Assignment #4 - IT 332 – Distributed Systems

spinabundantInternet and Web Development

Jul 30, 2012 (5 years and 2 months ago)

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King Saud University

College of Computer and Information Sciences

Department of information technology



IT 332







1
st

semester 1432/1433


Assignment

#
4




Q1

-

In many layered protocols, each layer has its own header. Surely it would be
more
efficient to have a single header at the front of each message with all the control
in it than all these separate headers. Why is this not done?


Q2

-

Consider a procedure
incr
with two integer parameters. The procedure adds one
to each parameter. Now suppose that it is called with the same variable twice, for
example, as
incr
(
i
,
i
). If
i
is initially 0, what value will it have afterward if call
-
by
-
reference is used? How about if
copy/restore is used?


Q3

-

Describe how connectionless communication between a client and a server
proceeds when using sockets.


Q4

-

Routing tables in IBM WebSphere, and in many other message
-
queuing systems,
are configured manually. Describe a simple wa
y to do this automatically
.


Q5

-

With persistent communication, a receiver generally has its own local buffer
where messages can be stored when the receiver is not executing. To create such a
buffer, we may need to specify its size. Give an argument why t
his is preferable, as
well as one against specification of the size.


Q6

-

Explain why transient synchronous communication has inherent scalability
problems, and how these could be solved
.


Q7

-

Give an example where multicasting is also useful for discrete datastreams.


Q8

-

How could you guarantee a maximum end
-
to
-
end delay when a collection of
computers is organized in a (logical or physical) ring?


Q9

-

How could you guarantee a minimum end
-
to
-
end delay when a collection of
computers is organized in a (logical or physical) ring
?