Can you explain what is meant by 'header' in the context of computer communications?

In the context of computer communications, the term "header" refers to a part of the data that precedes the main content (payload) and contains control information necessary for the proper processing and transmission of the message.

The header may include:

• Sender and receiver addresses
• Protocol type
• Message size
• Routing information
• Checksums for integrity verification

For example, in an HTTP request, headers contain information about the browser type, accepted formats, cookies, etc., while in network packets, the header contains IP addresses and port numbers.

Thus, the header helps systems correctly interpret and process data, ensuring reliable communication.