CS542 Bharat Bhargava
Homework 4
Due: 04/25/02
Max. Marks: 120
 

Question 1:
               a)  What are the communication requirements for building distributed
                    database systems? (6)
 
               b)  What facilities are needed for efficient distributed transaction processing
                    functions? (7)
 
               c)  What do we need to do for communication facility to build a large scale
                    distributed system (say 1,000 site system). (7)
 

Question 2:
               a)  Quote some numbers for the latency of communication or round trip times
                    for all types of networks across all distribution of physical sites (interprocess,
                    LAN, MAN, WAN in US or around the world). (4)
 
               b)  How can we measure the delays and round trip times between multiple sites
                    and how can we improve them? (8)
 
               c)  What do we need in transaction processing if we can not improve the
                    communication behavior any further and must deal with the way it exists? (8)
 

Question 3: How would you change the design and algorithms for distributed database
                    processing if the communication delay was three time higher than normal? (20)
 

Question 4: How would you change the design and algorithms for distributed database
                    processing if the communication delay was almost zero? (20)
 

Question 5: How would you change the design and algorithms for distributed database
                    processing if there were multiple and frequent failures (like sites failing and
                    recovering, network partitions, variable communication delays, many lost
                    messages) ? (20)
 

Question 6: Consider applications such as Digital Libraries, Electronic Commerce, Video
                    Conferencing.
 
                    a)  What type of communication behavior (in terms of round trip times, reliability)
                         are required in such applications? (7)
 
                    b)  How can we deal with the bandwidth and network capacity to realize such
                         applications and make them a success. (7)
 
                    c)  What will be the performance evaluation criterion for such systems? (6)