Good Afternoon, I've tried all I can think of for the following question and rewatched the example video over 7 times. I know it involves adding the maximum buffer sizes or rates to one another, but I just cannot seem to grasp it:
Consider two users communicating via a voice-over-IP service over a path with 10 routers and links all running at 100Mb/s. If each router has a 1MByte packet buffer, and if no packet is lost and retransmitted, what is an upper bound on the playback buffer needed at the receiver? Express your answer in milliseconds (rounded to the nearest integer). Assume 1MByte = 2^20 Bytes. Hint: Consider the maximum queuing delay introduced by each router.
Any help would be so appreciated, I've been stuck on this for days. Thank you.
Well, Suppose each router has queuing delay of 1MByte.
So, first convert 1MByte into bits: 2^20 * 8 = 8388608 bits
then, calculated according to packetization delay is:
8388608 bits / (100 Mb/s) = 8388608 bits / (100 * 10^6 b/s) = 0.08388608 sec (83.8861 ms)
So, for each router, the delay will of 83.8861 ms, that is 84 ms.
For 10 routers, it will be 840 ms.