A "data structure," as its name implies, has
structure. Your data does not have any initial structure other than packet lengths or delimiters, so it doesn't qualify as a data structure. Look at any other
data structure: it is a
container for data. What you're describing is just data. If you wrote a class that implemented the protocol you described and exposed the resulting elements as a collection of first-class objects,
then you would have a data structure. —
Robert Harvey 3 mins ago