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Transporting packets


The US postal service can serve as an analogy for Internet transport protocols.
The postal service offers various services:
  • First class letter: the default service with no extras.
  • Certified mail: sent using the standard route but provides the sender with proof that the letter was delivered.
  • Registered mail: sent using secure mechanisms along the way (e.g. locked cages).
Similarly, there are multiple transport protocols that can be used on top of IP, with TCP and UDP being the most popular.
Which analogy between the transport protocols and USPS services makes the most sense?
Choose 1 answer: