s***@gmail.com
2007-04-06 15:49:13 UTC
computer networks :
by Tanenbaum - 4th edition
chapter 2 - problem 43
43) Suppose that x bits of user data are to be transmitted over a k-
hop path in a packet-switched network as a series of packets, each
containing p data bits and h header bits, with x>>p+h. The bit rate of
the lines is b bps and the propagation delay is negligible. What value
of p minimizes the total delay?
Each packet (h+p) bits/packet
Number of packets = x/p
Total bits "data + header" = (h+p)(x/p) bits
Bit rate = b bits/sec
Time for transmitting T1 = ( (h+p)(x/p) ) / b sec
Retransmission T2 = ( (k-1)(h+p) ) / b sec
T = T1 + T2
Value of p to minimizes the total delay :
T1+T2 = 0
need to complete the answer if it correct and find dt/dp
by Tanenbaum - 4th edition
chapter 2 - problem 43
43) Suppose that x bits of user data are to be transmitted over a k-
hop path in a packet-switched network as a series of packets, each
containing p data bits and h header bits, with x>>p+h. The bit rate of
the lines is b bps and the propagation delay is negligible. What value
of p minimizes the total delay?
Each packet (h+p) bits/packet
Number of packets = x/p
Total bits "data + header" = (h+p)(x/p) bits
Bit rate = b bits/sec
Time for transmitting T1 = ( (h+p)(x/p) ) / b sec
Retransmission T2 = ( (k-1)(h+p) ) / b sec
T = T1 + T2
Value of p to minimizes the total delay :
T1+T2 = 0
need to complete the answer if it correct and find dt/dp