Question $3$:

$(25$ marks$)$

a$.$ Draw and explain important properties of distributed consensus with a suitable example.

$(4$ marks$)$

b$.$ Draw and explain various steps of a generic distributed consensus algorithm? Illustrate all the steps using the same example and a suitable diagram for each step. $(16$ marks$)$

c$.$ What is the required condition to manage crash fault and Byzantine fault in a consensus algorithm? Illustrate with a numerical example and a suitable diagram.

$(5$ marks$)$

Page $2$ of $3$

May $2024$

This assessment is subject to the University Assessment Regulations for Candidates

CS$2$IDS

Question $4$:

$(25$ marks$)$

a$.$ Draw and explain an underlay network and overlay network, and explain why do we use an overlay network.

$(5$ marks$)$

b$.$ Draw and explain the difference between the layer and tier in client$-$server architecture with a suitable example.

$(5$ marks$)$

c$.$ How does the earth's rotating speed affect our clocks? Explain how we adjust our clocks in both conditions if the earth rotates slower and faster.

$(5$ marks$)$

d$.$ Explain the difference between the DLS Consensus Algorithm and PBFT Consensus Algorithm based on:

Various Roles$/$Actors$,$

Various Rounds$/$Phases$,$

Leader Election and Failure,

Consensus Process $($e$.$g$.,$ Log Replication$/$ Propagation$/$ Commit Process$),$

Fault Tolerance, Recovery and Safety.

$(10$ marks$)$