  Blockchain has been considered as an important technique to enable secure
management of virtual network functions and network slices. To understand such
capabilities of a blockchain, e.g. transaction confirmation time, demands a
thorough study on the transaction characteristics of the blockchain. This paper
presents a comprehensive study on the transaction characteristics of Bitcoin --
the first blockchain application, focusing on the underlying fundamental
processes. A set of results and findings are obtained, which provide new
insight into understanding the transaction and traffic characteristics of
Bitcoin. As a highlight, the validity of several hypotheses/assumptions used in
the literature is examined with measurement for the first time.
