Many layers of protocols are described in the IEEE-1394 standard, and each serves a specific purpose. IEEE-1394 is a medium for data transmission and does not specify the protocol to use. The general specifications for computers are architectures for communicating with other devices. Protocols are a special set of communication guidelines that the nodes on a 1394 bus must use when sending packets to each other.
Protocols are necessary because they simplify and standardize data transmission between nodes.
They also encourage interoperability and push the limits of the FireWire bus because all similar devices speak the same language. For more information, please visit the Mindready website.