Exercise 3: Connections Service, Protocol Hierarchy, and Contention Deadline: Amount of points: Required submission: A) Connection...

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Exercise 3: Connections Service, Protocol Hierarchy, and Contention Deadline: Amount of points: Required submission: A) Connection services (6 points) 1) Give two example computer applications for which connection-oriented service is appropriate. 2) Now give two examples for which connectionless service is best. 3) Datagram networks route each packet as a separate unit, independent of all others. Virtual-circuit net- works do not have to do this, since each data packet follows a predetermined route. Does this observa- tion mean that virtual-circuit networks do not need the capability to route isolated packets from an arbitrary source to an arbitrary destination? Explain your answer. B) Protocol Hierarchy (8 points) 1) A system has an n-layer protocol hierarchy. Applications generate messages of length M bytes. At each of the layers, an h-byte header is added. What fraction of the network bandwidth is filled with headers? Feb. 25th 2020; 7am59 (CANVAS) 20 PDF document with name and person number 2) In Figure 1, a service is shown. Are any other services implicit in this figure? If so, where? If not, why not? Layer k + 1 Service provided by layer k Protocol Layer k Layer k-1 Layer k + 1 Layer k Layer k-1 Figure 1 - The relationship between a service and a protocol 3) Suppose the algorithms used to implement the operations at layer k is changed. How does this impact operations at layers k-1 and k + 1? 4) Suppose there is a change in the service (set of operations) provided by layer k. How does this impact services at layers k-1 and k+1? 5) Bonus-question without points: What does "negotiation" mean when discussing network protocols? Give an example. C) Throughput under contention (6 points) A disadvantage of a broadcast subnet is the capacity wasted when multiple hosts attempt to access the channel at the same time. As a simplistic example, suppose that time is divided into discrete slots, with each of the n hosts attempting to use the channel with probability p during each slot. What fraction of the slots will be wasted due to collisions? Exercise 3: Connections Service, Protocol Hierarchy, and Contention Deadline: Amount of points: Required submission: A) Connection services (6 points) 1) Give two example computer applications for which connection-oriented service is appropriate. 2) Now give two examples for which connectionless service is best. 3) Datagram networks route each packet as a separate unit, independent of all others. Virtual-circuit net- works do not have to do this, since each data packet follows a predetermined route. Does this observa- tion mean that virtual-circuit networks do not need the capability to route isolated packets from an arbitrary source to an arbitrary destination? Explain your answer. B) Protocol Hierarchy (8 points) 1) A system has an n-layer protocol hierarchy. Applications generate messages of length M bytes. At each of the layers, an h-byte header is added. What fraction of the network bandwidth is filled with headers? Feb. 25th 2020; 7am59 (CANVAS) 20 PDF document with name and person number 2) In Figure 1, a service is shown. Are any other services implicit in this figure? If so, where? If not, why not? Layer k + 1 Service provided by layer k Protocol Layer k Layer k-1 Layer k + 1 Layer k Layer k-1 Figure 1 - The relationship between a service and a protocol 3) Suppose the algorithms used to implement the operations at layer k is changed. How does this impact operations at layers k-1 and k + 1? 4) Suppose there is a change in the service (set of operations) provided by layer k. How does this impact services at layers k-1 and k+1? 5) Bonus-question without points: What does "negotiation" mean when discussing network protocols? Give an example. C) Throughput under contention (6 points) A disadvantage of a broadcast subnet is the capacity wasted when multiple hosts attempt to access the channel at the same time. As a simplistic example, suppose that time is divided into discrete slots, with each of the n hosts attempting to use the channel with probability p during each slot. What fraction of the slots will be wasted due to collisions?