How many packets are in the buffer on an average?

Question

Consider a router having buffer capacity to hold 5000 packets. The router is connected to multiple links which are having the bandwidth of 1 Gbps. Suppose the incoming data from 5 links are being redirected to one of its links. In these 5 flows, 4 flows(tiny flows) are sending 10000 packets/sec and another flow(huge flow) is sending 50000 packets/flow. Assume each packet in size in these flows is 10000 bits.
How many packets are in the buffer on an average?

1.   9
2.   0.9
3.   10

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here efficiency will be 9/10 as incomin bits are 9 * 10⁸ and outgoing flow is 10⁹..but how to calculate average pakctes in buffer?

Comments

9 ??

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yes..how??

Answer 1

Queue depth or no of packets in buffer=utilization/1-utilization.

Here utilization=Network load/ WAN Load.

Router having 5 multiple links and 4 are tiny flowing rate is=10000 packets/sec and another one is 50000packets/sec.

Consider entitre load on network it is $4*10^{4}+5*10^{4}$ ( 4 tiny flows and one huge flow).

Total load on network=9*$10^{4}$ packets .

but each packet is of length=10000bits.

So Total load on network=9*$10^{4}*10^{4}$=9*$10^{8}$.bits/sec

WAN load=1Gbps=$10^{9}$ bits/sec.

UTILIZATION=$\frac{9*10^{8}}{10^{9}}$

                    =0.9.

Queue depth=$\frac{0.9}{1-0.9}$=9.

Hence on an average no of packets in a buffer=9

Comments

Queue depth or no of packets in buffer=utilization/1-utilization.

whats the logic of this formula?

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i know the logic ,i found some where this formula in the internet.

Thank u for asking this question.Even i am also dont know how to calculate average no of packets in a buffers.

Now i got clarity.

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thanskyou :-)