Question

What is the difference between link utilisation and efficiency (in regards of data link layer)?

Comments

can you please tell difference..thanks..

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For the time being, I've got this. https://gateoverflow.in/55136/utilization-efficiency-utilization-throughput-utilization

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thanks a lot for this @Aghori

Answer 1

please read about S&R protocol before it

Take an example -

For S&R protocol -

Tt = 1ms       Tp = 19.5 ms        Bandwidth = 40 Mbps

then efficiency = 1/(1+2a)        where a = Tp/Tt

so efficiency = 1/40  i.e. we could have sent 39 more packets when we were waiting for acknowledge for 2*Tp time, but we sent only 1 packet instead.

so basically we are using only (1/40)th of bandwidth, so utilization = (1/40)*40 = 1 Mbps

so here we are sending only 1 packets in compare to capacity of 40 packets, so utilized bandwidth is 1 Mbps only. If we send 40 packets , then we will able to utilize entire bandwidth

So basically efficiency means "how much of total capacity of channel (bandwidth) you are consuming in terms of percentage" and utilization means "how much of total capacity of channel (bandwidth) you are consuming in terms of bps"