What is message formatting and encapsulation, and why is it important?

A message must use a specific structure (format) that both ends agree on; the format depends on the message type and the channel used to deliver it.

Message formatting means that when a message is sent, it must use a specific format or structure.

Key points:

• Message formats depend on the type of message and the channel used to deliver it
• Like a letter has specific fields (recipient address, sender address, content), network messages have specific header fields

Example: An IPv6 packet header contains fields like Version, Traffic Class, Flow Label, Payload Length, Next Header, Hop Limit, Source IP Address, and Destination IP Address - all in a specific 40-byte format.

Go deeper:

• Encapsulation (networking) — how each layer wraps data in its own header/trailer format.
• Communication protocol — message formatting — why a shared structure is required for both ends to parse a message.