In fact I googled https://www.google.com/search?q=Suppose+the+network+layer+provides+the+following+service.+The+network+layer+in+the+source+host+accepts+a+segment+of+maximum+size+1%2C200+bytes+and+a+des&ie=utf-8&oe=utf-8 and found it's been spammed on the web.
Don't do that.
Suppose the network layer provides the following service. The network layer in the source host accepts a segment of maximum size 1,200 bytes and a destination host address from the transport layer. The network layer then guarantees to deliver the segment to the transport layer at the destination host. Suppose many network application processes can be running at the destination host.
a. Design the simplest possible transport-layer protocol that will get application data to the desired process at the destination host. Assume the operating system in the destination host has assigned a 4-byte port number to each running application process.
b. Modify this protocol so that it provides a "return address" to the destination process.
c. In your protocols, does the transport layer "have to do anything" in the core of the computer network?
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