What term is defined as private data placed in a packet with a header containing routing information that allows the data to traverse a transit network, such as the internet?

Encapsulation

Explanation:

Encapsulation is referring to the concept that data buding with some approach or method that is applied to that selected data.  it also restricts the use of some internal data of an object. The motive behind restricting the data is to prevent the misuse of the data.

For example- in java, encapsulation is refer to the wrapping of code with the data in one unit.

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