Internet timeline: Identify the decade when the Internet was first implemented. Context: Consider the first operational packet-switched network (ARPANET) leading to today's Internet. Choose the correct decade.

Given data

• Target: Decade of first implementation.
• Hint: ARPANET's initial nodes went live before TCP/IP standardization.

Concept / Approach
The first operational packet-switched network, ARPANET, began in 1969, in the 1960s. TCP/IP became standard later (1983), but initial implementation dates to the 1960s.

Verification
1969: UCLA–SRI link established; network expanded in early 1970s.

Final Answer
1960s.