Header (information Technology)

In data transmission, the data following the header are sometimes called the '' Payload '' or '' Body ''.

It is vital that header composition follow a clear and unambiguous Specification or Format , to allow for Parsing .

Examples

In an E-mail , the text (body) is preceded by header lines indicating sender, recipient, subject, sending time stamp, receiving time stamps of all intermediate and the final Mail Transfer Agent s, and much more. (See RFC 2822 for details.)

In a data packet sent through the internet, the data (payload) are preceded by header information such as the sender's and the recipient's IP Address es, the Protocol governing the format of the payload and several other formats. The header's format is specified in the Internet Protocol .

In data packets sent by Wireless Communication , and in Sector s of data stored on Magnetic Media , typically the header begins with a Syncword to allow the receiver to adapt to analog amplitude and speed variations and for Frame Synchronization .

In Graphics File Format s, the header might give information about an image's size, resolution, number of colors, and the like. See HTML Element .

In some Programming Language s (for example C and C++ ) the Functions are declared in Header File s.

EXTERNAL LINKS

Reading Email Headers

	APPAREL
	BABY
	BEAUTY
	BOOKS
	CAR TOYS
	CELL PHONES
	DVD'S
	ELECTRONICS
	GOURMET FOOD
	GROCERIES
	HEALTH & PERSONAL
	HOME & GARDEN
	JEWELRY
	MUSIC
	MUSIC INSTRUMENTS
	OFFICE PRODUCTS
	SOFTWARE
	SPORTING GOODS
	TOOLS & HARDWARE
	TOYS
	VIDEO GAMES
	SHOPPING HOME

	MORE SHOPPING...

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Header (information Technology)