How to calculate file transfer time?

Kenrick

Hi Network Experts,
I have completed the following questions but I am not sure whether my answers are correct. Please correct me and guide me if I am wrong.


Consider the transfer of a data file of 106 bits from a source to a destination for the following switching network: • The data rate of the line is 1 Mbps.
• The file is divided into fixed packet size, each of which has a size of 4000 bits (including data and header), before transmitting. There is 250 bits in the header. If there is not enough data to fill a packet, it is filled with zeros before transmission. All frames sent have the same size.
• The propagation delay per transmission is 0.002 sec.
• Each packet must be transmitted 7 times before reaching destination.

i) Determine the number of packets needed to transmit the data file using packet switching.
Ans: 266.67

(ii) Determine the time it takes each host along the path to transmit the entire data file.
Ans: 1.002 second
(iii) Compute the end to end delay using datagram packet switching.
Ans: Tp + 8Td +8(Tp+Td)
=16.018 seconds