Consider the transfer of a data file of 2000000 bytes from a

Consider the transfer of a data file of 2000000 bytes from a source to a destination for the following switching network:
The data rate of the line is 1 Gbps.
The file is divided into fixed packet size, each of which has a size of 3000 bits(including data and header), before transmitting. There are 100 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 0.005 sec.
Each packet must be transmitted 5 times before reaching destination.

Assume that there are 8 bits in a byte.

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

(ii) Determine the time it take seach host along the path to transmit the entire data file.

(iii) Compute the end to end delay using datagram packet switching.

Solution

i)

SIZE OF PACKET = 3000 BITS

NO OF BITS IN HEADER= 100 BITS

THEREFORE, ONE PACKET =3000BITS – 100 BITS = 2900 BITS

ENTIRE DATA FILE= 2* 10^6 BYTES= 16810^6=5334 PACKETS

THEREFORE NO. OF PACKETS NEEDED TO TRANSMIT THE DATA FILE USING PACKET SWTITCHING = 5334 PACKETS.

II)

PROPAGATION DELAY PER TRANSMISSION IS GIVEN = .0005 SEC

TRANSMISSION TIME = 16*10^6/1*10^9=0.016 SECONDS

NOW TOTAL TIME CAN BE CONCLLUDED ={ 5334*5(PROPAGATION DELAY)} * 5 (EACH PACKET TRANSMITTED FIVE TIMES) = 133350ms=133.35 seconds