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zmau

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What is the max Full duplex throughput of Gigabit Ethernet ?

Hi!

This question comes from a friendly argument.

Theoritically, Gigabit Ethernet can Transmit/Receive about 100 MB/Sec.
Now most people understand that Full-Duplex means that you can Transmit/Receive at the same time (in otherwords transmitting and receiving data are independable).


Now this friend says that : "this is very resonable.  BUT in reality Gigabit Ethernet boards do not Transmit/Receive simultanouosly".

So, Who is right ?
Is the theoretical throughput of Transmit + Receive at the same time 100 MB or 200 MB ?
Is it true that in practice "Gigabit Ethernet boards do not Transmit/Receive simultanouosly" ?
I had spent yesterday a lot of time searching for the answer, but did not find :-(


Now here are 2 practical questions :
1) If I connect 2 Windows PCs directly, and try to transmit "tons of data in both directions", what is maximal expected throuput (Using Fullduplex gigabit Ethernet) ?
2) If I connect 2 Windows PCs through a "good gigabit Ethernet switch", and try to transmit "tons of data in both directions", what is maximal expected throuput (Using Fullduplex gigabit Ethernet) ?

Is there some where a C/C++ code which gives the answer for the two above questions ?


zmau
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netjgrnaut
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Avatar of Ernie Beek
By default Gigabit Ethernet is full-duplex but it supports half-duplex for hubs (repeaters).

In a departure from both 10BASE-T and 100BASE-TX, 1000BASE-T uses all four cable pairs for simultaneous transmission in both directions through the use of adaptive equalization and a 5-level pulse amplitude modulation (PAM-5) technique.

Source: http://en.wikipedia.org/wiki/Gigabit_Ethernet

The theoretical speed would be 125MB/s, though normally the speed depends on a lot of factors, not only the line speed. Bearing that in mind the maximal throughput in Q1 and Q2 would be: 125MB/s in either direction (theoretically speaking of course ;)
Ok, didn't realize I was typing that slow :-~
It must be my full duplex fingers. ;-)
Ah now I see, I had autonegotiation turned off :)
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zmau

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You are greate guys.
Just trying to do the best we can (be it full or half duplex ;).
That's why we guys have always are link up ;) Loved to read it...

~SG~
You can show some love by awarding points and marking this question as answered.  :-D
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I am sorry it took me so long to mark this question as answered.
I am not always near my computer...