I need help understanding how to do this network transmission rate calculation problem?

Question

I need help with a calculation of network speed and packets if anyone could help. I got a previous problem right but I have no idea how to work this new problem. The problem that I did get was this:

How long does it take to send a file of 64000 bits from host A to host B over a circuit-switched network. All links are 1.536mbs each link uses TDM with 24 slots / sec and 500 msec to establish end to end circuit.
My answer to that problem is: 1.536mbs = 1536000bps; 1536000bps / 24 slots = 64000bps per each slot. 640000bits / 64000bps = 10sec + 500msec = 10.5sec
So the answer is 500msec startup + 640kbits / 64kbps = 10.5sec and this has been verified by the instructor.

MY PROBLEM I NEED HELP WITH IS BELOW:
A packet of 1,000 bits travels from the network host A to another host B in a packet switching network through a direct communication link in between. Suppose that the length and propagation speed of the link are 300 km and 300,000,000 m/sec respectively. It takes 501 msec until it arrives at host B. What is the transmission rate of this network when nodal processing and queuing delays are negligible?
I know the packet size is 1000bits and that the length is 300km = 300000m and the speed is 300000000 m/sec. I have no idea how to set this problem up to find the transmission rate which I think they want to know how many bps. Please help me figure out how to do this one. The instructor wants us to figure it out and will not really help. Thank you.

Answer 1

Okay, well, this question doesn't make a lot of sense... let me tell you why. The first question is completely wrong.



A T-1 line is either 56k or 64k per channel times 24 channels. Typically channels are 64k. 64k x24 channels = 1,536,000 bits per second.



If you have to send 64000 bits, at a rate of 1,536,000 bits per second, that means it will take 1/24th of a second to transmit that much data. 1000ms/24 =41.67 milliseconds. If it takes 500 milliseconds to set up the circuit, then you're looking at 541.67 milliseconds, which is nowhere even remotely close to 10.5 seconds. How did your instructor verify this is correct?



Even 64000 BYTES at 1,536,000 bits per second would take (8x41.67) + 500 milliseconds, or 833 milliseconds.



Of course, this is kind of a trick question, because a 64000 bit file will have overhead, because of TCP or UDP headers and so forth, so 64000 bytes on a hard drive will take more bytes of network bandwidth, since it has to encapsulate that data in network headers. Even so, you're still not going to take more than 1 second.



Secondly, for the question you asked, it wants to know bits per second, but it has to tell us the bandwidth of the circuit for us to tell you anything about it. It will take 1ms to send a packet across the link (300km / 300,000km per seconds, or .001 seconds, times 1000ms/sec and it's 1 ms). So 1ms to get there, and 1ms to get back. The question is, does it have to wait for an acknowledgement before sending the next packet? Or is it just sending them with no regards to the other end? Quite frankly this whole thing doesn't make a lot of sense. It feels like some data is being left out, or else we need to know more context about how this question is being asked.



I guess in theory you could say 1000 bytes every 1ms or 2ms depending on if it needs to receive an acknowledgement, so either 1000x1000 or 1000x500 bits per second. But this whole thing seems sketchy to me.

Answer 2

300 km at 300,000 km/s = 1 ms



The total transfer time is 501 ms, so the data transfer bit rate passes 1000 bits in 500 ms.



This is 2 bits/ms or 2 kbps or 2000 bits/second.

Answer 3

i think of you will desire to seek for 802.11a upto 802.11g. you will get the specs the place they're going to point out the max bit expenses supported by potential of each of them. They variety for each form of wi fi implementation.