Provide a concrete example of the dilemma offered by Saltzer’s end-to-end argument in the context of the provision of middleware support for distributed applications (you may want to focus on one aspect of providing dependable distributed systems, for example related to fault tolerance or security).

Question

What will be an ideal response?

Answer 1

Saltzer’s end-to-end argument states that communication-related functions can only be completely and reliably implemented with the knowledge and help of the application and therefore providing that function as a feature of the communication system itself (or middleware) is not always sensible. One concrete example is in secure communication. Assume that in a given system, the communication subsystem provides encrypted communication. This is helpful but insufficient. For example, the pathway from the network to the application software may be compromised and this is unprotected. This solution also does not deal with malicious participants in the exchange of data.
Saltzer’s end-to-end argument states that communication-related functions can only be completely and reliably implemented with the knowledge and help of the application and therefore providing that function as a feature of the communication system itself (or middleware) is not always sensible. One concrete example is in secure communication. Assume that in a given system, the communication subsystem provides encrypted communication. This is helpful but insufficient. For example, the pathway from the network to the application software may be compromised and this is unprotected. This solution also does not deal with malicious participants in the exchange of data.