Editing Network packet (section)

== Examples ==

=== Internet protocol ===
IP packets are composed of a header and payload. The header consists of fixed and optional fields. The payload appears immediately after the header. An IP packet has no trailer. However, an IP packet is often carried as the payload inside an Ethernet frame, which has its own header and trailer.

Per the [[end-to-end principle]], IP networks do not provide guarantees of delivery, non-duplication, or in-order delivery of packets. However, it is common practice to layer a [[Reliability (computer networking)|reliable]] [[transport protocol]] such as [[Transmission Control Protocol]] on top of the packet service to provide such protection.

=== NASA Deep Space Network ===
The Consultative Committee for Space Data Systems ([[CCSDS]]) packet telemetry standard defines the protocol used for the transmission of spacecraft instrument data over the deep-space channel. Under this standard, an image or other data sent from a spacecraft instrument is transmitted using one or more packets.

=== MPEG packetized stream ===
[[Packetized elementary stream]] (PES) is a specification associated with the [[MPEG-2]] standard that allows an [[elementary stream]] to be divided into packets. The elementary stream is packetized by encapsulating sequential data bytes from the elementary stream between PES packet headers.

A typical method of transmitting elementary stream data from a video or audio encoder is to first create PES packets from the elementary stream data and then to encapsulate these PES packets inside an [[MPEG transport stream]] (TS) packets or an [[MPEG program stream]] (PS). The TS packets can then be transmitted using broadcasting techniques, such as those used in an [[ATSC tuner|ATSC]] and [[Digital Video Broadcasting|DVB]].

=== NICAM ===
In order to provide [[Monaural|mono]] ''compatibility'', the [[NICAM]] signal is transmitted on a [[subcarrier]] alongside the sound carrier. This means that the [[Frequency modulation|FM]] or [[Amplitude modulation|AM]] regular mono sound carrier is left alone for reception by monaural receivers. The NICAM packet (except for the header) is scrambled with a nine-bit pseudo-random bit-generator before transmission. Making the NICAM bitstream look more like [[white noise]] is important because this reduces signal patterning on adjacent TV channels.