Question #11

a. A client makes RMIs to a server. The client takes 5 ms to compute the arguments for each request, and the server takes 10 ms to process each request. The local OS processing time for each send or receive operation is 0.5 ms, and the network time to transmit each request or reply message is 3 ms. Marshalling or unmarshalling takes 0.5 ms per message.

Estimate the time taken by the client to generate and return from two requests

(i) if it is single-threaded, and

(ii) if it has two threads that can make requests concurrently on a single processor.

Is there a need for asynchronous RMI if processes are multi-threaded?

b. Network transmission time accounts for 20% of a null RPC and 80% of an RPC that transmits 800 user bytes (less than the size of a network packet). By what percentage will the times for these two operations improve if the network is upgraded from 5 megabits/second to 100 megabits/second?