# Stanford course

0 votes
447 views
If a voice call has missing data it makes it hard to understand the speaker. Therefore, we commonly allow time for a limited number of retransmissions before playing the sound to the listener. If the network path (in each direction) has total packetization delay of 15ms, total propagation delay of 25ms, and queuing delay varying between 0ms and 10ms, how large (in milliseconds) does the playback buffer need to be if we want to allow for one retransmission?
0
75 ??
0
nopes ............ what approach you used ?
0
what's answer ??

## 1 Answer

0 votes
The minimum e2e delay is 40ms. The maximum time for data to show up and be played back is 50ms (1st time, but missing) + 50ms (for the sender to find out) + 50ms (for the 2nd try to reach the receiver) = 150ms. Therefore, the playback buffer needs to hold at least 150ms - 40ms = 110ms of data.

## Related questions

1 vote
0 answers
1
437 views
Your packet has two bit errors, spaced 16 bits apart (for instance, bits 1 and 17), and no other errors. Which of the following schemes will detect the error at least 99.99% of the time? Choose all correct answers. 8-bit checksum 16-bit checksum 8-bit CRC 16-bit CRC 16-bit MAC 32-bit MAC
2 votes
1 answer
2
367 views
In one of the quizes, they asked the following question : "A server typically listens for TCP connections on a particular port (e.g. 80 for HTTP or 22 for SSH). Which fields can the server use to distinguish packets for a particular client connection?" Please ... IP address from the packet received from the client... (After all, this destination IP address corresponds to the Server itself !).
0 votes
0 answers
3
344 views
Assume the configuration below: A ---------------- B --------------- C where A-B has an MTU of 1500 bytes and B-C has an MTU of 400 bytes. Assume that link layer frames require 30 bytes of overhead, an IP header is 20 bytes, there is no loss ... the IP header) that A sends, how many bytes must B send to C (including link layer and IP header overhead)? 1050 bytes 1133 bytes 1135 bytes 1450 bytes
0 votes
0 answers
4
208 views
Suppose that you have two nodes communicating with an AP that are hidden terminals to one another. The AP, except for acknowledgments, remains silent and there are no other transmitters in the network. The two nodes are both transmitting packets whose active ... nodes start transmitting at exactly the same time, what is the minimum number of backoffs before a packet is delivered successfully?