Let's say we have a packet of length L bits. It is transmitted from system A through three links to system B. The three links are connected by two packet switches. di, si and Ri are the length, propagation speed and transmission rate for each link, i, in the example network. Each packet switch delays each packed by dproc (processing time).
Lets also say that there are no queuing delays; so how would i go about writing a formula for computing the end-to-end delay for a packet of length L on this theoretical network?
This is what i have so far:
End-End Delay = L/R_1 + L/R_2 + L/R_3 + d_1/s_1 + d_2/s_2 + d_3/s_3 +2(d_proc)
Is this correct, if not, what is the correct formula and why so?
Yes, your formula is correct, assuming that the processing time of each switch is the same. Also, is calculating actual delay be sure to use same dimensions for units - bits and bits/s for size and transfer rate and meters and meters/s for propagation. Take note that if the switches are connected by the fiber-optic links you will have to divide speed of light by the diffraction rating of the fiber in calculations.