Assume that there are 5 hops between two devices, A and B. The processing delay
ID: 3787335 • Letter: A
Question
Assume that there are 5 hops between two devices, A and B. The processing delay of interconnecting devices is 5 mu sec. All links have a speed of 1 Mbits/second. The speed of light in the link is 3 times l0^8 m/sec, and the length of each link is 1 km. With packet switched networking, the packet size is 1050Bytes, which includes 50 Bytes header. There are 10 packets that need to be transmitted from A to B. The queuing delay at each interconnecting devices is 5 msec What is the total delay for A to send the 10 packets to B using packet switching? What is the throughput of packet switching? What is the efficiency? Assume same amount of data needs to be transmitted over a circuit switching network. Let the total time needed for both setting up and terminating the connection be 70 mu sec. What is the total delay ill this case? What is the throughput of a circuit switching network? What is the efficiency? Compare the results to (b).Explanation / Answer
a.Number of hops M=5,
Number of packets N=10,
Per-hop processing delay P=5*10^-6 secs,
Link propagation delay L = distance/speed of light = 1000meters/ 3*10^8= 3*10^-6 secs
Packet size = 1000 bytes(1050-50) = 1000*8=8000 bits,
Packet transmission delay T = packet size/transmission speed = 8000/1*10^6 bits/sec =8*10^-3 secs
Queuing delay=5msecs
Delay =Processing Delay+Queueing Delay+Transmission Delay
ML + NT + (M-1)T + (M-1)P +Q=15*10^-6 secs+80msecs+32msecs+20*10^-6 secs+5 msecs
=5.035 msecs+112 msecs = 117.035 msecs=
Total delay =0.117 secs
b.
Throughput=Total number of bits transmitted/Total Delay = 10000bytes/0.137sec=72,992bytes/sec