Thanks, Peter,
So what you means is that network congestion caused my problem. I test
the bandwidth
between client1 and server using iperf, SEND and RECV are both 122MB/s.
I tried
different values for the total bandwidth, and I got the following numbers:
total bandwidth 120MB/s client1 SEND :10MB/s RECV :39MB/s
total bandwidth 110MB/s client1 SEND :16MB/s RECV :40MB/s
total bandwidth 100MB/s client1 SEND :30MB/s RECV :38MB/s
total bandwidth 90MB/s client1 SEND :39MB/s RECV :40MB/s
total bandwidth 80MB/s client1 SEND :39MB/s RECV :40MB/s
total bandwidth 70MB/s client1 SEND :40MB/s RECV :40MB/s
total bandwidth 60MB/s client1 SEND :40MB/s RECV :40MB/s
So TC works well as long as total bandwidth is below 90MB/s, which is
about 70% of the
wise speed. Is it possible that I can use the full bandwidth (122MB/s)
in my script?
william
Peter Rabbitson wrote:
William Xu wrote:
Hi,
I have a server and ten clients in a Gigabit network. The server has
125mbps network bandwidth.
I want that the server has 40Mbps bandwidth reserved for client 1 (IP
192.168.5.141), and the
rest bandwidth is for all other clients.
<snip>
I ran a test in which all 10 clients send/receive packets to/from the
server simultaneously. But
Client 1 only got 20mbps bandwidth for sending, and 38mpbs for
receiving. If I limit the rate of
both classes 1:1 to 60mbps instead of 125mbps, Client 1 got 39mbps
for sending, and 40mbps for
receiving.
I am not sure what might cause this. Is it because TC doesn't work
well when network is congested?
Or my script is not right?
No network will be able to operate at its theoretical maximum. In the
case of a gigabit network you will be lucky to get consistent 120mbps,
and it heavily depends on the hardware quality, and the number of
switches in between. So what you are doing is oversaturating the link,
the ACK packets can not get through, your speed drops due to
delays/retransmissions. Perform a test with only two systems sending
stuff to each other to see what is the actual bandwidth you can hope
for, and use that number instead of 125mbps.
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