Throughput calculation between layers?

Hey everyone,

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I was given a task to make some kind of inter-layer throughput converter (from L1(PHY) to L4(TCP) by OSI or updated TCP/IP model) network.

By this converterI mean an set of formulas in excel that could recalculate throughput from throughout layers (again between L1 and L4). Throughput at given layer, MTU and TCP header are used as an input data.

For example: I need to calculate available throughput at L4 while having say 100 Mb/s at L1. So do the following: L4thr = (L1thr[b/s]* (MTU[B]-IP[B]-TCP[B])*8)/((L1h[B]+L2h[B]+Payload[B])*8), where L1thr - throughput at L1, IP - IP header, TCP - TCP header, L1h - Layer1 header, L2h - Layer2 header.

My question is: is it even possible to create such calculator, because I am struggling finding any info about it on the internet and now have really doubts if it is even possible and not sure if my approach really works. Because when doing such conversions between layer some results do not match the other. By this I mean if I take L1 as input ex. 100Mb/s to calculate throughput at L2-L4, then if I take say L2 as a corresponding input ex. 97,5Mb/s which somehow refers to 100Mb/s at L1 my results at L3-L4 are different when the source is L1 thr. compared to the scenario, when the source is L2 thr.

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I a sorry in advance for possible stupid question or the way I am trying to explain my problem. I really would like to know if it is possible to create such converter and if yes, how should I correctly recalculate the values.