One Hop at a Time: teacher key

The Internet, grade 8 edition, written for 8th grade. A packet crosses the internet one hop at a time. Find out how routers choose a way, how TCP opens a connection, how names are looked up and how cables are laid on the sea floor.

Read the book. Print this page for the key.

Questions and answers

1. What is choosing which way to send a packet called?
   • Resolving
   • Routing (answer)
   • Handshaking
2. What happens when an IPv6 packet's hop limit reaches zero?
   • It is sent faster
   • It becomes an email
   • It is thrown away (answer)
3. Why was DNS developed in 1983?
   • Cables were too heavy
   • A list of every computer's number and name could not keep up with growth (answer)
   • Browsers needed pictures
4. What does a content delivery network do?
   • Sells domain names
   • Lays undersea cables
   • Answers each request from the closest server (answer)
5. What causes most damage to these cables, as of November 2026?
   • Fishing and ships dragging anchors (answer)
   • Sharks
   • Routers

Words

• routing: choosing a way
• handshake: connection setup
• resolver: DNS asker
• registrar: domain seller
• registry: runs a domain