags:
- White color (Official) if the application and port combination is in the http://www.iana.org/assignments/port-numbers IANA list of port assignments;
- Blue color (Unofficial) if the application and port combination is not in the IANA list of port assignments; and
- Yellowish color (Conflict) if the port is being used commonly for two applications or protocols.
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