Topic

CSMA/CD

5 questions in this topic.

2013 Q4(a)Link LayerCSMA/CD· 2 marks

If clients listen for an empty link before transmitting, how is it possible that collisions can occur?

Ethernetcollision

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2014 Q4(c)Link LayerCSMA/CD· 6 marks

Explain how CSMA/CD is implemented in Ethernet. You may express your answer as an algorithm if you wish.

Ethernetmedium accesscollision

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2014 Q4(f)Link LayerCSMA/CD· 2 marks

Explain how the use of full-duplex mode in a LAN can reduce collisions to zero.

Ethernetswitching

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2015 Q5(c)Link LayerCSMA/CD· 4 marks

CSMA/CD efficiency is governed by the equation shown. There are two ways to improve the efficiency of a CSMA/CD network 1) increase the transmission delay or 2) decrease the propagation delay. Explain how each of these could be achieved in an actual network without changing the medium of the link (ie you can’t change from optical fibre to copper). efficiency = 1/1 + 5tprop/ttrans

Ethernetefficiency

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2015 Q5(g)Link LayerCSMA/CD· 3 marks

Given that in a CSMA/CD protocol using binary exponential back off, the adapter waits K × 512 bit times after a collision, where K is drawn randomly. What is the maximum length of time the adapter will wait until the next transmission attempt given 7 collision has occured so far. Assume that you have a 10 Mbps broadcast channel?

Ethernetbackoff

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