4.$4.$ Answer the below questions:

a.$.$ Mistakenly, it is said that UDP is always faster than TCP.$.$ However, this is not the case always. Briefly explain why this is not the case always ($($In a few cases, TCP becomes faster than UDP. Please give a case).$).$

b.$.$ What is the purpose of $$timeout$$ mechanism? ($($Please give at least one purpose).$).$

c.$.$ What is $$pipelining$$ in a protocol?

d.$.$ How does TCP react to congestion in $$congestion avoidance$$ phase?

e.$.$ What is the function of Dijkstra algorithm?