QUESTION 1 (12 marks) Consider the internal operation of a packet switch such as an Internet Router. When designing such

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Question 1 12 Marks Consider The Internal Operation Of A Packet Switch Such As An Internet Router When Designing Such 1 (147.59 KiB) Viewed 34 times

QUESTION 1 (12 marks) Consider the internal operation of a packet switch such as an Internet Router. When designing such a switch, a key objective is to maximise utilisation of the switching fabric and avoid any bottlenecks that might result when the same resource is required by multiple packets being switched. a) When several input ports contain packets destined for the same output port, an obvious solution would be to use output port buffers to store switched packets before they are transmitted from the switch output. Why is this NOT considered a satisfactory solution? [3 mark] b) What is the "head-of-line blocking” problem? Explain with the aid of a diagram. [4 marks] c) Describe a switch architecture that would not suffer from the "head-of-line blocking" problem. Explain any major “cost" of your solution (e.g. it may require increased complexity, memory, processor speed, etc.). [5 marks]