How it works
Protocols are rules for communication. Packets are pieces of data that can travel across networks and be reassembled.
Identify which protocol idea fits the task: naming, routing, reliable delivery, secure web traffic, or email transfer.
Common error
Packets may travel different paths; this supports resilience but can also make timing unpredictable.
Worked example
Interpret packet switching and reliable application delivery.
Data / pseudocode
Message packets sent: 1, 2, 3
Observed arrival order: 2, 1
Packet 3: not yet receivedPacket networks can produce loss, delay, and reordering. A transport or application reliability mechanism can identify missing or reordered data and recover when needed. IP forwarding alone does not guarantee that all pieces arrive in order.
Exercises
4.2.1
Why can two packets from the same message take different network paths?
Show solution
Routers make forwarding decisions using current routing information and network conditions. Packet switching does not require one permanently reserved end-to-end path for the message.
4.2.2
What responsibilities are distinct between IP routing and a reliable transport mechanism?
Show solution
IP supports addressing and packet forwarding. A reliable transport mechanism additionally manages ordered delivery and recovery of missing data, subject to the protocol and connection conditions.