In 1986, NSFNET connected 6 university departments across the US. How many routes exist between NCAR and JVNC if any connection can fail?

In 1986, NSFNET connected 6 university departments across the US. How many routes exist between NCAR and JVNC if any connection can fail?

• A. 4 departments across the US.
• B. 8 departments across the US.
• C. 10 departments across the US.
• D. 6 departments across the US.

Answer: (D)

Redundancy is the idea here: when any single connection could fail, you want multiple independent routes between two sites. In 1986, NSFNET connected six university departments across the United States, so there are six potential routes between NCAR and JVNC—one route that can go through each department in the network. This means even if one link drops, there are other routes available, up to six distinct ways to get from NCAR to JVNC in this setup. The other numbers only reflect different ways of counting possible intermediate paths, but the question’s framing points to the total participating departments as the count of routes.

Redundancy is the idea here: when any single connection could fail, you want multiple independent routes between two sites. In 1986, NSFNET connected six university departments across the United States, so there are six potential routes between NCAR and JVNC—one route that can go through each department in the network. This means even if one link drops, there are other routes available, up to six distinct ways to get from NCAR to JVNC in this setup. The other numbers only reflect different ways of counting possible intermediate paths, but the question’s framing points to the total participating departments as the count of routes.