cnp3-ebook/exercises/reliability

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1 ../../exercises/reliability.rst:7

	English Reliable transfer 17/10000 · 17
2 ../../exercises/reliability.rst:11

	English Open questions 14/10000 · 14
3 ../../exercises/reliability.rst:13

	English Consider a `b` bits per second link between two hosts that has a propagation delay of `t` seconds. Derive a formula that computes the time elapsed between the transmission of the first bit of a `d` bytes frame from a sending host and the reception of the last bit of this frame on the receiving host. 300/10000 · 300
4 ../../exercises/reliability.rst:15

	English Transmission links have sometimes different upstream and downstream bandwidths. A typical example are access networks that use ADSL (Asymmetric Digital Subscriber Lines). Consider two hosts connected via an ADSL link having an upstream bandwidth of 1 Mbps and a downstream bandwidth of 50 Mbps. The propagation delay between the two hosts is 10 milliseconds. What is the maximum throughput, expressed in frames/second, that the alternating bit protocol can obtain on this link if each data frame has a length of 125 bytes and acknowledgments are 25 bytes long. Same question if the protocol is modified to support 1500 bytes long data frames. 642/10000 · 642
5 ../../exercises/reliability.rst:17

	English How would you set the duration of the retransmission timer in the alternating bit protocol ? 92/10000 · 92
6 ../../exercises/reliability.rst:19

	English A version of the Alternating Bit Protocol supporting variable length frames uses a header that contains the following fields : 126/10000 · 126
7 ../../exercises/reliability.rst:21

	English a `number` (0 or 1) 19/10000 · 19
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	English a `length` field that indicates the length of the data 54/10000 · 54
9 ../../exercises/reliability.rst:23

	English a Cyclic Redundancy Check (`CRC`) 33/10000 · 33
10 ../../exercises/reliability.rst:25

	English To speedup the transmission of the frames, a student proposes to compute the CRC over the data part of the frame but not over the header. What do you think of this proposed solution ? 183/10000 · 183
11 ../../exercises/reliability.rst:27

	English Derive a mathematical expression that provides the `goodput`, i.e. the amount of payload bytes that have been transmitted during a period of time, achieved by the Alternating Bit Protocol assuming that : 203/10000 · 203
12 ../../exercises/reliability.rst:29

	English Each frame contains `D` bytes of data and `c` bytes of control information 74/10000 · 74
13 ../../exercises/reliability.rst:30

	English Each acknowledgment contains `c` bytes of control information 61/10000 · 61
14 ../../exercises/reliability.rst:31

	English The bandwidth of the two directions of the link is set to `B` bits per second 77/10000 · 77
15 ../../exercises/reliability.rst:32

	English The delay between the two hosts is `s` seconds in both directions 65/10000 · 65
16 ../../exercises/reliability.rst:33

	English there are no transmission errors 32/10000 · 32
17 ../../exercises/reliability.rst:35

	English Consider a go-back-n sender and a go-back receiver that are directly connected with a 10 Mbps link that has a propagation delay of 100 milliseconds. Assume that the retransmission timer is set to three seconds. If the window has a length of 4 frames, draw a time-sequence diagram showing the transmission consisting of 10 data frames (each frame contains 10000 bits): 367/10000 · 367
18 ../../exercises/reliability.rst:37

	English when there are no losses 24/10000 · 24
19 ../../exercises/reliability.rst:38

	English when the third and seventh frames are lost 42/10000 · 42
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	English when every second acknowledgment is discarded due to transmission errors 72/10000 · 72

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