Understanding Broadband Speeds

[Marrijon]

Can somebody help me understand Broadband speeds. I think I have a problem but need more understanding.

I understand latency is related to the distance a signal has to travel. That is a speed test can report 5 to 10 msecs for a local server and several hundred for an international one. But should a speed test result be dependant on distance?

For example if I do a speediest to a South African server I get speed of 7.5 to 8.5 mbps which is what I pay for. However if I do the same test to an international site almost always get half this or less. For example this afternoon (Sunday) it was 8097 kbps (local) and 3196 kbps ( international). Is this normal. And should it always be the case? Or does my ISP have some sort of limit on its international bandwidth.

Some understanding would really be appreciated. Thanks

 

[Segg]

Not too sure how correct this statement is, I'm sure the more senior members will correct me but I think it has to do with your ISP's capacity and the overall networks current capacity ( I.E more users at a specific time of the day = slower overall speeds) but there are alot of overall conditions that come into play if I'm not mistaken, who is your ISP

Usually international is slower than local, however I don't think it should be that far off :wtf:

 

[NeonNinja]

Of course international is going to be slower. It has to travel further distance through different hoops to acquire the file.

3196Kbps and you're still complaining?

 

[ponder]

Of course international is going to be slower. It has to travel further distance through different hoops to acquire the file.

The speed is not related to distance. If the international capacity & contention ratios are up to scratch you should get the same speed as local in an ideal world.

@Marrijon, what speeds do you get when using a proper multithreaded download manager?

 

[NeonNinja]

So my Wayne, my neighbor hosts a 100MB file on his server. And Александр hosts his 100MB file in Adygeysk, Russia. You mean to say; in a perfect world scenario, there shouldn't be any difference in download time?

 

[ToxicBunny]

So my Wayne, my neighbor hosts a 100MB file on his server. And Александр hosts his 100MB file in Adygeysk, Russia. You mean to say; in a perfect world scenario, there shouldn't be any difference in download time?

Barring the latency to start retrieving the file from Russia, nope there will be no difference in download time.

 

[KhoisanX]

So my Wayne, my neighbor hosts a 100MB file on his server. And Александр hosts his 100MB file in Adygeysk, Russia. You mean to say; in a perfect world scenario, there shouldn't be any difference in download time?

Consider a single packet. If the same bandwidth is available between (you<->neighbor) and (you<->server in Russia) then once the transfer starts it should take the same amount of time to transfer this packet. It would take longer for the data to travel from Russia than from your neighbor, but the speed will be the same. Latency to your neighbor will be much lower since the distance that the signal has to travel is much shorter.

 

[NeonNinja]

Consider a single packet. If the same bandwidth is available between (you<->neighbor) and (you<->server in Russia) then once the transfer starts it should take the same amount of time to transfer this packet. It would take longer for the data to travel from Russia than from your neighbor, but the speed will be the same. Latency to your neighbor will be much lower since the distance that the signal has to travel is much shorter.

What data?

 

[KhoisanX]

Using a different example, you have two identical cars, say cars A and B, that are taking part in a drag race.

When you give the signal to start car A receives it 1 second before car B, i.e. car B is delayed by one second.

Both cars take 10 seconds from starting to crossing the finishing line, so from your start signal car A took 10 seconds to finish while car B took 11 seconds.

Now think of car A as your neighbor and car B as the server in Russia.
The one second delay at the start would be your increased latency to Russia. Both took 10 seconds from starting to finishing the race though, i.e. their speed was the same.

 

[NeonNinja]

I get that there is no difference between 1MB/s from S.A and 1MB/s from Russia, that's the same; what I don't fully get is how you can retrieve a file next door with the same speed as a file sitting in Russia. But yeah post 2, I think clarified. It can never happen. Well in the near future.

 

[Pada]

The speed is not related to distance. If the international capacity & contention ratios are up to scratch you should get the same speed as local in an ideal world.

@Marrijon, what speeds do you get when using a proper multithreaded download manager?

The speed is actually related to the distance, more precisely dependent on the RTT (RoundTrip Time). If you use a multi-threaded download manager, you can "bypass" that limitation.

With a single thread, you can expect about 3Mbps download speed when the latency/roundtrip time is 170ms.

For more details, you can have a look here: http://cisconet.com/traffic-analysis/throughput/104-tcp-throughput-calculation-formula.html