First Two Reviews

End-To-End Arguments In System Design
E2E arguments is the biggest design concept in computer networking. It argues for that we be careful with the functionalities we make in each layer of the network. As a programmer, we have to make design decisions as to where to put the functionalities for error-checking or reliable deliveries of the packets in the network. The paper gives an example of distributing files over the network; it's exactly at the heart of what torrent and all the latest cloud computing is dealing with. Distributing a reliable file online requires having a method for checking the correctness of the bits sent over and its designers choice as to where and when to check these. E2E argues that it should be done by the host and the final receiver of the file. The paper analyzes performance aspect of putting the file-checking at different hops the file-chunk visits but that is redundant. There is not a clear solution to follow for it really depends on you to think carefully about the functionality you are to implement and use examples from the paper to make a good design decision.

The Design Philosophy of the DARPA Internet Protocols
ARPANET originated from the need to have a reliable communication method even in the war times. It started with packet-switching which would have burdened the network with unnecessary header information. Even with the delays introduced by the packet-switching, DARPA Internet Protocol is brilliant to integrate packet-switching in the protocol because it greatly reduces the complexities for the endpoint host. IP and TCP that we use today arose from this project as well. In order to make the network more reliable and failure-tolerant, TCP builds on top of the IP layer and makes the packets to come to the right process of the machine. However, TCP is too complicated of a protocol to be suitable for any general purpose use, so they introduced UDP which meets the very minimum requirement for packet delivery. DARPA Internet Protocol has an innovating ideas as Datagrams and design decisions as fate-sharing. It provided a very simple protocol for anyone to be able to join the network. Because of simplicity, it still is enjoying its success.